September 28, 2001

(ST. LOUIS) MD Consult - A prospective study shows that bilateral, high-frequency stimulation of sites deep within the brain can significantly improve motor function for patients with Parkinson's disease who no longer respond to medical therapy, reports the Sept. 27 New England Journal of Medicine.

A total of 134 patients with advanced Parkinson's disease underwent bilateral electrode implantation: 96 in the subthalamic nucleus and 38 in the pars interna of the globus pallidus. Three months later, the patients were evaluated with stimulation on or off in randomized, double-blind, crossover fashion.

Stimulation at both sites significantly improved motor function, compared with Unified Parkinson's Disease Rating Scale scores with stimulation turned off. Median improvement in motor scores was 49% with subthalamic nucleus stimulation and 37% with pars interna stimulation.

Unblinded evaluations were performed at baseline and 1, 3, and 6 months. In that time, both groups had significant improvement in the proportion of the day during which they had good mobility without involuntary movements: from 27% to 74% in the subthalamic stimulation group and from 28% to 64% in the pallidal stimulation group.

Seven patients experienced intracranial bleeding, while two had to have the electrodes removed because of infection.

Loss of motor control in Parkinson's disease patients who could not otherwise achieve further improvement.

Source: N Engl J Med 2001;345:956-963