GPi and STN deep brain stimulation can suppress dyskinesia in Parkinson's disease

Objectives: To compare subthalamic nucleus (STN) to globus pallidus internus (GPi) deep brain stimulation (DBS) for control of motor fluctuations and for potential dyskinesia-suppressing qualities. Methods: We conducted a retrospective database review of all patients who underwent GPi or STN DBS for idiopathic Parkinson's disease. Direct dyskinesia suppression (dDS) was defined as improvement in dyskinesia subscore of the Unified Parkinson's Disease Rating Scale (UPDRS) part IV (items 32-34), despite lack of reduction in dopaminergic medication dosage. We analyzed the data using methods appropriate for a case-control study. Results: A total of 133 patients were evaluated. At the last evaluation Dyskinesia scores and motor fluctuations significantly improved in both the GPi (p < 0.0001) and STN groups (p < 0.0001). The GPi group was more likely than the STN group to experience dDS (odds ratio = 1.95, 95% CI = 0.556, 3.21). However, the association between DBS target and dDS was not statistically significant (Pearson chi-square = 2.286, p = 0.131). Conclusions: The overall clinical outcome of STN and GPi DBS for control of dyskinesia and motor fluctuations was similar. STN and GPi DBS both had some direct dyskinesia suppression effects. (C) 2012 Elsevier Ltd. All rights reserved.