Sleep disturbance and health-related quality of life in Parkinson's disease: A clear correlation between health-related quality of life and subjective sleep quality

Comorbid insomnia and poor sleep quality in Parkinson's disease (PD) are associated with a poor health-related quality of life (HRQoL). However, the relationship between HRQoL and sleep measures obtained using polysomnography (PSG) remains unclear. We aimed to examine the association between various sleep measures and HRQoL in PD patients.We retrospectively included patients with PD who underwent PSG and responded to self-administered questionnaires including the Pittsburgh Sleep Quality Index (PSQI) and Medical Outcomes Study 36-Item Short-Form Health Survey.The patients' (n = 120) mean age was 67.06 (SD = 8.77) years, and their mean Hoehn and Yahr stage was 2.25 (SD = 0.78). A higher PSQI score (worse subjective sleep quality) was correlated in PSG with shorter sleep latency, less N1 sleep, and more N2 sleep. Multiple regression analysis showed that the total PSQI score correlated with both physical and mental HRQoL (p 0.001 in both cases). However, neither type of HRQoL studied correlated with objective sleep measures, including indicators of sleep architecture, sleep-disordered breathing, and sleep related movement disorders.Despite the association between subjective sleep quality and HRQoL, the associations between objective measures and HRQoL were negligible. Objective sleep fragmentation may not be perceived as a sleep disturbance in patients with PD, and therefore may not adversely affect their subjective health, given the paradoxical correlation between PSQI score and sleep architecture.