Case Report A Case of Myoclonus–Dystonia Responding to Low-frequency Pallidal Stimulation Harini Sarva 1* , Joan Miravite 2 , Matthew C. Swan 2 , Andres Deik 3 , Deborah Raymond 2 , William Lawrence Severt 2 & Brian H. Kopell 4 1 Parkinson’s Disease and Movement Disorders Institute, Department of Neurology, Weill Cornell Medicine, New York, NY, USA, 2 Department of Neurology, Division of Movement Disorders, Icahn School of Medicine at Mount Sinai, Mount Sinai Beth Israel Medical Center, New York, NY, USA, 3 Parkinson Disease and Movement Disorders Center, Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA, 4 Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, Mount Sinai Medical Center, New York, NY, USA Abstract Background: High-frequency pallidal stimulation has been shown to improve various types of dystonia, including myoclonus-dystonia. Case Report: We report a case of epsilon sarcoglycan mutation-negative myoclonus–dystonia with response to low-frequency bilateral pallidal stimulation. Discussion: Low-frequency pallidal stimulation provides an effective means of treating various dystonias, regardless of genetic status, as in our case, as it provides increased programming options with fewer adverse effects. Keywords: Myoclonus–dystonia, deep brain stimulation, low-frequency stimulation Citation: Sarva H, Miravite J, Swan MC, et al. A case of myoclonus-dystonia responding to low-frequency pallidal stimulation. Tremor Other Hyperkinet Mov. 2017; 7. doi: 10.7916/D82Z1BS4 * To whom correspondence should be addressed. E-mail: has9059@med.cornell.edu Editor: Elan D. Louis, Yale University, USA Received: March 5, 2017 Accepted: April 17, 2017 Published: May 5, 2017 Copyright: ’ 2017 Sarva et al. This is an open-access article distributed under the terms of the Creative Commons Attribution–Noncommercial–No Derivatives License, which permits the user to copy, distribute, and transmit the work provided that the original authors and source are credited; that no commercial use is made of the work; and that the work is not altered or transformed. Funding: None. Financial Disclosures: None. Conflict of Interest: The authors report no conflict of interest. Ethics Statement: This study was reviewed by the authors’ institutional ethics committee and was considered exempted from further review. Introduction Myoclonus–dystonia (MD) is a genetically and phenotypically heter- ogenous condition, which presents with myoclonus of proximal muscles and dystonia, typically of the neck and arm. 1 Most commonly, mutations in the epsilon sarcoglycan (SGCE) gene are found but approximately 50% of cases do not have mutations in this gene. 2 Deep brain stimula- tion (DBS) can be effective in the treatment of MD, with most cases reporting positive effects of pallidal stimulation. 2 Although several reports demonstrated improvement with high-frequency pallidal stimulation, we report a case of SGCE mutation-negative MD whose myoclonus and dystonia responded to low-frequency bilateral pallidal stimulation. Case report The patient is a 36-year-old female without any significant medical or family history who presented to our movement disorders center after 7 years of difficulty walking and myoclonus. Her family reported that her walking difficulty began at the age of 14 years. Her symptoms continued to progress, and she developed severe alcohol- responsive myoclonus of the trunk and limbs, particularly of the right arm, hyperextension of the legs, and bilateral foot drag and plantar flexion. In addition, she developed adductor spasmodic dysphonia, tongue protrusion, jaw-opening dystonia, and retro- and laterocollis. Dystonia impaired ambulation, and negative myoclonus caused falls, resulting in her use of a motorized wheelchair. The myoclonus interfered with her right-hand movements, and she relied on her left for getting dressed and eating. Failed medication trials included sodium oxybate (1.5 grams (GM) orally twice a day), topiramate (200 mg orally three times a day), levetiracetam (500 mg orally twice a day), and clonazepam (2 mg orally three times a day). Botulinum toxin injections of the lateral pterygoids for jaw opening, genioglossus for tongue protrusion, and laryn- geal injections for spasmodic dysphonia (SD) temporarily improved speech. Pre-surgical mental status examination demonstrated normal lan- guage, attention, and memory, and general neurologic examination was likewise normal. On movement examination, she had a hoarse voice, constant low-amplitude myoclonic jerks of the trunk and pelvis Freely available online Tremor and Other Hyperkinetic Movements http://www.tremorjournal.org The Center for Digital Research and Scholarship Columbia University Libraries/Information Services 1