Restless legs syndrome and periodic limb movements in Parkinson’s disease

The symptoms of Parkinson’s disease (PD) commonly include a number of sleep disorders, including restless legs syndrome (RLS) and periodic limb movements of sleep (PLMS). RLS occurs in about 20 % of PD patients in most studies, but idiopathic RLS does not seem to precede the development of PD. In fact there is some evidence that idiopathic RLS may prevent the subsequent development of PD. In cases of PD/RLS the PD usually presents first, and RLS may represent one of many non-motor features associated with PD. Although common, RLS is usually not a major contributor to sleep deprivation or functional impairment in the PD population. PLMS are seen in many neurodegenerative disorders, as well as idiopathic RLS. Most studies report higher rates of PLMS in PD, but polysomnography studies suggest relatively little impact of PLMS on other sleep measures. The response of both PD and RLS to dopaminergics is of great interest, especially given the lack of overt dopamine pathology in RLS.