Rapid eye movement sleep behavior disorder after bilateral subthalamic stimulation in Parkinson's disease

The effect of subthalamic nucleus (STN) deep brain stimulation (DBS) on rapid eye movement sleep behavior disorder (RBD) in Parkinson's disease (PD) is not well known. We evaluated the change in the incidence of probable RBD after bilateral STN DBS in PD patients. Ninety patients with PD treated with bilateral STN DBS underwent retrospective assessment of RBD by interview before and after DBS. Forty-seven (52.2%) of the 90 patients had RBD preoperatively. RBD was resolved only in one patient and persisted in 46 patients at 1 year after DBS. RBD developed de novo in 16 patients (de novo RBD group) within 1 year after DBS, resulting in 62 (68.9%) of the 90 patients having RBD 1 year after DBS. Patients with RBD at any time within 1 year after DBS (RBD group, n = 63) were older than the patients without RBD (non-RBD group, n = 27). The sum of the Unified Parkinson Disease Rating Scale (UPDRS) axial score for the "on" state was lower in the RBD group than in the non-RBD group after DBS (p = 0.029). Comparing the de novo RBD group and non-RBD group, the UPDRS Part III and total score and the levodopa equivalent daily doses for the "on" states decreased more in the de novo RBD group than in the non-RBD group (p < 0.05). The incidence of clinical RBD increased after bilateral STN DBS because de novo RBD developed and pre-existing RBD persisted after DBS.