Objective sleep structure and cognitive function in Parkinson’s disease patients with rapid eye movement sleep behavior disorder

Abstract

Objective To evaluate the sleep structure and cognitive function in Parkinson’s disease (PD) patients with rapid eye movement (REM) sleep behavior disorder (RBD)，and then explore the correlation between sleep structure and cognitive function in PD patients with RBD. Methods It was a cross-sectional study.Ninety-seven patients in our sleep center，including 39 PD patients with RBD and 21 age-and sex-matched idiopathic RBD (iRBD) patients (control group)，37 PD patients without RBD (control group)，underwent video-polysomnography to acquire sleep parameters. Cognitive function was assessed with the Montreal Cognitive Assessment (MoCA) on the same day.A multiple linear regression model was used to find the score of cognition correlated with sleep structure. Results (1) The sleep efficiency，total sleep time，non-rapid eye movement (NREM) 2 and REM sleep time were all significantly decreased in PD patients with RBD than those in iRBD patients (60.9%±16.9% vs 77.8%±16.9%，(329.7±96.5) min vs (397.1±88.9) min，(127.6±67.6) min vs (188.0±94.7) min，(45.3±33.2) min vs (70.6±25.9) min，all P<0.05)，respectively.There were no significant differences of these above parameters compared to PD patients without RBD (61.3%±21.7%，(324.9±134.6) min，(132.6±65.6) min，(47.1±31.9) min).There was no statistical significance in sleep latency，REM-sleep latency，NREM1 time，the percentage of slow wave sleep，oxygen desaturation index，apnea hyponea index and periodic leg movement in sleep among three groups. (2) PD patients with RBD had the lowest MoCA scores.The score of visuospatial and executive function in PD patients with RBD was lower than that in iRBD (3.8±1.1 vs 4.4±0.7; F=3.426，P<0.05). (3) Multiple linear regression analysis showed that there was correlation between the score of visuospatial and executive functions and the course of RBD，sleep efficiency and NREM2 in PD patients with RBD. Conclusions The PD patients with RBD have the worst sleep efficiency and cognitive function，the shortest total sleep time，NREM2 and REM sleep time.The cognitive impairment may be correlated with the change of sleep structure. Key words: Parkinson’s disease; REM sleep behavior disorder; Polysomnography; Cognition