Subthalamic stimulation reduces motor disability and improves quality of life in patients with advanced Parkinson’s disease who have severe levodopa-induced motor complications. We hypothesized that neurostimulation would be beneficial at an earlier stage of Parkinson’s disease. In this 2-year trial, we randomly assigned 251 patients with Parkinson’s disease and early motor complications (mean age, 52 years, mean duration of disease, 7.5 years) to undergo neurostimulation plus medical therapy or medical therapy alone. The primary end point was quality of life. Major secondary outcomes included parkinsonian motor disability, activities of daily living, levodopa-induced motor and time with good mobility and no dyskinesia.
For the primary outcome of quality of life, the mean score for the neurostimulation group improved by 7.8 points, and that for the medical-therapy group worsened by 0.2 points. Neurostimulation was superior to medical therapy with respect to motor disability activities of daily living, levodopa-induced motor complications and time with good mobility and no dyskinesia. Serious adverse events occurred in 54.8% of the patients in the neurostimulation group and in 44.1% of those in the medical-therapy group. Serious adverse events related to surgical implantation or the neurostimulation device occurred in 17.7% of patients.