title: Brain Stimulation for Torsion Dystonia.
abstract: OBJECTIVE
  Dystonia is a heterogeneous neurologic disorder characterized by abnormal muscle contractions for which standard medical therapy is often inadequate. For such patients, therapeutic brain stimulation is becoming increasingly used.
  
  
  OBJECTIVE
  To review the evidence and effect sizes for treating different types of dystonia with different types of brain stimulation and to discuss recent advances relevant to patient selection, surgical approach, programming, and mechanism of action.
  
  
  METHODS
  PubMed was searched for publications on the clinical effect of brain stimulation in dystonia up through December 31, 2014. Recent meta-analyses, consensus statements, and evidence-based guidelines were incorporated. Emphasis was placed on deep brain stimulation (DBS) and randomized clinical trials; however, other stimulation modalities and trial designs were included. For each intervention the mean change in dystonia severity, number of patients studied, and evidence of efficacy based on American Academy of Neurology criteria were determined.
  
  
  RESULTS
  Strong (level B) evidence supports the use of DBS for the treatment of primary generalized or segmental dystonia, especially when due to mutation in the DYT1 gene, as well as for patients with cervical dystonia. Large effect sizes have also been reported for DBS treatment of tardive dystonia, writer's cramp, cranial dystonia, myoclonus dystonia, and off-state dystonia associated with Parkinson disease. Lesser benefit is generally seen in dystonia secondary to structural brain damage. Other brain stimulation techniques, including epidural cortical stimulation and noninvasive brain stimulation, have been investigated, but generally report smaller effect sizes in fewer patients.
  
  
  CONCLUSIONS
  Patients with dystonia that is not adequately controlled with standard medical therapy should be referred for consideration of DBS, especially patients with generalized, segmental, or cervical dystonia. Other less-invasive stimulation modalities require further research before being considered a therapeutic alternative.
authors.affiliation: Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts2Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Fox
authors.affiliation: Division of Neurosurgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Ron L
authors.initials: RL
authors.lastname: Alterman
mesh_terms: D046690:Deep Brain Stimulation / Q000379:methods*; D004422:Dystonia Musculorum Deformans / Q000628:therapy*; D006801:Humans