Cognitive impairment in Parkinson's disease

Abstract

Parkinson's disease cognitive impairment (PD-CI) is one of the major non-motor symtoms (NMS) of PD, including Parkinson's disease with mild cognitive impairment (PD - MCI) and Parkinson's disease dementia (PDD). Executive dysfunction is relatively prominent, but other cognitive domains as visuospatial ability, memory and language can also be affected. Main risk factors for PD-CI include male gender, advanced age, low education, severe motor symptoms, low baseline cognitive function and excessive daytime sleepiness (EDS). Lewy bodies are main pathological changes, and Alzheimer's disease (AD) related pathological changes can also be seen. The application value of decreased α?synuclein (α-Syn) and β-amyloid 1-42 (Aβ1-42) levels in cerebrospinal fluid (CSF) as biomarkers remains controversial. There are few related research and no defined pathogenic genes currently. Both dopaminergic pathway and acetylcholinergic pathway are involved in the occurrence of PD - CI as demonstrated in PET studies. Cortical and subcortical atrophy are associated with PD - CI as observed in MRI studies. Olfactory dysfunction may be one of the predictors of cognitive impairment. PDD and dementia with Lewy bodies (DLB) share common biological characteristics, therefore the differential diagnosis sometimes is difficult. Cholinesterase inhibitors (ChEIs) and memantine help to improve clinical symptoms, but treatment decision should be made with individualization. Cognitive behavioral treatment (CBT) has potential clinical value and should be investigated by more studies.

DOI: 10.3969/j.issn.1672-6731.2017.06.004