Cognitive Function in Early and Advanced Parkinson’s disease

Abstract

Objective: To investigate the occurrence of mild cognitive impairment (MCI) in early and advanced Parkinson's disease (PD) and identify the risk factors for PD-MCI.Methods: A total of 138 PD patients were recruited between April 2015 and December 2017. We evaluated demographic and clinical data, including sex, age, age of onset, disease duration, Hoehn and Yahr stage, Unified Parkinson's Disease Rating Scale (UPDRS) part Ⅲ, 39-item Parkinson's Disease Questionnaire (PDQ-39), Epworth Sleepiness Scale (ESS), Beck Depression Inventory (BDI) and Mini-Mental State Examination (MMSE) scores. Participants were divided into early and advanced PD groups according to Hoehn and Yahr stage. Group comparisons were performed using Student's t-tests or chi-square tests. Binary logistic regression was conducted to identify risk factors for PD-MCI. Results:There was no significant difference in MMSE scores between the early and advanced groups. According to PD-MCI Level 1 criteria, 27 individuals (30.0%) in the early group and 16 individuals (33.3%) in the advanced group were classified as having PD-MCI. The proportion of PD-MCI was not significantly different between the two groups (chi-square = 0.162, p = 0.687). No demographic or clinical factors were significantly associated with the development of PD-MCI. Conclusions:Cognitive impairment is stable in PD patients with short disease duration when the MMSE is used as a global cognitive test. The occurrence of PD-MCI is high, even in newly diagnosed PD patients.