Randomized double-blind multicenter trial comparing bilateral subthalamic nucleus Deep Brain Stimulation (DBS) and bilateral globus pallidus DBS for advanced Parkinson’s disease.

Patients with advanced Parkinson’s disease (PD) and long-term pharmacologic treatment often have response fluctuations and dyskinesias. Frequently they cycle between episodes with parkinsonism associated with severe disability (‘off’ phase) and episodes with good mobility (‘on’ phase), usually with dyskinesias. Continuous bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) is an effective surgical treatment for patients with advanced PD who have severe limitations in functioning despite optimal pharmacologic treatment. Recently however, the concerns about STN DBS and adverse effects are increasing, especially for the cognitive, mood, and behavioral features.
We hypothesize that bilateral globus pallidus internus (GPi) DBS produces greater functional improvement in PD than bilateral STN DBS because of a lower rate of complications.
The study will be a randomized, multicenter, double-blind trial comparing continuous bilateral GPi DBS with bilateral STN DBS in advanced PD. We will enroll 128 patients with advanced PD who have—despite optimal pharmacological treatment—at least one of the following symptoms: severe response fluctuations, dyskinesias, painful dystonias, or bradykinesia. Patients will be randomly assigned to bilateral GPi DBS or bilateral STN DBS. Baseline and outcome measurements at 12 months will be done in standardized off and on phases. The primary outcome measures are the number of patients with significant cognitive, mood, and behavioral adverse effects and the off-on phase weighted AMC Linear Disability Scale (functional improvement). Secondary outcome consists of symptom scales, activities of daily living scales, a quality of life questionnaire, adverse effects, and medication use. Additionally, patients will undergo an extensive neuropsychological and a standardized psychiatric assessment. Five centers in the Netherlands performing functional stereotactic neurosurgery will participate.

Assuming that the effects on Parkinson's disease symptoms and dyskinesias, and the rates of procedure-related and device-related complications are almost equal, then continuous bilateral GPi DBS may produce greater functional improvement than bilateral STN stimulation in Parkinson's disease, because the latter is associated with long-term cognitive, mood, and behavioral problems.

Stereotactic bilateral implantation of DBS electrodes in the globus pallidus internus or the nucleus subthalamicus.