ObjectiveTo study the effect of subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with Parkinson disease (PD) and moderate to severe restless legs syndrome (RLS) on their RLS symptoms.MethodsPatients undergoing STN DBS surgery for PD completed the International RLS Study Group Rating Scale (IRLS) and RLS Quality of Life (QoL) questionnaires preoperatively and postoperatively at 6 months, 1 year, and 2 years. The primary outcome measure was IRLS sum score and subscales (severity and impact) and the secondary measure was RLS QoL scores. Differences among the mean scores over time were analyzed using mixed model regression.ResultsTwenty-two patients were enrolled. The preoperative IRLS sum scores were 19.59 ± 6.95, severity subscale 12.91 ± 4.33, impact subscale 4.45 ± 2.72, and transformed RLS QoL score 68.30 ± 20.26. The differences between preoperative and averaged postoperative scores were IRLS sum score −7.80, severity subscale −5.50, impact subscale −1.20, and RLS QoL 4.73. The overall F tests demonstrated differences among the times for the means of the IRLS sum and subscales: p < 0.05. There were no correlations between RLS symptoms improvement and PD motor symptoms improvement or reduction in PD medications. Half of the patients had at least 50% improvement and 27% had resolution of their RLS symptoms (IRLS = 0).ConclusionsSTN DBS significantly decreased RLS symptoms in patients with PD despite a decrease in dopaminergic treatment. This improvement was sustained over a 2-year period.Classification of evidenceThis study provides Class IV evidence that for patients with PD and moderate to severe RLS, STN DBS improves RLS symptoms.