Relationship between sleep disorders and other non-motor symptoms in Parkinson's disease

The association between sleep disorders and other non-motor symptoms (NMS) in Parkinson's disease (PD) has been scarcely investigated.To describe the prevalence of insomnia and hypersomnia in PD and analyze their relationship with other NMS.Cross-sectional, multicenter study including 388 PD patients evaluated with Hoehn and Yahr, Clinical Impression of Severity Index for PD, Scales for Outcomes in Parkinson's Disease (SCOPA)-Sleep(S), SCOPA-Cognition, SCOPA-Psychiatric Complications, SCOPA-Autonomic, Hospital Anxiety and Depression Scale, and fatigue and pain visual analogue scales. Spearman correlation coefficients, Mann-Whitney test and multiple linear regression analysis were applied.Mean age (54% male) was 65.9 ± 11.2 years old, with disease duration of 8.1 ± 6.0 years and median HY = 2 (range: 1-5). Mean SCOPA-S nocturnal sleep (NS) was 5.4 ± 4.0 (range: 0-15), daytime sleepiness (DS) was 3.76 ± 3.04 (range: 0-15). Most of the sample declared nocturnal or daytime sleep problems (87.4%). Weak-to-moderate correlations were found between sleep disturbances and other NMS (range: 0.14-0.37). SCOPA-S subscales showed higher scores with the presence of most other NMS such as psychiatric complications and autonomic dysfunctions (p 0.05). Regression models showed that fatigue, depression, urinary, cardiovascular, and thermoregulatory dysfunctions were significant determinants of SCOPA-NS score (variance: 23%); cognitive impairment, urinary, cardiovascular, and pupillomotor disorders influenced SCOPA-DS score (variance: 14%).Insomnia and daytime sleepiness are extremely prevalent in PD. Depression, fatigue, cognitive impairment, cardiovascular, urinary and thermoregulatory dysfunctions may contribute to insomnia/hypersomnia. This is the first clinical study to relate cardiovascular and thermoregulatory dysfunctions with sleep in PD.