Sleep/wake problems in Parkinson's disease: pathophysiology and clinicopathologic correlations.

In his initial description of shaking palsy, James Parkinson first noted that sleep became disturbed with advancing paralysis agitans. More recent studies have confirmed that the majority of patients with Parkinson's disease (PD) suffer from some sleep disturbances. This can manifest as difficulty in falling or staying asleep, fractionated sleep, specific parasomnias, and daytime sleepiness. In this article, we will explore the pathophysiology of these varied sleep disorders. In most cases, however, the definitive etiology is debated, and phenotypes are often felt to be multifactorial. Some of these may be associated with dopaminergic dysfunction, some presumed to arise from varied non-dopaminergic PD pathology, and some from PD treatments.