The Impact of Subthalamic Deep Brain Stimulation on Restless Legs Syndrome in Parkinson's Disease.

INTRODUCTION: The study aimed at evaluating the effect of subthalamic deep brain stimulation (DBS-STN) on restless legs syndrome (RLS) in Parkinson's disease (PD) patients. MATERIALS AND METHODS: We assessed the presence of RLS before and 6 and 12 months after surgery in 36 patients. Differences between patients with RLS, without RLS, and with remission of RLS in terms of sleep measures (interview and validated questionnaires) and nonmotor symptoms (NMS). Polysomnography (PSG) was performed in 24 patients. Simple and multiple regression models were used to identify potential predictors of RLS outcome after DBS-STN. RESULTS: Before DBS-STN 14 of the 36 patients (39%) were diagnosed with RLS. DBS-STN resulted in the resolution of RLS in 43% (n = 6) and the emergence of RLS in 2 (9%) patients. During the study, 20 patients remained without RLS and the patients with unremitting RLS (n = 8) experienced alleviation of symptoms. At baseline patients with RLS had higher Non-Motor Symptoms Scale (NMSS) total and sleep domain, Unified Parkinson's Disease Rating Scale (UPDRS) part IV and lower Parkinson's Disease Sleep Scale (PDSS) scores. There were no differences between the groups without and with RLS in terms of PSG recordings. CONCLUSION: DBS-STN provided relief of symptoms in most of the patients with PD and RLS. We found that RLS was associated with worse subjective sleep quality, more severe NMS, and complications of levodopa therapy. DBS-STN may have direct impact on RLS rather than related indirectly through post-surgery change in medications.