Long-Term Outcomes on Pallidal Neurostimulation for Dystonia: A Controlled, Prospective 10-Year Follow-Up

Abstract

Background: Pallidal neurostimulation is an effective treatment for severe isolated dystonia, but long-term data from clinical trials are lacking.

Objectives: To evaluate long-term efficacy and safety of pallidal neurostimulation in patients with isolated generalized or segmental dystonia.

Methods: Extension study of the prospective multicenter trial (n = 40; July 2002 to May 2004), all patients received effective stimulation and underwent regular follow-up. The 10-year follow-up (n = 31) included Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) motor and disability score, Beck Depression Inventory, Beck Anxiety Inventory, and Mattis Dementia Rating Scale. Primary and secondary endpoints compared motor symptoms, disability scores, mood, and cognition changes.

Results: Thirty-one patients (12 female), aged 23-72 years, completed the 10-year study extension. Per protocol analysis showed sustained significant improvement in BFMDRS motor scores at 10 years compared with baseline, without significant change from the 6-month or 5-year follow-up. On average, motor scores decreased by 25.3 ± 5.2 points at 10 years (P < 0.0001; 56% improvement). Individual outcomes varied, with 27 responders (≥25% improvement; mean improvement 65.2 ± 21.4%) and 13 non-responders compared with baseline. Sustained improvements were seen in disability, mood, and anxiety scores. Cognition remained stable.

Conclusions: This study presents the longest prospective, multicenter follow-up of pallidal neurostimulation in generalized and segmental dystonia. Two-thirds of patients showed strong and stable long-term improvements of dystonia, confirming sustained efficacy and safety over 10 years in treatment-refractory dystonic patients. However, one-third experienced primary (3/40) or secondary (10/40) treatment failure. Diagnostic advances, including genetic testing, and technological progress in pallidal neurostimulation may help to reduce the non-responder rates in the future. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Keywords: DBS response; deep brain stimulation; dystonia; long‐term follow‐up; neurostimulation.

FIG. 1

(A, B) The whisker plots visually represent the distribution of absolute Burke–Fahn–Marsden Disease (BFMD) motor scores at baseline and after 6, 12, 24, 36, 48, 60, and 120 months of continuous pallidal neurostimulation separated for generalized (GD) and segmental dystonia (SD) patients along with individual datapoints for each patient. The whiskers extend from the minimum to the maximum values, showing the full range of the data. Each point represents an individual patient's data, providing a detailed view of the distribution. The box marks the interquartile range, located between the 25th and 75th percentiles, and encapsulates the middle 50% of the data. The line within the box denotes the median, indicating the central value of the dataset. (C, D) The scatter plots provide visual representation of individual BFMD motor score trajectories from all patients with GD and SD dystonia at baseline and after 6, 12, 24, 36, 48, 60, and 120 months of continuous pallidal neurostimulation.