Subthalamic Neurostimulation May Improve Quality of Life and Motor Function in Early Parkinson Disease
Medical treatment is generally effective for the control of motor symptoms that occur early in Parkinson disease. In advanced disease, deep brain neurostimulation of the subthalamic nucleus (or globus pallidus) is recommended for patients with motor fluctuations and dyskinesia unresponsive to medical treatment. In these patients, neurostimulation has been associated with reduced motor disability and improved quality of life. This treatment is commonly delayed until over a decade into the course of the disease. A recent randomized trial investigated the effects of earlier neurostimulation treatment in patients with Parkinson disease showing early signs of motor complications.
A total of 251 patients (mean age 52 years, mean duration of disease 7.5 years) were randomized to subthalamic neurostimulation plus medical therapy vs. medical therapy alone for 2 years. All patients had fluctuations or dyskinesia present for ≤ 3 years and mild-to-moderate impairment in social and occupational functioning. Best medical therapy was assessed for each patient based on European Federation of Neurological Societies and Movement Disorder Society guidelines. Patients were excluded for dementia, major depression with suicidal thoughts, or disease duration < 4 years. Quality of life was assessed with the 39-item Parkinson Disease Questionnaire (PDQ-39) and motor symptom severity assessed with Unified Parkinson’s Disease Rating Scale part III (UPDRS-III).
Subthalamic neurostimulation was associated with a 26% mean improvement in quality of life scores compared to a 1% worsening with medical therapy alone (p = 0.002). Mean motor symptom severity scores improved by 30% with neurostimulation and worsened by 12% with medical therapy alone (p < 0.001). Neurostimulation was also associated with significant improvements in levodopa-induced motor complications, time with good mobility and no dyskinesia, and with reduced daily levodopa dose. The primary outcome assessments were unblinded. Secondary blinded assessments (without intention-to-treat analysis) corroborated the primary findings. Adverse events were common with serious adverse events occurring in 55% of the neurostimulation group vs. 44% of the medical-therapy group. Serious adverse events specifically related to the surgical implantation or the neurostimulation device occurred in 18% of patients.