关键词: 帕金森病, 快速眼动睡眠行为障碍, 自主神经功能障碍, 疾病严重程度, 中介效应

Abstract: Background　Previous studies have showed that the rapid eye movement sleep behavior disorder（RBD） and autonomic dysfunction are associated with the severity of the Parkinson's disease（PD），but there is a lack of studies on whether autonomic dysfunction plays a role in the relationship between RBD and PD severity. Objective　To examine whether autonomic dysfunction plays an intermediary role in the relationship between RBD and PD severity，and whether the role is influenced by age. Methods　A total of 669 PD patients meeting the inclusion criteria were selected from the Parkinson's Progression Markers Initiative database from January to December 2018. General socio-demographics，RBD prevalence（assessed by the REM Sleep Behaviour Disorder Screening Questionnaire），autonomic dysfunction prevalence（assessed by the Scales for Outcomes in Parkinson's Disease-Autonomic questionnaire），and PD severity 〔assessed by the modified Hoehn and Hahr （H-Y） staging〕 were collected. Using the RBD as the independent variable，severity of PD as the dependent variable，the autonomic dysfunction as the intermediate variable，and age as the subgroup variable（less than 56 years，56-65 years and greater than 65 years），a model for investigating the intermediating effect size of autonomic dysfunction between RBD and PD severity was constructed. Results　Those aged above 65 years had a higher mean modified H-Y staging than those aged less than 56 or 56-65 years（P<0.05）. Pearson correlation analysis showed that the severity of PD was positively correlated with RBD and autonomic dysfunction（r=0.200，0.299，P<0.01），and RBD was positively correlated with autonomic dysfunction（r=0.384，P<0.01）. In all participants，autonomic dysfunction partially played an intermediary role between RBD and PD severity，with an effect size of 0.031 with Bootstrap 95%CI（0.022，0.041），accounting for 50.00% （0.031/0.062） of the total effect.For those aged less than 56 years，autonomic dysfunction fully played an intermediary role between RBD and PD severity，with an effect size of 0.034 with Bootstrap 95%CI（0.016，0.056）. For those aged between 56-65 years，autonomic dysfunction partially played an intermediary role between RBD and PD severity，with an effect size of 0.028 with Bootstrap 95%CI（0.014，0.046），accounting for 39.43% （0.028/0.071） of the total effect. For those older than 65 years，autonomic dysfunction fully played an intermediary role between RBD and PD severity，with an effect size of 0.027 with Bootstrap 95%CI（0.012，0.046）. Conclusion　Autonomic dysfunction may produce intermediating effect on the relationship between RBD and PD severity，and the effect size may be impacted by age.

Key words: Parkinson disease, Rapid eye movement sleep behavior disorder, Autonomic dysfunction, Severity of illness, Mediating effect