Probable REM sleep behaviour disorder and STN-DBS outcome in Parkinson's disease

Objective: To assess whether the presence of probable REM sleep behaviour disorder (pRBD) influences the long-term outcome of Parkinson's Disease (PD) patients undergoing Subthalamic Nucleus Deep Brain Stimulation (STN-DBS). Background: RBD is a parasomnia characterized by loss of muscular atonia and complex motor behaviours during REM sleep, frequently reported in PD patients. Recent evidence suggests that RBD is associated with akinetic rigid disease type and increased frequency of falls. We wondered whether the presence of RBD would also influence the long-term outcome of STN-DBS. Methods: Forty-one consecutive PD patients treated with bilateral STN-DBS were assessed. The diagnosis of pRBD was based on a clinical interview investigating the occurrence of diagnostic criteria for RBD. The Unified Parkinson's Disease Rating Scale was used to compare the on- and off-medication conditions preoperatively and the on-stimulation/on- and off-medication conditions 1 and 3 years postoperatively. The general linear model for multivariate measures was used to analyse the interaction of pRBD with STN-DBS outcome measures. Results: pRBD was present in 12 out of 41 patients (29%) undergoing STN-DBS. Patients with pRBD had a significantly poorer outcome three years after STN-DBS compared to patients without pRBD, in particular for axial symptoms. Conclusions: Our findings suggest that the presence of pRBD in PD patients undergoing STN-DBS may be associated with a less favourable outcome and a more prominent development of axial symptoms over time.