Psychometry in Dementia

Abstract

Grow in aging has led to an increasing number of people presenting with cognitive impairment and dementia. Most forms of dementia are classified by means of morphological techniques, assays of biomarkers in cerebrospinal fluid and neuropsychological assessment, into degenerative forms, dementia of vascular type and dementia secondary to other conditions. It is very difficult to make a clear-cut diagnosis of the different types of dementia by means of clinical methods. However, many psychometric tests play a prominent role in screening and evaluation of patients with cognitive impairment. Some tools can help clinicians in differential diagnosis among the various forms of dementia such as the ones that assess clinical aspects, tests that focus on specific cognitive areas or behavioral inventories. Still nowadays, there is not a consensus about the best strategies for screening and assessment of cognitive impairment among elderly subjects. The purpose of this chapter is to make a review of the screening tools and psychometric test instruments that healthcare professionals can use for screening and neuropsychological assessment of geriatric individuals with cognitive disorders to help diagnosis of dementia and to make differential diagnosis of the most common forms of dementia.

1. Introduction

All countries of the world have observed a substantial increase in the number of elderly people. This phenomenon resulted to an increase of chronic health conditions and cognitive impairments. With the consequence of world population senescence, the healthcare professionals need to differentiate expected changes due to aging from pathological conditions due to dementia.

The current state of knowledge allows a detection of neurodegenerative brain changes [1] with neuroimaging techniques such as magnetic resonance imaging [2] or positron emission tomography with amyloid binding tracers [3] and assays of biomarkers such as beta amyloid fragment or phosphorylated tau protein in cerebrospinal fluid [4]. These techniques make possible to identify degenerative forms of dementia (Alzheimer’s disease, Lewy bodies dementia and frontotemporal dementia), dementia of vascular type and dementia secondary to other conditions (such as traumatic brain injuries, human immunodeficiency infection, substance-induced dementia, Huntington disease, Parkinson’s disease and prion disease).

However, research studies show that preclinical diagnosis of neurodegenerative conditions is still possible with neuropsychological measurement of cognitive changes [5]. Different cognitive tasks used in combination can provide screening and assessment of cognitive impairment among elderly people, since if used together they can bring more information. Psychometric tests are also useful to differentiate pseudo-dementias [6] or other form of primary dementias that may mimic dementia of Alzheimer type such as frontotemporal dementia and Jacob–Creutzfeldt disease, predict increased or reduced risk of dementia and describe disease evolution in affected individuals.

There is no consensus regarding the best strategies for screening of cognitive impairment among elderly patients even if several brief instruments are recommended [7].

Most individuals and their caregivers would want to know a diagnosis of dementia as soon as possible to allow them to make decisions regarding future plans when they are still able to do it [8]. Furthermore, studies conducted to prevent cognitive decline and disability have demonstrated that pharmacological treatments and early interventions on healthy life-style factors such as social interactions, leisure activities, cognitive stimulation, Mediterranean diet and regular physical activity should be encouraged in patients with mid cognitive impairments as possible protectors against neurodegenerative disease of aging and progression of cognitive deficits [9].

2. Screening batteries for detection of cognitive impairment

Clinicians have developed many neuropsychological instruments that are best suited for middle-aged and older people. Brief screening tools are useful for identifying individuals with cognitive disorders, staging their severity, tracking progression over time and response to treatments. Most of them have a general applicability. The sensitivity of the screening test is defined as the number of positives correctively identified by the test as a percentage of the total number of the positives in the population studied (percentage of demented subjects). Conversely the specificity of the screening test is the number of negatives correctly identified by the test as a percentage of all the true negatives (percentage of not demented subjects). Screening tests are summarized in Table 1.

Battery	Total score	Sensitivity %	Specificity %	Cut-off scores	Administration time	Components of the battery
CDT	10	67–97.9	69–94.2	<7	4-5 min	A, VS, E, PR
Dem-Tect	18	100	92	≤12	8–10 min	M, L, E
MIS	8	43–86	93–97	≤4	4 min	M
Mini-Cog	5	76–99	85.3–96	≤3	2 min	A, M, L. VS, E
MSQ	10	92.3–100	86.5–100	≥3	2 min	O
SPMSQ	10	92.3–100	86.5–100	≥3	2 min	O, A, MT
BDRS	28	43	94	≥4	4–5 min	ADL
VFT	NA	37–89.5	43–97	12/13 or 14/15	4–5 min	M, L, E
SLUMS	30	92–100	76–100	23.5 or 25.5	7 min	O, M, L, A, C, VS, E
RAVLT-IR	75	97.9	17.9	≤30	10–15 min	A, M, L
RAVLT-DR	15	95.7	28.6	≤3	30 min	M, L
RAVLT-RT	15	91.5	46.4	<10	30–60 min	M, L
RAVLT-FC	15	92.6	67.9	<13	30–60 min	M, L
ACE-R	100	84–94	89–100	82 or 88	20 min	O, M, L, A, VS, E
CAMCOG	106	92	96	<80	30 min	O, L, M, A, PR, CA, AT, PE, VS
MMSE	30	88.3	86.2	23/24 or 24/25	6–10 min	O, M, L, A, C, VS, PR
MoCA	30	90–100	87	26	6–10 min	O, M, L, A, E, C, VS, PR

Table 1.

Screening tools for detection of cognitive impairment.

Abbreviations of the battery: CDT = Clock Drawing Test; Dem-Tect = Dementia Detection Test; MIS = Memory Impairment Screening Test; Mini-Cog = Mini Cognition Test; MSQ = Mental Status Questionnaire; SPMSQ = Short Portable Mental Status Questionnaire; BDRS=Blessed Dementia Rating Scale; VFT = Verbal Fluency Test; CAMCOG = Cambridge Cognitive Examination; MMSE = Mini Mental State Examination; MoCA = Montreal Cognitive Assessment; RAVLT-IR = Rey auditory verbal learning test-Immediate recall; RAVLT-DR = Rey auditory verbal learning test-Delayed recall; RAVLT-RT = Rey auditory verbal learning test-Recognition trial; RAVLT-FC = Rey auditory verbal learning test-Forced choice recognition.

Abbreviations of the components: A = attention; ADL = activities of daily living; AT = abstract thinking; C = calculation; E = executive functions; L = language; M = memory; MT = mental tracking; O = orientation; PE = perception; PR = Praxis; VS = visuo-spatial functions.

Some researchers consider the clock drawing test (CDT) as a possible instrument for the screening of dementia [10]. In this test subjects are asked to follow a two-step instruction: The first instruction consists in drawing a clock with all the numbers on it, while the second instruction consists in putting the hands of the clock on a specific time [11]. CDT is a very brief cognitive test (administration time < 5 min), easy to apply, but it is vulnerable to different interpretations of the final result, given by the different ways to analyze the clock that was drawn. The most common score in screening patients with Alzheimer disease is a total score of 10 points and a cut-off score of 7 [11]. A score of 10 corresponds to the best representation of the clock, while a score of 1 corresponds to the worst representation of the clock. Other authors propose a hierarchical classification system of errors from 1 (mild) to 5 (severe) with a total score of 5, determined by the highest level of error based on a classification system [12]. According to these authors, the errors could be classified as mild visuospatial errors, errors in denoting the time, perseverations, severely disorganization of the space and total inability to make any reasonable attempt at a clock [12].

The CDT has 67 to 97.9% sensitivity and 69 to 94.2% specificity in screening cognitive impairment [13]. It cannot be used among people with visual or motor difficulties that prevent them from using properly paper and pen. There is not a consensus on whether the CDT can distinguish mild cognitive impairment (MCI) from dementia even if this test can assess motor and executive functions, memory and verbal comprehension and has been used to differentiate dementia from cognition in different studies [14]. Finally, there are also multiple scoring methods for interpreting CDT (with different degree of complexity), and there is no consensus on the best method [13].

The DemTect is an instrument used by Kalbe to detect dementia [15]. It takes from 8 to 10 minutes to complete and includes different cognitive tests: immediate memory of a word list, late evocation of the same list, a numerical transcoding task, and a digit span test and a semantic verbal fluency test. Total score is independent from age and education. Maximum score is 18. A score of 13–18 points is adequate for age, a score of 9–12 points identifies MCI with sensitivity of 80% and specificity of 92%, a score of 8 points or below identifies dementia with sensitivity of 100% and specificity of 92% [15].

The memory impairment screening test (MIS) consists in a brief 4 items battery of neuropsychological tests (delayed and cued recall of words) that has been recommended as a preliminary test in screening for dementia, in conjunction with other screening tools [16]. Total score is 8, and the cut-off score is 4. Sensitivity of MIS in screening dementia ranges from 43 to 86%, and specificity ranges from 93 to 97% [13]. MIS can be applied within four minutes and does not require the ability to write [17]. However, it is sensitive to reading abilities that means educational level of the subjects tested influences the results.

The Mini-Cog is a brief screening tool that includes CDT and a test of immediate and late evocation of three words [18] with a total score of 5. Administration time requires about two minutes. The Mini-Cog has a moderate-high sensitivity (76–99%) and a moderate-great specificity (85.3–96%) [19]. In a study conducted by Fowler et al., where the Mini-Cog was applied together with MIS, authors concluded that Mini-Cog was suitable for routine screening of dementia within primary care [20]. The Mini-Cog classifies dementia from cognitive normal and is not influenced from language or education [18].

The mental status questionnaire (MSQ) is a brief and simple screening test that consists in ten questions [21]. Orientation questions deal with place and time, and general information questions concern personal information (age, month and year of birth, name of the current and the past president). Each incorrect response receives 1 point; the maximum score is 10. According to the authors, scores from 0 to 2 indicate absence or just moderate brain dysfunction, scores from 3 to 8 a moderate brain dysfunction and scores from 9 to 10 reflect a severe brain dysfunction. MSQ scores correlate significantly with measures of brain metabolism in cortical and subcortical areas of the brain [22]. Sensitivity of MSQ in screening dementia ranges from 92.3 to 100%, while specificity ranges from 86.5 to 100% [13]. This instrument is more accurate in identifying moderate to severely impaired patients and normal subjects, but produces a high rate of false negatives among mildly impaired patients [23]. Fillebaum suggests that just two items (date of birth and name of the previous president) are sufficient as a brief screening technique [24].

The short portable mental status questionnaire (SPMSQ) is another brief and simple ten-point test for screening of cognitive impairment [25]. Seven questions involve spatial, temporal and personal orientation (e.g. current date and place of the examination); two questions consist in asking the names of current and previous presidents, while the last tasks consist in tests of concentration and mental tracking. Sensitivity of MSQ in screening dementia ranges from 92.3 to 100%, while specificity ranges from 86.5 to 100% [13]. The SPMSQ is able to discriminate between cognitively intact patients and patients with three level of cognitive impairment severity. On the bases of a regression analysis study, the best items to identify cognitive impairment are the date of birth, the name of the previous president and the name of the current day of the week [24]. However, like most of the brief screening instruments, the SPMSQ does not identify mildly impaired subjects from early-demented patients [24].

The blessed dementia rating scale (BDRS) is a brief rating scale that registers functional behavior changes reported by informants [26]. The subjects are rated on a list of 22 items, covering changes in the previous six months in abilities in personal care/eating, dressing, sphincter control, performances in daily activities (moneys, finding one’s way), in personality, interests and drive. The BDRS contains items that score 1 and items weighted according the severity. Total possible score of this scale is 28 for the most deteriorated patients. Persons receiving a score less than 4 are considered unimpaired; persons with a score between 4 and 9 are considered with mild impairment; patients with a score of 10 or higher are considered with a moderate to severe impairment [27]. In a study conducted to recognize dementia in general practice, BDRS showed a sensitivity of 43% and a specificity of 94% [28]. Blessed and colleagues find a highly significant correlation between mean plaque counts and scores of this scale in a group of patients examined before they died and later came to autopsy [26].

The verbal fluency test (VFT) [29] is a very brief test for evaluation of language, memory and executive functions. The phonological VFT version consists in asking to list words that begin with a particular letter of the alphabet in a time interval of a minute. Instead, the semantic VFT version consists in asking to list categories of colors, animals, fruits or cities in one minute. The VFT is a simple test that can be easily applied and is very effective in evaluating language abilities and executive functions since the test requires the ability to self-regulate working memory through the ability to search and retrieve information stored in long-term memory. The VFT has a range of sensitivity from 37 to 89.5% and a specificity from 43 to 97% [13]. The VFT is quite accurate for screening early stages of cognitive impairment or dementia. It is also able to distinguish between individuals with or without normal cognition. This test is simple and does not require any materials other than a device to keep track of the time and number of words produced. Performances in the test are influenced by subject’s level of age and education, and consequently raw scores must be corrected for these variables.

The Saint Louis University Mental Status examination (SLUMS) is a 30-point screening questionnaire [30]. It explores orientation, attention, memory, calculation, executive functions, language and visuo-spatial functions. It takes about 7 minutes to complete. The optimal cut-off scores are 23.5 for subjects with less school education and 25.5 for subjects with high school education [30]. The cut-off scores for dementia are 19.5 for subjects with less school education and 21.5 for subjects with high school education [30]. The sensitivity is 92–100%, while the specificity is 76–100% [30].

The Rey auditory verbal learning test (RAVLT) is an easy screening test based on assessment of verbal memory [31]. It consists of five presentations with recall of a 15-word list, one presentation of a second 15-word list and a sixth recall trial which altogether take from 10 to 15 minutes. Retention is generally examined after 30 minutes. The immediate free recall trial (RAVLT-IR) gives information on immediate word span recall and provides a learning curve that reveals learning strategies. The delayed recall trial (RAVLT-DR) gives information on how well the patient recalls what was once learned. The score for each trial is the number of words correctly recalled. Total score of the immediate free recall is the sum of the five trials; the maximum score is 75. Total score of the delayed recall trial is the number of words recalled with a maximum score of 15.

Many clinicians and researchers also include a recognitions trial (RAVLT-RT) that is assessed after a time of 30–60 minutes first developed by Lezak [32]. In the recognition task, the examiner asks the patient to identify as many words as possible from the first list when shown a list of 50 words containing words that are semantically associated or phonemically similar of the 15-words target list.

Porech et al. presented in 2016 an auditory verbal learning forced-choice recognition task (RAVLT-FC) and proposed its use as part of a routine neuropsychological assessment [33]. In this procedure, the examiner reads a pair of words and asks the subject to choose the word from each pair that had been presented in the original list. The RAVLT-FC is then composed of 15 FC items, each consisting of the target list of 15 words paired with 15 distractors. RAVLT-FC total score consists in the number of words correctly identified; maximum score is 15. Authors have considered for each trial cut off scores that minimize risk of false positive and that have high specificity values. According to a recent study on the validity of the Rey auditory verbal learning test, RAVL-IR (total 1–5 trial) at a level of cut-off less than 30 has a specificity of 97.9% and sensitivity of 17.9%; RAVL-DR (long delay recall) at a level of cut-off less than 3 has a specificity of 95.7% and sensitivity of 28.6%; RAVL-RT (recognition task) at a level of cut-off less than 10 has a specificity of 91.5% and sensitivity of 46.4%; RAVL-FC (forced-choice trial total score) at a level of cut-off less than 13 has a strong specificity (92.6%) and a sensitivity of 67.9% [34]. As in all learning tests, age effects are prominent and tend to affect all the relevant measures [35].

The Addenbrooke’s cognitive examination-revised (ACE-R) is a brief neuropsychological battery with an approximately administration time of 20 minutes. It includes five subdomain scores that are orientation/attention, memory, verbal fluency, language and visual–spatial abilities. A cut-off as 88 is indicative of presence of dementia with a sensitivity of 94% and a specificity of 89%. However, the cut-offs are defined as 82, with a sensitivity of 84% and a specificity of 100%. The ACE-R is recommended both in general hospital settings than in memory clinics [36].

The Cambridge cognitive examination (CAMCOG) is a brief neuropsychological battery since it takes about 30 minutes to complete. The CAMCOG consists in eight major subscales that are orientation, attention, memory, calculation, language, abstract thinking, perception and praxis. The CAMCOG has been designed to detect dementia and mild degrees of cognitive impairment [37]. The total score is 106, and the cut-off score for diagnosis of cognitive impairment is less than 80. The sensitivity is 92%, specificity is 96% [38], and there is not a ceiling effect [37].

The mini–mental state examination (MMSE) is one on the most widely used brief screening instrument for recognition of cognitive impairment [39]. It takes approximately 8 minutes to complete [40] and is generally considered a gold standard in clinical practice for dementia [41]. MMSE has been validated for application both in the community and in primary care in many countries [42]. It is a screening tool for cognitive impairment and identification of individuals for a more complex evaluation. MMSE is a rapid tool influenced by levels of age and formal education. The MMSE explores orientation (in time and space), attention and concentration (spell of words backwards and subtractions), memory (immediate and delayed recall of 3 words), language (denomination of 3 objects, repetition of words, execution of a three- stage command, reading and obey to an order and writing a sentence) and visuospatial construction (ability to copy a geometrical figure). Each correct response receives 1 point of score; the maximum score is 30 [43]. A suggested cut-score of 23 versus 24 (23/24) was recommended for detecting dementia in a primary care setting in persons with at least 8 years of education [39]. Scores of 21 to 24, 10 to 20 and 9 or less indicate, respectively, mild, moderate and severe cognitive impairment [44]. Sensitivity and specificity of MMSE are 88.3% and 86.2%, respectively [13].

However, MMSE is not suitable for the screening of the initial phases of dementia and is not useful to evaluate executive functions. It is effective in discriminating patients with moderate or greater cognitive deficits from control subjects [45]. It is sensitive for the follow up of progressive deterioration in dementing patients [46]. Item analyses indicate that the three-word recall is the most sensible item to dementia while the second most failures are orientation for date [47]. Given to its susceptibility to ceiling effect [48] and sociodemographic factors [49], the MMSE should not be used in isolation to definitively diagnose or rule out of dementia [50].

The montreal cognitive assessment (MoCA) is a brief battery of 30 point tests frequently used to screen mild forms of cognitive impairment (MCI) [51]. The MoCA has better sensitivity and specificity than MMSE in detecting MCI and dementia [52]. The MoCA covers all cognitive domains and has more tests of executive functions. Using a cut-off of 26 the MoCA assesses different cognitive domains such as orientation, memory, attention, executive functions, naming, language, abstraction and visuospatial abilities. According to some authors, it is the test with the highest predictive value for differentiating MCI and Alzheimer’s dementia (AD) from normal individual cases, with a sensitivity of 90% and 100%, respectively [53]. The MoCA also has a high specificity in identifying 87% of healthy controls [54]. However, MoCA has significant correlations with age and level of formal education as other cognitive batteries such as mini–mental state examination [39], clock drawing test [55], Cambridge cognitive examination or verbal fluency test [29]. The MoCA is a tool that provides a superior overall assessment in the early stages of cognitive decline [56], but has the disadvantage of taking longer than MMSE, and it presents limitations with regard the capabilities of illiterate individuals to perform proposed tasks. The MoCA is also useful in identifying non-anamnestic forms of MCI, behavioral variant of frontotemporal dementia [57] and mild cognitive impairment in patients with Parkinson’s disease [58].

3. Functional assessment of subjects with cognitive deficits

As suggested by Jiang et al. [59], changes in instrumental activities daily living for domestic works are common in patients with mild cognitive impairment. Therefore, it is recommendable the use of functional scales during the screening of subjects with cognitive deficits (Table 2).

Functional scale	Total score	Sensitivity %	Specificity%	Cut-off	Administration time	Cognitive and functional domains of daily living
IQCODE	26–130	75–83	65–90	3.3	10–20 min	M, O, J, PS, CA, HH, PC
PFAQ	30	88.3	76.5	>10	15–20 min	M, O, J, PS, CA, HH, PC
CDR	18	95	94	>6	20–30 min	M, O, J, PS, CA, HH, PC

Table 2.

Functional evaluation scales.

Abbreviations of the functional scale: IQCODE = Informant Questionnaire on Cognitive Decline in the Elderly; PFQAQ = Pfeiffer Functional Activity Questionnaire; CDR = Clinical Dementia Rating scale.

Abbreviations of the functional domains: CA = community affairs; J = judgment; HH = home and hobbies; M = memory; O = orientation; PS = problem solving.

The informant questionnaire on cognitive decline in the elderly (IQCODE) is an example of functional scale [60] with an administration time less than 20 minutes. It consists in a 26 items questionnaire applied to individuals that accompanying the patient. The examiner asks various questions about different performances of the patient in different activities of daily living (ADLs). The IQCODE has a sensitivity of 75% to 83 and a specificity from 65–90% for a cut-point of approximately 3.3 [13]. According to some researchers, this scale has better precision of results than MMSE in cases of MCI [61].

The Pfeifer functional assessment questionnaire (PFAQ) consists in simple questions about performance of elderly people regarding their functional ability in ten activities of daily living such as paying bills, making out business papers, shopping, playing a game of skill, making a cup of coffee, preparing a meal, keeping track of current events, paying attention to TV programs, remembering appointments and travel [62]. For every activity the examiner assigns four level of function from 0 (normal) to 3 (it requires assistance). Total score is 30. This questionnaire can be completed in 15–20 minutes. In a clinical study, the use of PFAQ combined with VFT showed a sensitivity of 88.3% and a specificity of 76.5%, suggesting that these tests could be useful for screening of cognitive impairment among elderly subjects [29].

The clinical dementia rating scale (CDR) is another functional tool to assess behavior and cognition among elderly and to establish the degree of dementia [63]. The administration time is about 20 minutes. This instrument is a 0–3-point numeric scale that explores cognitive and behavioral functions, in order to assess the influence of cognitive impairment on functional capacity to perform activity daily living. The domains explored are six: memory, orientation, judgment, problem solving, community affairs, home and hobbies and personal care. For each domain, a score of 0 means an absence of impairment, while a score of 3 means a severe impairment; total score is 18.

In a study where CDR was used for screening of dementia, the authors found a sensitivity of 95% and a specificity of 94% [64].

The CDR is used in clinical practice and research studies to stage dementia severity and monitor disease progression over times. Since its first version, researchers have developed a modified version of CDR that includes domains of language, behavior and personality disorders to capture a range of symptoms beyond memory impairment associated with less common dementia types [65].

4. Assessment of cognitive functions in demented patients

Comprehensive test batteries provide a baseline of an individual with dementia and monitor symptoms progression over time. Most of the psychometric test planned for the examination of dementia consist in batteries that incorporates pre-existing neuropsychological tests that their creators brought together [66]. Each battery generally contains published tests or tasks specifically developed for the battery. The neuropsychological evaluation typically includes a clinical interview and assessment of different cognitive domains [67].

Orientation assessment consists in asking information about spatial, temporal and personal components.

Complex attention has different domains that include sustained attention, divided attention, selective attention and processing speed. Sustained attention is the ability to maintain attention over time and is tested in tasks where the subjects have to execute specific tasks in a determined time. Divided attention consists in executing two or more tasks in the same period of time. Selective attention consists in maintenance of attention despite distracting stimuli. Examples of attention tasks consist in mental calculations tasks, backwords spans and barrage tasks. Processing speed measures times of reaction in the attention tasks.

Memory comprises recent memory (ability to encode new information), semantic memory (memory of facts), long-term autobiographical memory (memory of personal events) and implicit memory (procedural learning). These sub-domains can be studied using verbal and non-verbal materials. For example, recent and long-term verbal memory are studied using tasks of free recall of words, delayed recall of words, cued recall and recognition. Spatial long-term memory can be studied using tasks of delayed reproduction of geometrical figures.

Executive and processing functions include different sub-components such as working memory, planning, decision-making, feedback error corrections and mental flexibility. Clinicians have many techniques to assess executive functions that include trail-making tests, planning tasks, problem-solving tasks, inhibition tasks based on Stroop interference effect [68], backwords spans, tasks of abstraction, matrix reasoning, verbal judgments and category fluencies.

Language has subdomains that include expressive abilities (naming, fluency, vocabulary and word finding), grammar, syntax and receptive language. Expressive language abilities are generally studied by asking the patient to name objects visually presented. Grammar and syntax errors can be observed during naming and fluency tests. During language assessment examiners generally study also reading, writing, trans-codification abilities and verbal comprehension.

Perceptual-motor functions include visual perception, visual-constructional reasoning, motor coordination, praxis and gnosis. The usual method to detect these deficits is to ask the patients to draw simple and complex geometrical figures such as the Rey–Osterrieth complex figure [69] or block design. Examiners can test visual perception function using line bisection tasks and visual perception tasks. Perception tasks can include facial and colors recognition tasks.

The entire neuropsychological exam can take from several minutes to several hours on the bases of the battery of tests used. The most common batteries used in assessment of cognitive functions are summarized in Table 3.

Battery	Sub-tests	Administration time	Main cognitive functions explored
IBMD	TO; BVRT; COWAT	10–20 minutes	O, VS, L, M, E, PR, VS
DAB	FTT; FDS; NT; ViMT; VeMT; TT; WFT; SDST; CD; NCT	45 min	A, L, M, E, AT, VS
CERAD	VFT; NT; MMSE; WLMT; CP; WLRecall; WLRecog	20–30 min	O, L, E, M, A, VS, PR, C
MFI	MMSE; RCPM; SDST	15–25 min	O, M, L, A, VS, AT
NSB	GENERAL NEUROPSYCHOLOGY TESTS	30–45 min	O, A, M, L, VS, PR
MDB	VFT; PC; WLMT; RCPM; ViMT; CD	40–75 min	VS, L, M, AT, VS, PR
CCT	PinfT; CAT; PIntT; MT; PRS; MF; VR; RLDO	45 min	O, AT, VS, M
DRS	FDS; FTT; CD; VeMT	30–45 min	A, E, PR, AT, M
ABCD	MSQ; SR; WLMT; NT; VC; CD	45–90 min	O, L, M, PR
CSD	VT; VR; VSR; VeMT; OM	120 min	L, E, VS, M
ADAS	MSQ; BSQ	45 min	O, L, M, PR

Table 3.

Neuropsychological batteries for assessment of cognitive functions in dementia.

Abbreviations of the batteries: IBMD=Iowa Battery for Mental Decline; DAB=Dementia Assessment Battery; CERAD=Consortium to Establish a Registry of Alzheimer Disease; MFI = Mental Function Index; NSB=Neuropsychological Screening Battery; MDB = Mental Deterioration Battery; CCT = Cognitive Competency Test; DRS=Dementia Rating Scale; ABCD = Arizona Battery for Communicate Disorders of Dementia; CSD=Cognitive Scales for Dementia; ADAS = Alzheimer’s Disease Assessment Scale.

Abbreviations of the sub-tests: BSQ = behavioral state questionnaires; BVRT = Benton Visual retention test; CAT = card arrangement test; CD = copying designs; CP=Construction praxis; COWAT = Controlled oral association test; FDS=Forward digit span; FTT = finger tapping test; NCT = number cancelation test; MF = management of finances; MMSE = Mini Mental State examination; MSQ = Mental status questionnaires; MT = memory test; NT = naming test; OM = object memory; PC = phrase construction; PInfT = personal information test; PintT = picture interpretation test; PRS=Practical reading skills; RCPM = Raven colored progressive matrices; RLDO = route learning and directional orientation; SDST = symbol digit substitution test; SR = story recall; TO = temporal orientation; TT = token test; VC = verbal comprehension; VeMT = verbal memory test; ViMT = Visual memory test; VFT = Verbal Fluency test; VR = verbal reasoning; VSR = visuo spatial reasoning; VT = vocabulary test; WFT = Word fluency test; WLMT = word list memory test; WLRecall = word list recall; WLRecog = word list recognition.

Abbreviations of the functions explored: O = orientation; A = Attention; M = memory, VS = visuo-spatial function; E = executive functions; L = Language; PR = Praxis; C=Calculation, AT = abstract thinking, PE = perception.

5. Neuropsychological batteries

The Iowa screening battery for mental decline is one of the shortest battery with an administration time of less than 20 minutes [70]. It consists of just three tests: temporal orientation, Benton visual retention test and controlled oral word association test. This battery is able to discriminate patients with dementia due to many aetiologies (degenerative, vascular, mixed or other aetiologies) from normal subjects. The authors use this battery as a screening test and submit to further evaluations subjects with possible dementia.

Another battery of tests generally used for assessment of dementia is the dementia assessment battery (DAB) [71]. This neuropsychological battery consists in administration of ten tests. The finger tapping test consists a 15 seconds trial. Forward digit span consists in two-digit sets. The naming test assesses the abilities to denominate four sets of items of the 60 Boston naming test. Visual memory test consists in four sets of three items of geometric designs similar to those of the Benton visual retention test. Verbal memory test consists in four nine-items lists to be repeated three times in the recall trial and recognized among other words in the recognition trial. Token test is an oral understanding task that comes from the multilingual Aphasia examination battery. Word fluency test is a task of generation of lists of words that comes from the multilingual Aphasia examination battery. Symbol digit substitution test is a five-symbol form of digit symbol that comes from Wechsler intelligence scale. Copying designs is a constructive apraxia task that uses for models Benton visual retention test figures. Number cancelation test is a task specifically developed for this battery. The dementia assessment battery takes about 45 minutes to administer.

Probably the best known of dementia batteries is that developed by the Consortium to Establish a Registry of Alzheimer’s Disease (CERAD) [46]. This battery consists of seven tests. Verbal fluency for semantic category is a test in which the subject has to tell a list of words in the category of animals [72]. The naming test consists in the presentation of 15 items of the Boston naming test with five words each of low, medium and high frequency of occurrence. Mini–mental state is the battery for examination of mental status. Word list memory test is a task consisting in three learning trials of list of ten words. Constructional praxis consists in copying four geometric figures. Word list recall is the delayed recall of the list of the ten words of the word list memory test. Word list recognition consists in the identification of the ten target words among ten distractors. This neuropsychological battery is generally completed within 20 to 30 minutes. The CERAD is both a diagnostic and a follow-up tool.

The mental function index (MFI) is a screening battery [73] that incorporates three tests: the mini–mental state examination (MMSE), The Raven’s colored progressive matrices (RCPM) and the symbol digit modalities test (SDMT). The three tests required 15–20 minutes for normal and mildly demented individuals; very obsessive, very depressed, or confused persons required up to 25 minutes. The scores of the three tests enter into a discriminant function equation to arrive to a mental function index. A score equal or superior to zero is typical in demented patients, while a negative score characterizes no demented patients. This index has a high level of agreement with diagnosis made by neurologists and is useful to discriminate among normal subjects, depressed patients and demented patients. It can be used as a follow-up tool to put in evidence increasing deterioration over a period of several years.

The neuropsychological screening battery [45] consists in 18 tests that cover the major areas of cognitive functioning. The battery is used in an original or an abbreviated form and requires 30–45 minutes. Cut-off scores have been developed for middle age subjects. The battery is enough effective to discriminate between Alzheimer’s patients and normal elderly control subjects by comparing their performance in the different tasks.

The mental deterioration battery (MDB) is a neuropsychology battery generally used in Italy [74]. It is composed by three tests that explore verbal functions and three tests that explore visuo-constructive functions. The verbal tasks are the word fluency, phrase construction and Rey’s 15 words memory, while non-verbal tasks are The Raven’s colored progressive matrices, immediate visual memory test and copying drawings. Phrase construction test consists in asking to the subject to compose sentences from two or three words. Immediate visual memory test uses some of the items of the colored matrices that the patient has to recognize for three seconds among four alternative response choices. In copying drawings, the subject copies a star, a cube and a house on a blank paper, then copies the same figures on a paper containing “landmarks”. The administration time of this neuropsychological battery is about 40–75 minutes. Studies conducted on this battery have demonstrated that non-aphasic subjects with predominant dysfunction in left hemisphere have prevalent deficits in verbal tasks while subjects with predominant dysfunction in right hemisphere have prevalent deficits in visuospatial tasks [75]. Word fluency demonstrated particular sensitivity to dysfunction in anterior cerebral areas, while copying drawings demonstrated particular sensitivity to posterior cerebral areas.

Some psychometric test has been specifically designed to measure competency of elderly patients with dementia [66].

The cognitive competency test [76] is a battery validated on a sample of subjects with an age range from 50 to 93 years. The approximate administration time is 45 minutes. The battery consists of eight tests for each of which have been developed cutting scores. Personal information test requires the subject to write his information on an application form such as the ones used to open a bank account. Card arrangement test requires the subject to give the correct sequence of practical activities such as doing the laundry or making a phone call. Picture interpretation test consists in asking to the subject to explain what is happening in a set of five pictures. The memory test consists in a task of immediate and delayed recall of everyday activities such as time and place of an appointment or a short list of words. Practical reading skills consist in a presentation of pictures of daily situations and asking the subject to choose the proper response. In management of finances, the subject receives an envelope containing ten money-related items such as bills, a credit card application or a blank check and the instructions to sort these items for a bank deposit, pay a bill or doing other financial operations. Verbal reasoning consists in solving practical questions about time management or personal care. Finally, route learning and directional orientation consist in tasks about the correct use of a map of towns and routes, ability to discovery a route or trace a simple path.

The dementia rating scale (DRS) consists in five scales that examine the areas that characterize dementia of Alzheimer’s type [77]. Attention is examined using digit forwards and backward tasks. Initiation and perseveration is examined studying the capabilities to repeat a series of one-syllable rhymes, perform a double alternating hand movements and copying tasks. Construction abilities are studied in a set of tasks of copy a set of figures and lines. Conceptual functions are explored by similarities items. Memory functions consist in tests of delayed recall of lists of words, sentences and designs. In the research used with this battery authors reported age effects, while educational levels did not affect performances [78]. Mattis reports that the examination of demented patients can take 30–45 minutes. The total score of this battery of tests discriminates Alzheimer’s patients from normal control subjects [23] and mildly impaired patients from control subjects [79]. Subscales appear sensitive to different neuropathological conditions. For example, mildly and moderated Alzheimer’s patients were more impaired in the attention and concept formation subscales [78], patients with frontal damage resulted more impaired only in initiation and perseveration subscales, and Korsakoff patients had worse scores in memory subscales [80].

The Arizona battery for communication disorders of dementia (ABCD) is a 14 sub-tests battery constructed for examining speech, language, verbal memory and communication deficits of demented patients [81]. The administration time is from 45 to 90 minutes. The battery consists in mental status, story recall, word learning, description and naming tests, verbal comprehension, but also drawing and copying tasks. Most of these tests have been subjected to reliability and validity evaluation [82]. The subtests of this battery are able to discriminate Alzheimer’s patients from both normal subjects and aphasic stroke patients [82].

Some cognitive scales for dementia [83] are useful to distinguish levels of dysfunction in patients with dementia in particular of Alzheimer’s typology. This cognitive battery consists in a set of six scales developed to assess patients at mild to moderate levels of deterioration to normal elderly subjects. The scales contain from 48 to 122 items. The scales are vocabulary, verbal reasoning, visual–spatial reasoning, verbal memory and object memory. A series of mazes are used to measure executive functions. Testing may take as long as two hours. This battery lowers the floor level and allows for gradations in patient’s performances.

The Alzheimer disease assessment scale (ADAS) is a 21-item scale which combines a mental states examination (items from 1 to 11) and a behavioral examination (items from 12 to 21) [84]. The mental status questions concern orientation, language (speech and comprehension), memory (recall and recognition of a list of words), constructional praxis (ability to copy geometric figures) and ideational praxis (ability to prepare and send a letter). Most items are scored on a scale from one to five. Higher scores indicate severity of dysfunction. Interrater reliability is high for both the cognitive and the behavior sections of the scale. Items analysis shows data differences in relationship to the progression of the severity of the dementia. The ADAS is administered in approximately 45 minutes.

6. Psychometric tools for differential diagnosis of cognitive impairment

Psychometric assessment with specific tools can help clinicians in the process of differential diagnosis of cognitive impairments and dementia (see Table 4).

Type of Cognitive impairment	Psychometric tools for differential diagnosis
Mild cognitive impairment	MMSE, MoCA, ACE-R, DemTect, IQCODE, CAMCOG, SLUMS
Alzheimer’s disease	MMSE, MoCA, MIS, Mini-Cog, CDT, RAVLT, CAMCOG, NPI, Behave-AD
Frontotemporal dementia	FAB, Exit-25
Vascular cognitive impairment	HIS, TMT, DS, MMSE, CAMCOG, ACE-R, MoCA
Parkinson’s disease dementia	MoCA, SCOPA-COG, ACE-R, PD-CRS

Table 4.

Psychometric tools for differential diagnosis of the most common forms of cognitive impairment.

Abbreviations of the psychometric tools: ACE-R = Addenbrooke cognitive examination revised, Behave-AD = Behavioral pathology in Alzheimer’s disease interview, CAMCOG = Cambridge Cognitive Examination, CDT = Clock drawing test, DS=Digit span, Exit-25 = Executive interview, FAB = frontal assessment battery, HIS=Hatchinski ischemic score, IQCODE = Informant Questionnaire on Cognitive Decline in the Elderly, MIS = memory impaired screening test, MMSE = Mini mental state examination, NPI = neuropsychiatric inventory, PD-CRS=Parkinson disease cognitive rating scale, RAVLT = Rey auditory verbal learning test, SCOPA-COG = Scales for outcomes of Parkinson disease-cognition, SLUMS=Saint Louis University Mental Status examination, TMT = trail making test.

Mild cognitive impairment (MCI) is a clinical condition generally involving memory (in amnestic forms) but not functioning so that it do not meets clinical criteria for dementia [85]. Other major criteria included by the International Working Group consist in suboptimal performance on cognitive tests without evidence of functional limitations [86]. The assessment and follow-up of these subjects is necessary due to their increased risk for developing dementia [87]. The most commonly test used in clinical practice for diagnosis of MCI are MMSE, MoCA, ACE-R, DemTect, SLUMS, IQCODE and CAMCOG. The sensitivity of MMSE in the diagnosis of MCI varies from 18.1% to 85.7%, while specificity varies from 48–100% [88]. The MoCA for screening of MCI has a sensitivity of 90% and a specificity of 87% [54] and is probably the best alternative to the MMSE in detecting MCI among patients older than 60 [89]. Also, the ACE-R has high sensitivity (84%) and specificity (100%) in the screening of MCI [90]; however, both MoCA and ACE-R have failed to discriminate patients with MCI minimally educated and healthy controls matched for age and education [91]. DemTect has a sensitivity of 80% in screening of MCI [15]. Another psychometric instrument for the assessment of MCI is the Saint Louis University Mental Status Examination (SLUMS) with a sensitivity of 92–95% and a specificity of 76–81%. SLUMS is probably better than MMSE in detecting MCI [30].

Alzheimer’s disease (AD) is the most common form of degenerative dementia. The typical presentation consists in memory impairment and executive dysfunction interfering with daily life activities [92]. Many tests have been validated for screening of patients with moderate Alzheimer’s disease such as MMSE, MoCA, MIS, Mini-Cog, CDT, CAMCOG and RAVLD. Study of delayed memory impairment conducted using RAVL-DR (Rey auditory verbal learning test—delayed recall of a list of 15 words) have demonstrated that it can predict AD with an accuracy of 75.9% [93]. Some authors suggest that a supraspan learning task in the immediate recall task can give information about short-term retention and learning capabilities [94]. Patients with defective learning abilities (such as patients with Alzheimer’s dementia) show a better recall of the words at the end of the list than those at the beginning (known as “recency effect”). On the other hand, normal subjects have generally better recall of the words at the beginning of the list then most of the other words (known as “primacy effect”). Many subjects with good learning capability repeat the list in almost the same order as it is given [66]. Patients with early Alzheimer’s type dementia have a very low recall for the first presentation of the 15-words list and performances characterized by many more intrusions than patients with other diagnostic groups [95].

Some psychometric tools such as neuropsychiatric inventory [96] or behavioral pathology in Alzheimer’s disease focus the attention on different aspects of behavior disorders that are common in this form of dementia. The behavioral pathology in Alzheimer’s disease (Behave-AD) [97] reviews seven categories of behavior symptoms. These are paranoid and delusional ideation (e.g. hallucinations or activity disturbances), aggressivity, diurnal rhythm disturbances, affective disorders, anxieties and phobias. The behavioral symptoms often create problems for caregivers of demented patients but could be pharmacologically treated. Each of the behavioral symptoms is rated on a four-point scale in which a score of zero indicates that the symptom is not present, while a score of 3 indicates that the symptom is present and not tolerated by the caregiver. A follow up of behavioral symptoms thought the course of the disease is possible with this instrument.

Frontotemporal dementia is a degenerative form of dementia less common than Alzheimer’s disease. Neuropsychological instruments focused on detection of impairments in executive functions are important for the diagnosis of this form of dementia [98]. An example is the frontal assessment battery (FAB), a short battery that takes about 10 minutes to complete [99]. The score of FAB ranges from 0 to 18. Subjects with a lower score have a more severe impairment [100]. The FAB is effective to differentiate patients with frontal lobe impairment from healthy subjects [100]. The executive interview (EXIT-25) is another screening toll exploring executive functions that takes about 10 minutes to complete [101]. FAB and EXIT-25 have a similar diagnostic power for distinguishing frontotemporal dementia from Alzheimer’s disease [98].

Cerebrovascular diseases are a common cause of cognitive impairments known as vascular cognitive impairment and vascular dementia. Clinical tools such as the Hatchinski ischemic score [102] sometimes modified [103] help clinicians to distinguish vascular dementias from other primary dementia types such as Alzheimer’s disease. Some items have a score of 2 points such as abrupt onset of dementia, fluctuating course, history of strokes, presence of focal neurological symptoms and presence of focal neurological signs. Other items have a score of 1 point such as stepwise deterioration, presence of nocturnal confusion, relative preservation of personality, presence of depression, somatic complaints, emotional continence, history of hypertension and evidence of associated atherosclerosis. The total score of the Hatchinski Ischemic score is 18. Studies conducted by Hatchinski and his colleagues [102] demonstrated that the ischemic score clearly differentiated patients suffering from Alzheimer’s dementia from patients with multi-infarct dementia. In fact, the higher the score the more likely is that the patient is suffering from vascular dementia. Prominent cognitive deficits in vascular cognitive impairment are executive and attentional functions while episodic memory is relatively intact. The best neuropsychological tools for assessment of patients with small vessels disease are the trail making test and digit spans [104]. The MoCA and the informant-based cognitive screening test (IBCST) are screening tools for diagnosis of multidomain cognitive impairment in stroke and post-stroke dementia [105]. Other screening tools that can be used for differential diagnosis of post-stroke dementia include the MMSE, the Rotterdam-CAMCOG [37] and the Addenbrooke’s cognitive examination [36].

Cognitive impairment in Parkinson disease generally includes fronto-subcortical dysfunctions such as attention, frontal and executive functions deficits. Less common are cortical dysfunctions such as memory and visuospatial deficits. The MoCA is a tool that can be suited for screening of cognitive impairment in Parkinson disease [106]. Another valid instrument sensitive to cognitive deficits in Parkinson’s disease is the scale for outcomes of Parkinson’s disease-cognition (SCOPA-COG). SCOPA-COG is a 10-item scale with a maximum score of 43 [107]. The ACE-R with a cut-off less than 89 has a sensitivity of 69% and a specificity of 84% in detecting mild cognitive impairment in Parkinson disease. Finally, the Parkinson’s disease cognitive rating scale (PD-CRS) is a tool that identifies both fronto-subcortical than cortical deficits associated with Parkinson’s disease [108]. The PD-CRS has a sensitivity of 94% and specificity of 94% in diagnosis of dementia in Parkinson’s disease [108].

7. Conclusions

There are many neuropsychological tools for screening and assessment of cognitive functions among elderly people. Scales, inventories and other tests designed for the screening of dementia contain items and tasks that are sensitive to the most common dementing processes especially recent and remote memory and some aspects of attention. The mini–mental state examination is still the most commonly used in screening of dementia. Other commonly used screening tools include the montreal cognitive assessment and the clinical dementia rating scale.

For a detailed cognitive profile of the dementia and differential diagnosis of the different forms of dementia, examiners must explore many cognitive areas that include memory, attention, executive functions, language and visuo-spatial functions. It involves the use of neuropsychological batteries of tests, each one measuring a distinct cognitive ability with greater sensitivity and specificity than a screening toll. Diagnostic accuracy may be enhanced by combining data from several of the instruments described in this chapter.

Neuropsychological measurements play an important role in identification conditions of normal aging, dementia assessment, prediction of development of cognitive impairment, measurement of residual functional abilities and identification of possible targets of intervention [109].

However, still nowadays it is necessary to create new cognitive instruments used by general practitioners within primary care services as routine procedures in order to reduce negative effects of dementia on elderly people.