Clément Desjardins, Cécilia Bonnet, Elena Moro, David Grabli, Valérie Fraix, Marie-Laure Welter, Laurent Vercueil, Soledad Navarro, Carine Karachi, Thibaud Charrier, Sylvie Raoul, Mathilde Guibourd de Luzinais, Emmanuel Cuny, Stéphan Chabardes, Pierre Burbaud, Dominique Guehl, Pascal Derkinderen, Marie Vidailhet, French SPIDY Study Group
Over 15 years, interindividual therapeutic benefit diverged while axial parkinsonism emerged in nearly all patients. These findings highlight the need for systematic long-term monitoring extending beyond dystonia control after GPi-DBS. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
BACKGROUND: Bilateral pallidal deep brain stimulation (GPi-DBS) is effective for dystonia. Long-term evolution of therapeutic benefit and emergence of parkinsonism have not been systematically characterized.
OBJECTIVES: To assess 15-year dystonia outcomes and characterize parkinsonism after bilateral GPi-DBS.
METHODS: Dystonia severity and disability were evaluated at baseline,1, 3, and 15 years postoperatively with the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). Parkinsonism was assessed at last visit using the Movement Disorder Society-Unified Parkinson's Disease Rating Scale-Part III and freezing of gait (FoG) questionnaire.
RESULTS: Of 17 patients reassessed at 15 years, 41% maintained clinical benefit. Parkinsonism was observed in 94%, predominantly axial, with self-reported FoG in 67%. Higher baseline BFMDRS-Motor scores predicted last follow-up axial parkinsonism (R = 0.800, P < 0.001).
CONCLUSIONS: Over 15 years, interindividual therapeutic benefit diverged while axial parkinsonism emerged in nearly all patients. These findings highlight the need for systematic long-term monitoring extending beyond dystonia control after GPi-DBS. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.