Objective To investigate the sleep structure of Parkinson's disease (PD) patients with rapid eye movement sleep behavior disorder (RBD) and its correlations with cognitive function, depressive state and motor function.

Methods A total of 120 PD patients were enrolled in this study, and divided into PD+RBD group (n=45) and PD group (n=75) based on the presence or absence of RBD. Sleep structure was recorded for both groups. The scores of the Montreal Cognitive Assessment (MoCA), Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD), Unified Parkinson's Disease Rating Scale Part Ⅲ (UPDRS-Ⅲ) and Scales for Outcomes in Parkinson's Disease-Autonomic (SCOPA-AUT) were compared between the two groups. The correlations of MoCA, HAMA, HAMD, UPDRS-Ⅲ and SCOPA-AUT scores with sleep structure in the PD+RBD group were analyzed.

Results The PD+RBD group showed significantly higher percentage of non-rapideye movement (NREM) at stage 1, arousal index, periodic limb movements during sleep (PLMS) and apnea-hypopnea index (AHI) compared to the PD group, while the percentages of NREM at stage 3, rapid eye movement (REM) sleep, sleep efficiency and lowest oxygen saturation were significantly lower (P < 0.05). The PD+RBD group also had significantly higher HAMA, HAMD, UPDRS-Ⅲ and SCOPA-AUT scores, and significantly lower MoCA scores compared to the PD group (P < 0.05). In the PD+RBD group, the percentages of NREM at stage 1, arousal index, PLMS and AHI were positively correlated with HAMA, HAMD, UPDRS-Ⅲ and SCOPA-AUT scores, and negatively correlated with MoCA scores (P < 0.05). Conversely, the percentages of NREM at stage 3, REM sleep, sleep efficiency and lowest oxygen saturation were negatively correlated with HAMA, HAMD, UPDRS-Ⅲ and SCOPA-AUT scores, and positively correlated with MoCA scores (P < 0.05).

Conclusion PD patients with RBD exhibit disrupted sleep structure, which is closely associated with cognitive function, depressive state, motor function, and autonomic nervous system function.