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

BackgroundThe association between sleep disorders and other non-motor symptoms (NMS) in Parkinson's disease (PD) has been scarcely investigated.ObjectiveTo describe the prevalence of insomnia and hypersomnia in PD and analyze their relationship with other NMS.MethodsCross-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.ResultsMean 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%).ConclusionsInsomnia 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.