Asymmetric Deep Brain Stimulation Electrodes for Parkinson's Disease: A Pilot Study of Symptom-Tailored Stimulation

Abstract

INTRODUCTION: Bilateral subthalamic nucleus (STN) and globus pallidus interna (GPi) deep brain stimulation (DBS) are well established targets for the management of Parkinson's disease (PD). Each target has its own advantage, we presume the simultaneous unilateral STN and contralateral GPi DBS may compromise side effects of bilateral stimulation and keep each nucleus and its own efficacy on the motor and nonmotor symptoms. METHODS: Eight patients with idiopathic PD with this kind of procedure were retrospectively reviewed. Motor, nonmotor symptoms, quality of life were measured before surgery, 6 mo, 1-yr post surgery under following conditions: medication on and off, bilateral stimulation on and off, unilateral STN stimulation on. Medication and stimulation parameters were noted. RESULTS: Unilateral STN and contralateral GPi DBS significantly improved the UPDRS-? scores, with a 45% reduction at 6 mo and a 43% reduction at 1 yr. In total, 41% of levodopa equivalent daily dose was reduced at 1-yr follow-up. In the medication on condition, bilateral stimulation improved axial symptoms by 28.4% at 1-yr follow-up. In total, 3 m TUG (Time-Up Go test) improved by 41% at 6-mo followup compared to baseline, which lasts for 1 yr. In total, 64% reduction was found between baseline and 1-yr follow-up in gait and fall questionnaires. No deterioration was found in nonmotor measurements. No adverse events other than stimulation related were reported. CONCLUSION: Our results provide the first evidence that supports unilateral STN and contralateral GPi DBS might be effective and safe in advanced PD patients. Future efforts are needed to explore the potential advantage in axial and cognitive symptoms in long term.