Akathisia, restless legs and periodic limb movements in sleep in Parkinson's disease.

Restless legs syndrome (RLS) symptoms are often reported in Parkinson's disease (PD), but prevalence studies of RLS in PD are few and the results are inconsistent. In addition, clinical overlapping between RLS, "wearing-off"-related lower limb discomfort and restlessness, and akathisia complicate the clinical assessments of true RLS in PD. Underlying pathophysiology potentially shared by RLS and PD is mainly suggested by similarities in treatment response. Functional imaging studies in RLS are still inconclusive, although some authors have found subtle deficits in nigrostriatal terminal function. Long-term prospective studies of RLS cohorts will clarify whether or not RLS is associated with an increased risk for development of PD.