Thalamic Deep Brain Stimulation May Improve Restless Legs Syndrome in Patients With Essential Tremor

OBJECTIVES To determine change in restless legs syndrome (RLS) symptoms in essential tremor (ET) patients undergoing bilateral thalamic ventral intermedius (VIM) deep brain stimulation (DBS) surgery. MATERIALS AND METHODS We retrospectively reviewed our database of ET patients with RLS who had undergone VIM DBS for tremor from 2012 to 2020. We reviewed the patients with available International Restless Leg Syndrome Study Group RLS scale scores before and after DBS. Percentage of responders, defined as proportion of patients experiencing three or more point improvement of RLS scores post-DBS, was calculated. We performed two-tailed t-test of pre-DBS and post-DBS RLS scores. RESULTS We identified 13 patients with ET and RLS who had undergone bilateral VIM DBS, of whom nine (69%) were responders post-DBS. Five of 13 patients (38%) had complete resolution of RLS post-DBS. For all patients, mean pre-DBS RLS score was 15.8 ± 7.9 which improved by 46% post-DBS to a mean of 8.5 ± 8.8 (p = 0.007). Four patients rated their RLS scale one night with the stimulator OFF and another night with the stimulator ON. The mean RLS score with stimulator ON was 15.5 ± 7.6 which improved by 53% to a mean of 6.25 ± 7.8 (p = 0.008), with two having complete resolution of RLS with stimulator ON. Of the nine responders, six preferred to keep their stimulator ON at night due to relief of RLS and better subjective quality of sleep. CONCLUSIONS We report for the first time improvement of RLS in patients with ET after bilateral thalamic DBS. Although many ET patients with nonrechargeable DBS systems switch off their stimulator at night to conserve battery life, those with RLS may potentially benefit from keeping their stimulator ON at night to relieve their RLS.