Parkinsonism and Related Disorders 81 (2020) 78–81 Available online 15 October 2020 1353-8020/© 2020 Elsevier Ltd. All rights reserved. Short communication Bilateral pallidal stimulation improves cervical dystonia for more than a decade Alain Kaelin-Lang a, b, c , Hana You a , Jean-Marc Burgunder a, d , Tarja L¨ onnfors-Weitze e, l , Thomas J. Loher a, f , Ethan Taub g , Ioannis U. Isaias h , Joachim K. Krauss i, j, *, 1 , W. M. Michael Schüpbach a, k, 1 a Department of Neurology, Inselspital, Berne University Hospital, Berne, Switzerland b Neurocenter of Southern Switzerland, Lugano, Switzerland c Faculty of Biomedical Sciences, Universita Della Svizzera Italiana, Lugano, Switzerland d Neurocenter Siloah, Gümligen-Muri, Switzerland e University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Berne University Hospital, Berne, Switzerland f Neurocenter Berne, Berne, Switzerland g Functional Neurosurgery Unit, Department of Neurosurgery, Kantonspital, University Hospital, Basel, Switzerland h Department of Neurology, University Hospital, Würzburg, Germany i Department of Neurosurgery, Medical School Hannover, Hannover, Germany j Center of Systems Neuroscience, Hannover, Germany k Institute of Neurology, Konolfngen, Switzerland A R T I C L E INFO Keywords: Cervical dystonia Deep brain stimulation Long term follow-up Globus pallidus internus ABSTRACT Introduction: Deep brain stimulation (DBS) is an effective treatment in medically resistant cervical dystonia (CD) with a documented therapeutic effect. Long term outcome beyond a decade, however, has not been studied systematically. Methods: To investigate the impact of pallidal DBS beyond 10 years in CD we followed a series of fve consecutive patients with severe medication-resistant CD. Severity of head and neck deviation, disability, and pain related to dystonia were assessed by the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) in the frame of a prospective study. The primary endpoint of this study was a change in the TWSTRS total score. Secondary endpoints were changes in the subscores of the TWSTRS. Results: The mean follow-up time was 11.5 years (range 10–12.8). Comparing baseline and the last follow-up, CD improved by 53% on the total TWSTRS score, by 54.1% on the severity score, and by 70.1% on the disability score, while pain did not improve signifcantly. Improvement was stable over time. Patients with a tonic pattern of CD responded less to DBS than patients with a phasic pattern. DBS had no signifcant effect on mood and cognition. Two patients underwent electrode revisions. One patient had an infection of the proximal cable two years after surgery. Conclusions: Chronic bilateral pallidal stimulation improves severity of dystonia and disability over more than a decade in treatment resistant CD. Results may vary among individual patients. 1. Introduction Pallidal deep brain stimulation (DBS) has become an accepted treatment for isolated idiopathic dystonia within the past two decades [1]. Although the effcacy of DBS for complex cervical dystonia (CD) had been reported as early as in 1999 [2] and several smaller series have described favorable results subsequently [3,4], it became more widely accepted only recently [5,6]. It has been shown that pallidal DBS improves severity, disability and pain associated with CD with a relatively low frequency of side effects, and that long disease duration may have a negative impact on outcome [5–7]. Only few series, however, have included blinded or randomized * Corresponding author. Department of Neurosurgery, MHH, Hannover Medical School, Germany. E-mail address: krauss.joachim@mh-hannover.de (J.K. Krauss). 1 Authors contributed equally. Contents lists available at ScienceDirect Parkinsonism and Related Disorders journal homepage: www.elsevier.com/locate/parkreldis https://doi.org/10.1016/j.parkreldis.2020.10.028 Received 5 June 2020; Received in revised form 13 October 2020; Accepted 14 October 2020