title: Deep brain stimulation of the posterior subthalamic area in the treatment of tremor.
abstract: BACKGROUND
  Several studies have described lesional therapy in the posterior subthalamic area (PSA) in the treatment of various movement disorders. Recently, some publications have illustrated the effect of deep brain stimulation (DBS) in this area in patients with Parkinson's disease, essential tremor, MS-tremor, and other forms of tremor. Even though the clinical series is small, the reported benefits prompted us to explore DBS in this area in the treatment of tremor.
  
  
  METHODS
  Five patients with tremor were operated using unilateral DBS of the PSA. Two patients had dystonic tremor, one primary writing tremor, one cerebellar tremor and the other neuropathic tremor. All patients were assessed before and 1 year after surgery using items 5 and 6 (tremor of the upper extremity), 11-14 (hand function), and when appropriate item 10 (handwriting) from the essential tremor rating scale.
  
  
  RESULTS
  The mean improvement on stimulation after 1 year was 87%. A pronounced and sustained microlesional effect was seen in several of the patients, and while the mean improvement off stimulation was 56% the reduction in the three patients with the most pronounced effect was 89%. The two patients with dystonic tremor did also become free of the dystonic symptoms and pain in the treated arm. No severe complication occurred.
  
  
  CONCLUSIONS
  DBS of the PSA in this small group of patients had an excellent effect on the different forms of tremor, except for the neuropathic tremor where the effect was moderate. These preliminary results suggest PSA to be an effective target for the treatment of various forms of tremor. Further studies concerning indications, safety and efficacy of DBS in the posterior subthalamic area are required.
authors.affiliation: Department of Neurosurgery, University Hospital of Northern Sweden, Umeå, Sweden. patric.blomstedt@neuro.umu.se
authors.forename: P
authors.initials: P
authors.lastname: Blomstedt
authors.forename: A
authors.initials: A
authors.lastname: Fytagoridis
authors.forename: S
authors.initials: S
authors.lastname: Tisch
mesh_terms: D000328:Adult; D000368:Aged; D001479:Basal Ganglia / Q000503:physiopathology; D046690:Deep Brain Stimulation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D004567:Electrodes, Implanted / Q000009:adverse effects / Q000592:standards; D020329:Essential Tremor / Q000503:physiopathology / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D009434:Neural Pathways / Q000503:physiopathology; D010300:Parkinson Disease / Q000503:physiopathology / Q000628:therapy; D011183:Postoperative Complications / Q000503:physiopathology; D011446:Prospective Studies; D020127:Recovery of Function / Q000502:physiology; D020531:Subthalamic Nucleus / Q000033:anatomy & histology / Q000502:physiology; D020530:Subthalamus / Q000033:anatomy & histology / Q000502:physiology*; D016896:Treatment Outcome; D014202:Tremor / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*