Study Objectives: Insomnia and daytime sleepiness are common complaints in Parkinson disease (PD), but the main causes remain unclear. We examined the potential impact of both motor and non-motor symptoms of PD on sleep problems. Methods: Patients with PD (n = 128) were assessed using the Insomnia Severity Index, Epworth Sleepiness Scale, Unifi ed Parkinson Disease Rating Scale, Beck Depression Inventory, Fatigue Severity Scale, Survey of Autonomic Symptoms, and the 39-item Parkinson Disease Questionnaire. A subset of subjects (n = 38, 30%) also completed nocturnal polysomnography and a multiple sleep latency test (MSLT)
S C I E N T I F I C I N V E S T I G A T I O N SS leep-related disturbances, including insomnia and excessive daytime sleepiness, are some of the most common complaints of patients with Parkinson disease (PD). As many as 60% to 76% of PD patients experience insomnia.1,2 Nocturnal hypokinesia, nocturnal and early morning dystonia, and impaired bed mobility are thought to be common causes.2,3 In practice, attention often focuses on motor symptoms of PD, and these are probably considered fi rst as possible causes of sleep disturbance. Although non-motor symptoms, such as depressed mood, anxiety, pain, or frequent nocturia tend to receive less clinical consideration, such symptoms could have substantial impact on sleep. 4 In particular, depression is the most common psychiatric problem in PD, with an estimated prevalence of 17% to 50%, 5,6 depending on the rating scales or structured clinical diagnosis used to identify the problem. Several studies have examined the relationship between depressed mood and sleep disturbance in PD patients. 7 The relative contributions, however, of motor and non-motor features to sleep disturbance remains unclear, despite the important impact that sleep disturbance can have on quality of life in patients with PD. Furthermore, the potential value of objective sleep laboratory data, in understanding sleep-related complaints in PD, remains unclear. The main objective of this study was to examine associations of both motor and non-motor PD symptoms with reported sleep problems. We hypothesized that non-motor and motor symptoms of PD patients would each show independent association with subjective insomnia or daytime sleepiness. In a subset of patients, we also assessed the extent to which polysomnography and the multiple sleep latency test (MSLT) may help to understand sleep complaints in PD.
BRIEF SUMMARYCurrent Knowledge/Study Rationale: Sleep disturbance and daytime somnolence are common complaints in patients with Parkinson disease (PD), but the main causes remain unclear. This study was done to explore associations between sleep-related complaints and potential contributors, including both motor and non-motor PD symptoms. Study Impact: Non-motor features of PD, such as mild depressive symptoms, fatigue, and autonomic symptoms, are associated with subjective insomnia, whereas fatigue and dopaminergic medication dose are associated with subjective daytime sleepiness. I...