Sleep-related problems of Parkinson's disease.

OBJECTIVE To define the epidemiology, characteristics and aetiology of nocturnal symptoms and sleep disorders in patients with Parkinson's disease (PD) and evaluate the available methods for their diagnosis and management. METHODS A review of the English-language literature pertaining to sleep disturbances associated with PD, using the Medline database and bibliographies in relevant articles. RESULTS Sleep-related problems specific to PD may occur early and even predate the diagnosis of the disease but are generally more frequent and more severe in patients with advanced PD. These problems can seriously compromise patients' quality of life and lead to impaired functioning in daily activities. Scales designed specifically for the assessment of sleep problems in patients with PD have recently been developed. Evidence base for the treatment of sleep disturbances in PD is poor, and only nocturnal akinesia, excessive day-time sleepiness and rapid eye movement behaviour disorder have been partially addressed. CONCLUSIONS Sleep disorders associated with PD are a common and under-recognised problem. The assessment of sleep should be part of the routine evaluation of patients with PD, and large-scale controlled therapeutic trials are necessary.