title: Deep Brain Stimulation for Tourette-Syndrome: A Systematic Review and Meta-Analysis.
abstract: BACKGROUND
  A significant proportion of patients with Tourette syndrome (TS) continue to experience symptoms across adulthood that in severe cases fail to respond to standard therapies. For these cases, deep brain stimulation (DBS) is emerging as a promising treatment option.
  
  
  OBJECTIVE
  We conducted a systematic literature review to evaluate the efficacy of DBS for GTS.
  
  
  METHODS
  Individual data of case reports and series were pooled; the Yale Global Tic Severity Scale (YGTSS) was chosen as primary outcome parameter.
  
  
  RESULTS
  In total, 57 studies were eligible, including 156 cases. Overall, DBS resulted in a significant improvement of 52.68% (IQR = 40.74, p < 0.001) in the YGTSS. Analysis of controlled studies significantly favored stimulation versus off stimulation with a standardized mean difference of 0.96 (95% CI: 0.36-1.56). Disentangling different target points revealed significant YGTSS reductions after stimulation of the thalamus, the posteroventrolateral part and the anteromedial part of the globus pallidus internus, the anterior limb of the internal capsule and nucleus accumbens with no significant difference between these targets. A significant negative correlation of preoperative tic scores with the outcome of thalamic stimulation was found.
  
  
  CONCLUSIONS
  Despite small patient numbers, we conclude that DBS for GTS is a valid option for medically intractable patients. Different brain targets resulted in comparable improvement rates, indicating a modulation of a common network. Future studies might focus on a better characterization of the clinical effects of distinct regions, rather than searching for a unique target.
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Kerpener Strasse 62, 50937 Cologne, Germany. Electronic address: juan.baldermann@uk-koeln.de.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Baldermann
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Kerpener Strasse 62, 50937 Cologne, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schüller
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Kerpener Strasse 62, 50937 Cologne, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Huys
authors.affiliation: Institute of Medical Statistics, Informatics and Epidemiology, University of Cologne, Kerpener Strasse 62, 50937 Cologne, Germany.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Becker
authors.affiliation: Department of Neurology, University of Cologne, Kerpener Strasse 62, 50937 Cologne, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Timmermann
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Kerpener Strasse 62, 50937 Cologne, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Jessen
authors.affiliation: Department of Stereotactic and Functional Neurosurgery, University of Cologne, Kerpener Strasse 62, 50937 Cologne, Germany.
authors.forename: Veerle
authors.initials: V
authors.lastname: Visser-Vandewalle
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Kerpener Strasse 62, 50937 Cologne, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Kuhn
mesh_terms: D000375:Aging; D001921:Brain / Q000502:physiology / Q000503:physiopathology; D046690:Deep Brain Stimulation / Q000379:methods*; D003863:Depression / Q000628:therapy; D006801:Humans; D009771:Obsessive-Compulsive Disorder / Q000628:therapy; D005879:Tourette Syndrome / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D016896:Treatment Outcome
keywords: DBS; Deep brain stimulation; Meta-analysis; Review; Tourette; Tourette syndrome