Sleep disorders in Parkinson's disease: epidemiology and management

Sleep problems are an under-emphasised cause of disability in Parkinson's disease (PD) and may be seen independently of PD, associated with primary PD pathology, or as a result of antiparkinsonian medications. Common sleep disorders include excessive daytime sleepiness, rapid eye movement (REM) sleep behaviour disorder, night-time wakefulness and restless legs syndrome. A number of strategies may be used to improve sleep cycle disturbances, and often these interventions do not require pharmacological manipulation. Restoring traditional mealtimes and scheduling activities during predicted periods of sleepiness may help alleviate daytime somnolence; the use of controlled-release levodopa preparations or administration of a catechol-O-methyl transferase (COMT) inhibitor with levodopa at bedtime may reduce periods of night-time wakefulness. Administration of clonazepam at bedtime may assist with REM sleep behaviour disorder but, because this agent can result in daytime somnolence, experimentation with dosage times is recommended. Sleep attacks are described as a sudden, unavoidable transition from wakefulness to sleep and, although rare, have been described with pramipexole, ropinirole and other dopamine agonists. Although the condition has yet to be recognised by the International Association of Sleep Disorders, patients with PD who report rapid sleep onset should be evaluated for the possibility of sleep attacks. If sleep attacks are suspected, it is reasonable to strongly caution patients regarding potentially risk-associated activities such as driving, and to consider careful withdrawal of dopaminergic therapy.