Weight change after globus pallidus internus or subthalamic nucleus deep brain stimulation in Parkinson's disease and dystonia

Background: Weight gain has been described in Parkinson's disease (PD) patients after subthalamic nucleus (STN) deep brain stimulation (DBS). Objectives: We examined change in weight following DBS in both PD and dystonia patients to further investigate the role of disease and brain target (STN or globus pallidus internus, GPi) specificity. Methods: Data was retrospectively collected on 61 PD DBS patients (STN n = 31 or GPi n = 30) and on 36 dystonia DBS patients (STN n = 9 and GPi n = 27) before and after surgery. Annual change in body mass index (BMI) was evaluated with nonparametric tests between groups and multiple quantile regression. Results: PD patients treated with STN DBS had a small increase in median BMI while those with GPi had a small decrease in BMI. Dystonia patients treated with STN DBS had a greater increase in BMI per year compared to those treated with GPi DBS. Multivariable regression analyses for each disease showed little difference between targets in weight gain in those with PD, but STN target was strongly associated with weight gain in dystonia patients (STN vs. GPi, +7.99 kg, p = 0.012). Conclusions: Our results support previous reports of weight gain after DBS in PD. This is the first report to suggest a target-specific increase in weight following STN DBS in dystonia patients.