Abstract
OBJECTIVE: Cognitive impairment is an important symptom of Parkinson's disease (PD) and seriously affects patients' quality of life and prognosis. However, its cause is still uncertain. In about one-third of patients, PD is associated with rapid eye movement sleep behavior disorder (RBD), which is an independent risk factor for PD-associated dementia; but whether or not it relates to the cognitive function of patients with nondemented PD is still controversial. METHODS: The data from 89 enrolled PD patients were retrospectively analyzed. The RBD Questionnaire Hong-Kong (RBD-HK) was used to diagnose possible RBD (pRBD). There are 46 patients with possible RBD (the PD-pRBD) and 43 without (the PD-npRBD). PD disease severity, neuropsychological function, overall cognitive function, and various cognitive functions were assessed. RESULTS: There were significant between-group differences in scores on the Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), Digit Symbol Test (DST), Trail Making Test-A (TMT-A)-Time, TMT-Trail Making Test-B (TMT-B)-Time, Stroop Color-word Test, Clock Drawing Test (CDT), Boston Naming Test (BNT), Verbal Fluency Test (fruit), etc. (P < 0.05). INTERPRETATION: Patients in the PD-pRBD group had more cognitive impairment.