Cognitive impairment is one of the common non-motor complications in Parkinson’s disease. The underlying mechanism remains elusive due to multiple reasons. As a result, treatment options for cognitive decline in Parkinson’s disease are limited and not as effective as those for motor symptoms. Recent advances in neuroscience have developed new models for the pathophysiology of Parkinson’s disease dementia, based on which clinical research have showed promising results. The role of multiple neurotransmitter systems in cognitive impairment have been emphasized. The change in different functional neural networks (including microscale, mesoscale, and macroscale) resulting from abnormal neurobiochemical environment partly explains the clinical picture. Accordingly, neuromodulation methods can be good candidates for symptomatic management. Several preliminary studies on deep brain stimulation have demonstrated positive results. The nucleus basalis of Meynert, a hub in the cognitive network, is chosen by most studies as the stimulation target. Deep brain stimulation for motor symptoms, on the other hand, may also cause or aggravate patients’ cognitive dysfunction. Their influence on cognition is multifaceted and should be taken into account during patient selection, target design, and programming.
Part of the book: Dementia in Parkinson’s Disease