The impact of nocturnal disturbances on daily quality of life in patients with Parkinson’s disease

OBJECTIVES The aims of this study were to explore nocturnal disturbances in patients with Parkinson's disease (PD) and to assess their impact on quality of life (QoL). METHODS A total of 211 patients with PD were recruited for this study, and each participant was evaluated using the mini-mental state examination, PD sleep scale - second version (PDSS-2), pittsburgh sleep quality index (PSQI), PD QoL questionnaire (PDQ), Epworth sleepiness scale, Hoehn and Yahr (H&Y) staging, and unified Parkinson's disease rating scale (UPDRS). Multiple regression analyses were performed to determine the contribution of the predictive variables on QoL. RESULTS There were 56.4% males (mean age: 64.08 years; disease duration: 6.02 years; H&Y stage: 2.25; and UPDRS: 33.01) in this study. Our patients' actual sleep time was 5.96±1.16 hours and the average sleep efficiency was 82.93%±12.79%. Up to 64.4% of patients were classified as "poor" sleepers and 23.8% suffered from daytime sleepiness. The final stepwise regression model revealed that UPDRS parts I and II, the sleep disturbance and daytime dysfunction components of the PSQI, the PD symptoms at night subscale of the PDSS-2, and the levodopa equivalent dose were significant predictors of the PDQ score (R (2)=53, F 7,165=28.746; P<0.001). CONCLUSION Most of the PD patients have sleep problems, and nearly one-quarter of them have abnormal daytime somnolence. The nocturnal disturbances were found to result in worse QoL in PD patients. Ethnicity-specific effects of susceptibility to sleep disturbances were discussed, and these results also highlighted the direction for further studies to explore when examining effective management programs toward these disturbances.