Restless Legs Syndrome (RLS) and Parkinson's disease (PD)-related disorders or different entities?

The relationship between Restless Legs Syndrome (RLS) and Parkinson's disease (PD) is still controversial. Most genetic, pathological, and imaging data argue against a close association of these two disorders. Still, many studies reported an increased prevalence of RLS in PD patients. These studies are difficult to interpret because the current diagnostic criteria for RLS have not been validated in PD patients. Although many PD patients suffer from motor restlessness due to parkinsonism and may thus mimic RLS, the risk for (secondary) RLS in PD patients is probably slightly increased. This review provides an overview of the current pertinent literature and discusses the possible association between RLS and PD.