Pallidal stimulation in Parkinson's patients with contraindications to subthalamic target: A 3 years follow-up.

Introduction: Over a 3-year period, we monitored the efficacy and safety of deep-brain stimulation of the globus pallidus pars interna in patients with advanced Parkinson's disease whose cognitive, psychiatric impairment and/or dopa-resistant axial motor signs made them ineligible for surgery targeting the subthalamic nucleus.

Methods: A total of 25 patients were assessed before surgery, 1 year and 3 years after surgery, on the UPDRS and a neuropsychological battery.

Results: We noted a significant improvement of 65.9% in the Clinical global self-perceived Improvement by Visual Analog Scale and an improvement of 20.6% in the total UPDRS-III motor score at 3 years in the off-dopa condition compared to before surgery. There was an improvement in the treatment's motor complications, as measured by the UPDRS-IV, with a particularly marked reduction of 50% in the Dyskinesia subscore. Cognitive performances remained stable at 1 year but had fallen by the third year. We interpreted this deterioration as due to disease progression.

Conclusion: Bilateral pallidal stimulation in patients with contraindications to subthalamic surgery therefore seems to be effective over the long term in treating motor symptoms, especially dyskinesias, with good neuropsychological safety.