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

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.

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

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.

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.