Sleep efficiency in patients with Parkinson’s disease with cognitive impairment

Abstract

Objective To assess the sleep quality in the Parkinson’s disease (PD) patients with cognitive impairment and to analyze the possible relationship between sleep disorders and cognitive impairment in PD patients. Methods One hundred and nine PD patients were assessed cognitive function using Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA) and Wechsler Intelligence Scale and Wechsler Memory Scale, and sleep quality was evaluated using the Parkinson’s Disease Sleep Scale-2 (PDSS-2), Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale. All PD patients were divided into abnormal cognitive group (n=46) and normal cognitive group (n=63). Results PDSS-2 and PSQI scores were significantly higher in abnormal cognitive group than in normal cognitive group (23.88±13.00 vs 13.80±9.76, t=-3.745, P<0.01; 10.58±4.89 vs 6.87±4.64, t=-3.269, P=0.001). The scores of PDSS-2 in PDSS-2-2, 3, 4, 5, 6, 9 and 〖JP2〗PSQI in sleep quality (1.76±1.00), sleep time (1.42±1.09), sleep efficiency (1.52±1.28) as well as sleep disorder (1.61±〖JP〗0.56) were also significantly higher in abnormal cognitive group than in normal cognitive group (1.04±0.85, 0.91±1.08, 0.89±1.17, 1.25±0.65, t=-3.134, -2.286, -2.363, -2.590, all P<0.05). The correlations between the scores of MoCA and PDSS-2, MoCA and PSQI were significant (r=-0.24, P=0.03; r=-0.23, P=0.04). Conclusions The PD patients with abnormal cognition have lower sleep quality than those with normal cognition. Combining PDSS-2 with PSQI could preliminarily understand the underlying causes and the degree of PD patients with sleep disorders. Key words: Parkinson disease; Cognition disorders; Sleep disorders; Sleep