Combined unilateral subthalamic nucleus and contralateral globus pallidus interna deep brain stimulation for treatment of Parkinson disease: A pilot study of symptom-tailored stimulation

BACKGROUND: Subthalamic nucleus (STN) and globus pallidus interna (GPi) are the most effective targets in deep brain stimulation (DBS) treatment for Parkinson disease (PD). However, the individualized selection of targets remains a clinical challenge. OBJECTIVE: To combine unilateral STN and contralateral GPi stimulation (STN DBS in one brain hemisphere and GPi DBS in the other) to maximize the clinical advantages of each target while inducing fewer adverse side effects in selected patients with PD because each target has its own clinical effects and risk profiles. METHODS: We reviewed the clinical outcomes of 8 patients with idiopathic PD treated with combined unilateral STN and contralateral GPi DBS. Clinical outcome assessments, focusing on motor and nonmotor symptoms, were performed at baseline and 6-mo and 12-mo follow-up. We performed the assessments under the following conditions: medication on and off (bilateral stimulation on and off and unilateral STN stimulation on). RESULTS: Patients showed a significant improvement in motor symptoms, as assessed by the Unified Parkinson Disease Rating Scale III (UPDRS-III) and Timed Up-and-Go Test (TUG), in the off-medication/on-stimulation state at 6-mo and 12-mo follow-up. Also, patients reported a better quality of life, and their intake of levodopa was reduced at 12-mo follow-up. In the on-medication condition, bilateral stimulation was associated with an improvement in axial symptoms, with a 64% improvement in measures of gait and falls at 12-mo follow-up. No irreversible adverse side effects were observed. CONCLUSION: Our findings suggest that combined unilateral STN and contralateral GPi DBS could offer an effective and well-tolerated DBS treatment for certain PD patients.