The clinical characteristics and cognitive features of mild cognitive impairment in Parkinson's disease and the analysis of relevant factors.

The purpose of this work is to investigate the clinical characteristics, cognitive impairment features, and subgroup types of Parkinson's disease (PD) subjects with mild cognitive impairment (PD-MCI) in the Chinese population and to analyze relevant risk factors for PD-MCI. A total of 234 non-dementia PD subjects were collected. Standardized neuropsychological assessments of overall cognitive level and four cognitive domains (memory, executive function, attention and visuospatial function) were performed using MDS Task Force diagnostic criteria for PD-MCI. PD-MCI subjects were further divided into four subgroups: nonamnestic single-domain impairment type (PD-naMCI-SD), nonamnestic multiple-domain impairment type (PD-naMCI-MD), amnestic single-domain impairment type (PD-aMCI-SD), and amnestic multiple-domain impairment type (PD-aMCI-MD). The clinical characteristics of and risk factors for all subgroups were analyzed. PD-MCI was found in 45.3% of the non-dementia PD subjects. Differences between the PD-MCI and PD with normal cognition groups with respect to age, age of onset, years of education, and motor symptom severity were significant (P < 0.05). The single-domain impairment type was the largest PD-MCI subgroup (52.83%). Memory and executive function impairment were most frequent (22.64% and 20.75%, respectively). Among the four subgroups, the number of years of education was significantly different (P = 0.003). The overall cognitive function in amnestic multiple-domain impairment type was significantly worse compared with that in those with single-domain impairment type. Regression analysis results showed that old age, high UPDRS-III score, and hyperhomocysteinemia were risk factors for PD-MCI, whereas high education level was a protective factor. Early prevention of MCI-related risk factors provides effective means to retard cognitive decline in PD patients.