Insomnia, Sleep Quality, and Quality of Life in Mild to Moderate Parkinson's Disease

Rationale: Sleep disorders are prevalent in Parkinson's disease but underreported in clinical settings. The contribution of sleep disorders to health-related quality of life (HRQOL) for patients with this degenerative neurological disease are not well known. Objectives: To evaluate the impact of insomnia symptoms, obstructive sleep apnea (OSA), and poor sleep quality on HRQOL in a cohort of patients with idiopathic Parkinson's disease. Methods: We enrolled a convenience sample of 66 adults seen in the University of Miami Movement Disorders Clinic between July 2011 and June 2013. Participants completed validated questionnaires to determine insomnia symptoms, OSA risk, depression, anxiety, and HRQOL. All patients underwent unattended polysomnography to confirm OSA. Results were compared for those with and without insomnia symptoms. Principal component and regression analyses were performed to evaluate determinants of HRQOL. Measurements and Main Results: Participants were predominately Hispanic males with mild to moderate Parkinson's disease. Insomnia symptoms were reported for 46% of the study subjects. OSA (apnea-hypopnea index, >= 5) was noted in 47%, with a mean apnea-hypopnea index of 8.3 +/- 11.0. Fairly bad to very bad sleep quality was reported by 21% of the participants. Insomnia (r = 0.71; P < 0.001), daytime sleepiness (r = 0.36; P = 0.003), depression symptoms (r = 0.44; P, 0.001), and anxiety symptoms (r = 0.33; P = 0.006) were significant correlates of poor sleep quality. OSA, severity of Parkinson's disease, and dopaminergic therapy were not. In the principal component analysis, sleep quality was a significant component of the "psychological factor" that in turn was a significant determinant of overall HRQOL. Conclusions: Insomnia symptoms, OSA, and subsequent poor sleep quality are prevalent in Parkinson's disease. In this single-center, exploratory study, we found that insomnia and poor sleep quality, but not OSA, play important roles in determining overall quality of life for patients with this disease.