Long-Term Outcomes of Bilateral Pallidal Deep Brain Stimulation for X-Linked Dystonia and Parkinsonism

Abstract

Background: X-linked dystonia parkinsonism (XDP) causes adult-onset progressive dystonia and parkinsonism, which may not respond to pharmacotherapy. Objective: Previous case reports have reported beneficial effects from bilateral pallidal (GPi) deep brain stimulation (DBS). Here, we report the long-term clinical outcomes of 3 patients treated at our center. Methods: All patients presented with medication refractory dystonia and parkinsonism. They were followed prospectively. Clinical evaluations included the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and the Unified Parkinson’s Disease Rating Scale (UPDRS). Adverse events were recorded. Results: The average length of follow-up was 45.7 months. No serious adverse events occurred. All patients experienced an immediate and sustained improvement in dystonia. Mean percentage improvement in motor subscores of BFMDRS was 63.5% at the last follow-up visit. Parkinsonism was less responsive to neuromodulation, with a mean improvement in UPDRS-III of 39.5%. Standard pallidal stimulation parameters were used. Freezing of gait developed after DBS therapy in 2 patients, stimulation-induced in one and due to disease progression in the other. Conclusion: Bilateral pallidal DBS resulted in significant and sustained improvement in dystonia and moderate improvement in parkinsonism. Pallidal DBS represents an important treatment option for XPD for the management of motor symptoms.