title: Improvement of Isolated Myoclonus Phenotype in Myoclonus Dystonia after Pallidal Deep Brain Stimulation.
abstract: BACKGROUND
  Myoclonus-dystonia is a condition that manifests predominantly as myoclonic jerks with focal dystonia. It is genetically heterogeneous with most mutations in the epsilon sarcoglycan gene (SGCE). In medically refractory cases, deep brain stimulation (DBS) has been shown to provide marked sustainable clinical improvement, especially in SGCE-positive patients. We present two patients with myoclonus-dystonia (one SGCE positive and the other SGCE negative) who have the isolated myoclonus phenotype and had DBS leads implanted in the bilateral globus pallidus internus (GPi).
  
  
  METHODS
  We review their longitudinal Unified Myoclonus Rating Scale scores along with their DBS programming parameters and compare them with published cases in the literature.
  
  
  RESULTS
  Both patients demonstrated complete amelioration of all aspects of myoclonus within 6-12 months after surgery. The patient with the SGCE-negative mutation responded just as well as the patient who was SGCE positive. High-frequency stimulation (130 Hz) with amplitudes greater than 2.5 V provided therapeutic benefit.
  
  
  CONCLUSIONS
  This case series demonstrates that high frequency GPi-DBS is effective in treating isolated myoclonus in myoclonus-dystonia, regardless of the presence of SGCE mutation.
authors.affiliation: Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Division of Movement Disorders, Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Ritesh A
authors.initials: RA
authors.lastname: Ramdhani
authors.affiliation: Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Frucht
authors.affiliation: Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Anousheh
authors.initials: A
authors.lastname: Behnegar
authors.affiliation: Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Division of Movement Disorders, Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Brian H
authors.initials: BH
authors.lastname: Kopell
keywords: Myoclonus–dystonia; deep brain stimulation; epsilon sarcoglycan gene