Purpose of the Study: Sleep problems are frequently encountered in Parkinson's disease (PD), including sleep fragmentation, rapid eye movement (REM) sleep behavior disorder (RBD), excessive daytime sleepiness, and sleep-disordered breathing. In this study, we aimed to examine the relationship between sleep structure and sleep disorders on motor and nonmotor symptoms of PD. Basic Procedures: Seventy-three consecutive patients diagnosed as having PD based on the United Kingdom Brain Bank Criteria were prospectively enrolled. Detailed histories of PD-related symptoms, sleep anamnesis, subjective evaluation of nocturnal sleep, and daytime sleepiness were made. All participants underwent one-night video-polysomnography (PSG) and multiple sleep latency test (MSLT) in a sleep laboratory. Main Findings: A significant correlation was present between female sex and RLS (P = 0.009). Age and body mass index showed no significant correlations with PD-related parameters including Unified Parkinson's Disease Rating Scale (UPDRS) scores and PSG parameters. RLS or RBD showed no significant correlation with PD-related variables. Among PSG parameters, higher REM sleep percentages showed a statistically significant correlation with increased scores of UPDRS part III (P = 0.007). A statistically significant negative correlation was present between apnea-hypopnea index and PD duration (P = 0.005), and the presence of obstructive sleep apnea syndrome (OSAS) was statistically significantly correlated with lower scores of UPDRS part II (P = 0.050). The mean sleep latency in MSLT decreased as the dose of dopaminergic treatment increased (P = 0.016). Principal Conclusions: Our study demonstrated that changes in sleep structure and sleep-related disorders observed in PD could be attributed to intrinsic disease-related properties. The presence of changes in sleep structure as higher REM sleep percentages and sleep-related disorders such as OSAS show correlations with the severity of PD. Department of Neurology, Faculty of Medicine, Istanbul University Cerrahpasa Our study was funded by the Department of Neurology, Faculty of Medicine, Istanbul University Cerrahpasa.
