\r\n\tThis book will address the various modern, technical, and practical aspects of smart technology for capturing solar radiation and converting it into different forms of energy, as well as enabling it for renewables integration in energy generation and transformation, built environment, transportation, buildings, and agriculture.
\r\n
\r\n\tThe book will cover the most recent developments, innovations and applications concerning the following topics: \r\n\t• Solar radiation – Smart and enabling technologies for measurement, modelling, and forecasting \r\n\tHigh-resolution measurement sensor and instrument technology (Pyranometers, Albedometers, Pyrheliometers, UV Radiometers, Sun Trackers, Spectroradiometer, Pyrgeometers, etc.), Artificial intelligence techniques for modelling and forecasting of solar radiation, Solar Irradiance forecast with satellite data, Solar potential analysis, Short-term forecasting of photovoltaic power and solar irradiance prediction with sky imagers. \r\n\t• Renewable energy integration – Smart solutions for integration of RE in distributed generation, energy storage, and demand-side management. \r\n\tIntegrated Photovoltaics: Smart technology for vehicle-integrated PV, Building Integrated PV, Agrivoltaics, Road-Integrated PV, Floating PV, Product-integrated PV. \r\n\tRenewable Energy Applications in Built Environment and mobility: Solar cars, solar-powered electric charging stations, passive solar systems, solar heating, and cooling systems, building-integrated vegetation, multifunctional solar systems, solar pumps, solar lighting, solar shading, Natural lighting, Solar dryer, Greenhouse.
",isbn:null,printIsbn:null,pdfIsbn:null,doi:null,price:0,priceEur:0,priceUsd:0,slug:null,numberOfPages:0,isOpenForSubmission:!0,isSalesforceBook:!1,hash:"0400d540d2b8fb55d4cc8590e1e58844",bookSignature:"Dr. Mohammadreza Aghaei and Associate Prof. Amin Moazami",publishedDate:null,coverURL:"https://cdn.intechopen.com/books/images_new/11493.jpg",keywords:"High-Resolution Measurement Technology, Solar Irradiance Prediction, Integrated Photovoltaics, Energy Storage, Photovoltaics Technology, Nano Materials, Life Cycle Assessment, Photovoltaic Power Plants, UAV-Based Aerial Inspection, Bankability, Blockchain Technology, Circular Solar Economy",numberOfDownloads:null,numberOfWosCitations:0,numberOfCrossrefCitations:null,numberOfDimensionsCitations:null,numberOfTotalCitations:null,isAvailableForWebshopOrdering:!0,dateEndFirstStepPublish:"May 5th 2022",dateEndSecondStepPublish:"June 2nd 2022",dateEndThirdStepPublish:"August 1st 2022",dateEndFourthStepPublish:"October 20th 2022",dateEndFifthStepPublish:"December 19th 2022",remainingDaysToSecondStep:"16 days",secondStepPassed:!1,currentStepOfPublishingProcess:2,editedByType:null,kuFlag:!1,biosketch:"Dr. Aghaei is a pioneering researcher in Renewable Energy, Solar photovoltaics, Energy systems, Autonomous and Smart Monitoring, Aerial Robotics, and Artificial Intelligence. He received a Ph.D. degree in electrical engineering from Politecnico di Milano. Dr. Aghaei was a Postdoctoral Scientist at Fraunhofer ISE and Helmholtz-Zentrum Berlin-PVcomB, Germany. He joined the University of Freiburg as a lecturer. He also fulfilled another 2 years postdoc at the Eindhoven University. He is IEEE senior member.",coeditorOneBiosketch:"Dr. Moazami is a pioneering researcher in smart buildings and energy flexibility and distributed intelligence (Swarm Intelligence, Collective Intelligence, Multi-Agent systems) for energy management. He is appointed as head of the Energy Management and Efficiency Research Group (EMERGE). He is the coordinator of the COLLECTiEF project and was actively involved in several national and international projects.",coeditorTwoBiosketch:null,coeditorThreeBiosketch:null,coeditorFourBiosketch:null,coeditorFiveBiosketch:null,editors:[{id:"317230",title:"Dr.",name:"Mohammadreza",middleName:null,surname:"Aghaei",slug:"mohammadreza-aghaei",fullName:"Mohammadreza Aghaei",profilePictureURL:"https://mts.intechopen.com/storage/users/317230/images/system/317230.jpg",biography:"Mohammadreza Aghaei is a senior researcher in the field of photovoltaic solar energy and energy system. \nHe received the Ph.D. degree in electrical engineering from Politecnico di Milano, Italy, in 2016. He was a Postdoctoral Scientist with Fraunhofer ISE and Helmholtz-Zentrum Berlin (HZB)-PVcomB, Germany, in 2017 and 2018, respectively. He is a Guest Scientist with the Department of Microsystems Engineering (IMTEK)/Department of Sustainable Systems Engineering (INATECH), Solar Energy Engineering, the University of Freiburg since 2017. He also fulfilled another two years postdoc in the Design of Sustainable Energy Systems Group, at Eindhoven University of Technology (TU/e), The Netherlands. Dr. Aghaei is currently a senior scientist with the Faculty of Engineering, Norwegian University of Science and Technology Norwegian (NTNU), Norway. He is also co-coordinator of EU-project 'COLLECTiEF” - Collective Intelligence for Energy Flexibility.\nHe has authored numerous publications in international refereed journals, book chapters, and conference proceedings. Main his research interests include Energy transition, Energy flexibility, Solar Energy, Photovoltaics, predictive and autonomous monitoring, solar cells, Artificial intelligence (AI), and Unmanned Aerial vehicle (UAV). Dr. Aghaei is a member of the International Energy Agency (IEA), PVPS program - Task 13, and International Solar Energy Society (ISES). Since 2019 he has been the chair/vice-chair of the working group 2: reliability and durability of PV in EU COST Action PEARL PV.",institutionString:"Norwegian University of Science and Technology",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"0",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Norwegian University of Science and Technology",institutionURL:null,country:{name:"Norway"}}}],coeditorOne:{id:"327897",title:"Associate Prof.",name:"Amin",middleName:null,surname:"Moazami",slug:"amin-moazami",fullName:"Amin Moazami",profilePictureURL:"https://s3.us-east-1.amazonaws.com/intech-files/0033Y00002zb1jQQAQ/Profile_Picture_2022-04-26T08:22:52.jpg",biography:"Amin Moazami received a Ph.D. degree in building energy performance from the Norwegian University of Science and Technology (NTNU) in 2019.\r\nHe is an Associate Professor in the Department of Ocean Operations and Civil Engineering at NTNU. He has strong experience in building performance simulation, energy flexibility, climate robustness and resilience in buildings, occupant behaviour, etc. He is the coordinator of the COLLECTiEF project and was actively involved in several national and international projects. In 2019, he has been awarded an innovation grant (innovasjonsstipend 2019) for the proposal “A simulation-based tool for the development of Collective Intelligence (CI) at the urban scale to mitigate the impacts of extreme climate conditions”, focusing on developing a new solution for increasing the energy demand flexibility of urban areas.",institutionString:"Norwegian University of Science and Technology",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"0",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Norwegian University of Science and Technology",institutionURL:null,country:{name:"Norway"}}},coeditorTwo:null,coeditorThree:null,coeditorFour:null,coeditorFive:null,topics:[{id:"10",title:"Earth and Planetary Sciences",slug:"earth-and-planetary-sciences"}],chapters:null,productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"},personalPublishingAssistant:{id:"429342",firstName:"Zrinka",lastName:"Tomicic",middleName:null,title:"Ms.",imageUrl:"https://mts.intechopen.com/storage/users/429342/images/20008_n.jpg",email:"zrinka@intechopen.com",biography:"As an Author Service Manager, my responsibilities include monitoring and facilitating all publishing activities for authors and editors. From chapter submission and review to approval and revision, copyediting and design, until final publication, I work closely with authors and editors to ensure a simple and easy publishing process. I maintain constant and effective communication with authors, editors and reviewers, which allows for a level of personal support that enables contributors to fully commit and concentrate on the chapters they are writing, editing, or reviewing. I assist authors in the preparation of their full chapter submissions and track important deadlines and ensure they are met. I help to coordinate internal processes such as linguistic review, and monitor the technical aspects of the process. As an ASM I am also involved in the acquisition of editors. Whether that be identifying an exceptional author and proposing an editorship collaboration, or contacting researchers who would like the opportunity to work with IntechOpen, I establish and help manage author and editor acquisition and contact."}},relatedBooks:[{type:"book",id:"5962",title:"Estuary",subtitle:null,isOpenForSubmission:!1,hash:"43058846a64b270e9167d478e966161a",slug:"estuary",bookSignature:"William Froneman",coverURL:"https://cdn.intechopen.com/books/images_new/5962.jpg",editedByType:"Edited by",editors:[{id:"109336",title:"Prof.",name:"William",surname:"Froneman",slug:"william-froneman",fullName:"William Froneman"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"1591",title:"Infrared Spectroscopy",subtitle:"Materials Science, Engineering and Technology",isOpenForSubmission:!1,hash:"99b4b7b71a8caeb693ed762b40b017f4",slug:"infrared-spectroscopy-materials-science-engineering-and-technology",bookSignature:"Theophile Theophanides",coverURL:"https://cdn.intechopen.com/books/images_new/1591.jpg",editedByType:"Edited by",editors:[{id:"37194",title:"Dr.",name:"Theophile",surname:"Theophanides",slug:"theophile-theophanides",fullName:"Theophile Theophanides"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"3161",title:"Frontiers in Guided Wave Optics and Optoelectronics",subtitle:null,isOpenForSubmission:!1,hash:"deb44e9c99f82bbce1083abea743146c",slug:"frontiers-in-guided-wave-optics-and-optoelectronics",bookSignature:"Bishnu Pal",coverURL:"https://cdn.intechopen.com/books/images_new/3161.jpg",editedByType:"Edited by",editors:[{id:"4782",title:"Prof.",name:"Bishnu",surname:"Pal",slug:"bishnu-pal",fullName:"Bishnu Pal"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"371",title:"Abiotic Stress in Plants",subtitle:"Mechanisms and Adaptations",isOpenForSubmission:!1,hash:"588466f487e307619849d72389178a74",slug:"abiotic-stress-in-plants-mechanisms-and-adaptations",bookSignature:"Arun Shanker and B. Venkateswarlu",coverURL:"https://cdn.intechopen.com/books/images_new/371.jpg",editedByType:"Edited by",editors:[{id:"58592",title:"Dr.",name:"Arun",surname:"Shanker",slug:"arun-shanker",fullName:"Arun Shanker"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"3092",title:"Anopheles mosquitoes",subtitle:"New insights into malaria vectors",isOpenForSubmission:!1,hash:"c9e622485316d5e296288bf24d2b0d64",slug:"anopheles-mosquitoes-new-insights-into-malaria-vectors",bookSignature:"Sylvie Manguin",coverURL:"https://cdn.intechopen.com/books/images_new/3092.jpg",editedByType:"Edited by",editors:[{id:"50017",title:"Prof.",name:"Sylvie",surname:"Manguin",slug:"sylvie-manguin",fullName:"Sylvie Manguin"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"72",title:"Ionic Liquids",subtitle:"Theory, Properties, New Approaches",isOpenForSubmission:!1,hash:"d94ffa3cfa10505e3b1d676d46fcd3f5",slug:"ionic-liquids-theory-properties-new-approaches",bookSignature:"Alexander Kokorin",coverURL:"https://cdn.intechopen.com/books/images_new/72.jpg",editedByType:"Edited by",editors:[{id:"19816",title:"Prof.",name:"Alexander",surname:"Kokorin",slug:"alexander-kokorin",fullName:"Alexander Kokorin"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"2270",title:"Fourier Transform",subtitle:"Materials Analysis",isOpenForSubmission:!1,hash:"5e094b066da527193e878e160b4772af",slug:"fourier-transform-materials-analysis",bookSignature:"Salih Mohammed Salih",coverURL:"https://cdn.intechopen.com/books/images_new/2270.jpg",editedByType:"Edited by",editors:[{id:"111691",title:"Dr.Ing.",name:"Salih",surname:"Salih",slug:"salih-salih",fullName:"Salih Salih"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"117",title:"Artificial Neural Networks",subtitle:"Methodological Advances and Biomedical Applications",isOpenForSubmission:!1,hash:null,slug:"artificial-neural-networks-methodological-advances-and-biomedical-applications",bookSignature:"Kenji Suzuki",coverURL:"https://cdn.intechopen.com/books/images_new/117.jpg",editedByType:"Edited by",editors:[{id:"3095",title:"Prof.",name:"Kenji",surname:"Suzuki",slug:"kenji-suzuki",fullName:"Kenji Suzuki"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"3828",title:"Application of Nanotechnology in Drug Delivery",subtitle:null,isOpenForSubmission:!1,hash:"51a27e7adbfafcfedb6e9683f209cba4",slug:"application-of-nanotechnology-in-drug-delivery",bookSignature:"Ali Demir Sezer",coverURL:"https://cdn.intechopen.com/books/images_new/3828.jpg",editedByType:"Edited by",editors:[{id:"62389",title:"PhD.",name:"Ali Demir",surname:"Sezer",slug:"ali-demir-sezer",fullName:"Ali Demir Sezer"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"872",title:"Organic Pollutants Ten Years After the Stockholm Convention",subtitle:"Environmental and Analytical Update",isOpenForSubmission:!1,hash:"f01dc7077e1d23f3d8f5454985cafa0a",slug:"organic-pollutants-ten-years-after-the-stockholm-convention-environmental-and-analytical-update",bookSignature:"Tomasz Puzyn and Aleksandra Mostrag-Szlichtyng",coverURL:"https://cdn.intechopen.com/books/images_new/872.jpg",editedByType:"Edited by",editors:[{id:"84887",title:"Dr.",name:"Tomasz",surname:"Puzyn",slug:"tomasz-puzyn",fullName:"Tomasz Puzyn"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},chapter:{item:{type:"chapter",id:"77725",title:"Clinical Diagnosis and Treatment Management of Normal Pressure Hydrocephalus",doi:"10.5772/intechopen.99222",slug:"clinical-diagnosis-and-treatment-management-of-normal-pressure-hydrocephalus",body:'
1. Introduction
The brain and spinal cord are soft and vulnerable structures by their very nature. Cerebrospinal fluid (CSF) is the air cushion of the central nervous system (CNS), which protects the nerve tissue by reducing the speed of the blows to the CNS. 90% of this fluid is produced continuously by specialized cells called choroid plexus in the ventricle and 10% by ependymal cells lining the ventricle surface. CSF, which flows through F. Luschka and F. Magendie into the subarachnoid space to surround the brain and spinal cord, drains into the venous system via arachnoid granulation. Colombian neurosurgeon Hakim et al. [1, 2, 3] described a clinic in 1964 characterized by progressive cognitive decline with ventricular dilatation (normal CSF pressure during lumbar puncture), difficulty walking, and urinary incontinence syndrome. Hakim named this syndrome Normal Pressure Hydrocephalus (NPH). Although a clear clinical triad has been defined, there are important differences in the clinical presentation and progression of this syndrome. This situation leads to an increase in the problems related to the diagnosis and treatment of NPH. In fact, although there have been remarkable developments in the field of medicine since NPH was first defined in 1964, the guidelines determining the diagnosis, management, and operation criteria of NPH were first prepared in 2004 to be implemented only in Japan. Only in 2008 did Ishikawa et al. [4] produce worldwide applicable guidelines for its diagnosis and treatment. The information presented above is the most convincing evidence of the type of dynamic disease we are dealing with. On the other hand, due to reasons such as advancements in health, improved treatment options, increased education level, and conscientious diet, the share of the older population is constantly increasing. It is projected that as people’s quality of life improves and their life expectancy rises, more old people would develop this condition. In the light of current information, it is predicted that 20% of the world population will be individuals over 65 years old by 2050. While the world’s population has grown 4 times in the last 100 years (1950–2050), the fact that the elderly population will grow 10 times is a significant point that should be highlighted. In this case, it becomes even more important to age healthy and to keep the elderly population active. The most important task of neurologists, neurosurgeons, and psychiatrists in society is to provide early diagnosis and appropriate treatment of patients with NPH in society, especially given the socioeconomic consequences of this disease, particularly the burden of dementia on the individual, their families, and society. This is because it is emphasized that the earlier these patients are diagnosed and treated correctly, the more (most if not all) of the clinical symptoms are reversible.
2. Classification
NPH is divided into two groups as secondary NPH (sNPH) that develops due to decreased resorption of CSF due to inflammation and fibrosis at the arachnoid granulation level caused by subarachnoid hemorrhage, intraventricular hemorrhage, meningitis, or traumatic brain injury, and the second is the idiopathic NPH (iNPH) which does not have a causal disorder. A common feature of both diseases is that they do not contain any obstructions to the flow of CSF within the ventricular system of the brain. iNPH and sNPH do not differ in terms of prognosis. The sole significant clinical difference between them is that sNPH affects people of all ages, whereas iNPH often occurs more in the 60-70s [5, 6].
3. Incidence-prevalence
Epidemiological data on NPH are limited. Furthermore, due to the lack of uniform diagnostic criteria, reports on the incidence and prevalence of this disease, which has a wide clinical range, are partially inconsistent. The annual incidence of NPH is estimated to be between 0. 2 and 5.5 cases per 100,000 individuals. Its prevalence is reported to be 0.003% for persons under 65 years of age and 0. 2% to 2.9% for persons 65 years and older [7, 8]. In an epidemiological study conducted by Jaraj et al. [9], the probable prevalence of iNPH was found to be 0. 2% in people aged 70–79, and 5.9% in people aged 80 and older. Another recent epidemiological study also confirmed the inadequacy of incidence-prevalence reports of NPH [10]. Like other neurodegenerative diseases, the prevalence and incidence of NPH increases in direct proportion to age. In various studies, it was determined that there was no difference between males and females in terms of incidence [11, 12, 13].
4. Pathophysiology
It is important to clarify its pathophysiology for reliable diagnosis and treatment of NPH patients. Its pathophysiology is yet unknown, and it differs from other adult hydrocephalus causes. In addition to the fact that pathological alterations change CSF pressure, it is also related to changes in CSF dynamics. The CSF circulation spaces in the brain parenchyma within a rigid cranium work as a dynamic system that continually seeks to adapt to new situations in order to keep the ICP constant. These structures give instantaneous responses to changes in CSF production-absorption, changes in arterial–venous flow to the brain, changes in the compliance of intracranial structures, and changes in intracranial pressure. This process is very important in terms of ensuring the correct functioning of the brain. Cerebral blood flow differs with heart rhythm. The arterial supply is pulsative, whereas the venous flow is non-pulsative, causing temporary rises in CSF pressure. In two ways, the system tries to compensate for this. First, vascular structures can reduce arterial blood flow by changing compliance. The second is that the outflow of CSF increases along the cerebral aqueduct. ICP is attempted to be kept constant thanks to these compensatory mechanisms. The decrease in arterial modulation is first compensated by increased pulsatile CSF flow. However, the progressive increase of the pulsatility amplitude causes large ICP pulsations that determine the “water-hammer” effect. These enhanced vibrations create venous damage in the periventricular region, and the process of pushing the brain against the skull continues to expand the ventricles, resulting in hydrocephalus. As a result, the compensatory mechanisms, that are activated in order to maintain the ICP stable, create pathological changes in neural tissue [14]. In fact, hydrocephalus can be defined as the expansion of the ventricles in response to the reduction of the subarachnoid space in the cerebral tissue. This situation is secondary to the increase in the pressure gradient between the ventricles and the subarachnoid space, known as the transmantle pressure [15]. It is still unclear what triggers the initial reduction in arterial compliance in this process. Ischemia emerging in the white matter surrounding arterioles could explain the insufficiency in autoregulation. The ventricular enlargement causes the arterioles and venules around the ventricle to compress and stretch over time, resulting in poor/insufficient cerebral perfusion [16, 17, 18, 19]. Moreover, a strong relationship has been described between impaired cerebral blood flow and NPH. Therefore, clinically, the association of NPH with cerebrovascular disease is frequently encountered. Ischemic changes in cerebral tissue caused by decreased/insufficient perfusion were shown in Cranial MRI. These structural changes detected by neuro-radiological imaging have also been supported by neuropathological studies [20, 21, 22, 23]. Vascular changes that occur as a natural consequence of aging in humans may be the triggering mechanism in the reduction of vascular compliance. This may explain the relationship between iNPH and vascular disease [24].
NPH also reduces compliance in large vascular structures such as the superior sagittal sinus [25, 26]. Increased transvenular resistance in the sagittal sinuses has been hypothesized as a factor in the onset of NPH. According to this viewpoint, CSF resorption will be affected by increased transvenular resistance [27, 28]. As a result, none of the proposed theories can adequately explain how NPH develops, what factors trigger it, or how structural alterations occur. Although these presented hypotheses appear to complement one other, the debates about pathogenesis continue.
5. Clinic
Symptoms in NPH have been defined as a “triad”. However, having all of the symptoms at the same time is not necessary for diagnosis. The presence of two or more of the key symptoms (even a cardinal clinical symptom) such as apraxia of gait, dementia, and urinary incontinence, as well as bilateral dilatation of the ventricles, is necessary to diagnose the disease. The clinical signs and symptoms of this syndrome are highly diverse. Symptoms of this disease, which has an insidious onset, appear gradually over a period of at least 6 months. The rate and extent of worsening of symptoms vary from one patient to another. Some patients and families are unaware of symptoms until a triggering event, such as surgery, occurs. Careful questioning can clarify the nature of symptom onset.
Decreased cerebral perfusion as a result of ventriculomegaly may be a reason for the classic symptoms of NPH. Neurological signs and symptoms, such as apraxia of walking, are thought to be caused by a combination of mechanical stretching of the periventricular fiber tracts, disruption of brain parenchyma tissue as a result of reduced cerebral blood flow, and periventricular edema [29, 30, 31, 32, 33, 34]. Neuro-psychiatric symptoms have been suggested to be associated with brain regions such as the anterior cingulate cortex (ACC) and thalamus [35, 36, 37] because it has been determined that there is low perfusion in the anterior cingulate cortex and thalamus in NPH patients. Dysfunction in these regions is effective in the emergence of psychiatric symptoms. Therefore, increased/improved cerebral perfusion and oxygen metabolism from the frontal cortex and thalamus may cause neuropsychiatric and other symptoms in NPH patients after shunt surgery [38, 39]. There are publications reporting that psychiatric symptoms and syndromes occurring in the NPH clinic are related to changes in central neurotransmitter activity [40].
Although any of the main symptoms can present as the initial symptom in the NPH clinic, gait and balance disorders usually occur early and have a substantial impact on the individual’s life. Dementia and urinary incontinence are symptoms that progress with the disease, albeit they usually appear at later stages of the disease [41].
6. Gait disorder
As described in many published series and guidelines, gait disturbance is the first clinical symptom that affects almost all patients. Dizziness is a common initial complaint among patients. The instability in NPH is better with the patient’s eyes open, but patients still stand on a wide base even with their eyes open. When a patient’s walking ability is compromised, it has a detrimental influence on their quality of life. At first, gait and balance disorders may appear to be mild. Patients initially complain of climbing and descending stairs, as well as getting up and sitting in a chair. Parallel to the progression of the disease, the patient’s gait pattern deteriorates. Instead of the heel-to-toe gait cycle, which should normally be accomplished by raising the feet, these patients tend to slide their feet on the ground. This way of walking is described as “robotic”, “sticky-footed” or “magnetic phenomenon” [42]. The disconnection between the basal ganglia and the frontal cortex during walking, as well as the co-contraction of opposing muscles, is suggested to be the source of this gait pattern, which is usually found in parkinsonism (bradykinetic, magnetic) [43, 44]. In the absence of primary sensorimotor deficits, these patients have a higher level of gait disturbance and impaired postural and locomotor reflexes [45]. Gait apraxia develops with the advent of cognitive disorders in the later stages of the disease, and individuals become unable to walk. If these patients are not diagnosed and treated early, they are eventually confined to a wheelchair.
Extrapyramidal symptoms may occur rarely in patients with NPH, but spasticity, hyperreflexia, and other upper motor neuron signs and lateralizing findings are not common. Since the symptoms are bilateral in NPH, lateralizing findings should alert the clinician to the presence of other neuropsychiatric disorders in the differential diagnosis. To assess diagnosis and prognosis, a standard gait assessment (e.g., Tinetti score, Boon Scale) should be performed both before and after the lumbar puncture (LP). The clinical finding with the highest probability of recovery (more than 85 percent) after shunt surgery is apraxia of walking, which is frequently the first main symptom of the disease [46, 47, 48].
7. Cognitive disorder
Cognitive deficit in NPH is basically of the “subcortical” type, which includes memory impairment, psychomotor retardation, and impaired ability to apply/use the acquired knowledge [49, 50]. These cognitive and behavioral disorders accompanying NPH are generally defined as “frontal-subcortical dementia or frontal-subcortical dysfunction” [51, 52]. This term is used to describe a pattern of mental decline marked by a lack of interest (apathy) in one’s surroundings and oneself, as well as a lack of inner strength (amotivation) that drives one’s activities and behaviors [53, 54]. For this reason, patients have difficulty in performing their daily living activities even at the onset of the disease. In this period, it is possible that an abnormality will not be identified in the psychometric tests that will be done on the patients.
Dementia is the most serious symptom in the clinical triad, as it has a negative impact on patients’ work capacity as well as their social functioning. NPH is thought to be the etiological cause of 5% of dementia [55]. Even everyday activities like driving, shopping, and keeping track of appointments are challenging for these patients. There is no single type of dementia since dementia symptoms in NPH span a broad clinical spectrum. Instead, depending on the degree of permanent brain damage that has occurred, there are variable degrees of cognitive alteration. For this reason, it is not a very correct approach to define cognitive disorders that occur in NPH as dementia in the early period. Some patients have no clinical evidence of dementia, only mild or moderate cognitive deficits, and most of these patients respond well to shunt surgery [56, 57]. At least two of the following must be present for cognitive abnormalities in NPH patients to be defined as dementia.
In the late phase of the disease, indifference/indifference to environmental stimuli, decreased desire to speak/not speaking at all, decreased thinking/reasoning ability [58].
Since the Mini-Mental State Test and the DEMTEC Test were designed to evaluate cortical dementias, they are not appropriate for evaluating subcortical frontal lobe deficiencies (cognitive deficits) in NPH [59]. The Stroop test, digit span test, and Rey auditory-verbal learning test can be used instead. However, personality changes, anxiety, depression, psychotic syndromes such as delusions, hallucinations, and aggression may also be seen in NPH patients, as well as obsessive–compulsive disorder, Othello syndrome, and various other cognitive disorders such as theft, and mania [60, 61, 62, 63]. Depression can be seen in the NPH clinic, although it is rare. In fact, only a tiny portion of these patients who show clinical signs of depression is really diagnosed with depression. Symptoms such as apathy and bradyphrenia that occur in NPH patients may mimic depression. Differential diagnosis between depression and NPH can be challenging as neuropsychological assessment profiles are similar [64, 65]. Therefore, before being diagnosed with depression, NPH patients should have a thorough psychiatric examination, and therapy should be started if actual depression is present. Again, delirium is not encountered in the NPH clinic, and its presence implies the existence of another disease or pharmacological side effect accompanying the disease [41]. Boon AJ et al. [66] reported that iNPH patients showed severe attention deficits. Although the NPH clinic contains quite different and complex neuropsychiatric symptoms, the decision to have an early shunt surgery can continue to improve cognitive deficits in approximately 80% of patients with NPH, however, the presence of vascular dementia, Alzheimer’s dementia, or comorbid diseases at the same time affects the success of surgical treatment negatively and reduces the recovery rate.
8. Urinary incontinence
Urinary symptoms in NPH may occur as urinary frequency, urgency, or incontinence. The bladder dysfunction of NPH is usually in the form of urinary urgency and this condition is almost always present [67, 68]. These patients have difficulty in preventing bladder emptying [69]. Patients have difficulties keeping urinary continence and may suffer urgency with a few drops of urine leakage before reaching the toilet, even though they are aware of the need to urinate at first. Therefore, nocturia is common in NPH patients. Incontinence or having wet clothes are not characteristic of NPH. True urinary incontinence develops later in the course of the disease. While patients initially suffer from increased urinary frequency, they then develop sudden incontinence and eventually persistent urinary incontinence. Bladder dysfunction is due to stretching of the periventricular nerve fibers and loss of subsequent inhibition (partial) of bladder contractions. Bladder function disorders in NPH are caused by detrusor overactivity due to a lack of central inhibitory control, which can be partial or complete [70]. It is extremely rare for fecal incontinence to occur as a symptom of NPH. Therefore, the presence of fecal incontinence in a patient with NPH should first raise suspicion of another type of neurodegenerative disease in the clinician. If a patient with NPH has fecal incontinence as one of the clinical indicators, it suggests he has severe frontal subcortical dysfunction.
When applied early, a CSF shunt can help about 80% of NPH patients with bladder dysfunction; however, if surgery is done at an advanced stage in the disease, as in other symptoms, the percentage would be no more than 50-60%.
9. Diagnosis
For diagnosis, the physical and neurological examinations, clinical symptoms, neuropsychological and neuroimaging findings should all be evaluated as a whole. For this purpose, the clinician should clearly demonstrate the presence of hydrocephalus and the absence of severe cortical atrophy. All patients with NPH should have enlarged ventricles. Although ventriculomegaly is detected in many neurodegenerative diseases and senile cerebral atrophy, these patients may not have any clinical signs of hydrocephalus. Hence, the terms hydrocephalus and ventriculomegaly are not synonymous. To summarize, not all elderly patients with large ventricles have NPH. Ventriculomegaly makes sense when accompanied by clinical symptoms.
Today, in most cases where neurological symptoms are new, Computerized Brain Tomography (CBT) is often used because it is quick and easy to obtain, or Magnetic Resonance Imaging (MRI) because it provides more detailed information about cerebral anatomy/pathology. Furthermore, high-speed and high-resolution MRI techniques can better define aqueductal stenosis, and MRI phase-contrast techniques show the hyperdynamic aqueductal CSF flow that has been associated with shunt-responsive NPH.
Radiological findings detected by MRI/CBT (Figure 1).
Disproportionate ventricular enlargement to sulcal atrophy with typical rounding of frontal horns.
Periventricular high-density and/or low-density areas (leukoaraiosis) seen diffusely/locally in the white matter due to the transependymal passage of CSF.
Thinning and elevation of the corpus callosum [71].
The Evans index, as determined by dilatation of the third and lateral ventricles without obstruction in the CSF circulation and by MRI or CT, should be at least 0. 3 [72].
Flow gap in the aqueduct detected in spin-echo sequences and called hyperdynamic aqueduct or jet sign (this should be confirmed by hyperdynamic aqueduct phase-contrast MRI) [73].
Figure 1.
MRI images of NPH a: Periventricular hyperintensity, B: Enlargement of Sylvian cistern (sagittal), C: Enlargement of Sylvian cistern (coronal), D: Dilatation in the third ventricle, E: Callosal angle, F: Evans index, G: Hyperintensity in white matter, H: Bulging on the roof of the ventricle, I: Effacement of sulci at midline vertex.
The presence of a narrow CSF area in high convexity/midline areas on radiological imaging, and disproportionately enlarged subarachnoid spaces particularly in the Sylvian fissure and basal cisterns, are termed ‘Disproportionally Enlarged Subarachnoid Spaces Hydrocephalus’ (DESH). This is an indirect sign that CSF flow between the basal cisterns and the arachnoid granulations is being blocked. The existence of this symptom is thought to be the most sensitive indicator for shunt surgery, while its absence indicates brain atrophy [74]. So far, no characteristic neuropathological lesion of NPH has been detected [75, 76, 77].
Neuroimaging tests are necessary but not sufficient to diagnose NPH. Invasive tests such as lumbar puncture (LP). and External Lumbar Drainage (ELD) are needed in addition to non-invasive procedures like radiological imaging to improve diagnostic and prognostic accuracy in these patients. Both International and Japanese guidelines recommend diagnostic LP and/or ELD to all patients with suspected NPH. While there is a response to CSF intake in the presence of NPH, there is no response to CSF intake in the absence or minimal level of NPH. CSF drainage also has predictive value for shunt surgery. Patients whose symptoms are relieved by CSF drainage are expected to respond positively to shunt surgery as well. With LP taking 30–50 mL of CSF, changes in gait and cognitive functions are expected after 30 minutes to 4 hours (rarely a few days). If there is a positive response to the tap test, shunt surgery may be recommended, but failure to respond does not exclude the shunt response, because even in patients with normal CSF pressure in the LP, recovery was observed in approximately 50% of them following shunt surgery [78, 79, 80, 81, 82]. ELD may be considered in patients who do not respond to the Tap test but are still clinically suspected of having NPH. With ELD, controlled CSF drainage of approximately 10 mL/h for 2–3 days or 150 to 200 mL per day for 2 to 7 days is performed. The patient’s gait and neuropsychological tests are recorded daily before the procedure, during CSF drainage, and after catheter removal.
It is difficult to explain the detection of CSF pressure at normal levels in NPH dynamics. Although normal CSF pressure can be detected with a single LP, in fact, 24-hour monitoring might occasionally reveal abnormally high pressures or consistently high/normal pressures. Although CSF pressure has been found to be normal in a single LP, there is a consensus that episodes of increased CSF pressure occur in NPH. For the development of iNPH or sNPH, it is predicted that the baseline ICP is high, at least during the disease stages, and that this high pressure decreases with dilatation of the ventricles. Long-term intracranial pressure (ICP) measurements, such as those taken by some centers for 24 to 72 hours, are not advised for routine usage, both because their predictive values have not yet been adequately documented and because they necessitate specialized equipment and expertise.
10. Differential diagnosis
Regression in motor and cognitive functions, as well as urine incontinence, are common with aging. The addition of other neurodegenerative diseases, such as those that increase with age, and some surgery (cervical/lumbar spinal stenosis) and internal diseases (hypothyroidism, vitamin B12 deficiency) make the differential diagnosis difficult. It may not be easy to distinguish Alzheimer’s disease (AD) and Parkinson’s disease, which exhibit similar clinical symptoms such as gait disturbance and dementia, from NPH. Also, having vascular or Alzheimer’s dementia simultaneously in three-quarters (75%) of their patients with NPH makes the situation even more complicated. On the other hand, because each of the cardinal symptoms of NPH has a variety of etiologies, it might mimic a variety of neurodegenerative diseases. Patients with isolated NPH are extremely uncommon in clinical practice due to the numerous comorbidities that often accompany the symptoms of NPH. The clinical triad peculiar to this disease is actually non-classical, as similar symptoms can be found in a variety of disorders. Therefore, a comprehensive differential diagnosis table ranging from psychiatric disorders to neurological diseases should be considered when distinguishing NPH from other diseases in elderly patients. The differential diagnosis of gait disorders includes peripheral neuropathy, inner ear disorders, spinal cord diseases, alcohol use, and deficiencies of vitamins such as B6 and B12. Clinical and neuroimaging data are very important in the differential diagnosis. Early and accurate determination of the differential diagnosis will save both the clinician and the patient from a series of invasive and noninvasive tests.
Findings that make a diagnosis of NPH less likely include the following:
ICP: Above 25 cm H2O.
AGE: Patients younger than 40 years old.
SYMPTOM: Asymmetrical or transient symptoms.
CORTICAL DYSFUNCTION: Having deficits such as aphasia, paresis.
DEMENTIA: The absence of gait disturbance accompanying the dementia clinic.
CLINICAL PROCESS: No progression of symptoms.
Some of the diseases frequently encountered in the differential diagnosis are Alzheimer’s disease (AD) and Parkinson’s disease. Similar to Parkinson’s disease, episodes of hesitation and freezing may occur in the gait of NPH patients. However, resting tremors and the typically unilateral symptoms of Parkinson’s disease are uncommon in NPH. NPH patients’ failure to respond to anti-parkinsonian medicines may also help with diagnosis.
The subject AD, another common disease in differential diagnosis, is quite complex and difficult. AD is thought to account for 50–60% of all dementias in the elderly [83, 84, 85]. It is not always possible to distinguish between patients with NPH and those with AD based solely on their medical history and physical examination. Thanks to data gained from MRI and neuropsychological tests, distinguishing AD from NPH is now easier than in past years. The mental disorder in NPH is a subcortical type. While the severity of cognitive impairment is mild or moderate in patients with NPH, mental disorders in AD patients are both the first symptom and advanced. Again, dementia signs occur with more severe symptoms in AD than in NPH. This condition was confirmed by the presence of hippocampal atrophy on CT or MRI [86, 87, 88, 89]. Again, motor symptoms such as gait disturbance are rare in AD. In AD, long-term, short-term, and sensory memories are all impaired, while in NPH memory is partially preserved. In NPH, brain dysfunction mainly arises in the frontal cortex, whereas in AD, the major dysfunction originates from the medial temporal lobe, thus, medial temporal lobe atrophy on MRI suggests AD [90]. On the other hand, when considering the response to shunt surgery, it is critical to distinguish these two diseases, which overlap in terms of clinical symptoms. From this standpoint, many studies have investigated biomarkers in CSF to both improve diagnosis and predict shunt efficacy. The specific combination of low Aβ-42 and increased P-tau detected in the CSF has actually been accepted as the biological signature of AD [91]. In contrast, Graff-Radford [92] reported that CSF markers are not useful in distinguishing between the NPH patients from the patients with comorbid AD. Complete blood count, biochemical profile, neuropsychological tests, MRI of the cervical, thoracic or lumbar spine in addition to cranial MRI, electromyography/nerve conduction velocity study and urology consultation can be performed to comprehensively evaluate the differential diagnosis.
11. Treatment
Although NPH is a clinically well-known disease, the indications for shunt surgery and the estimation of surgical outcomes are not clear. Although many devoted articles have been published to identify the most suitable candidates for surgical treatment, there is still no consensus on who is the best candidate for surgery and how to select these patients. Reliable indications of good surgical response are still lacking, particularly with regard to the shunt procedure. In the presence of short history, a known cause of hydrocephalus, predominance of gait disturbances, and CT or MRI findings for hydrodynamic hydrocephalus, it is not difficult to decide on surgery and recommend a shunt to the patient. Today, identifying patients with NPH and applying effective treatment methods still pose challenges for neurosurgeons. However, despite all these difficulties, if diagnosed and treated early, the unusual appearance of these symptoms affecting elderly individuals can be prevented and significant improvements in their life quality can be achieved.
Advanced diagnostic and therapeutic methods and clinical successes have shown that surgical treatment for NPH is superior to conservative treatment. Even if one or two main symptoms are present, NPH should be diagnosed and treated, as waiting for the clinical triad to occur for diagnosis can drastically diminish the response to shunt surgery. This is because the longer NPH patients go without treatment, the worse their prognosis becomes and the shorter their life expectancy becomes.
Using a catheter to alter the flow path of CSF is now the recognized therapeutic procedure all around the world. Shunt surgery is indicated for patients who respond to CSF drainage or who have CSF hydrodynamic variables consistent with NPH [75, 93, 94, 95].
However, it is crucial to identify other diseases that mimic NPH before deciding on surgical treatment as it will directly affect the quality of life of patients. There is no evidence that the time spent identifying and treating these disorders in the differential diagnosis lowers the chances of response to shunt surgery. The most essential component that promotes surgical success is a more thorough evaluation performed without haste. Moreover, it should be noted that not all patients with NPH are candidates for shunt surgery. For each patient, the benefit–risk ratio should be assessed separately. Before the surgical operation, possible complications of shunt surgery (infection, embolization, shunt failure, subdural hematoma, and effusion) should be considered and patients should be informed about the surgical risks as well as the potential benefit. Patients should be informed about the problems they will encounter in their daily lives (such as gait disturbance, dementia, incontinence) and potential complications of shunt surgery if they are not operated on. Providing information on the following issues prior to surgical consent will improve the patient’s and their relatives’ compliance with post-surgery treatment.
After surgical treatment, iNPH has a potential cure rate of 30-50% and sNPH of 50-70%.
The least reversible symptom with surgical treatment is dementia.
The complication rate of surgical treatment varies between 20% and 40%, but serious complications do not exceed 5-8%.
The passage of CSF from one compartment to another by bypassing the natural flow pathways with the aid of a catheter remains the main treatment method for NPH. This shunt procedure is based on the notion that it will minimize the elevated transmantle pressure caused by ventriculomegaly, therefore relieving the symptoms associated with NPH [14]. Today, ventriculoperitoneal (VP) shunts are the most commonly used ones for this purpose. Shunt valves and configuration are dependent on surgeon experience and patient preference. There is no objective evidence that one type of shunt is superior to another. Low-pressure shunts were frequently employed in the past, and the clinical response was better. However, because complications including excessive drainage and subdural hematoma are more common with these shunts, they have been phased out except in rare circumstances. Today, medium pressure shunts or adjustable shunts are more preferred. Adjustable shunts have the advantage of allowing the pressure setting to be gradually lowered or raised until the patient’s symptoms improve. In this way, complications that may arise as a result of under or excess drainage can be avoided by changing the pressure without surgery. Another advantage is that it can be administered safely in patients who are on anticoagulation therapy for cardiac or neurological disorders [96].
In Japan, patients with iNPH are mainly treated with lumbar peritoneal shunts. In recent years, this surgical procedure has been widely used all over the world. In terms of effectiveness, one type of shunt has no superiority over the other. However, although the complication rate associated with the device itself is higher in lumbar peritoneal shunts than in ventriculoperitoneal shunts, the fact that lumbar peritoneal shunts are minimally invasive, do not have the fatal complications seen in ventriculoperitoneal shunts, and are more economical has allowed them to be a step forward in treatment [97]. Endoscopic third ventriculostomy has not been proven to be effective in the treatment of iNPH. In patients who are debilitated and shunt surgery is contraindicated, serial lumbar punctures are not recommended as an alternate treatment, except for a limited period of time.
Although it is difficult to draw definitive conclusions, three decades of publications on NPH and surgical experience have summarized the factors that can help predict post-shunt outcomes as follows [98].
Factors predicting a good surgical outcome.
Clinical gait disturbances appearing before cognitive deficits.
Short duration of mental deterioration history.
Mild or moderate level of mental disorder.
Presence of hydrocephalus with known etiology such as subarachnoid hemorrhage, meningitis.
Detection of significant improvement in clinical findings after CSF drainage.
Occurrence of 50% or more B waves in continuous intracranial pressure monitoring.
Absence of significant white matter lesions on MRI.
Factors predicting poor surgical outcomes.
Dementia being the first symptom among clinical findings.
Detection of clinical signs of severe dementia.
Detection of significant cerebral atrophy or diffuse white matter involvement on MRI.
Although some studies have indicated a high success (recovery) rate of roughly 80-90% in the improvement of clinical symptoms following surgery [99, 100], the overall rate has been reported to be 65-70% for sNPH cases and 30-50% for iNPH cases [50, 82, 101]. This discrepancy in surgical outcomes could be attributed to the presence of other NPH-related neurodegenerative and/or cerebrovascular disorders. Therefore, meticulousness in differential diagnosis and early treatment of comorbidities can eliminate this inconsistency.
However, the reasons why patients treated with shunts do not respond to shunt surgery are not fully understood. Before concluding that the surgical treatment was unsuccessful, it should be suspected that the failure was due to candidate selection or that the shunt was ineffective in cases where the desired clinical improvement was not achieved after surgery, particularly in patients whose ventricular size did not decrease after shunt or in those who only experienced temporary improvement after surgery [102].
Acknowledgments
I would especially like to thank my colleague İsmail KAYA for his help in English editing of the chapter.
\n',keywords:"normal pressure hydrocephalus, elderly individuals, neurodegenerative diseases, cognitive deficits, early surgical treatment",chapterPDFUrl:"https://cdn.intechopen.com/pdfs/77725.pdf",chapterXML:"https://mts.intechopen.com/source/xml/77725.xml",downloadPdfUrl:"/chapter/pdf-download/77725",previewPdfUrl:"/chapter/pdf-preview/77725",totalDownloads:156,totalViews:0,totalCrossrefCites:0,totalDimensionsCites:0,totalAltmetricsMentions:1,impactScore:0,impactScorePercentile:43,impactScoreQuartile:2,hasAltmetrics:1,dateSubmitted:"June 17th 2021",dateReviewed:"July 3rd 2021",datePrePublished:"July 29th 2021",datePublished:"January 19th 2022",dateFinished:"July 29th 2021",readingETA:"0",abstract:"Inadequate absorption of cerebrospinal fluid (CSF) at the arachnoid granulation level during circulation results in an increase in CSF in the ventricle and certain neuropsychiatric clinical findings. This syndrome, which often presents with ventricular dilatation, progressive cognitive decline, walking difficulties, and urinary incontinence symptoms in elderly individuals, is called Normal Pressure Hydrocephalus (NPH). It is projected that as people’s quality of life improves and their life expectancy rises, more old people would develop this condition. Although a clear clinical triad has been defined, the identification of patients with NPH and the application of effective treatment modalities still pose a number of challenges for neurosurgeons today. However, despite all these difficulties, if diagnosed and treated early, the unusual appearance of these symptoms affecting elderly individuals can be prevented and significant improvements in quality of life can be achieved.",reviewType:"peer-reviewed",bibtexUrl:"/chapter/bibtex/77725",risUrl:"/chapter/ris/77725",book:{id:"11018",slug:"cerebrospinal-fluid"},signatures:"Hüseyin Yakar",authors:[{id:"354970",title:"Assistant Prof.",name:"Hüseyin",middleName:null,surname:"Yakar",fullName:"Hüseyin Yakar",slug:"huseyin-yakar",email:"hsyakar@gmail.com",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",institution:null}],sections:[{id:"sec_1",title:"1. Introduction",level:"1"},{id:"sec_2",title:"2. Classification",level:"1"},{id:"sec_3",title:"3. Incidence-prevalence",level:"1"},{id:"sec_4",title:"4. Pathophysiology",level:"1"},{id:"sec_5",title:"5. Clinic",level:"1"},{id:"sec_6",title:"6. Gait disorder",level:"1"},{id:"sec_7",title:"7. Cognitive disorder",level:"1"},{id:"sec_8",title:"8. Urinary incontinence",level:"1"},{id:"sec_9",title:"9. Diagnosis",level:"1"},{id:"sec_10",title:"10. Differential diagnosis",level:"1"},{id:"sec_11",title:"11. Treatment",level:"1"},{id:"sec_12",title:"Acknowledgments",level:"1"}],chapterReferences:[{id:"B1",body:'Hakim S, Adams RD. The special clinical problem of symptomatic hydrocephalus with normal cerebrospinal fluid pressure. Observations on cerebrospinal fluid hydrodynamics. J Neurol Sci. 1965; 2: 307-327'},{id:"B2",body:'Hakim S, Venegas JG, Burton JD. The physics of the cranial cavity, hydrocephalus and normal pressure hydrocephalus: mechanical interpretation and mathematical model. Surg Neurol. 1976; 5: 187-210'},{id:"B3",body:'Adams RD. Fisher CM, Hakim S. et al. Symptomatic occult hydrocephalus with “normal” cerebrospinal-fluid pressure. A treatable syndrome. N Engl J Med. 1965; 273: 117-126'},{id:"B4",body:'Ishikawa M, Hashimoto M, Kuwana N, Mori E, Miyake H, Wachi A, Takeuchi T, Kazui H, Koyama H. Guidelines for management of idiopathic normal pressure hydrocephalus. Neurologia Medico-Chirurgica. 2008;48 (Suppl):1-23'},{id:"B5",body:'Torkelson RD, Leibrock LG, Gustavson JL, Sundell RR. Neurological and neuropsychological effects of cerebrospinal fluid shunting in children with assumed arrested “normal pressure” pressure hydrocephalus. J Neurol Neurosurg Psychiatry. 1985;48: 799-806'},{id:"B6",body:'Bret P, Chazal J. Chronic (“normal pressure”) hydrocephalus in childhood and adolescence. A review of 16 cases and reappraisal of the syndrome. Childs Nerv Syst. 1995; 11:687-691'},{id:"B7",body:'Brean A, Eide PK. Prevalence of probable idiopathic normal pressure hydrocephalus in a Norwegian population. Acta Neurol Scand. 2008; 118:48-53.'},{id:"B8",body:'Hiraoka K, Meguro K, Mori E. Prevalence of idiopathic normal-pressure hydrocephalus in the elderly population of a Japanese rural community. Neurol Med Chir. 2008; 48: 197-199'},{id:"B9",body:'Jaraj D, Rabiei K, Marlow T. et al. Prevalence of idiopathic normal-pressure hydrocephalus. Neurology. 2014; 82:1449-1454.'},{id:"B10",body:'Martin-Laez R, Caballero-Arzapalo H, Lopez-Menendez LA, Arango-Lasprilla JC, Vázquez-Barquero A. Epidemiology of idiopathic normal pressure hydrocephalus: A systematic review of the literature. World Neurosurgery. 2015;87:298-310.'},{id:"B11",body:'Brean A, Fredo HL, Sollid S, Muller T, Sundstrom T, Eide PK. Five- year incidence of surgery for idiopathic normal pressure hydrocephalus in Norway. Acta Neurol Scand. 2009; 120: 314-316'},{id:"B12",body:'Tanaka N, Yamaguchi S, Ishikawa H, Ishii H, Meguro K. Prevalence of possible idiopathic normal-pressure hydrocephalus in Japan: the Osaki-Tajiri project. Neuro-epidemiology 2009; 32: 171-175.'},{id:"B13",body:'Krauss JK, Halve B: Normal pressure hydrocephalus: surveyon contemporary diagnostic algorithms and therapeutic decision making in clinical practice. Acta Neurochir. 2004; 146: 379-388.'},{id:"B14",body:'Gooriah R, Raman A. Idiopathic normal pressure hydrocephalus: An overview of pathophysiology. Clinical Features, Diagnosis and Treatment. 2016. DOI: 10.5772/64198'},{id:"B15",body:'Greitz D, Greitz T, Hindmarsh T. A new view on the CSF-circulation with the potential for pharmacological treatment of childhood hydrocephalus. Acta Paediatrica. 1997;86:125-132'},{id:"B16",body:'Bradley WG. Normal pressure hydrocephalus: New conceptson etiology and diagnosis. AJNR. American Journal of Neuroradiology. 2000; 21:1586-1590'},{id:"B17",body:'Greitz T. Effect of brain distension on cerebral circulation. Lancet. 1969; 2: 863-865'},{id:"B18",body:'Sato O, Ohya M, Nojiri K, Tsugane R. Microcirculatory changes in experimental hydrocephalus: morphological and physiological studies. In: Shapiro K,Marmarou A, Portnoy H (eds) Hydrocephalus. Raven, 1984; 215-230'},{id:"B19",body:'Del Bigio MR, Bruni JE Changes in periventricularvasculature of rabbit brain following induction of hydrocephalu sand after shunting. J Neurosurg. 1988; 69:115-120'},{id:"B20",body:'Krauss JK, Droste DW, Vach W, Regel JP, Orszagh M,Borremans JJ, Tietz A, Seeger W. Cerebrospinal fluid shunting in idiopathic normal-pressure hydrocephalus of the elderly: Effectof periventricular and deep white matter lesions. Neurosurgery. 1996;39(2):292-300'},{id:"B21",body:'Tullberg M, Jensen C, Ekholm S, Wikkelsø C. Normal pressure hydrocephalus: Vascular white matter changes on MR images must not exclude patients from shunt surgery. Am J Neuroradiol. 2001;22(9):1665-1673'},{id:"B22",body:'Akai K, Uchigasaki S, Tanaka U, Komatsu A. Normal pressure hydrocephalus. Neuro-pathological study. Acta Pathologica Japonica. 1987;37(1):97-110'},{id:"B23",body:'Del Bigio MR. Neuropathological changes caused by hydrocephalus. Acta Neuropathologica. 1993;85(6):573-585'},{id:"B24",body:'Grünewald RA. Normal pressure hydrocephalus: Pathophysiology. Practical Neurology. 2006;6:264-266'},{id:"B25",body:'Mase M, Yamada K, Banno T, Miyachi T, Ohara S, Matsumoto T. Quantitative analysis of CSF flow dynamics using MRI in normal pressure hydrocephalus. Acta Neurochirurgica. Supplement. 1998;71:350-353'},{id:"B26",body:'Bateman GA. Vascular compliance in normal pressure hydrocephalus. Am J Neuroradiol. 2000;21(9):1574-1585'},{id:"B27",body:'Castro ME, Portnoy HD, Maesaka J. Elevated cortical venous pressure in hydrocephalus. Neurosurgery. 1991;29:232-238'},{id:"B28",body:'Portnoy HD, Branch C, Castro ME. The relationship of intracranial venous pressure to hydrocephalus. Child’s Nervous System. 1994;10:29-35'},{id:"B29",body:'Oliveira MF, Pinto FCG, Nishikuni K, Botelho RV, Lima AM, Rotta JM. Revisiting hydrocephalus as a model to study brain resilience. Front Hum Neurosci. 2011;5:181.'},{id:"B30",body:'Greitz TVB, Grepe AOL, Kalmer MSC. Pre- and post-operative evaluation of cerebral blood flow in low pressure hydrocephalus. J Neurosurg. 196931:644-51.'},{id:"B31",body:'Fisher CM. Hydrocephalus as a cause of gait disturbances in the elderly. Neurology. 1982;32: 1258-1263.'},{id:"B32",body:'Grubb RL, Raichle ME, Gado MH, Eichling JO, Hughes CP. Cerebral blood flow oxygen utilisation and blood volume in dementia. Neurology. 1977;27:905-910'},{id:"B33",body:'Meyer JS, Kitagawa Y, Tanahashi N, et al. Pathogenesis of normal pressure hydrocephalus preliminary. Surg Neurol. 1985; 23(2): 121-133'},{id:"B34",body:'Mathew NT, Meyer JS, Hartmann A, Ott EO. Abnormal cerebrospinalfluid-blood flow dynamics. Implications in diagnosis, treatnent andprognosis in normal pressure hydrocephalus. Arc Neurol. 1975;32:657-664'},{id:"B35",body:'Craig AH, Cummings JL, Fairbanks L, Itti L, Miller BL, Liand J, Mena I. Cerebral blood flow correlates of apathy in Alzheimer disease, Archives of Neurology. 1996;53: 1116-1120.'},{id:"B36",body:'Lanctot KL, Moosa S, Herrmann N, Leibovitch FS, Rothenburg L, Cotter A, Black SE, A SPECT study of apathyin Alzheimer’s disease, Dementia and Geriatric Cognitive Disorders. 2007;24: 65-72.'},{id:"B37",body:'Marshall GA, Monserratt L, Harwood D, Mandelkern M. Cummings JL, Sultzer DL. Positron emission tomography metabolic correlates of apathy in Alzheimer disease, Archives of Neurology. 2007;64 :1015-1020'},{id:"B38",body:'J. Miyamoto, K. Tatsuzawa, Y. Inoue, Y. Imahori and K.Mineura, Oxygen metabolism changes in patients with idiopathic normal pressure hydrocephalus before and after shunting operation, Acta Neurologica Scandinavica. 2007 116137-116143'},{id:"B39",body:'Tullberg M, Hellstrom P, Piechnik SK, Starmark JE, Wikkelso C. Impaired wakefulness is associated with reduced anterior cingulate CBF in patients with normal pressure hydrocephalus, Acta Neurologica Scandinavica. 2004;110:322-330'},{id:"B40",body:'Markianos M, Lafazanos S, Koutsis G, Sfagos C, Seretis A. CSF neurotransmitter metabolites and neuropsychiatric symptomatology inpatients with normal pressure hydrocephalus. Clin Neurol Neurosurg. 2009;111:231-234'},{id:"B41",body:'Williams MA, Relkin NR. Diagnosis and management of idiopathic normal-pressure hydrocephalus. Neurology Clinical Practice. 2013;3:375-385.'},{id:"B42",body:'Haan J, Jansen ENH, Oostrom J, Roos RAC Falling spells in normal pressure hydrocephalus: A favourable prognostic sign? Eur Neurol. 1987; 27:216-220'},{id:"B43",body:'Estanol BV Gait apraxia in communicating hydrocephalus. J Neurol Neurosurg Psychiatry. 1981 ;44: 305-308'},{id:"B44",body:'Knutsson E, Lying-Tunell U. Gait apraxia in normal-pressure hydrocephalus: patterns of movement and muscle activation. Neurology. 1985; 35: 155-160'},{id:"B45",body:'Nutt JG, Marsden CD, Thompson PD. Human walking and higher-level gait disorders, particularly in the elderly. Neurology. 1993;43:268-279.'},{id:"B46",body:'Fisher CM (1982) Hydrocephalus as a cause of disturbances of gait inthe elderly. Neurology 32:1358-1363'},{id:"B47",body:'Sørensen PS, Jansen EC, Gjerris F. Motor disturbances in normal pressure hydrocephalus. Special reference to stance and gait. ArchNeurol. 1986;43:34-38'},{id:"B48",body:'Graff-Radford NR, Godersky JC. Normal-pressure hydrocephalus. Onset of gait abnormality before dementia predicts good surgical outcome. Arch Neurol. 1986; 43:940-942.'},{id:"B49",body:'Thomsen AM, Børgesen SE, Bruhn P, Gjerris F. Prognosis of dementia in normal-pressure hydrocephalus after a shunt operation. Ann Neurol. 1986; 20:304-310'},{id:"B50",body:'Cummings JL, Benson DF Hydrocephalic dementia. In:Dementia: a clinical approach, 2nd edn. Butterworth Heinemann, Boston. 1992:267-291'},{id:"B51",body:'Ogino A, Kazui H, Miyoshi N, Hashimoto M, Ohkawa S, Tokunaga H,Ikejiri Y, Takeda M. Cognitive impairment in patients with idiopathic normal pressure hydrocephalus Dementia and Geriatric Cognitive Disorders. 2006;21(2):113-119'},{id:"B52",body:'Tarnaris A, Toma AK, Pullen E, Chapman MD, Petzold A, CipolottiL, Kitchen ND, Keir G, Lemieux L, Watkins LD. Cognitive, biochemical,and imaging profile of patients suffering from idiopathic normal pressure hydrocephalus. Alzheimer’s & Dementia. 2011;7(5):501-508.'},{id:"B53",body:'Larsson A, Wikkelsö C, Bilting M, Stephensen H. Clinical parametersin 74 consecutive patients shunt operated for normal pressure hydrocephalus. Acta Neurologica Scandinavica. 1991;84(6):475-482.'},{id:"B54",body:'Mega MS, Cummings JL. Frontal-subcortical circuits and neuropsychiatric disorders. The Journal of Neuropsychiatry and Clinical Neurosciences. 1994;6(4):358-370.'},{id:"B55",body:'Vanneste JA. Diagnosis and management of normal-pressure hydrocephalus, J Neurol. 2000;247: 5-14.'},{id:"B56",body:'Fisher CM. Hydrocephalus as a cause of disturbances of gait in the elderly. Neurology. 1982:32:1358-1363'},{id:"B57",body:'Gerloff C, Pickard JD Normal pressure hydrocephalus. In:Brandt T, Caplan LR, Dichgans J, Diener HC, Kennard C (eds) Neurological disorders– course and treatment. Academic, San Diego. 1996:773-778'},{id:"B58",body:'Michael K, Andreas U. The Differential Diagnosis and Treatment of Normal-Pressure Hydrocephalus. | Dtsch Arztebl Int 2012; 109 (1-2):15-26'},{id:"B59",body:'Hellstrom P, Edsbagge M, Blomsterwall E, et al.:Neuropsychological effects of shunt treatment in idiopathic normal pressure hydrocephalus. Neurosurgery. 2008; 63: 527-535.'},{id:"B60",body:'McIntyre AW, Emsley RA. Shoplifting associated with normal pressure hydrocephalus: report of a case. J Geriatr Psychiatry. Neurol. 1990;3:229-230.'},{id:"B61",body:'Kwentus JA, Hart RP. Normal pressure hydrocephalus presenting as mania. J Nerv Ment Dis. 1987;175:500-502.'},{id:"B62",body:'Bloom KK, Kraft WA. Paranoia - an unusual presentation of hydrocephalus. Am J Phys Med Rehabil. 1998;77:157-159.'},{id:"B63",body:'Yusim A, Anbarasan D, Bernstein C, et al. Normal pressure hydrocephalus presenting as Othello syndrome: case presentation and review of the literature. Am J Psychiatry 2008;165:1119-1125.'},{id:"B64",body:'Rosen H, Swigar ME Depression and normal pressure hydrocephalus.A dilemma in neuropsychiatric differential diagnosis. J Nerv Ment Dis. 1976;163:35-40'},{id:"B65",body:'Hart RP, Kwentus JA. Psychomotor slowing and subcortical type dysfunction in depression. J Neurol Neurosurg Psychiatry. 1987;50: 1263-1266'},{id:"B66",body:'Boon AJ, Tans JT, Delwel EJ, Egeler-Peerdeman SM, Hanlo PW, Wurzer HA, Avezaat CJ, de Jong DA, Gooskens RH, Hermans J. Dutch normal pressure hydrocephalus study: Prediction of outcome after shunting by resistance to outflow of cerebrospinal fluid. Journal of Neurosurgery. 1997;87:687-693.'},{id:"B67",body:'Fisher CM Hydrocephalus as a cause of disturbances of gait in the elderly. Neurology 1982;32:1358-1363'},{id:"B68",body:'Bret P, Chazal J (L’hydrocéphalie chronique de l’adulte.Neurochirurgie. 1990 ; 36 [Suppl] :1-159'},{id:"B69",body:'Sakakibara R, Kanda T, Sekido T, et al. Mechanism of bladder dysfunction in idiopathic normal pressure hydrocephalus. Neurourol Urodyn 2008;27:507-510'},{id:"B70",body:'Sakakibara R, Uchiyama T, Kanda T, Uchida Y, Kishi M, Hattori T. Urinary dysfunction in idiopathic normal pressure hydrocephalus. Brain and Nerve. 2008;60(3):233-239'},{id:"B71",body:'Ishii K, Kanda T, Harada A, Miyamoto N, Kawaguchi T, Shimada K,Ohkawa S, Uemura T, Yoshikawa T, Mori E. Clinical impact of the callosal angle in the diagnosis of idiopathic normal pressure hydrocephalus. European Radiology. 2008;18(11):2678-2683.'},{id:"B72",body:'Gyldensted C. Measurements of the normal ventricular system and hemispheric sulci of 100 adults with computed tomography. Neuroradiology.1977;14(4):183-192'},{id:"B73",body:'Bradley WG Jr. CSF flow in the brain in the context of normal pressure hydrocephalus. American Journal of Neuroradiology.2015;36(5):831-838.'},{id:"B74",body:'Sasaki M, Honda S, Yuasa T, Iwamura A, Shibata E, Ohba H. Narrow CSF space at high convexity and high midline areas in idiopathic normal pressure hydrocephalus detected by axial and coronal MRI. Neuroradiology. 2008;50(2):117-122'},{id:"B75",body:'Mori E, Ishikawa M, Kato T, et al. Guidelines for management of idiopathic normal pressure hydrocephalus: second edition.Neurol Med Chir 2012;52:775-809'},{id:"B76",body:'Hashimoto M, Ishikawa M, Mori E, Kuwana N. Study of INPH on neurological improvement (SINPHONI): diagnosis of idiopathic normal pressure hydrocephalus is supported by MRI-basedscheme: a prospective cohort study. Cerebrospinal Fluid Res. 2010;7:18.'},{id:"B77",body:'Williams MA, Malm J (2016) Diagnosis and Treatment of Idiopathic Normal Pressure Hydrocephalus. Continuum (Minneap Minn) 22:579-599'},{id:"B78",body:'Greenberg JO, Shenkin HA, Adam R(1977) Idiopathic normal pressure hydrocephalus- a report of 73 patients. J Neurol Neurosurg Psychiatry. 40:336-341.'},{id:"B79",body:'Black PMcL Idiopathic normal- pressure hydrocephalus. Results of shunting in 62 patients. J Neurosurg. 1980:53:371-377'},{id:"B80",body:'Pickard JD (1984) Normal pressure hydrocephalus – to shunt or not to shunt. In: Warlow C, Garfield J (eds) Dilemmas in the management of the neurological patient. Churchill Livingstone, Edinburgh, pp. 207-214'},{id:"B81",body:'Petersen RC, Mokri B, Laws ER . Surgical treatment of idiopathic hydrocephalus in elderly patients. Neurology. 1985; 35:307-311'},{id:"B82",body:'Vanneste JAL. Three decades of normal pressure hydrocephalus: are we wiser now? J Neurol Neurosurg Psychiatry. 1994; 57:1021-1025'},{id:"B83",body:'Ebly EM, Parhad IM, Hogan DB, Fung TS. Prevalence and types of dementia in the very old: results from the Canadian Study of Health and Aging. Neurology. 1994; 44: 1593-1599'},{id:"B84",body:'Ichinowatari N, Tatsunuma T, Makiya H. Epidemiological study of old age mental disorders in the two rural areas of Japan. Jpn J Psychiatry Neurol. 1987;41: 629-636'},{id:"B85",body:'Sulkava R, WikstroÈm J, Aromaa A, Rautsalo R, Lehtinen V, LahtelaK, Palo J. Prevalence of severe dementia in Finland. Neurology 1985; 35: 1025-1029'},{id:"B86",body:'Golomb J, de Leon MJ, George AE et al (Hippocampal atrophy in normal pressure hydrocephalus is associated with severity of cognitive impairment. Neurology. 1993;43 [Suppl] 2: 211-212'},{id:"B87",body:'George AE, de Leon MJ, Miller J, Kluger A, Smith DC CT diagnostic features of Alzheimer’s disease: importance in the choroidal/hippocampal fissure complex. Am J Neuroradiol. 1990;11:101-107'},{id:"B88",body:'Golomb J, de Leon MJ, George AE, Kluger A, Convit A, Rusinek H,de Santi S, Litt A, Foo SH, Ferris SH. Hippocampal atrophy correlates with severe cognitive impairment in elderly patients with suspected normal pressure hydrocephalus. J Neurol Neurosurg Psychiatry. 1994; 57:590-593'},{id:"B89",body:'Holodny AI, Waxman R, George AE, Rusinek H, Kalnin AJ, de Leon M. MR differential diagnosis of normal-pressure hydrocephalus and Alzheimer disease: significance of peri-hippocampal features. Am J Neuroradiol. 1998;19:813-819'},{id:"B90",body:'Jack CR Jr, Petersen RC, Brien PC, Tangalos EG. MR-based hippocampal volumetry in the diagnosis of Alzheimer disease. Neurology 1992;42(1):183-188.'},{id:"B91",body:'Blennow K, Hampel H CSF markers for incipient Alzheimer’sdisease. Lancet Neurol. 2003; 2:605-613.'},{id:"B92",body:'Graff-Radford NR. Alzheimer CSF biomarkers may be misleading innormal-pressure hydrocephalus. Neurology. 2014;83(17):1573-1575'},{id:"B93",body:'Relkin N, Marmarou A, Klinge P, Bergsneider M, Black PM. Diagnosing idiopathic normal-pressure hydrocephalus: INPH Guidelines, part II. Neurosurgery. 2005;57:4-16.'},{id:"B94",body:'Marmarou A, Bergsneider M, Klinge P, Relkin N, Black PM. The value of supplemental prognostic tests for the preoperative assessment of idiopathic normal-pressure hydrocephalus: INPH Guidelines, part III. Neurosurgery. 2005;57:17-28.'},{id:"B95",body:'Bergsneider M, Black PM, Klinge P, Marmarou A, Relkin N.Surgical management of idiopathic normal-pressure hydrocephalus: INPH Guidelines, part IV. Neurosurgery. 2005;57:29-39.'},{id:"B96",body:'Goodwin CR, Kharkar S, Wang P, Pujari S, Rigamonti D,Williams MA. Evaluation and treatment of patients with suspected normal pressure hydrocephalus on long term warfarin anticoagulation therapy Neurosurgery. 2007;60:497-501.'},{id:"B97",body:'Nakajima M, Miyajima M, Ogino I, Sugano H, AkibaC, Domon N, Karagiozov KL, Arai H. Use of external lumbar cerebrospinal fluid drainage and lumboperitoneal shunts with strata NSC valves in idiopathic normal pressure hydrocephalus: A single-center experience. World Neurosurgery. 2015;83(3):387-393.'},{id:"B98",body:'Klinge P, Hellström P, Tans J, Wikkelsø C. European iNPH multicenter study group. One-year outcome in the European multicentre study on iNPH. Acta Neurologica Scandinavica. 2012;126(3):145-153.'},{id:"B99",body:'Vanneste JAL. Diagnosis and management of normal-pressure hydrocephalus. Neurol. 2000;247:5-14'},{id:"B100",body:'Black PML, Ojemann RG, Tzouras A (1985) CSF shunts for dementia, incontinence, and gait disturbance. Clin Neurosurg 32:632-651'},{id:"B101",body:'Poca MA, Solana E, Martínez-Ricarte FR, Romero M, Gándara D,Sahuquillo J. Idiopathic normal pressure: Results of a prospective cohort of 236 shunted patients. Acta Neurochirurgica. Supplement. 2012;114:247-253.'},{id:"B102",body:'Williams MA, Razumovsky AY, Hanley DF. Evaluation of shunt function in patients who are never better, or better then worse after shunt surgery for NPH. Acta Neurochir. 1998;71:368-370'}],footnotes:[],contributors:[{corresp:"yes",contributorFullName:"Hüseyin Yakar",address:"hsyakar@gmail.com",affiliation:'
Department of Neurosurgery, Faculty of Medicine, Niğde Ömer Halisdemir University, Niğde, Turkey
'}],corrections:null},book:{id:"11018",type:"book",title:"Cerebrospinal Fluid",subtitle:null,fullTitle:"Cerebrospinal Fluid",slug:"cerebrospinal-fluid",publishedDate:"January 19th 2022",bookSignature:"Pınar Kuru Bektaşoğlu and Bora Gürer",coverURL:"https://cdn.intechopen.com/books/images_new/11018.jpg",licenceType:"CC BY 3.0",editedByType:"Edited by",isbn:"978-1-83969-696-1",printIsbn:"978-1-83969-695-4",pdfIsbn:"978-1-83969-697-8",reviewType:"peer-reviewed",numberOfWosCitations:0,isAvailableForWebshopOrdering:!0,editors:[{id:"95341",title:"Prof.",name:"Bora",middleName:null,surname:"Gürer",slug:"bora-gurer",fullName:"Bora Gürer"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,coeditorOne:{id:"244230",title:"M.D.",name:"Pinar",middleName:null,surname:"Kuru Bektaşoğlu",slug:"pinar-kuru-bektasoglu",fullName:"Pinar Kuru Bektaşoğlu"},coeditorTwo:null,coeditorThree:null,coeditorFour:null,coeditorFive:null,topics:[{id:"1056"}],productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"},chapters:[{id:"79717",type:"chapter",title:"History, Anatomy, Histology, and Embryology of the Ventricles and Physiology of the Cerebrospinal Fluid",slug:"history-anatomy-histology-and-embryology-of-the-ventricles-and-physiology-of-the-cerebrospinal-fluid",totalDownloads:152,totalCrossrefCites:0,signatures:"Pinar Kuru Bektaşoğlu and Bora Gürer",reviewType:"peer-reviewed",authors:[{id:"95341",title:"Prof.",name:"Bora",middleName:null,surname:"Gürer",fullName:"Bora Gürer",slug:"bora-gurer"},{id:"244230",title:"M.D.",name:"Pinar",middleName:null,surname:"Kuru Bektaşoğlu",fullName:"Pinar Kuru Bektaşoğlu",slug:"pinar-kuru-bektasoglu"}]},{id:"78216",type:"chapter",title:"Circulation of Cerebrospinal Fluid (CSF)",slug:"circulation-of-cerebrospinal-fluid-csf-",totalDownloads:300,totalCrossrefCites:0,signatures:"Hayriye Soytürk, Murat Yılmaz, Cansu Önal, Eylem Suveren and Ümit Kılıç",reviewType:"peer-reviewed",authors:[{id:"355396",title:"Dr.",name:"Hayriye",middleName:null,surname:"Soytürk",fullName:"Hayriye Soytürk",slug:"hayriye-soyturk"},{id:"356118",title:"Dr.",name:"Murat",middleName:null,surname:"Yılmaz",fullName:"Murat Yılmaz",slug:"murat-yilmaz"},{id:"425645",title:"Dr.",name:"Cansu",middleName:null,surname:"Önal",fullName:"Cansu Önal",slug:"cansu-onal"},{id:"425646",title:"Dr.",name:"Eylem",middleName:null,surname:"Suveren",fullName:"Eylem Suveren",slug:"eylem-suveren"},{id:"425647",title:"Dr.",name:"Ümit",middleName:null,surname:"Kılıç",fullName:"Ümit Kılıç",slug:"umit-kilic"}]},{id:"77557",type:"chapter",title:"Normal Pressure Hydrocephalus: Revisiting the Hydrodynamics of the Brain",slug:"normal-pressure-hydrocephalus-revisiting-the-hydrodynamics-of-the-brain",totalDownloads:195,totalCrossrefCites:0,signatures:"Fernando Hakim, Daniel Jaramillo-Velásquez, Martina González, Diego F. Gómez, Juan F. Ramón and Mateo Serrano-Pinzón",reviewType:"peer-reviewed",authors:[{id:"356309",title:"M.D.",name:"Daniel",middleName:null,surname:"Jaramillo-Velásquez",fullName:"Daniel Jaramillo-Velásquez",slug:"daniel-jaramillo-velasquez"},{id:"356311",title:"Dr.",name:"Fernando",middleName:null,surname:"Hakim",fullName:"Fernando Hakim",slug:"fernando-hakim"},{id:"421784",title:"Dr.",name:"Martina",middleName:null,surname:"González",fullName:"Martina González",slug:"martina-gonzalez"},{id:"421785",title:"Dr.",name:"Diego F.",middleName:null,surname:"Gómez",fullName:"Diego F. Gómez",slug:"diego-f.-gomez"},{id:"421786",title:"Dr.",name:"Juan",middleName:null,surname:"F. Ramón",fullName:"Juan F. Ramón",slug:"juan-f.-ramon"},{id:"421787",title:"Dr.",name:"Mateo",middleName:null,surname:"Serrano-Pinzón",fullName:"Mateo Serrano-Pinzón",slug:"mateo-serrano-pinzon"}]},{id:"77725",type:"chapter",title:"Clinical Diagnosis and Treatment Management of Normal Pressure Hydrocephalus",slug:"clinical-diagnosis-and-treatment-management-of-normal-pressure-hydrocephalus",totalDownloads:156,totalCrossrefCites:0,signatures:"Hüseyin Yakar",reviewType:"peer-reviewed",authors:[{id:"354970",title:"Assistant Prof.",name:"Hüseyin",middleName:null,surname:"Yakar",fullName:"Hüseyin Yakar",slug:"huseyin-yakar"}]},{id:"78390",type:"chapter",title:"Lesions at the Foramen of Monro Causing Obstructive Hydrocephalus",slug:"lesions-at-the-foramen-of-monro-causing-obstructive-hydrocephalus",totalDownloads:187,totalCrossrefCites:0,signatures:"Ashish Chugh, Sarang Gotecha, Prashant Punia and Neelesh Kanaskar",reviewType:"peer-reviewed",authors:[{id:"307717",title:"Dr.",name:"Sarang",middleName:null,surname:"Gotecha",fullName:"Sarang Gotecha",slug:"sarang-gotecha"},{id:"423827",title:"Dr.",name:"Ashish",middleName:null,surname:"Chugh",fullName:"Ashish Chugh",slug:"ashish-chugh"},{id:"423838",title:"Dr.",name:"Prashant",middleName:null,surname:"Punia",fullName:"Prashant Punia",slug:"prashant-punia"},{id:"423839",title:"Dr.",name:"Neelesh",middleName:null,surname:"Kanaskar",fullName:"Neelesh Kanaskar",slug:"neelesh-kanaskar"}]},{id:"77599",type:"chapter",title:"Infections in CSF Shunts and External Ventricular Drainage",slug:"infections-in-csf-shunts-and-external-ventricular-drainage",totalDownloads:138,totalCrossrefCites:0,signatures:"Roger Bayston",reviewType:"peer-reviewed",authors:[{id:"414390",title:"Prof.",name:"Roger",middleName:null,surname:"Bayston",fullName:"Roger Bayston",slug:"roger-bayston"}]},{id:"77779",type:"chapter",title:"Germinal Matrix-Intraventricular Hemorrhage: Current Concepts and Future Direction",slug:"germinal-matrix-intraventricular-hemorrhage-current-concepts-and-future-direction",totalDownloads:116,totalCrossrefCites:0,signatures:"Sadhika Sood and Rohit Gulati",reviewType:"peer-reviewed",authors:[{id:"355618",title:"Assistant Prof.",name:"Rohit",middleName:null,surname:"Gulati",fullName:"Rohit Gulati",slug:"rohit-gulati"},{id:"423659",title:"Dr.",name:"Sadhika",middleName:null,surname:"Sood",fullName:"Sadhika Sood",slug:"sadhika-sood"}]}]},relatedBooks:[{type:"book",id:"6374",title:"Hydrocephalus",subtitle:"Water on the Brain",isOpenForSubmission:!1,hash:"b431d113b9d7fca7e67c463f0970ed04",slug:"hydrocephalus-water-on-the-brain",bookSignature:"Bora Gürer",coverURL:"https://cdn.intechopen.com/books/images_new/6374.jpg",editedByType:"Edited by",editors:[{id:"95341",title:"Prof.",name:"Bora",surname:"Gürer",slug:"bora-gurer",fullName:"Bora Gürer"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"},chapters:[{id:"61650",title:"Introductory Chapter: History of the Hydrocephaly",slug:"introductory-chapter-history-of-the-hydrocephaly",signatures:"Bora Gürer",authors:[{id:"95341",title:"Prof.",name:"Bora",middleName:null,surname:"Gürer",fullName:"Bora Gürer",slug:"bora-gurer"}]},{id:"58993",title:"Visualization and Characterization of Cerebrospinal Fluid Motion Based on Magnetic Resonance Imaging",slug:"visualization-and-characterization-of-cerebrospinal-fluid-motion-based-on-magnetic-resonance-imaging",signatures:"Satoshi Yatsushiro, Saeko Sunohara, Hideki Atsumi, Mitsunori\nMatsumae and Kagayaki Kuroda",authors:[{id:"227834",title:"Prof.",name:"Kagayaki",middleName:null,surname:"Kuroda",fullName:"Kagayaki Kuroda",slug:"kagayaki-kuroda"},{id:"231084",title:"Ph.D. Student",name:"Satoshi",middleName:null,surname:"Yatsushiro",fullName:"Satoshi Yatsushiro",slug:"satoshi-yatsushiro"},{id:"238254",title:"Ms.",name:"Saeko",middleName:null,surname:"Sunohara",fullName:"Saeko Sunohara",slug:"saeko-sunohara"},{id:"238255",title:"Dr.",name:"Hideki",middleName:null,surname:"Atsumi",fullName:"Hideki Atsumi",slug:"hideki-atsumi"},{id:"238256",title:"Dr.",name:"Mitsunori",middleName:null,surname:"Matsumae",fullName:"Mitsunori Matsumae",slug:"mitsunori-matsumae"}]},{id:"58783",title:"Craniocervical Junction Syndrome: Anatomy of the Craniocervical and Atlantoaxial Junctions and the Effect of Misalignment on Cerebrospinal Fluid Flow",slug:"craniocervical-junction-syndrome-anatomy-of-the-craniocervical-and-atlantoaxial-junctions-and-the-ef",signatures:"Scott Rosa, John W. Baird, David Harshfield and Mahan\nChehrenama",authors:[{id:"232739",title:"Dr.",name:"Scott",middleName:null,surname:"Rosa",fullName:"Scott Rosa",slug:"scott-rosa"},{id:"232757",title:"Dr.",name:"John",middleName:null,surname:"Baird",fullName:"John Baird",slug:"john-baird"},{id:"232759",title:"Dr.",name:"David",middleName:null,surname:"Harshfield",fullName:"David Harshfield",slug:"david-harshfield"},{id:"232760",title:"Dr.",name:"Mahan",middleName:null,surname:"Chehrenama",fullName:"Mahan Chehrenama",slug:"mahan-chehrenama"}]},{id:"59026",title:"Clinical and Cognitive Features of Idiopathic Normal Pressure Hydrocephalus",slug:"clinical-and-cognitive-features-of-idiopathic-normal-pressure-hydrocephalus",signatures:"Elena Sinforiani, Claudio Pacchetti, Marta Picascia, Nicolò Gabriele\nPozzi, Massimiliano Todisco and Paolo Vitali",authors:[{id:"214458",title:"Dr.",name:"Elena",middleName:null,surname:"Sinforiani",fullName:"Elena Sinforiani",slug:"elena-sinforiani"},{id:"223726",title:"Dr.",name:"Claudio",middleName:null,surname:"Pacchetti",fullName:"Claudio Pacchetti",slug:"claudio-pacchetti"},{id:"223727",title:"Dr.",name:"Marta",middleName:null,surname:"Picascia",fullName:"Marta Picascia",slug:"marta-picascia"},{id:"223728",title:"Dr.",name:"Nicolò Gabriele",middleName:null,surname:"Pozzi",fullName:"Nicolò Gabriele Pozzi",slug:"nicolo-gabriele-pozzi"},{id:"223730",title:"Dr.",name:"Massimiliano",middleName:null,surname:"Todisco",fullName:"Massimiliano Todisco",slug:"massimiliano-todisco"},{id:"223731",title:"Dr.",name:"Paolo",middleName:null,surname:"Vitali",fullName:"Paolo Vitali",slug:"paolo-vitali"}]},{id:"59236",title:"Hydrocephaly: Medical Treatment",slug:"hydrocephaly-medical-treatment",signatures:"Fethi Gul, Reyhan Arslantas and Umut Sabri Kasapoglu",authors:[{id:"215553",title:"Dr.",name:"Fethi",middleName:null,surname:"Gul",fullName:"Fethi Gul",slug:"fethi-gul"},{id:"227504",title:"Dr.",name:"Umut Sabri",middleName:null,surname:"Kasapoglu",fullName:"Umut Sabri Kasapoglu",slug:"umut-sabri-kasapoglu"},{id:"227505",title:"Dr.",name:"Reyhan",middleName:null,surname:"Arslantas",fullName:"Reyhan Arslantas",slug:"reyhan-arslantas"}]},{id:"59183",title:"Endoscopic Third Ventriculostomy, Indications and Challenges",slug:"endoscopic-third-ventriculostomy-indications-and-challenges",signatures:"Ehab Ahmed El Refaee and Ahmed A Abdullah",authors:[{id:"224592",title:"Associate Prof.",name:"Ehab",middleName:null,surname:"El Refaee",fullName:"Ehab El Refaee",slug:"ehab-el-refaee"},{id:"236220",title:"Dr.",name:"Ahmed",middleName:null,surname:"Abdullah",fullName:"Ahmed Abdullah",slug:"ahmed-abdullah"}]},{id:"60499",title:"Endoscopic Third Ventriculostomy",slug:"endoscopic-third-ventriculostomy",signatures:"Tugrul Cem Unal and Aydin Aydoseli",authors:[{id:"224770",title:"M.D.",name:"Tugrul Cem",middleName:null,surname:"Unal",fullName:"Tugrul Cem Unal",slug:"tugrul-cem-unal"},{id:"224775",title:"Dr.",name:"Aydin",middleName:null,surname:"Aydoseli",fullName:"Aydin Aydoseli",slug:"aydin-aydoseli"}]},{id:"58682",title:"Presentation of the Success Rate of ETV in Distinct Indication Cases of Hydrocephalus",slug:"presentation-of-the-success-rate-of-etv-in-distinct-indication-cases-of-hydrocephalus",signatures:"Joachim M.K. Oertel and Akos Csokonay",authors:[{id:"59895",title:"Prof.",name:"Joachim",middleName:null,surname:"Oertel",fullName:"Joachim Oertel",slug:"joachim-oertel"},{id:"216390",title:"Mr.",name:"Akos",middleName:null,surname:"Csokonay",fullName:"Akos Csokonay",slug:"akos-csokonay"}]}]}],publishedBooks:[{type:"book",id:"1359",title:"Underlying Mechanisms of Epilepsy",subtitle:null,isOpenForSubmission:!1,hash:"85f9b8dac56ce4be16a9177c366e6fa1",slug:"underlying-mechanisms-of-epilepsy",bookSignature:"Fatima Shad Kaneez",coverURL:"https://cdn.intechopen.com/books/images_new/1359.jpg",editedByType:"Edited by",editors:[{id:"31988",title:"Prof.",name:"Kaneez",surname:"Fatima Shad",slug:"kaneez-fatima-shad",fullName:"Kaneez Fatima Shad"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"1360",title:"Mechanisms in Parkinson's Disease",subtitle:"Models and Treatments",isOpenForSubmission:!1,hash:"823c4dc5acbf952ba3723cae01f7f67a",slug:"mechanisms-in-parkinson-s-disease-models-and-treatments",bookSignature:"Juliana Dushanova",coverURL:"https://cdn.intechopen.com/books/images_new/1360.jpg",editedByType:"Edited by",editors:[{id:"36845",title:"Dr.",name:"Juliana",surname:"Dushanova",slug:"juliana-dushanova",fullName:"Juliana Dushanova"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"1441",title:"Neurodegeneration",subtitle:null,isOpenForSubmission:!1,hash:"8c57eafa17b6fd6f54306661bd58413f",slug:"neurodegeneration",bookSignature:"L. Miguel Martins and Samantha H.Y. Loh",coverURL:"https://cdn.intechopen.com/books/images_new/1441.jpg",editedByType:"Edited by",editors:[{id:"101220",title:"Dr.",name:"L. Miguel",surname:"Martins",slug:"l.-miguel-martins",fullName:"L. Miguel Martins"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"2041",title:"Advanced Understanding of Neurodegenerative Diseases",subtitle:null,isOpenForSubmission:!1,hash:"b56de330191b07690544d005fe678de7",slug:"advanced-understanding-of-neurodegenerative-diseases",bookSignature:"Raymond Chuen-Chung Chang",coverURL:"https://cdn.intechopen.com/books/images_new/2041.jpg",editedByType:"Edited by",editors:[{id:"33396",title:"Dr.",name:"Raymond Chuen-Chung",surname:"Chang",slug:"raymond-chuen-chung-chang",fullName:"Raymond Chuen-Chung Chang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9519",title:"Epilepsy",subtitle:"Update on Classification, Etiologies, Instrumental Diagnosis and Treatment",isOpenForSubmission:!1,hash:"9074ae871f3044a2cfa973e8f516f546",slug:"epilepsy-update-on-classification-etiologies-instrumental-diagnosis-and-treatment",bookSignature:"Sandro Misciagna",coverURL:"https://cdn.intechopen.com/books/images_new/9519.jpg",editedByType:"Edited by",editors:[{id:"103586",title:null,name:"Sandro",surname:"Misciagna",slug:"sandro-misciagna",fullName:"Sandro Misciagna"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],publishedBooksByAuthor:[]},onlineFirst:{chapter:{type:"chapter",id:"80757",title:"A Proposal of Haptic Technology to be Used in Medical Simulation",doi:"10.5772/intechopen.102508",slug:"a-proposal-of-haptic-technology-to-be-used-in-medical-simulation",body:'
1. Introduction
Teleoperation and virtual reality systems are intrinsically related since they make a human operator interact with the environments without being in physical contact with them. In the first one, these environments are real, while in the second one, we generate them in a computer simulation. However, both types of systems must make the operator perceive, as realistically as possible, the characteristics of the remote or virtual environment. Some variables used to reproduce these characteristics are position and force, which provide visual and haptic feedback, respectively. The biggest difference between them is the procedure of generating the information received by the operator. In the teleoperation case, both signals exist physically and are transmitted via a control algorithm. The algorithm receives both signals from sensors. Both signals do not exist in virtual reality and we must generate computationally them.
Stimulating the senses of sight and touch, as precisely as possible, is essential during the interaction process, since they are the principal channels with which the operator perceives the world around them. For teleoperation, in the visual case, the communication comes directly from the environment or, if the operator is in a remote place, using a camera and a computer screen. The virtual reality system generates the environment through a digital simulation, and the operator receives the visual information through a screen. We need additional devices since the tactile issue is more complex. Those devices must be capable of transmitting the generated forces in the environment. Such a process implies including haptic robots in the systems because of their capability to generate forces and torques that the human operator can perceive in a tactile way. We need for teleoperation systems two physical robots, while in a virtual reality system we only need one robot and the virtual environment as the other.
The medical area has actively seized on both teleoperation and virtual reality systems. In the first case, a specialist can perform surgery procedures over long distances, eliminating the need for the physical presence of either the physicians or patients in the same location [1]. Practically, the specialist can examine or operate on the patient at a different geographic location without having to travel.
In Figure 1, we showed the emblematic Da Vinci Surgical Robotic System. Operating based on a master-slave control concept. The system provides the medical expert with a realistic operating environment that includes a high-quality stereo visualization and a human-machine interface that directly transfers the doctor’s hand gestures to the instrument inside the patient [2].
Figure 1.
Da Vinci surgical robotic system.
In the second case, someone has widely used virtual reality systems for medical training simulation. With the development of computer graphics, nowadays practically any surgical procedure can be visually simulated. Minimally invasive surgery has been the most beneficial area. It has implemented virtual environments in laparoscopy, neurosurgery, and urology, to name a few [3]. As an example, in Figure 2 we showed the simulator of Transurethral Resection of the Prostate TURP Mentor. Clinicians can improve their skills without endangering their patients to avoid Live practice with humans by using this system. Tactile feedback inclusion is an important factor in the improvement of such skills. It must synchronize tactile feedback with both the virtual reality simulation and the operator’s movements.
Figure 2.
URP Mentor (simulator).
The challenge for researchers in graphic computing and control systems is to design mathematical tools that fit with the object’s physical characteristics to be simulated within the virtual environment. Regarding the visual feedback, the position where such objects are located is essential for the operator to perceive his movements in the Cartesian virtual space. About the force, reproducing rigidity and softness takes special interest when the virtual environment includes penetrable and nonpenetrable objects. Here, the complexity of the mathematical tools increases because their physical laws are not always easy to simulate on a computer. For this reason, it must establish an interchange between visual and haptic realism because of the finite capacity of digital processing.
1.1 State-of-the-art
Teleoperation and virtual reality applications have developed in areas as different as automotive and video games. However, an important application is for medical surgery [4], where the operator on the master side needs to be sure of the force he feels. Such a force, generated in opposition to his movements, must be ideally the same as that the robot applies over the patient at the slave side. It has widely used virtual reality systems in minimally invasive surgical simulation, where the operator should feel the same forces that it would feel in a real procedure, [5].
Goertz presented the first master-slave teleoperation system [6]. It was used to handle toxic waste using two coupled manipulators. Subsequently, using electrical signals, he included a rudimentary force generation device. Since then, we have used this system in areas such as micro and nano-manipulation [7] underwater exploration [8], and tele-surgery [9]. Haptic feedback takes special relevance in this last area since it is crucial for the surgeon to receive an accurate force response. The most effective way to do so is to have force sensors at both master and slave sides, and a control algorithm that guarantees an accurate tracking between the contact forces present in the remote environment and those sent to the operator [10].
The idea of force feedback on virtual reality systems began with the fundamental work of Sutherland [11]. He established that the interaction between the human operator and the virtual environment should not only be visual but also tactile. It was not until the 1990s that he adapted the Goertz device to provide force feedback during virtual molecular coupling [12]. Since then, the use of manipulators in virtual reality applications has spread to CAD/CAM assembly [13], aerospace maintenance [14], and especially in medical training through simulators [15] where, unlike systems of master-slave teleoperation, neither the environments nor the contact forces exist. It must transmit the actual forces to the operator with precision. The quality of this transmission depends on the characteristics of the haptic interface and the corresponding force control algorithm [3].
Articulated robots play a major role in medical training simulation systems with force feedback since this kind of electromechanical device can measure spatial position and generate torques. There has been a large effort to design robot haptic interfaces such as the widely used Phantom serial robot [16], the Delta Haptic parallel robot [17], and the combination of passive elements such as brakes and springs with motors [18]. Such robots are examples of impedance types devices, i.e. they read position and control force in response. There are another robots that read forces and control motion, called admittance type devices. The difference between using one or another type relies on the characteristics of the virtual environment (e.g., stiffness, inertia, damping, friction).
Along with haptic interfaces, there has been an intense development of graphical simulation tools capable of reproducing a wide range of virtual environments. The principal aim is for the operator to perceive, as realistic as possible, objects with a high quality of detail. The applications developed include microscopic exploration [19], aviation [20], and clinical neuropsychology [21], among many others. With medical training simulation, a correct synergy between visual and tactile feedback is essential to heighten the skills of medicine students. However, to increase immersion and consequently the realism of the virtual reality displays, it is necessary to model environments that combine haptic and graphics to the same complexity [22]. This is not always possible since it limited the computational processing and it cannot execute the applications in real-time.
Salisbury et al. [23] presented the basic architecture for a virtual reality application with visual and haptic feedback. They established that the force rendering algorithms must be geometry-dependent. This is a disadvantage in medical training simulation since the virtual objects to be reproduced include bones and organs with irregularities or indentations. There are cases in which the interaction occurs not only on the surfaces of the object, but we must also calculate the penetration forces, as we do in surgery simulators. The alternative is to design algorithms based on physical laws that involve the dynamic and movement of the objects when the operator interacts with them [24]. The perfect scenario would be to render forces by combining physical approaches with the most sophisticated haptic interfaces. However, as mentioned before, doing that is computationally more expensive, not to mention the high costs it would entail.
The more realistic the force transmitted to the operator, the higher the quality of the method used. The factors mentioned above cause a series of compensations between haptic and visual realism, real-time execution, and system costs. Such offsets allowed for establishing two principal methods for rendering forces from virtual environments [25]. The first one is the penalty method, which is widely used for its simplicity since it required a penetration measure starting at the contact point with the virtual object. The second approach is the imposed motion method, where it is considering the contact as a bilateral constraint and it is calculating the contact force response using Lagrange multipliers. Computer graphics and haptic applications use both methods. Ruspini et al. established the differences between using both methods [22].
It is to assume, according to the penalty method, virtual objects are formed geometrically or algebraically by defined primitives such as lines, planes, spheres, and cylinders [26]. Therefore, the force rendering depends on an implicit equation and a contact point given by a collision detection algorithm. In 1991, Sclaroff and Pentland proposed a generalization using the implicit function representation method to allow collision detection for common 3D shapes [27]. The method is to replace the polygon and spline with their previous versions. By using this technique, it is possible to use local gradients in the normal direction of the virtual surface [28]. In this sense, the concept of impedance takes special relevance since it addressed the force rendering problem as an energy exchange phenomenon, allowing to study of the stability of the haptic system [29].
Using the imposed motion method implies considering the contacts with the virtual object as bilateral constraints [25]. Therefore, haptic systems are a master-slave scheme where the rigid object, the virtual representation of the haptic interface, is the master. This entails employing Lagrange multipliers to compute the magnitude of the contact force. In 1994, Bayo and Avello designed an algorithm by considering the dynamics of a multi-body system as a constraint [30]. The advantage of this approach is that the force response can not only be in terms of a single contact point, but it can also be in terms of the dynamic characteristics of the surfaces [31]. However, the hardware requirement for haptic rendering in 3D is for the haptic interface to have at least 3 degrees of freedom.
The methods mentioned above have been the cornerstone for virtual forces generation both in graphic computing and haptic systems. One of the principal requirements in such areas is that the systems be capable of reproducing the forces that would be present during contact with rigid and soft objects. This is especially important in the development of simulators used in medical training, where the tactile sensations caused by contact between a virtual tool and bones or organs must reproduce [32]. Depending on the goals of the design, we must make a compromise between haptic and visual realism.
2. Preliminaries
In order to implement a virtual reality application, it is important to combine and match both visual and haptic feedback in real-time. Next, we introduce the fundamentals of virtual surface representation, which allow us to show how works the force rendering method, proposed in [33]. The mathematical nature of holonomic and non-holonomic constraints is presented by introducing some basic concepts of differential topology and the mathematical model of the haptic system. For this, a teloperation scheme is adapted considering the slave robot as virtual. It simulated its dynamic model within the virtual environment. Said robot is in contact with holonomic or non-holonomic virtual constraints, whose mathematical representation is also presented. The process for rendering the forces to be transmitted to the operator is detailed below, as well as some observations on the validity of the approach, especially regarding the differences when using both types of constraints.
2.1 Virtual surfaces representation
It is important to distinguish between the different representations of virtual surfaces, both from the point of view of computer graphics and from the point of view of haptic systems. Because the physics of light (with visual representation) differs from the physics of mechanical interactions. It is important to consider that although the graphical and haptic simulation can share the coding of certain properties, such as the shape, they must differ in other aspects, such as models, mathematical techniques, and implementation [32]. It is important to note that haptic rendering in practice avoids the many complex renderings developed by the graphics computing community over the years. However, in this section, the basics of such representations are given to introduce the fundamentals of the proposed haptic representation method, which central idea is to relate holonomic and non-holonomic constraints, which mathematically have a kinematic basis, with the rigid and soft tissues of the body. Surface dynamic complexity is avoided, and instead, from a purely haptic approach, it is classified as nonpenetrable and penetrable. By using the approach of a manipulator in constrained motion, it includes the dynamic of the virtual robot to exemplify that it is possible to model the virtual tool, in a more complex way than that of a single point probe used commonly in computer graphics [34].
2.1.1 Nonpenetrable virtual surfaces
In order to represent forces coming from rigid surfaces, it suffices to define algebraically an implicit equation in joint coordinates (task space), or at least two of its geometric characteristics such as normal and tangential vectors, or distance and angle relationships between points, lines, and planes [35]. This simplifies the graphical and haptic implementation since it is possible to define the surface as the zero set of a function f valued at R as Sf=x∈R3fx=0 [36]. Based on this approach, lines, points, and mainly zero-width polygons, assembled by vertices, form rigid virtual environments, [31]. For example, in Figure 3, a human skull using a triangle mesh with Phys X® by NVIDIA graphics engine is modeled.
In this case, a PxGeometry Class by NVIDIA, part of a geometry class, from the common base class, is used. Each geometry class defines a volume or surface with a fixed position and orientation. We can implement it in many geometry types, as simple as spheres, capsules, boxes and planes, and others more complex as convex meshes, triangle meshes, and height fields [37]. Besides, the methods to build a complex object as a human skull and its properties include triangle mesh collision and convex decomposition, Figure 3. The haptic interaction for virtual objects formed by such geometries and methods comes from a normal vector over the geometry, as we can see in Figure 4, where the haptic interaction with a sphere occurs using a collision detection algorithm of a single point.
Figure 4.
Haptic interaction with a sphere. (a) Applied external forces. (b) Collision detection. (c) Collision response. (a) Original mesh. (b) Delaunay triangulation. (c) Mass-spring like system.
2.1.2 Penetrable virtual surfaces
The case of deformable surfaces is more complex since, from a biomedical approach, a physically realistic simulation must consider all the nonlinearities of material deformation (e.g. stress, strain, elasticity, and viscoelasticity). One strategy is to combine a finite element discretization of the geometry together with a finite difference discretization of time and an updated Lagrangian iterative scheme [38]. Another very used representations of deformable surfaces in computer graphics are the particle-based model. Their location, speed, acceleration, mass, and any other parameter needed for an application describe particles and they develop according to Newtonian mechanical laws [36]. For example, in Figure 5, we model a deformable tissue using the graphic engine FLEX® by NVIDIA where, from a polygon-based mesh, a particle system is got through a Delaunay triangulation.
Figure 5.
Particle model by FLEX (soft tissue). (a) Original mesh. (b) Delaunay triangulation. (c) Mass-spring like system.
Using particle-based models allows to visually reproduce more complex processes such as cutting and slitting, processes very common in medical training. However, no matter how complicated the underlying model is, the force response because of deformation is a function of deflection only, that is, we define deformation as the displacement of the initial contact point between an instrument and a body. Deformable, even if it is a very large deformation, [32]. This characteristic allows us to study the contact from a kinematic perspective, it moved once the manner tool inside the soft object.
More sophisticated graphic tools such as SOFA (Simulation Open Framework Architecture) address the description of the object, typically by using three models: an internal model with independent degrees of freedom, the mass, and the constitutive laws, a collision model with contact geometry, and a visual model with detailed geometry and rendering parameters [39]. During runtime, it synchronizes the models using a generic mechanism called mapping, which is used to propagate forces and displacements and to enforce coherence between them. Normally, the internal model acts as the master system, imposing its displacements on the slave systems (the visual and collision model).
Let f be the function used to map the positions xm of a master model to the position xs of a slave model
xs=fxm.E1
We map the velocities similarly to
ẋs=JxmẋmE2
where the Jacobian matrix Jxm encodes the linear relationship between the velocities of the master and slave systems. In linear assignments, the operators f and Jxm are the same, otherwise f is not linear regarding xm, and we cannot write it as a matrix.
Given forces λs applied to a slave model, the mapping computes the equivalent forces λm applied to its master. Since equivalent forces must have the same energy, [39], the following relation holds
Since Eq. (4) holds for all velocities ẋm, the principle of virtual work allows us to simplify it to get
λm=JTxmλs.E5
The kinematic mappings (1), (2), and (5) allow to compute displacements and to apply forces. They are also used to connect generalized coordinates, such as joint angles, to task space geometries.
2.2 Geometry of a constrained sub-manifold
From a robot control approach, we can consider a tool in contact with an object as a robot in constrained motion. The constraints of this system will be well defined if we associate them with physically realizable forces. This occurs, for example, with an industrial robot in contact with a proper surface (a real one) like a car bonnet in a painting or welding task. But with virtual environments, where surfaces do not exist, there are no physical constraint forces associated to them. Thus, the constraints are not well defined, and they are called virtual constraints, [40]. It mathematically addressed the nonpenetrable and penetrable virtual surfaces as virtual constraints. In this sense, it is important to introduce the geometric properties of such constraints in order to define them as either holonomic or non-holonomic.
Let Q be the n-dimensional smooth manifold configuration space of an unconstrained manipulator and q∈Rn its local generalized coordinates. The tangent space to Q at q, denoted τqQ comprises all generalized velocity vectors q̇∈Rn of the system.
Definition 2.1. A geometric constraint on Q is a relation of the form
hiq=0i=1,…,k<n,E6
where hi:Q→R limits the admissible motions of the system to a n−k-dimensional smooth sub-manifold of Q■.
Constraints that involve not only the generalized coordinates but also their first derivatives in the form
aiqq̇=0i=1,…,k<n,E7
with aiqq̇∈τqQ, are called kinematic constraints. These limit the allowable movements of the manipulator to a n−k-dimensional smooth sub-manifold of Q by restricting the set of generalized velocities that can be achieved in a configuration.
Definition 2.2. A Pfaffian constraint on Q is a set of k kinematic constraints, which are linear in velocity in the following form
aiTqq̇=0i=1,…,k<n,E8
where aiqq̇:Q→Rn is assumed to be smooth and linearly independent.■
A kinematic constraint can be integrable, there are k real-valued functions hiq such that
∂∂qhiq=aiTqi=1,…,k<n.E9
Here, the kinematic constraints are, in fact, geometric constraints. Pfaffian constraints set of aiq is known as holonomic if it is integrable, the system has a geometric limitation. For example, by considering a set of holonomic constraints characterized by
where Jφq∈Rk×n is the Jacobian of the holonomic constraint. Therefore, holonomic constraints are characterized by equivalent equations in terms of position variables, we can get the position equations by integrating them, if velocity equations initially described the constraints, [41].
Property 2.1. Given n generalized coordinates q in a sub-manifold Q and k holonomic constraints, the space tangent to Q in a configuration can be described by adequately defining n−k new generalized coordinates of the restricted sub-manifold that characterize the real degrees of freedom of the system [42].■
The set of Pfaffian constraints aiq is called non-holonomic if it is nonintegrable, the system has a kinematic limitation. Assuming again that the vectors ai:Q→Rn are smooth and linearly independent, the non-holonomic constraints can be expressed as
Aqq̇=0E12
where Aq∈Rk×n is the Pfaffian matrix of non-holonomic constraints and which image space produces forces to ensure that the system does not move in those directions. The presence of these constraints limits the system mobility completely differently if compared to holonomic ones, even if its generalized velocities at each point are constrained to a n−k dimensional sub-manifold space, it is still possible to reach any configuration in Q.
Property 2.2. Given n generalized coordinates q in a sub-manifold Q and k non-holonomic constraints, the space tangent to Q in a configuration has n−k degrees of freedom but the number of generalized coordinates cannot be reduced, [43].■
Remark 2.1. We assume that velocity-level gives non-holonomic constraints Eq. (12), and position-levelEq. (10) describes holonomic constraints. In practical problems, it may describe both types of constraints as velocity-level equations.■
2.2.1 Integrability of the constraints
A vector field g:Rn→τqRn is a smooth mapping assigning to each point q∈Rn a tangent vector gq∈τqRn. In local coordinates, we can represent q as a column vector whose elements depend on q as
gq=g1q⋮gnq,E13
where g is smooth if each giq is smooth.
Given g1 and g2, we define the Lie bracket of these vectors fields as
g1g2=∂∂qg2g1−∂∂qg1g2E14
where g1g2 is a new vector field.
A distribution assigns a subspace of the tangent space to each point in Rn smoothly. A special case is a distribution defined by a set of smooth vector fields, g1,…,gm. Here, we can define distribution as
Δ=spang1…gm,E15
where the span over the set of smooth real-valued functions on Rn is taken. Evaluated at any point q∈Rn, the distribution defines a linear subspace of the tangent space
Δq=spang1q…gmq⊂τqRn.E16
A distribution is involutive if it is closed under the Lie bracket, i.e.,
gigj∈Δ,∀gi,gj∈Δ.E17
We said distribution Δ of dimension k to be integrable if, for every point q∈Rn, there are a set of smooth functions hi:Rn→R for i=1,…,n−k such that the row vectors ∂∂qhi are linearly independent at q and for every g∈Δ.
∂∂qhigq=0i=1,…,n−k.E18
The hypersurfaces defined by the level sets h1q=c1…hn−kq=cn−k are called integral manifolds for the distribution Δ. Eq. (18) shows that Δ coincides with the tangent space to its integral manifold at q. We relate integral manifolds to involutive distributions by the following so-called Frobenious theorem, [43].
Theorem 2.1. A distribution is integrable if and only if it is involutive.■
This theorem gives a necessary and sufficient condition for the complete integrability of a distribution. Thus, if Δ is a k-dimensional involutive distribution, then locally there are n−k functions hi:Rn→R such the level surfaces h=h1…hn−k give that integral manifolds of Δ. The result mentioned above gives conditions for the integrability of a set of kinematic constraints in the following proposition.
Proposition 2.1. [44] The set of k Pfaffian constraints, described in (8), is holonomic if and only if Δ its an involutive distribution.■
So it is possible to establish when a Pfaffian constraint is non-holonomic by checking if its distribution is not involutive.
2.3 Haptic system overview
A common practice in the computer graphics community is to associate the position and orientation of virtual tools directly with that of the haptic interface. However, this assumption is because some real tools have negligible dynamics, such as a scalpel. From a teleoperation approach, we assumed that even the simplest tool has some dynamic properties to consider in the virtual environment. This section presents a description of this proposal, both mathematical and intuitive.
In order to describe the operation of the haptic system, two independent sets of task space coordinates are considered as shown in Figure 6.
Figure 6.
Haptic system.
The operator manipulates the haptic interface, i.e., the master robot in the real environment and we denote whose Cartesian coordinates as xm∈SE3, where pm∈R3 is the end-effector position and Rm∈SO3 its orientation. The virtual tool must respond to the movements of such interface in the virtual environment with Cartesian coordinates xv∈SE3, where pv∈R3 is the virtual tool position and Rv∈SO3 its orientation. In a teleoperation context, the position of the master robot acts as a reference for the virtual tool and it is visually projected on the screen through the virtual avatar of the system. The operator moves the virtual tool freely until the collision detection algorithm shows that contact with the virtual surface is taking place. Until now, the master robot exerts a force that is measured by a force sensor that serves as a reference for the virtual robot and must apply to that surface. By closing the feedback loop, the control algorithm produces a tactile sensation for the operator. Ideally, both visual and haptic feedback must coincide, allowing the operator to have a visual reference to the virtual tool and the feeling of the dynamic changes of its contact with the virtual surface.
In a similar approach, Faurlin et al. clarify in [44] that the virtual environment can be represented by a set of generalized coordinates qv∈R3, which are related to the task-space coordinates of the master robot by a nonlinear kinematic equation
xm=fqvE19
which is a mapping between the real and virtual environment, similar to that of Eq. (1) but where the former acts as a master model.
The set of coordinates qv allows the dynamic model of the virtual tool to be described in terms of Euler-Lagrange equations of motion. A set of holonomic or non-holonomic constraints that represent the virtual surface can be embedded into the kinematic mapping (19), relating independent master robot task-space coordinates and dependent virtual robot task-space coordinates. The virtual tool moves according to the physic simulation propagated in the virtual environment coordinates and always satisfies such constraints.
2.3.1 Dynamic model and properties
Consider a real master (m) and a virtual slave (v) robot system composed of two manipulators, each of them with n degrees of freedom but not necessarily with the same kinematic configuration. Each robot spans a k-dimensional task space and, based on master/virtual devices, can be scaled to meet the desired virtual application. The master dynamics is given by
Hmqmq¨m+Cmqmq̇mq̇m+Dmq̇m+gmqm=τm−τhE20
while the virtual slave dynamics is modeled by
Hvqvq¨v+Cvqvq̇vq̇v+Dvq̇v+gvqv=τv+τsE21
where the subscripts m and v denote the real master and the virtual slave manipulators, respectively. For i=m,v,qi∈Rn is the vector of generalized coordinates, Hiqi∈Rn×n is the inertia matrix, Ciqiq̇iq̇i∈Rn×n is the vector of Coriolis and centripetal forces, Diq̇i∈Rn×n is a diagonal matrix of viscous friction coefficients, giqi∈Rn is the vector of gravitational torques, τi∈Rn is the vector of generalized inputs, τh∈Rn is the real torque applied by the human operator on the master side and τs∈Rn is the virtual torque generated because of the contact with the virtual constraint [45].
Property 2.3. With a proper definition of the robot parameters, it is possible to express the robot dynamics as
Hiqiq¨i+Ciqiq̇iq̇i+Diq̇i+giqi=Yiqiq̇iq¨iθiE22
where Yiqiq̇iq¨i∈Rni×l is the regressor and θi∈Rl is a constant vector of parameters.■
Assumption 2.1. The master and the virtual slave robots share the same geometric structure, but they do not necessarily have the same parameters of the dynamic model, that is, the matrices and vectors of the models described in (20) and (21) do not have to be the same.■
External torques are acting in both robots, either the real torque τh applied by the human on the master side or the virtual torque τs generated because of the contact between the virtual robot and the virtual surface. We can define the torque applied by the human operator as
τh=JmTqmFhE23
where Fh∈R3 is the force applied by the operator in the task-space coordinates and JmTqm∈R3×n the geometric Jacobian of the master manipulator. In the same way, the torque applied on the virtual surface can be expressed as
τs=JvTqvFsE24
where Fv∈R3 is the force applied on such surface in task-space coordinates.
2.3.2 Virtual holonomic constraints
Whit of holonomic constraints we assume that, in virtual task space coordinates, the virtual robot is subject to k virtual holonomic constraints characterized by
φvxv=0E25
where a suitable normalization is done for the gradient of this constraint,
Jφxvxv=∇φvxv∈Rk×n,E26
to be unitary.
The representation of constraint (25) in generalized virtual coordinates is
φvqv=0E27
where qv∈Rn is the vector of the virtual robot end-effector joint coordinates. The gradient of the constraint (27) is
Jφvqv=∇φvqv∈Rk×n.E28
These two gradients are related by
Jφxvqv=JφxvxvJvqvE29
where Jvqv∈Rk is the geometric Jacobian of the virtual manipulator. Hence, the torque because of the contact with the virtual surface in (1) can be defined as
τs=JφvqvλvE30
where λv∈Rk is a vector of Lagrange multipliers that represents the virtual force applied over the surface. Then, it is possible to rewrite the whole Eq. (21) as
Hvqvq¨v+Cvqvq̇vq̇v+Dvq̇v+gvqv=τv+JφvTqvλv.E31
According to Property 2.1, the virtual holonomic constraints (2.26) reduce the number of degrees of freedom of the virtual robot and the dimension of its configuration space to a n−k–dimensional sub-manifold, [43].
2.3.3 Virtual non-holonomic constraints
With non-holonomic constraints, something well known is that we cannot express them as a function of only the generalized coordinates as in (25) or (27). Instead, they are commonly expressed as Pfaffian constraints. In the present case, these constraints are written more intuitively in terms of the virtual end-effector velocities vv=ṗvωvT as
Avxvvv=0,E32
where ṗv∈R3 and ωv∈R3 are the linear and angular velocities of the virtual end-effector, respectively, and Avxv∈Rk×n is the corresponding Pfaffian constraint matrix. If the dynamic equations are defined in the virtual joint-space coordinates qv, these constraints are projected via Faurling et al. [44].
Avqv=AvxvJvqvE33
Assuming that the virtual robot is subject to k velocity-level equations of non-holonomic constraints characterized by
Avqvq̇v=0E34
the torque because of the contact with the virtual environment in (21) can be expressed as
τs=AvTqvλvE35
where λv∈Rk is the vector of Lagrange multipliers which determines the magnitude of the constraint forces over the virtual surface. Then, it is possible to rewrite Eq. (21) as
Hvqvq¨v+Cvqvq̇vq̇v+Dvq̇v+gvqv=τv+AvTqvλv.E36
The non-holonomic constraints reduce the number of virtual robot available degrees of freedom to an n−k-dimensional sub-manifold, but they do not reduce the dimension of its configuration space [43, 46].
3. System implementation
In this section, the theoretical and practical aspects of implementing a virtual reality system with virtual restrictions are presented. The principal aspect concerned is the design of a controller capable to perform accurate haptic feedback that makes to feel the operator to be in contact with either a penetrable or nonpenetrable virtual surface. The method for visually reproducing the virtual tool in contact with the virtual objects is presented. It is important to note that this method avoids the complexity of the virtual environments currently implemented in the simulators used in medical training. However, the basic aspects addressed to show that the virtual constraints approach can be used practically, and eventually adapted to sophisticated graphic computing tools.
3.1 Virtual environment design
As mentioned in Section 2, the important aspect to get realistic haptic feedback from a surface embedded into a virtual environment comprises defining its geometry. In Figure 7, we show an idealized representation of a virtual point probe in contact with either an nonpenetrable or penetrable virtual surface.
Figure 7.
(⋯) Penetrable and (__) nonpenetrable surfaces.
In the first case, we assume that the contact arises at a single point over the surface from where the virtual probe cannot move forward, i.e., its velocity is equal to zero. Therefore, a normal force vector, which magnitude increases depending on the force applied by the operator, avoids motion. In robot control, if we are supposed to connect the probe to the end effector of a manipulator, according to Property 2.1, the number of degrees of freedom of the system in contact with the surface is reduced. Intuitively, that means that the virtual probe cannot move forward from where the contact arises, which can be at any point on the surface [47]. Actually, if the virtual object is built up by using a polygonal method, there will be a set of surfaces φ0φ1…φn joined by vertices as shown in Figure 7.
The best way to find the place of the contact point (which belongs to a set of points defining each surface) is by establishing an implicit equation φvxv containing such a point. The set of points defining the virtual surface are
φvxv=0,E37
which coincides with the holonomic constraint of Eq. (25) in Cartesian coordinates or Eq. (27) in generalized coordinates. From those expressions, it can establish a collision detection algorithm by defining the following conditions:
If φvxv>0, the virtual probe is in free motion, i.e., it is not in contact with the virtual surface.
If φvxv=0 the virtual probe is in contact with the virtual surface and it stays over the surface only, staying in constrained motion.
If φvxv<0 virtual probe is in restricted movement, but we violate restriction i.e., it is inside of the virtual surface.
For the virtual reality system, it is important to remember that the vector xv represents the virtual robot’s end-effector position. The virtual probe would share such a position. By extending the approach proposed, the virtual robot acts in fact as the virtual tool and it projected its position to the operator by the avatar of the system. In the second case, for an nonpenetrable constraint, even when the contact starts at a single point, the properties of the surface allow the virtual probe to stay in motion, as we can see in Figure 7. Intuitively, the process is more complex since, at a certain moment, the virtual probe must stop. In a medical context, that means the deformable tissue has a limited resistance that depends on its elastic properties. Since the aim is to get a reaction force that depends on the motion of the virtual probe once inside the deformable object, it is necessary to describe such motion properly. Unlike the non-deformable surfaces, the force does not arise normally to the surface at a single point, but lateral forces occur when the operator tries to move the virtual probe in such directions. Ideally, this would be true for any method to represent soft tissues, including finite element meshes and particle-based models. Figure 8 shows the virtual tool motion inside a virtual object.
Figure 8.
Motion in 2D of the virtual tool inside a virtual object.
For easy visualization, it showed the motion in 2D but during the simulation, we must reproduce it in 3D with the aim of increase the realism of the application by improving the operator’s dexterity. The contact begins in stage A where the virtual tool penetrates the object by following a straight trajectory, represented by a blue arrow, to reach the position in stage B. It can follow other trajectories, represented by dashed red lines, to reach the position of stage D or stage C. However, because of the surrounding tissue, the tool cannot move laterally because of the reaction forces (represented by the red arrows) preventing it along the trajectories. In contrast to what happens in the holonomic case, the virtual tool may stay in motion, i.e., its velocity differs from zero until the operator stops voluntarily. The process described above is like the motion of a wheeled car in 2D, which is perfectly described by non-holonomic constraints. In fact, if we add a third dimension, Property 2.2 remains forever and the virtual tool can reach any point on the virtual object.
The trajectories of the virtual tool shown in Figure 8 are common in noninvasive surgical procedures. For example, in the simulator of Transurethral Resection of the Prostate (TURP Mentor) of Figure 2, the medical trainee performs a straight trajectory that, in the first place, simulates the insertion of the resectoscope into the patient’s penis. Once within the virtual prostate, the resectoscope needs to be moved to remove, through an incandescent resection loop, the benign tissue that obstructs the flow of urine to the urethra. These movements follow a similar route to the one represented with red dotted lines in Figure 8. These movements use a pivot where the tool changes its direction.
The contribution of this approach is, in contrast to common single point haptic feedback methods, that we produce forces that prevent lateral movement of the virtual tool. However, the major disadvantage is that the environment’s elastic properties are not considered. As a result, the reaction of the force that limits the movement of the operator, depending on such properties, is not reproduced and can move the virtual tool interchangeably within the virtual object, which does not happen in real life. For example, in human organs, elastic properties and parameters such as Young’s modulus or Poisson’s ratio establish limits of movement for the tool that, when exceeded, the tissue is damaged.
3.1.1 Virtual environment design
In Figure 9, we show a scheme in 2D of the contact between a virtual tool and a virtual surface to illustrate the use of the model given by Eq. (21).
Figure 9.
Virtual robot in interaction with a penetrable surface.
We attach the tool to the virtual robot’s last DOF, acting as its end-effector. It is important to note that the manipulator dynamic model is used to reproduce a classic bilateral teleoperation system and assuming that, since it is simulated digitally, it can be exchanged by a simpler or more complex model, including those of medical instruments such as forceps endoscopes, gripers, and retractors. This assumption leads to the proposition that, if we use the model of a surgical tool during the simulation, the realism of the contact with the surface would increase. The principal difference between defining a holonomic and a non-holonomic constraint is a need for an expression of φvxv. Based on Section 2.1.1, from an implicit representation approach, we build rigid virtual objects from 3D basic geometric primitives as cones, pyramids, planes, cubes, and spheres, [22]. Ultimately, the base of a highly complex virtual environment composed of rigid objects is a set of basic geometric shapes that we can represent through mathematical expressions. Therefore, it is enough to define a zero set of functions as in (25) that are individually expressed as φvxv and a collision detection algorithm based on the inequalities stated above. For non-holonomic constraints and considering again the virtual robot of Figure 9, let 0pv∈R3 be the Cartesian position of the virtual robot end–effector and 0Rv∈SO3 a rotation matrix that describes its orientation. Dividing this rotation matrix into three column vectors as
0Rv=0xnv0ynv0znv,E38
for which each column represents a vector of the end-effector coordinate frame, described in the base frame. This allows defining Pfaffian constraints like (29) in an intuitive form, i.e.,
Av0xnv,0ynv,0znvvv=0.E39
We claim that a set of non-holonomic constraints can be defined if the manipulator degrees of freedom are greater than those necessary to control the end-effector position, i.e., n>2 for planar robots and n>3 for robots in a three-dimensional workspace. The end-effector velocities of the virtual robot can be described by
vv=0ṗv0ωnE40
where ωn is the angular velocity over an axis normal to the robot plane, and 0ṗv is the linear velocity defined as
ṗv=0ṗvx0pvyE41
If the robot may not move in the 0ynv direction, the corresponding Pfaffian constraint is given by
as a basis for the null-space of the Pfaffian matrix, the equivalent control system
q̇v=g1u1+g2u2E46
can be constructed, representing the directions of allowed motion, [42].
It is easy to verify that the Lie bracket is
g1g2=−sinqv1+qv2+qv3cosqv1+qv2+qv30,E47
which shows the non-involutivity of the distribution and thus establishes the non-holonomic nature of the constraints according to Proposition 2.1.
Notice also that if the degrees of freedom were 2, the null-space would be of dimension 1, which is necessarily involutive, and the constraints would be holonomic.
3.2 Position-force controllers design
A correct haptic rendering largely depends on the force control algorithm. In classic haptic systems, the common solution is to define indirect impedance or compliance control schemes. In contrast, in this section, we present two hybrid control algorithms for haptic interaction with virtual constrained systems. As mentioned in Section 2, the usual practice is to associate the position of the haptic interface directly with that of the virtual avatar. Therefore, a position control scheme is unnecessary, as the operator’s movements are reflected in the graphical application accurately. However, in the proposed approach, the task space coordinates of the virtual environment depend on the correct tracking between the position of the haptic robot and that of the virtual one, i.e., the control algorithm generates the virtual environment itself. This is due to including the virtual robot dynamics and the fact that the operator should feel the virtual tool because of the masking effect. In order to address this, we explored a control scheme used in teleoperation to achieve both position and force tracking. Next, we show a block diagram of this scheme in Figure 10.
Figure 10.
Block diagram of the proposed scheme.
Considering once again i,j=m,v where i≠j. We define
qdit≜qjtE48
as the desired position trajectories, and
q̇dit≜q̇jtE49
as the desired velocity trajectories, i.e., if i=m, then j=v and vice versa.
where Kβi∈Rn×n is a positive definite diagonal matrix and
signsi=signsi1⋮signsinE53
with sij element of si for j=1,…,n.
Now, by considering the velocity reference as
q̇ri=q̇ri+ΛxiΔqi−Kγiσi,E54
where Kγiσi∈Rn×n is a positive definite diagonal matrix.
We define also the auxiliary variable
sai=q̇i−q̇ri.E55
By supposing that both robots are in free movement, for that case, the control laws for the master and the virtual robots are proposed as
τm=−Kamq̇m−KpmsamE56
τv=Kavq̇v+Kpvsav,E57
respectively, where Kam,Kpm,Kav and Kpv are positive definite diagonal matrices.
3.2.1 Virtual holonomic constraints
Making an approximation of what happens during the tactile interaction of a point probe with a rigid surface, we considered the one-dimensional case (φv:Rn→R). As mentioned in Section 3.1, that is ideally the normal force generated at a single point of contact where other reactions, as friction or tangential forces, we can omit them, [32]. In order to reproduce this effect, we use the implicit surface method, which λv=λv represents the normal force of the virtual manipulator over the virtual surface. To reflect such contact force, the Generic Penalty Method computed a Lagrange multiplier as used by [49], i.e.,
λv=αvφ¨vqv+2ξωnφ̇vqv+ωn2φvqvE58
where ξ,ωn>0. Considering that force measurements are available at the master side in Cartesian coordinates and mapping the virtual force to this space as
Fv=JφxvTxvλv,E59
we use a PID-like controller for the virtual reality system. Consider that Fh∈R3 is the normal force component measured with a force sensor mounted at the master robot end-effector. After (23), (24), and (58), we can use a PI controller for the virtual reality system.
By defining
Fdit≜FitE60
as the desired force trajectory where if i=h then j=v and vice versa, as stated before.
The force tracking errors are
ΔFi=Fi−FdiE61
and the corresponding integral, the momenta tracking error, is
Δρi=∫0tΔFidt.E62
Note that we use the standard notation for momenta ρ, although also the same notation is for the position. We claim that there is no confusion because it always appears Δρ in that case. Instead of using Eqs. (56) and (57) to describe the master and the virtual robot, we gave the corresponding control laws by
τm=Ymqmq̇mq¨mθm−Kamq̇m−Kpmsam+JmTqmFv−KfmΔρhE63
τv=Kavq̇v+Kpvsav−JvTqvFh−KfvΔρv,E64
respectively, where Kfi∈Rn×n are diagonal matrices. In order for the operator to feel the virtual tool in contact with the virtual environment, we can carry out a dynamic cancelation of the master manipulator dynamics, as shown in (63).
3.2.2 Virtual non-holonomic constraints
In contrast with the holonomic case, when the constraints are non-holonomic, we cannot define them as a function of a set of generalized coordinates, as stated by the Frobenius theorem. As a result, we cannot compute the Lagrange multipliers as in (58). We define these constraints in the form (31) or equivalently (34). One problem arising from these constraints is how to compute the Lagrangian multipliers to satisfy (36). These multipliers represent the forces required to maintain such constraints. Unfortunately, most of the methods used to calculate the lagrange multipliers are designed for systems with holonomic constraints [30, 49, 50] and, therefore, these methods require a position-level definition of the Pfaffian constraints as in (25) or (27). As stated in (45), the calculation presented in [42] can be used for this case. However, it is well known that this solution is unstable since its underlying mechanism is a second-order integrator with zero input. In this work, a modification of the approach used in [50] is proposed as follows. For simplicity, we define
with αv,βv>0 chosen to ensure rapid convergence to the origin.
Note that the constraint function ψ can be defined in terms of the velocities of the end-effector,
ψ=ψxvvv=Avxvvv.E72
Therefore, the initial condition of the integral term on the left-hand side of (72) can be set to zero. Each element λv is a function of qv,q̇v and τv since the constraints change with the configuration, velocity and virtual applied force.
By substituting (71) in the motion Eq. (72), a complete description of the dynamics of the system is gotten. Regarding force, sensor measurements Fv on the master side can calculate the real Lagrange multiplier as
λm=AvAvT−1AvFh.E73
By defining
λdit≜λjtE74
as the desired force trajectory in joint space. The corresponding integral is
Δλi=∫0tλi−λdjdtE75
Finally, instead of (56) and (57), for the master and virtual robot the proposed position-force control for a virtual dynamic system subject to non-holonomic constraints is
τm=Ymqmq̇mq¨mθm−Kamq̇m−Kpmsam+AvTqvλv−KfmΔλmE76
τvm=Kavq̇v+Kpvsav−AvTqvλm−KfvΔλvE77
Note that the novelty of the approach is not the control scheme because very well-known techniques are employed, but the novelty lies in the effective use of non-holonomic constraints to describe penetrable virtual surfaces. Therefore, a technical stability proof is not provided, but it shows a set of reliable experiments in the next section with the aim of validating the proposed approach.
3.3 Visual components of the virtual environment
A fundamental part of the developed virtual reality system is visual feedback. In dynamic systems and control research, there is no interest in including such elements but in real-world applications, as surgery simulators, it is essential. Nowadays, in those developments, we compose the virtual environments by merging several numeric techniques that, combined with the fast velocity of today’s processors, give the virtual objects and surfaces a realism that before would seem impossible to reach., since the goal of this dissertation is to show how a teleoperation control scheme can be used in a virtual reality system, we design the environment by using the fundamentals of graphic computing. The tool used to design the virtual environment was the graphic standard OpenGL 2.0 which is an API, which is a software library for accessing features in graphics hardware. It contains different commands that are used to specify objects, images, and operations needed to produce interactive three-dimensional graphic applications, [51]. Among those operations, the possibility to give texture1 and lighting to the virtual objects is possible, besides proportioning position and orientation changes to the scene’s camera, i.e., the way the operator sees the images on the computer screen regarding height, deep, viewing angles as pitch, roll, and yaw, etc. As we can see in Figure 11, the environment of the developed application comprises a motionless floating sphere and the virtual avatar of the system.
Figure 11.
Virtual environment developed in OpenGL 2.0.
For simplicity’s sake, there are no changes in the camera’s position and orientation, but we gave lighting and texture to the scene. We appreciate a notable difference in Figure 12, where the avatar has no lighting, the quality of its texture is less and the background color changes.
Figure 12.
Virtual avatar of the system.
Here, a set of aligned cylinders becomes the avatar, which directly related position and orientation to those of the end-effector of the haptic interface. Since OpenGL has the instructions to create elements from primitives, the generation of such cylinders and the floating sphere was straightforward.
3.3.1 Rigid sphere
It is important to remember that, from a haptic rendering approach, we established the classification of nonpenetrable and penetrable objects for rigid and deformable objects, respectively. With the rigid object, the Open GL instruction glutSolidSphere() build automatically a solid sphere with a specific radius by defining the number of subdivisions around (sectors) and along (stacks) the z axis, as we can see in Figure 13.
Figure 13.
Sectors and stacks of a solid sphere.
We give the effect of rigidity because that vertex’s position is not changed when contact with the virtual avatar occurs. However, giving the haptic effect of highly rigid objects to the operator was difficult since an impedance device was used. For such reason, it is important to establish the control scheme (63) and (64) that compensates, as possible, the limitations of hardware and make feel it produced contact with a rigid object.
3.3.2 Deformable sphere
The real challenge comes when the virtual object is deformable. Saying that an object is deformable has many implications, mainly related to mechanics. Therefore, the visual effect of deformation is more complex than that produced by stiffness, because a real deformable object has an infinite number of degrees of freedom. For this reason, virtual objects need a high resolution, which gives a better rendering quality to visual and haptic feedback [52] and more realism to the application. However, this is always limited to the computational resources available. We must run both the graphics and the control algorithm in a single program, with the smallest sample time that the system allows. If the graphics part occupies more processing resources, this sampling time will increase and there will be unwanted effects, delays, and, finally, an application crash. We drew the sphere by defining four vertices a,b,c and d, which form a plane that is replicated iteratively according to several parallels p and meridians m defined by the operator. We intrinsically linked the value of the iteration to resolving the sphere. Figure 14, it showed the deformable sphere with different resolutions. In the sphere on the left, the values used were p=m=50 while in the central sphere were p=m=100. For the sphere on the right, the values were p=m=150.
Figure 14.
Surface mesh generated using different values for p and m. (a) p = m = 50. (b) p = m = 100. (c) p = m = 150.
As mentioned before, the more the resolution of the sphere, the more the realism of the application. However, the computational processing when using the resolution of the last case did not allow a correct performance of the graphic or haptic part. For this reason, a resolution p=m=100 was chosen. For simplicity’s sake, the sphere was built by placing two hemispheres, one above the other, regarding a common axis. The contact with the virtual avatar will arise in a single point xvyvzv computed parametrically as
xv=rcosαcosβE78
yv=rcosαsinβE79
zv=rsinαE80
where r is the radius of the sphere, and α and β are the angles from whose ranges parallel and meridians are drawn. For code optimization, meridians have the range of 0,360 and parallels of 0,180. Such ranges correspond to the upper hemisphere while the lower is drawn by considering the zv axis negative part.
Every vertex a,b,c and d must take the value of Eqs. (78)–(80) in order to visualize its initial position in the virtual environment. To improve the interaction with the virtual avatar, we include an offset roff in the equations that define the vertices as
vnx=r−roffcosαcosβE81
vny=r−roffcosαsinβE82
vnz=r−roffsinαE83
where n=a,b,c,d and roff take an arbitrary value defined experimentally. The contact with the virtual avatar occurs in some plane defined iteratively by (81)–(83) using a collision detection algorithm consisting on validating the value of each vertex of every plane and comparing the value of each component xvyvzv with the position of the master robot pm. If such values belong to the range of the plane, then the avatar is in contact with the sphere. The next step is to produce the effect of motion of the contact plane. Algorithm 1 shows the pseudocode of such a process, which uses an auxiliary normal force in which direction the plane will move. This force does not belong to that calculated using the non-holonomic constraint but the gradient of Eq. (29) and we use it only for visual effect. The process described above makes only one plane to move and, if that happens, the deformation effect is not realistic. For this reason, moving the adjacent planes is necessary. It moved the more planes, the more realistic the effect of the object deformation. However, in the application developed, we changed only the position of the surrounding planes to the contact plane, since the method is purely geometric and not based on continuum mechanics. Using such an approach implies a lot of considerations that are beyond this research.
Algorithm 1 shows the part of the pseudocode where the modification of the adjacent planes takes place. This does not occur at the same time as the modification of the contact plane, since the code has not yet created these. Figure 15 shows the visual effect that the motion, both of the contact plane and adjacent planes produce. It is important to note that the code implemented needs to be optimized and, above all, to be adapted to the force rendering algorithm through non-holonomic constraints.
Figure 15.
Deformation effect of the sphere. (a) Contact. (b) Deformation effect.
4. Experimental platform
The experimental platform comprises a Geomagic Touch haptic robot with six revolute joints, having only the first three of them actuated. An ATI Nano–17 six-axis force sensor is adapted at the last link, as shown in Figure 16. A PC executes the control loop with a sample time of T=2 milliseconds.
Figure 16.
Experimental platform.
As mentioned in Section 3, the virtual environment comprises a sphere developed using the graphic standard OpenGL 2.0. We should note that both the control algorithm and the graphic simulation run in the same application developed in Visual Studio/C++.
A practical limitation of the Geomagic Touch robot is that it actuated only the first three joints. Therefore, a projection of both the force reflection and the controller torques is necessary, i.e., the contribution of the last two joint torques is neglected. The virtual robot does not have this limitation, and therefore is considered to be fully actuated. The master robot limitation is not so restrictive, since the virtual environment considers only force but not end-effector torque feedback, avoiding the problem of sensor/actuators asymmetry haptic interfaces [53]. The contribution of the last two joints to the force reflection is much less in magnitude when compared with the contribution of the first three joints.
4.1 Task description
A detailed description of the interaction process between the virtual tool and the virtual environment is presented, simulating separately a rigid and a penetrable sphere. Since the goal of this research was to extend the use of the control scheme to medical training applications, we adopted the shape of the avatar as a needle, as we can see in Figure 11. In medicine, procedures that use this tool are very common, with needle insertion being the most studied and simulated procedure [54]. In this procedure, the operator takes a sterile needle and slowly brings it closer to the patient, once in contact, the operator must be very careful and, through a tactile sensation, know if the soft tissue (muscle, organ) or rigid (bone) has been affected. In both cases, the contact surface produces a reaction force in opposition to the operator’s movements.
While on a rigid surface, the force does not let the needle penetrate the tissue, in a penetrable surface this is possible. The force behaviors are different, as in the first case, there is a major contribution in the normal direction, which would allow the operator to move the needle laterally over the surface. In the second case, the normal force contribution is smaller and the surrounding tissue would not allow moving the needle in the lateral directions.
In the approach presented, we assume we attach the virtual tool to the end-effector of a five degrees-of-freedom manipulator, which is not visible in the graphic simulation. It may seem counterintuitive because, evidently in real life, a needle does not have such dynamics. We use the robot model as a demonstrative example of other medical tools such as an endoscope, resectoscope, forceps. Attached to teleoperated surgical robot arm have such complex dynamics that must be modeled. The graphic simulations in those cases include pulling, gripping, clamping, and cutting, and therefore it is convenient to have a complete description of both the kinematics and the dynamics of the tool-tissue interaction, [3]. The task starts with the Geomagic Touch robot in its home position. The operator grasps the master robot stylus using the force sensor adapter tip to later gently bring it closer to the virtual surface. We imposed the desired trajectory in free motion in this way. The virtual robot moves following such a trajectory in the virtual environment, with no scaling between the virtual and the real workspaces. It perceived visually both the avatar movement and the virtual surface through a computer screen. When the collision-detection algorithm detects contact with the surface, the force-response algorithm generates a virtual force trajectory by computing the corresponding Lagrangian multipliers, either by employing (58) or (70). The operator perceives an interaction force exerted by the master robot and registered by the Nano-17 force sensor until the contact is over. Finally, the operator returns the sensor adapter to its initial position, thus completing the task.
4.2 Holonomic constraint experiment
For simplicity’s sake, the surface used to test the validity of the proposed approach is a sphere described by
φvxv=xv−h2+yv−k2+zv−l2−r2=0,E84
where xv=xvyvzvT is the vector that stands for the virtual environment task-space coordinates, r=0.1 [m] is the radius, and hkl=0.4,0,0 [m] are the sphere center coordinates. It is important to note that, in contrast with other works, we added a third dimension zv in order to heighten the realism of the virtual reality application. For example, in [44, 49], the authors consider only two dimensions to test different control schemes for a haptic and a teleoperation system, respectively. The gains of the master manipulator, described in (63), and the virtual manipulator, are shown in Table 1.
Variable (control law)
Value
Variable (virtual manipulator)
Value
Kam
0.0550 I
Kav
0.20 I
Kpm
0.0055 I
Kpv
diag0.2,0.2,0.2,0.1,0.1
Kfm
10.050 I
Kfv
0.20 I
Λxm
0.2500 I
Λxv
20.0 I
Kβm
0.0100 I
Kβv
1.00 I
Kγm
0.0150 I
Kγv
0.20 I
Table 1.
Gains from the control law and the virtual manipulator (Holonomic constraint experiment).
I is the identity matrix, which has the appropriate dimensions.
Finally, by using the Generic Penalty Method, the surface parameters are αv=0.002,ξ=100 and ωn=200.
4.3 Non-holonomic constraint experiment
As mentioned before, we cannot express a deformable surface implicitly, even when the operator perceives it as a sphere both visually and haptically. We use a discrete representation similar to that presented in [52], where we assume the surface to comprise many neighboring planes defined by shared nodes. We propose a technique that comprises iteratively choosing a small neighborhood of planes where the contact will occur, depending on the position of the virtual tool. Subsequently, we associate the Lagrange multipliers in Eq. (70) with a pair of planes using the impulse-based technique for multiple rigid body simulations, [55]. The micro-collisions with this technique occur only in the chosen vicinity of the sphere and Lagrange multipliers replace the impulses preventing body interpenetration. In the collision’s case detection algorithm, the implicit surface representation replaces the convex polyhedra decomposition, [56], using the Eq. (84). We did this for ease and to reduce the computational cost of the application, otherwise, the control algorithm sample time would increase. Considering the case where the needle is inside the sphere, but it may not move laterally. However, it may pivot to change orientation.
We adequately describe this kind of scenario by employing non-holonomic constraints. As mentioned in Section 1, non-holonomic constraints have been little exploited to represent the interaction with penetrable surfaces. For example, in [57] it is claimed that to model a surgeon’s scalpel both holonomic and non-holonomic constraints could be employed by limiting the depth of its incision and the direction of its motion, respectively. However, there is not any analysis or modeling of this process in such work.
The most representative proposal is the derivation of the non-holonomic generalized unicycle model presented in [58], where a coordinate-free representation is used to model the insertion of a flexible needle into soft tissue. We employed a similar approach by using the homogeneous matrix representation, but taking into consideration both the kinematic and the dynamic model of the virtual robot and the fact that non-holonomic constraints are more intuitively got if we define them in task space coordinates. The computation of the Lagrangian multipliers for non-holonomic constraints, which is proposed in (71), is an important improvement regarding the cited works. The experiment comprised five degrees of freedom virtual manipulator interacting with a deformable sphere. Once in contact, the end-effector may not move laterally, i.e., along the 0y5v and 0z5v axes, after a conventional Denavit-Hartenberg allocation, but it may move along the 0x5v axis, i.e., along the pointing direction of the end-effector. The end-effector may rotate (pivoting) to change direction (as a three-dimensional version of the non-holonomic unicycle) and the Pfaffian matrix is computed as
Avxvvv=0y5v01×30z5v01×3ρ̇vωv=0E85
The experiment has four steps, as shown in Figure 17. First, the virtual robot is in free motion and only the teleoperation part of the controller (77) is active. In the second part, we insert the needle into the sphere. Next, in the third part, approximately 45 degrees rotate the needle without changing its position. Finally, we insert the needle deeper into the sphere with a new orientation.
Figure 17.
Interaction sequence between the avatar and the non-holonomic virtual surface. (a) Free motion. (b) Insertion. (c) Pivoting. (d) Insertion.
The force of the human operator in the lateral directions of the needle is difficult to measure directly with the force sensor. Instead, we take advantage of the projection of such forces on the torque of the master manipulator joint, we calculate λm from (20), (23), and (73).
The gains of the master manipulator, described in (76), and the virtual manipulator, are shown in Table 2.
Variable (control law)
Value
Variable (virtual manipulator)
Value
Kam
0.0550 I
Kav
0.20 I
Kpm
0.0550 I
Kpv
diag0.2,0.2,0.2,0.1,0.1
Kfm
0.010 I
Kfv
2.00 I
Λxm
0.2500 I
Λxv
20.0 I
Kβm
0.0150 I
Kβv
1.00 I
Kγm
0.0150 I
Kγv
0.20 I
Table 2.
Gains from the control law and the virtual manipulator (Non-holonomic constraint experiment).
I is the identity matrix, which has the appropriate dimensions.
5. Conclusions
We present a proposal on chaptic interaction with holonomic and non-holonomic virtual constraints. Since extensive research on haptic interaction with rigid surfaces has been presented in the literature, the principal aim was to reproduce the forces generated by the interaction with soft surfaces from a force feedback approach.
Throughout the document, we introduced the theory to establish an optimal relationship between the visual and haptic interaction for the virtual reality system developed. The key lies in adapting the mathematical properties of the holonomic and non-holonomic constraints to the tool’s kinematics in contact with a nonpenetrable and penetrable virtual surface, respectively. However, it is important to note that we made this adaptation to achieve haptic feedback purposes only and consider the basic contact properties of simulated rigid and soft tissues.
Adapting a teleoperation control scheme to a virtual reality system was the strategy to follow since it allowed embedding a robot’s dynamic model into the virtual environment. By doing this, we addressed the teleoperated slave system as a problem of a virtual robot in constrained motion and either holonomic or non-holonomic constraints gave whose contact force.
We studied the differences between one or another representation, both mathematically and intuitively, and the particularities of each one. Among them, there is the fact that they could render forces using the Generic Penalty Method or the Pfaffian constraints matrix, respectively. We centered the interest on reproducing the contact with a soft surface by employing non-holonomic constraints.
The principal use detected is that such a method can render similar forces to those arising from contact between a tool and a penetrable surface. We can see, non-holonomic constraints have been used to reproduce the operator’s tactile sensations with practical meaning. We can eventually use this approach in virtual reality medical simulators, and it presented the fundamentals to do that throughout this document. However, adapting the developed method to complex virtual environments, such as those found in the medical field, requires more research both in control and computer graphics. In the first case, adapting more accurately the teleoperation controller presented is necessary and makes it fit with the current methods of graphic computing. Finding more optimal ways to model force using non-holonomic constraints is essential to heighten the realism of the applications. Regarding graphic computing, it is necessary to design numerical methods that adapt more efficiently to the control algorithms designed and that are capable of running with continuum mechanics models.
Naturally, this will increase computational processing and require more analysis to establish the compensation between real-time processing and control performance, without sacrificing application realism. All this requires a wide range of knowledge that does not belong to control or computer graphics.
Acknowledgments
The authors are grateful for the support provided by PRODEP-BUAP ID90934 and the DGAPA-UNAM under grant IN117820.
Algorithm 1: Deformable sphere
Require: Number of Parallels p.
Require: Number of Meridians m
Require: Radius r
Require: Offset roff
Define: Vertex vax,vay,vaz
Define: Vertex vbx,vby,vbz
Define: Vertex vcx,vcy,vcz
Evaluate:Δ1=180∘/p and Δ2=360∘/m
1: for alli=0 to p/2do
2: for allj=0 to mdo
3: α=i×Δ1
4: β=j×Δ2
5: Calculate the vertices of the upper hemisphere using (81)-(83).
6: if avatar touches a superior plane then
7: Move the contact plane through the auxiliary normal force
8: Store data of the contact plane (based on p and m)
9: end if
10: Compute vertices of the lower hemisphere
11: if avatar touches an inferior plane then
12: Move the contact plane using (81)-(83) and the negative numbers on the zv axis.
13: Store data of the contact plane (based on p and m)
14: end if
15: end for
16: end for
17: if avatar touches a plane then
18: Reordering adjacent planes
19: end if
20: for alli=0 to p/2do
21: for allj=0 to mdo
22: Draw plane
23: end for
24: end for
\n',keywords:"Haptics, virtual reality system, bilateral teleoperation, holonomic constraint, non-holonomic constraint, position-force control",chapterPDFUrl:"https://cdn.intechopen.com/pdfs/80757.pdf",chapterXML:"https://mts.intechopen.com/source/xml/80757.xml",downloadPdfUrl:"/chapter/pdf-download/80757",previewPdfUrl:"/chapter/pdf-preview/80757",totalDownloads:48,totalViews:0,totalCrossrefCites:0,dateSubmitted:null,dateReviewed:"January 6th 2022",datePrePublished:"March 6th 2022",datePublished:null,dateFinished:"March 6th 2022",readingETA:"0",abstract:"For medical training aims, tele-operation systems have inspired virtual reality systems. Since force sensors placed on the robotic arms provide interaction force information that is transmitted to the human operator, such force produces a tactile sensation that allows feeling some remote or virtual environment properties. However, in the last two decades, researchers have focused on visually simulating the virtual environments present in a surgical environment. This implies that methods that cannot reproduce some characteristics of virtual surfaces, such as the case of penetrable objects, generate the force response. To solve this problem, we study a virtual reality system with haptic feedback using a tele-operation approach. By defining the operator-manipulated interface as the master robot and the virtual environment as the slave robot, we have, by addressing the virtual environment as a restricted motion problem, the force response. Therefore, we implement a control algorithm, based on a tele-operation system, to feedback the corresponding force to the operator. We achieve this through the design of a virtual environment using the dynamic model of the robot in contact with holonomic and non-holonomic constraints. In addition, according to the medical training simulator, before contact, there is always a free movement stage.",reviewType:"peer-reviewed",bibtexUrl:"/chapter/bibtex/80757",risUrl:"/chapter/ris/80757",signatures:"Pablo Sánchez-Sánchez, José Daniel Castro-Díaz, Alejandro Gutiérrez-Giles and Javier Pliego-Jiménez",book:{id:"10663",type:"book",title:"Haptic Technology - Intelligent Approach to Future Man-Machine Interaction",subtitle:null,fullTitle:"Haptic Technology - Intelligent Approach to Future Man-Machine Interaction",slug:null,publishedDate:null,bookSignature:"Prof. Ahmad Hoirul Basori, Dr. Sharaf J. Malebary and Dr. Omar M. Barukab",coverURL:"https://cdn.intechopen.com/books/images_new/10663.jpg",licenceType:"CC BY 3.0",editedByType:null,isbn:"978-1-80355-067-1",printIsbn:"978-1-80355-066-4",pdfIsbn:"978-1-80355-068-8",isAvailableForWebshopOrdering:!0,editors:[{id:"13394",title:"Prof.",name:"Ahmad Hoirul",middleName:null,surname:"Basori",slug:"ahmad-hoirul-basori",fullName:"Ahmad Hoirul Basori"}],productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"}},authors:null,sections:[{id:"sec_1",title:"1. Introduction",level:"1"},{id:"sec_1_2",title:"1.1 State-of-the-art",level:"2"},{id:"sec_3",title:"2. Preliminaries",level:"1"},{id:"sec_3_2",title:"2.1 Virtual surfaces representation",level:"2"},{id:"sec_3_3",title:"2.1.1 Nonpenetrable virtual surfaces",level:"3"},{id:"sec_4_3",title:"2.1.2 Penetrable virtual surfaces",level:"3"},{id:"sec_6_2",title:"2.2 Geometry of a constrained sub-manifold",level:"2"},{id:"sec_6_3",title:"2.2.1 Integrability of the constraints",level:"3"},{id:"sec_8_2",title:"2.3 Haptic system overview",level:"2"},{id:"sec_8_3",title:"2.3.1 Dynamic model and properties",level:"3"},{id:"sec_9_3",title:"2.3.2 Virtual holonomic constraints",level:"3"},{id:"sec_10_3",title:"2.3.3 Virtual non-holonomic constraints",level:"3"},{id:"sec_13",title:"3. System implementation",level:"1"},{id:"sec_13_2",title:"3.1 Virtual environment design",level:"2"},{id:"sec_13_3",title:"3.1.1 Virtual environment design",level:"3"},{id:"sec_15_2",title:"3.2 Position-force controllers design",level:"2"},{id:"sec_15_3",title:"3.2.1 Virtual holonomic constraints",level:"3"},{id:"sec_16_3",title:"3.2.2 Virtual non-holonomic constraints",level:"3"},{id:"sec_18_2",title:"3.3 Visual components of the virtual environment",level:"2"},{id:"sec_18_3",title:"3.3.1 Rigid sphere",level:"3"},{id:"sec_19_3",title:"3.3.2 Deformable sphere",level:"3"},{id:"sec_22",title:"4. Experimental platform",level:"1"},{id:"sec_22_2",title:"4.1 Task description",level:"2"},{id:"sec_23_2",title:"4.2 Holonomic constraint experiment",level:"2"},{id:"sec_24_2",title:"4.3 Non-holonomic constraint experiment",level:"2"},{id:"sec_26",title:"5. Conclusions",level:"1"},{id:"sec_27",title:"Acknowledgments",level:"1"},{id:"sec_28",title:"",level:"1"}],chapterReferences:[{id:"B1",body:'Avgousti S, Christofouru EG, Panaydes AS, Voskarides S, Novales C, Nouaille L, et al. Medical telerobotic systems: Current status and future trends. Biomedical Engineering Online. 2016;15(96):1-44. DOI: 10.1186/s12938-016-0217-7'},{id:"B2",body:'Ballantyne GH, Moll F. The da vinci telerobotic surgical system: The virtual operative field and telepresence surgery. The Surgical Clinics of North America. Dec 2003;6(83):1293-1304. DOI: 10.1016/S0039-6109(03)00164-6. PMID: 14712866'},{id:"B3",body:'Basdogan C, De S, Kim J, Muniyandi M, Kim H, Srinivasan MA. Haptics in minimally invasive surgical simulation and training. IEEE Computer Graphics and Applications. 2004;24(2):56-64'},{id:"B4",body:'Hannaford B, Rosen J, Friedman DW, King H, Roan P, Cheng L, et al. Raven-ii: An open platformfor surgical robotics research. IEEE Transactions on Biomedical Engineering. 2013;60(4):954-959'},{id:"B5",body:'Dy M-C, Tagawa K, Hiromi TT, Masaru K. Collision detection and modeling of rigid and deformable objects in laparoscopic simulator. In: Proc. SPIE 9415, Medical Imaging 2015: Image-Guided Procedures, Robotic Interventions, and Modeling, 941525 1-6 (18 March 2015). Orlando, Florida, United States; 2015. DOI: 10.1117/12.2081344'},{id:"B6",body:'Goertz, RC, Thompson WM. Electronically Controlled Manipulator. Nucleonics (US) Ceased Publication. 1954;12(11). DOI: 10.1146/annurev.ns.04.120154.002153'},{id:"B7",body:'Hollis RL, Salcudean S, Abraham DW. Toward a tele-nanorobotic manipulation system with atomic scale force feedback and motion resolution. In: IEEE Proceedings on Micro Electro Mechanical Systems, An Investigation of Micro Structures, Sensors, Actuators, Machines and Robots. Napa Valley, CA, USA; 1990. pp. 115-119. DOI: 10.1109/MEMSYS.1990.110261'},{id:"B8",body:'Khatib O, Yeh X, Brantner G, Soe B, Kim B, Ganguly S, et al. Ocean one: A robotic avatar for oceanic discovery. IEEE Robotics Automation Magazine. 2016;23(4):20-29'},{id:"B9",body:'Kim K, Song H, Suh J, Lee J. A novel surgical manipulator with workspace conversion ability for telesurgery. IEEE/ASME Transactions on Mechatronics. 2013;18(1):200-211'},{id:"B10",body:'Hansen T et al. Implementing force-feedback in a telesurgery environment, using parameter estimation. In: 2012 IEEE International Conference on Control Applications. Dubrovnik, Croatia; 2012. pp. 859-864. DOI: 10.1109/CCA.2012.6402708'},{id:"B11",body:'Sutherland IE. The ultimate display. In: Proceedings of the IFIP Congress. Vol. 2. London: Macmillan and Co; 1965. pp. 506-509'},{id:"B12",body:'Brooks FP, Ouh-Young M, Batter JJ, Jerome Kilpatrick P. Project gropehaptic displays for scientific visualization. SIGGRAPH Computer Graphics. 1990;24(4):177-185'},{id:"B13",body:'Chu CP, Dani TH, Gadh R. Multimodal interface for a virtual reality based computer aided design system. In: Proceedings of International Conference on Robotics and Automation. Vol. 2. Albuquerque, NM, USA; 1997. pp. 1329-1334. DOI: 10.1109/ROBOT.1997.614321'},{id:"B14",body:'Penn P, Petrie H, Colwell C, Kornbrot D, Furner S, Hardwick A. The haptic perception of texture in virtual environments: an investigation with two devices. In: Brewster S, Murray-Smith R, editors. Haptic Human-Computer Interaction. Haptic HCI 2000, Lecture Notes in Computer Science. Vol. 2058. Berlin, Heidelberg: Springer; 2001. DOI: 10.1007/3-540-44589-7_3'},{id:"B15",body:'Hamza-Lup FG, Bogdan CM, Popovici DM, Costea OD. A survey of visuo-haptic simulation in surgical training. In: Proceedings on Mobile, Hybrid, and On-line Learning. Athens, Greece; 2011. pp. 57-62. ISBN: 978-1-61208-689-7'},{id:"B16",body:'Massie T, Salisbury JK. The PHANTOM haptic interface: A device for probing virtual objects. In: American Society of Mechanical Engineers Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems. Vol. 1. Chicago, IL: Semantic Scholar; 1994. pp. 295-301'},{id:"B17",body:'Grange S, Conti F, Helmer P, Rouiller P, Baur C. Overview of the delta haptic device. In: Eurohaptics ‘01. Vol. 1. Birminghan, England: Semantic Scholar; 2001'},{id:"B18",body:'Conti F, Khatib O. A new actuation approach for haptic interface design. The International Journal of Robotics Research. 2009;28(6):834-848'},{id:"B19",body:'Finch M, Chi VL, Taylor RM, Falvo M, Washburn S, Superfine R. Surface modification tools in a virtual environment interface to a scanning probe microscope. In: Proc. Symposium on Interactive 3D Graphics, 13–24 New York, NY, USA, California, USA: Monterey; 1995'},{id:"B20",body:'Bliss JP, Tidwell PD, Guest MA. The effectiveness of virtual reality for administering spatial navigation training to firefighters. Presence: Teleoperators and Virtual Environments. 1997;6(1):73-86'},{id:"B21",body:'Rizzo A et al. Virtual environment applications in clinical neuropsychology. In: Proceedings IEEE Virtual Reality 2000 (Cat. No.00CB37048). New Brunswick, NJ, USA; 2000. pp. 63-70. DOI: 10.1109/VR.2000.840364'},{id:"B22",body:'Ruspini DC, Kolarov K, Khatib O. The haptic display of complex graphical environments. In: SIGGRAPH 97 Computer Graphics Proceedings Anual Conference. Los Angeles, California; 1997. pp. 140-147'},{id:"B23",body:'Salisbury K, Conti F, Barbagli F. Haptic rendering: Introductory concepts. IEEE Computer Graphics and Applications. 2004;14:24-32'},{id:"B24",body:'Escobar-Castillejos D, Noguez J, Neri L, Magana A, Benes B. A review of simulators with haptic devices for medical training. Journal of Medical Systems. 2016;104(40):177-185'},{id:"B25",body:'Duriez C, Dubois F, Kheddar A, Andriot C. Realistic haptic rendering of interacting deformable objects in virtual environments. IEEE Transactions on Visualization and Computer Graphics. 2006;12(1):1-12'},{id:"B26",body:'Terzopoulus D, Platt J, Barr A, Fleischer K. Elastically deformable models. Computer Graphics. 1987;21(4):205-214'},{id:"B27",body:'Sclaroff S, Pentland A. Generalized implicit functions for computer graphics. SIGGRAPH Computer Graphics. 1991;25(4):247-250'},{id:"B28",body:'Minsky M, Ming O, Steele O, Brooks FP, Behensky M. Feeling and seeing: Issues in force display. SIGGRAPH Computer Graphics. 1990;24(2):235-241'},{id:"B29",body:'Adams RJ, Hannaford B. Stable haptic interaction with virtual environments. IEEE Trans. on Robotics and Automation. 1999;15(3):465-474'},{id:"B30",body:'Bayo E, Avello A. Singularity-free augmented lagrangian algorithms for constrained multibody dynamics. Nonlinear Dynamics. 1994;5(2):209-231'},{id:"B31",body:'Zilles CB, Salisbury JK. A constraint-based god-object method for haptic display. In: Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots. Vol. 3. Pittsburgh, PA, USA; 1995. pp. 146-151. DOI: 10.1109/IROS.1995.525876'},{id:"B32",body:'Mavhash M, Hayward V. High-fidelity haptic synthesis of contact with deformable bodies. IEEE Computer Graphics and Applications. 2004;24(2):48-55'},{id:"B33",body:'Castro-Díaz JD, Sánchez-Sánchez P, Gutiérrez-Giles A, Arteaga-Pérez MA, Pliego-Jiménez J. Experimental results for haptic interaction with virtual holonomic and nonholonomic constraints. IEEE Access. 2020;8:120959-120973'},{id:"B34",body:'Monroy C, Kelly R, Arteaga M, Bugarin E. Remote visual Servoing of a robot manipulator via Internet2. Journal of Intelligent and Robotic Systems. 2007;49:171-187'},{id:"B35",body:'Rodríguez A, Basañez L, Colgate JE, Faulring EL. Haptic display of dynamic systems subject to holonomic constraints. In: IEEE Int. Conference on Intelligent Robots and Systems. France: Nice; 2008'},{id:"B36",body:'Montagnat J, Delignette H, Ayache N. A review of deformable surfaces: Topology, geometry and deformation. Image and Vision Computing. 2001;19:1023-1040'},{id:"B37",body:'Heredia SA, Harada K, Padilla- Castaneda M, Marques-Marinho M, Márquez-Flores JA, Mitsuishi M. Virtual reality simulation of robotic transsphenoidal brain tumor resection: Evaluating dynamic motion scaling in a master-slave system. The International Journal of Medical Robotics and Computer Assisted Surgery. 2019;15(1):1-48. DOI: 10.1002/rcs.1953. Epub 2018 Oct 18. PMID: 30117272; PMCID: PMC658796'},{id:"B38",body:'Maurel W, Wu Y, Magnenat N, Thalman D. Biomedichal Models for Soft Tissue Simulation. Heidelberg, Germany: Springer; 1998'},{id:"B39",body:'Faure F, DuriezHervé C, Delingette H, Allard J, Gilles B, Marchesseau S, et al. SOFA: A multi-model framework for interactive physical simulation. In: Payan Y, editor. Soft Tissue Biomechanical Modeling for Computer Assisted Surgery. Studies in Mechanobiology, Tissue Engineering and Biomaterials. Vol. 11. Berlin, Heidelberg: Springer; 2012. DOI: 10.1007/8415_2012_125'},{id:"B40",body:'Selig JM. Geometric Fundamentals of Robotics. New York, USA: Springer Science and Business; 1996'},{id:"B41",body:'Xiaoping Y, Sarkar N. Unified formulation of robotics systems with holonomic and nonholonomic constraints. IEEE Transaction on Robotics and Automation. 1998;14:640-650'},{id:"B42",body:'Murray RM, Li Z, Sastry SS. A Mathematical Introduction to Robotic Manipulation. Boca Raton, Florida, USA: CRC Press; 1994'},{id:"B43",body:'Luca AD, Oriolo G. Modelling and control of nonholonomic mechanical systems. In: Angeles J, Kecskeméthy A, editors. Kinematics and Dynamics of Multi-Body Systems. CISM International Centre for Mechanical Sciences (Courses and Lectures). Vol. 360. Vienna: Springer; 1995. DOI: 10.1007/978-3-7091-4362-9_7'},{id:"B44",body:'Faurling EL, Lynch KM, Colgate JE, Peshkin MA. Haptic display of constrained dynamic systems via admittance displays. IEEE Transactions on Robotics. 2007;23:101-111'},{id:"B45",body:'Arteaga MA, Gutiérrez-Giles A, Pliego-Jiménez J. Bilateral teleoperation. In: Local Stability and Ultimate Boundedness in the Control of Robot Manipulators, Lecture Notes in Electrical Engineering. Vol. 798. Cham: Springer; 2022. DOI: 10.1007/978-3-030-85980-0_9'},{id:"B46",body:'Garcia-Valdovinos LG, Parra-Vega V, Arteaga MA. Higher-order sliding mode impedance bilateral teleoperation with robust state estimation under constant unknown time delay. In: Proceedings, 2005 IEEE/ASME International Conference on Advanced Intelligent Mechatronics. Monterey, CA, USA. pp. 1293-1298. ISBN:0-7803-9047-4. DOI: 10.1109/AIM.2005.1511189'},{id:"B47",body:'Arteaga MA. Tracking control of flexible robot arms with a nonlinear observer. Automatica. 2000;36(9):1329-1337'},{id:"B48",body:'Arteaga MA, Castillo-Sánchez A, Parra-Vega V. Cartesian control of robots without dynamic model and observer design. Automatica. 2006;42(3):473-480'},{id:"B49",body:'Gutiérrez-Giles A, Arteaga-Pérez MA. Transparent bilateral teleoperation interacting with unknown remote surfaces with a force/velocity observer design. International Journal of Control. 2019;92(4):840-857. DOI: 10.1080/00207179.2017.1371338'},{id:"B50",body:'Gudiño Lau J, Arteaga MA. Dynamic model and simulation of cooperative robots: A case study. Robotica. 2005;23:615-624'},{id:"B51",body:'Shreiner D, Sellers G, Kessenich J, Licea-Kane B. OpenGL Programming Guide Eight Edition, The Official Guide to Learning OpenGL. The Khronos OpenGL ARB Working Group. Ann Arbor, Michigan: Addison-Weasley; 2013. ISBN 978-0-321-77303-6'},{id:"B52",body:'Zafer N, Yilmaz S. Nonlinear viscoelastic contact and deformation of freeform virtual surfaces. Advanced Robotics. 2016;30(4):246-257'},{id:"B53",body:'Barbagli F, Salisbury K. The effect of sensor/actuator asymmetries in haptic interfaces. In: 11th Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, 2003. HAPTICS 2003. Proceedings. Los Angeles, CA, USA; 2003. pp. 140-147. ISBN:0-7695-1890-7. DOI: 10.1109/HAPTIC.2003.1191258'},{id:"B54",body:'Yang C, Xie Y, Liu S, Sun D. Force modeling, identification, and feedback control of robot-assisted needle insertion: A survey of the literature. Sensors (Basel). 12 Feb 2018;18(2):1-48. DOI: 10.3390/s18020561. PMID: 29439539; PMCID: PMC5855056'},{id:"B55",body:'Constantinescu D, Salcudean SE, Croft EA. Haptic rendering of rigid contacts using impulsive and penalty forces. IEEE Transactions on Robotics. 2005;21(3):309-323'},{id:"B56",body:'Kim YJ, Otaduy MA, Lin MC, Manocha D. Six-degree-of-freedom haptic display using localized contact computations. In: Proceedings 10th Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems. HAPTICS. Vol. 2002. Orlando, FL, USA; 2002. pp. 209-216. ISBN: 0-7695-1489-8. DOI: 10.1109/HAPTIC.2002.998960'},{id:"B57",body:'Faurling EL, Lynch KM, Colgate JE, Peshkin MA. Haptic interaction with constrained dynamic systems. In: Proceedings of the 2005 IEEE International Conference on Robotics and Automation. Barcelona, Spain; 2005. pp. 2458-2464. ISSN: 1050-4729. DOI: 10.1109/ROBOT.2005.1570481'},{id:"B58",body:'Webster RJ III, Seob J, Cowan NJ, Chirikjian GS, Okamura AM. Nonholonomic modeling of needle steering. The International Journal of Robotic Research. 2006;25(5–6):509-525. DOI: 10.1177/0278364906065388'}],footnotes:[{id:"fn1",explanation:"In graphic computing, we refer texture to the feature of give color or combinations of colors to the objects."}],contributors:[{corresp:"yes",contributorFullName:"Pablo Sánchez-Sánchez",address:"pablo.sanchez@correo.buap.mx",affiliation:'
Facultad de Estudios Superiores ARAGON, UNAM, Mexico
'},{corresp:null,contributorFullName:"José Daniel Castro-Díaz",address:null,affiliation:'
Facultad de Ciencias de la Electrónica, Benemérita Universidad Autónoma de Puebla, Mexico
Applied Physics Division, Electronics and Telecommunications Department, CISESE-CONACYT, Mexico
'}],corrections:null},book:{id:"10663",type:"book",title:"Haptic Technology - Intelligent Approach to Future Man-Machine Interaction",subtitle:null,fullTitle:"Haptic Technology - Intelligent Approach to Future Man-Machine Interaction",slug:null,publishedDate:null,bookSignature:"Prof. Ahmad Hoirul Basori, Dr. Sharaf J. Malebary and Dr. Omar M. Barukab",coverURL:"https://cdn.intechopen.com/books/images_new/10663.jpg",licenceType:"CC BY 3.0",editedByType:null,isbn:"978-1-80355-067-1",printIsbn:"978-1-80355-066-4",pdfIsbn:"978-1-80355-068-8",isAvailableForWebshopOrdering:!0,editors:[{id:"13394",title:"Prof.",name:"Ahmad Hoirul",middleName:null,surname:"Basori",slug:"ahmad-hoirul-basori",fullName:"Ahmad Hoirul Basori"}],productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"}}},profile:{item:{id:"100115",title:"Dr.",name:"Joan E.",middleName:null,surname:"Rodríguez-Gil",email:"juanenrique.rodriguez@uab.cat",fullName:"Joan E. Rodríguez-Gil",slug:"joan-e.-rodriguez-gil",position:null,biography:null,institutionString:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",totalCites:0,totalChapterViews:"0",outsideEditionCount:0,totalAuthoredChapters:"2",totalEditedBooks:"0",personalWebsiteURL:null,twitterURL:null,linkedinURL:null,institution:{name:"Autonomous University of Barcelona",institutionURL:null,country:{name:"Spain"}}},booksEdited:[],chaptersAuthored:[{id:"30344",title:"Spermiomics: A New Term Describing the Global Survey of the Overall Sperm Function by the Combined Utilization of Immunocytochemistry, Metabolomics, Proteomics and Other Classical Analytical Techniques",slug:"spermiomics-a-global-survey-of-the-overall-sperm-function",abstract:null,signatures:"Joan E. Rodríguez-Gil",authors:[{id:"100115",title:"Dr.",name:"Joan E.",surname:"Rodríguez-Gil",fullName:"Joan E. Rodríguez-Gil",slug:"joan-e.-rodriguez-gil",email:"juanenrique.rodriguez@uab.cat"}],book:{id:"1436",title:"Applications of Immunocytochemistry",slug:"applications-of-immunocytochemistry",productType:{id:"1",title:"Edited Volume"}}},{id:"38559",title:"Energy Management of Mature Mammalian Spermatozoa",slug:"energy-management-of-mature-mammalian-spermatozoa",abstract:null,signatures:"Joan E. Rodríguez-Gil",authors:[{id:"100115",title:"Dr.",name:"Joan E.",surname:"Rodríguez-Gil",fullName:"Joan E. Rodríguez-Gil",slug:"joan-e.-rodriguez-gil",email:"juanenrique.rodriguez@uab.cat"}],book:{id:"3206",title:"Success in Artificial Insemination",slug:"success-in-artificial-insemination-quality-of-semen-and-diagnostics-employed",productType:{id:"1",title:"Edited Volume"}}}],collaborators:[{id:"51451",title:"Dr.",name:"Carlos",surname:"Bidot",slug:"carlos-bidot",fullName:"Carlos Bidot",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Miami",institutionURL:null,country:{name:"United States of America"}}},{id:"99081",title:"Dr.",name:"Shyam",surname:"Gajavelli",slug:"shyam-gajavelli",fullName:"Shyam Gajavelli",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Miami",institutionURL:null,country:{name:"United States of America"}}},{id:"100799",title:"Prof.",name:"Katharina",surname:"DHerde",slug:"katharina-dherde",fullName:"Katharina DHerde",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Ghent University",institutionURL:null,country:{name:"Belgium"}}},{id:"101746",title:"Prof.",name:"Dirk",surname:"Snyders",slug:"dirk-snyders",fullName:"Dirk Snyders",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Antwerp",institutionURL:null,country:{name:"Belgium"}}},{id:"102138",title:"Dr.",name:"Elke",surname:"Bocksteins",slug:"elke-bocksteins",fullName:"Elke Bocksteins",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Antwerp",institutionURL:null,country:{name:"Belgium"}}},{id:"102139",title:"Dr.",name:"Andrew",surname:"Shepherd",slug:"andrew-shepherd",fullName:"Andrew Shepherd",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Iowa",institutionURL:null,country:{name:"United States of America"}}},{id:"102140",title:"Prof.",name:"Durga",surname:"Mohapatra",slug:"durga-mohapatra",fullName:"Durga Mohapatra",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Iowa",institutionURL:null,country:{name:"United States of America"}}},{id:"119044",title:"Dr.",name:"Araceli",surname:"Diez-Fraile",slug:"araceli-diez-fraile",fullName:"Araceli Diez-Fraile",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Ghent University",institutionURL:null,country:{name:"Belgium"}}},{id:"119045",title:"Dr.",name:"Christopher J.",surname:"Guérin",slug:"christopher-j.-guerin",fullName:"Christopher J. Guérin",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Ghent University",institutionURL:null,country:{name:"Belgium"}}},{id:"119046",title:"MSc.",name:"Nico",surname:"Van Hecke",slug:"nico-van-hecke",fullName:"Nico Van Hecke",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Ghent University",institutionURL:null,country:{name:"Belgium"}}}]},generic:{page:{slug:"compacts",title:"IntechOpen Compacts",intro:"
IntechOpen Compacts provide a mid-length publishing format which bridges the gap between journal articles, book chapters and monographs, and cover content across all scientific disciplines. Compacts are the preferred publishing option for brief research reports on new topics, in-depth case studies, dissertations, or essays exploring new ideas, issues or broader topics on the research subject.
",metaTitle:"IntechOpen Compacts",metaDescription:"IntechOpen Compacts present a mid-length publishing format which bridges the gap between journal articles, book chapters, and monographs and covers content across all scientific disciplines.",metaKeywords:null,canonicalURL:"/page/compacts",contentRaw:'[{"type":"htmlEditorComponent","content":"
Without sacrificing the quality of carefully edited and produced peer-reviewed content, Compacts are published as part of IntechOpen’s book collection but on a faster schedule, typically 4-6 weeks after acceptance. With an average of 132,000 visitors per week, publishing in Compacts not only guarantees high visibility but also facilitates international content sharing. As a fully Open Access publisher, the utilization of a CC BY NC 4.0 license means that other researchers will never have to pay permission fees and can adapt, use, and further build upon the material published in Compacts, eliminating any barriers to the further development of scientific research.
\\n\\n
COMPACTS-SHORT FORM MONOGRAPH
\\n\\n
\\n\\t
50 - 130 pages
\\n\\t
Peer-reviewed
\\n\\t
Self-contained works on a particular subject compiled by one or more authors
\\n\\t
A unique hybrid between a book chapter and monograph
\\n\\t
Online only, and print options available
\\n
\\n\\n
COST
\\n\\n
4,000 GBP Compacts Monograph - Short Form
\\n\\n
The final price will depend on the volume of the publication and includes project management, editorial and peer-review services, technical editing, language copyediting, cover design, book layout, book promotion and ISBN assignment.
\\n\\n
*The price does not include Value-Added Tax (VAT). Residents of European Union countries need to add VAT based on the specific rate applicable in their country of residence. Institutions and companies registered as VAT taxable entities in their own EU member state will not pay VAT by providing us with their VAT registration number. This is made possible by the EU reverse charge method.
\\n\\n
Optional Services
\\n\\n
IntechOpen has collaborated with Enago, through its sister company, Ulatus – one of the world’s leading providers of book translation services. The services are designed to convey the essence of your work seamlessly to readers from across the globe in their own language. Enago’s expert translators incorporate cultural nuances in translations to make the content relevant for local audiences while retaining the original meaning and style. With a high degree of linguistic and subject expertise, Enago translators are equipped to handle all complex and multiple overlapping themes encompassed in a single book to deliver a superior quality of translation.
\\n\\n
IntechOpen Authors that wish to use this service will receive a 20% discount on all translation work. For more information or a quote, please visit: https://www.enago.com/intech.
\\n\\n
FUNDING
\\n\\n
We feel that financial barriers should never prevent researchers from publishing their research. Please consult our Open Access Funding page to explore funding opportunities and learn more about how you can finance your IntechOpen publication.
\\n\\n
BENEFITS
\\n\\n
\\n\\t
Peer-review
\\n\\t
Rapid publishing process: publication 4 to 6 weeks following acceptance
\\n\\t
Language proofreading and technical formatting included in the cost
\\n\\t
Personal support throughout the publishing process
\\n\\t
Tailor-made service: choose between online only or online and print editions of your Compact
\\n\\t
+560,000 visitors per month guarantees high visibility and opportunities for international content sharing
\\n\\t
You retain copyright to your work
\\n\\t
Wide dissemination and distribution to scientific databases and university libraries
\\n\\t
Competitive pricing with funding opportunities
\\n
\\n\\n
PUBLISHING PROCESS STEPS
\\n\\n
See a complete overview and description of the steps involved in the publishing process here.
\\n\\n
SEND YOUR PROPOSAL
\\n\\n
If you are interested in publishing your book with IntechOpen, please submit your book proposal by completing the Publishing Proposal Form.
Without sacrificing the quality of carefully edited and produced peer-reviewed content, Compacts are published as part of IntechOpen’s book collection but on a faster schedule, typically 4-6 weeks after acceptance. With an average of 132,000 visitors per week, publishing in Compacts not only guarantees high visibility but also facilitates international content sharing. As a fully Open Access publisher, the utilization of a CC BY NC 4.0 license means that other researchers will never have to pay permission fees and can adapt, use, and further build upon the material published in Compacts, eliminating any barriers to the further development of scientific research.
\n\n
COMPACTS-SHORT FORM MONOGRAPH
\n\n
\n\t
50 - 130 pages
\n\t
Peer-reviewed
\n\t
Self-contained works on a particular subject compiled by one or more authors
\n\t
A unique hybrid between a book chapter and monograph
\n\t
Online only, and print options available
\n
\n\n
COST
\n\n
4,000 GBP Compacts Monograph - Short Form
\n\n
The final price will depend on the volume of the publication and includes project management, editorial and peer-review services, technical editing, language copyediting, cover design, book layout, book promotion and ISBN assignment.
\n\n
*The price does not include Value-Added Tax (VAT). Residents of European Union countries need to add VAT based on the specific rate applicable in their country of residence. Institutions and companies registered as VAT taxable entities in their own EU member state will not pay VAT by providing us with their VAT registration number. This is made possible by the EU reverse charge method.
\n\n
Optional Services
\n\n
IntechOpen has collaborated with Enago, through its sister company, Ulatus – one of the world’s leading providers of book translation services. The services are designed to convey the essence of your work seamlessly to readers from across the globe in their own language. Enago’s expert translators incorporate cultural nuances in translations to make the content relevant for local audiences while retaining the original meaning and style. With a high degree of linguistic and subject expertise, Enago translators are equipped to handle all complex and multiple overlapping themes encompassed in a single book to deliver a superior quality of translation.
\n\n
IntechOpen Authors that wish to use this service will receive a 20% discount on all translation work. For more information or a quote, please visit: https://www.enago.com/intech.
\n\n
FUNDING
\n\n
We feel that financial barriers should never prevent researchers from publishing their research. Please consult our Open Access Funding page to explore funding opportunities and learn more about how you can finance your IntechOpen publication.
\n\n
BENEFITS
\n\n
\n\t
Peer-review
\n\t
Rapid publishing process: publication 4 to 6 weeks following acceptance
\n\t
Language proofreading and technical formatting included in the cost
\n\t
Personal support throughout the publishing process
\n\t
Tailor-made service: choose between online only or online and print editions of your Compact
\n\t
+560,000 visitors per month guarantees high visibility and opportunities for international content sharing
\n\t
You retain copyright to your work
\n\t
Wide dissemination and distribution to scientific databases and university libraries
\n\t
Competitive pricing with funding opportunities
\n
\n\n
PUBLISHING PROCESS STEPS
\n\n
See a complete overview and description of the steps involved in the publishing process here.
\n\n
SEND YOUR PROPOSAL
\n\n
If you are interested in publishing your book with IntechOpen, please submit your book proposal by completing the Publishing Proposal Form.
\n'}]},successStories:{items:[]},authorsAndEditors:{filterParams:{},profiles:[{id:"396",title:"Dr.",name:"Vedran",middleName:null,surname:"Kordic",slug:"vedran-kordic",fullName:"Vedran Kordic",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/396/images/7281_n.png",biography:"After obtaining his Master's degree in Mechanical Engineering he continued his education at the Vienna University of Technology where he obtained his PhD degree in 2004. He worked as a researcher at the Automation and Control Institute, Faculty of Electrical Engineering, Vienna University of Technology until 2008. His studies in robotics lead him not only to a PhD degree but also inspired him to co-found and build the International Journal of Advanced Robotic Systems - world's first Open Access journal in the field of robotics.",institutionString:null,institution:{name:"TU Wien",country:{name:"Austria"}}},{id:"441",title:"Ph.D.",name:"Jaekyu",middleName:null,surname:"Park",slug:"jaekyu-park",fullName:"Jaekyu Park",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/441/images/1881_n.jpg",biography:null,institutionString:null,institution:{name:"LG Corporation (South Korea)",country:{name:"Korea, South"}}},{id:"465",title:"Dr",name:"Christian",middleName:null,surname:"Martens",slug:"christian-martens",fullName:"Christian Martens",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"479",title:"Dr.",name:"Valentina",middleName:null,surname:"Colla",slug:"valentina-colla",fullName:"Valentina Colla",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/479/images/358_n.jpg",biography:null,institutionString:null,institution:{name:"Sant'Anna School of Advanced Studies",country:{name:"Italy"}}},{id:"494",title:"PhD",name:"Loris",middleName:null,surname:"Nanni",slug:"loris-nanni",fullName:"Loris Nanni",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/494/images/system/494.jpg",biography:"Loris Nanni received his Master Degree cum laude on June-2002 from the University of Bologna, and the April 26th 2006 he received his Ph.D. in Computer Engineering at DEIS, University of Bologna. On September, 29th 2006 he has won a post PhD fellowship from the university of Bologna (from October 2006 to October 2008), at the competitive examination he was ranked first in the industrial engineering area. He extensively served as referee for several international journals. He is author/coauthor of more than 100 research papers. He has been involved in some projects supported by MURST and European Community. His research interests include pattern recognition, bioinformatics, and biometric systems (fingerprint classification and recognition, signature verification, face recognition).",institutionString:null,institution:null},{id:"496",title:"Dr.",name:"Carlos",middleName:null,surname:"Leon",slug:"carlos-leon",fullName:"Carlos Leon",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Seville",country:{name:"Spain"}}},{id:"512",title:"Dr.",name:"Dayang",middleName:null,surname:"Jawawi",slug:"dayang-jawawi",fullName:"Dayang Jawawi",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Technology Malaysia",country:{name:"Malaysia"}}},{id:"528",title:"Dr.",name:"Kresimir",middleName:null,surname:"Delac",slug:"kresimir-delac",fullName:"Kresimir Delac",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/528/images/system/528.jpg",biography:"K. Delac received his B.Sc.E.E. degree in 2003 and is currentlypursuing a Ph.D. degree at the University of Zagreb, Faculty of Electrical Engineering andComputing. His current research interests are digital image analysis, pattern recognition andbiometrics.",institutionString:null,institution:{name:"University of Zagreb",country:{name:"Croatia"}}},{id:"557",title:"Dr.",name:"Andon",middleName:"Venelinov",surname:"Topalov",slug:"andon-topalov",fullName:"Andon Topalov",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/557/images/1927_n.jpg",biography:"Dr. Andon V. Topalov received the MSc degree in Control Engineering from the Faculty of Information Systems, Technologies, and Automation at Moscow State University of Civil Engineering (MGGU) in 1979. He then received his PhD degree in Control Engineering from the Department of Automation and Remote Control at Moscow State Mining University (MGSU), Moscow, in 1984. From 1985 to 1986, he was a Research Fellow in the Research Institute for Electronic Equipment, ZZU AD, Plovdiv, Bulgaria. In 1986, he joined the Department of Control Systems, Technical University of Sofia at the Plovdiv campus, where he is presently a Full Professor. He has held long-term visiting Professor/Scholar positions at various institutions in South Korea, Turkey, Mexico, Greece, Belgium, UK, and Germany. And he has coauthored one book and authored or coauthored more than 80 research papers in conference proceedings and journals. His current research interests are in the fields of intelligent control and robotics.",institutionString:null,institution:{name:"Technical University of Sofia",country:{name:"Bulgaria"}}},{id:"585",title:"Prof.",name:"Munir",middleName:null,surname:"Merdan",slug:"munir-merdan",fullName:"Munir Merdan",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/585/images/system/585.jpg",biography:"Munir Merdan received the M.Sc. degree in mechanical engineering from the Technical University of Sarajevo, Bosnia and Herzegovina, in 2001, and the Ph.D. degree in electrical engineering from the Vienna University of Technology, Vienna, Austria, in 2009.Since 2005, he has been at the Automation and Control Institute, Vienna University of Technology, where he is currently a Senior Researcher. His research interests include the application of agent technology for achieving agile control in the manufacturing environment.",institutionString:null,institution:null},{id:"605",title:"Prof",name:"Dil",middleName:null,surname:"Hussain",slug:"dil-hussain",fullName:"Dil Hussain",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/605/images/system/605.jpg",biography:"Dr. Dil Muhammad Akbar Hussain is a professor of Electronics Engineering & Computer Science at the Department of Energy Technology, Aalborg University Denmark. Professor Akbar has a Master degree in Digital Electronics from Govt. College University, Lahore Pakistan and a P-hD degree in Control Engineering from the School of Engineering and Applied Sciences, University of Sussex United Kingdom. Aalborg University has Two Satellite Campuses, one in Copenhagen (Aalborg University Copenhagen) and the other in Esbjerg (Aalborg University Esbjerg).\n· He is a member of prestigious IEEE (Institute of Electrical and Electronics Engineers), and IAENG (International Association of Engineers) organizations. \n· He is the chief Editor of the Journal of Software Engineering.\n· He is the member of the Editorial Board of International Journal of Computer Science and Software Technology (IJCSST) and International Journal of Computer Engineering and Information Technology. \n· He is also the Editor of Communication in Computer and Information Science CCIS-20 by Springer.\n· Reviewer For Many Conferences\nHe is the lead person in making collaboration agreements between Aalborg University and many universities of Pakistan, for which the MOU’s (Memorandum of Understanding) have been signed.\nProfessor Akbar is working in Academia since 1990, he started his career as a Lab demonstrator/TA at the University of Sussex. After finishing his P. hD degree in 1992, he served in the Industry as a Scientific Officer and continued his academic career as a visiting scholar for a number of educational institutions. In 1996 he joined National University of Science & Technology Pakistan (NUST) as an Associate Professor; NUST is one of the top few universities in Pakistan. In 1999 he joined an International Company Lineo Inc, Canada as Manager Compiler Group, where he headed the group for developing Compiler Tool Chain and Porting of Operating Systems for the BLACKfin processor. The processor development was a joint venture by Intel and Analog Devices. In 2002 Lineo Inc., was taken over by another company, so he joined Aalborg University Denmark as an Assistant Professor.\nProfessor Akbar has truly a multi-disciplined career and he continued his legacy and making progress in many areas of his interests both in teaching and research. He has contributed in stochastic estimation of control area especially, in the Multiple Target Tracking and Interactive Multiple Model (IMM) research, Ball & Beam Control Problem, Robotics, Levitation Control. He has contributed in developing Algorithms for Fingerprint Matching, Computer Vision and Face Recognition. He has been supervising Pattern Recognition, Formal Languages and Distributed Processing projects for several years. He has reviewed many books on Management, Computer Science. Currently, he is an active and permanent reviewer for many international conferences and symposia and the program committee member for many international conferences.\nIn teaching he has taught the core computer science subjects like, Digital Design, Real Time Embedded System Programming, Operating Systems, Software Engineering, Data Structures, Databases, Compiler Construction. In the Engineering side, Digital Signal Processing, Computer Architecture, Electronics Devices, Digital Filtering and Engineering Management.\nApart from his Academic Interest and activities he loves sport especially, Cricket, Football, Snooker and Squash. He plays cricket for Esbjerg city in the second division team as an opener wicket keeper batsman. He is a very good player of squash but has not played squash since his arrival in Denmark.",institutionString:null,institution:null},{id:"611",title:"Prof.",name:"T",middleName:null,surname:"Nagarajan",slug:"t-nagarajan",fullName:"T Nagarajan",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Universiti Teknologi Petronas",country:{name:"Malaysia"}}}],filtersByRegion:[{group:"region",caption:"North America",value:1,count:6581},{group:"region",caption:"Middle and South America",value:2,count:5888},{group:"region",caption:"Africa",value:3,count:2381},{group:"region",caption:"Asia",value:4,count:12507},{group:"region",caption:"Au