One-Year Effect on Levodopa Equivalent Daily Dose of Thalamic VIM Nucleus Stimulation Compared to Subthalamic Nucleus Stimulation in Patients With Parkinson's Disease

Thesis Summary: Deep brain stimulation (DBS) is a well-established therapeutic option for patients with advanced Parkinson's disease. The two most commonly targeted structures are the subthalamic nucleus (STN) and the ventral intermediate nucleus (VIM) of the thalamus. While STN stimulation is known to allow a significant reduction in the levodopa equivalent daily dose (LEDD), the effects of VIM stimulation on medication dosage remain less clear, particularly in patients selected for predominant tremor. Objectives: To compare the evolution of LEDD one year after DBS targeting the VIM versus the STN in patients with Parkinson's disease. To assess whether VIM stimulation also enables a meaningful reduction in dopaminergic medication. To contribute to refining surgical indications based on the patient's clinical profile. Hypotheses: STN stimulation leads to a greater reduction in LEDD compared to VIM stimulation. VIM stimulation, though primarily used for tremor control, may result in moderate LEDD reduction in specific patient profiles. Surgical target selection should be personalized, considering not only motor symptom control but also the impact on medication requirements.