Sleep and daytime sleepiness in Parkinson's disease

Disturbances of sleep and wakefulness in patients with Parkinson's disease (PD) have multiple contributing factors and multiple clinical manifestations.The causes, however, are incompletely understood. Although several ofthese disturbances have first been described decades ago, awareness for their clinical implications has only increased in recent years, which also prompted new research into the underlying pathomechanisms. The spectrum of sleep and wakefulness disorders in Parkinson's disease comprises sleep fragmentation, microstructural changes, REM-sleep behaviour disorder, periodic limb movements in sleep, respiratory disturbances, autonomic disturbances and daytime sleepiness, which are discussed in detail. Among the contributing factors, dopamine deficiency, motor impairment, the influence of age and comorbid depression, possible genetic influences and the effect of dopaminergic therapy on night sleep and daytime sleepiness are reviewed. Interactions between sleep or sleep deprivation and motor states are discussed (e.g. sleep benefit). One chapter is dedicated to the issue of driving in patients with Parkinson's disease. The final chapter reviews the evaluation of PD patients with sleep disorders and treatment, namely treatment of daytime sleepiness.