title: Deep brain stimulation of the ventral intermediate nucleus of the thalamus for tremor in patients with multiple sclerosis.
abstract: BACKGROUND
  Tremor is an important cause of disability in patients with multiple sclerosis (MS). Deep brain stimulation (DBS) in the ventral intermediate nucleus (VIM) of the thalamus is said to be beneficial for MS tremor.
  
  
  OBJECTIVE
  To assess the long-term efficacy of VIM DBS for MS disabling tumor.
  
  
  METHODS
  We treated 10 patients (4 men and 6 women) with advanced MS-related medication-resistant tremor with DBS at the VIM thalamic nucleus. DBS was unilateral in 9 patients and bilateral in 1 patient in 2 stages. Contralateral arm tremor was assessed with the Fahn-Tolosa-Marin tremor rating scale.
  
  
  RESULTS
  At 1 year, 5 of 10 patients (5 of 11 hemispheres) had a reduction in tremor scores with stimulation compared with baseline; in 3 patients, the reduction was > 50%. After 36 months, 3 patients continued benefiting from stimulation, 2 having > 50% improvement. Of the 6 symptomatic sides that did not benefit at 1 year, 3 failed to have even initial benefit, and 3 had a transient improvement lasting < 1 year. One patient stopped using stimulation because of a lack of improvement at 5 months after surgery and was lost to follow-up.
  
  
  CONCLUSIONS
  Approximately one-half of the patients derived some benefit from VIM DBS 1 year after surgery, but this benefit reached a > 50% reduction in only 30% of the patients. This level of improvement may be related to the variability of the demyelinating lesions and the superimposition of ataxia in the MS patients. Developing better treatments for MS tremor continues to be a challenge.
authors.affiliation: Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, University Health Network, Toronto, Ontario, Canada.
authors.forename: Cristina V
authors.initials: CV
authors.lastname: Torres
authors.forename: Elena
authors.initials: E
authors.lastname: Moro
authors.forename: Adriana-Lucia
authors.initials: AL
authors.lastname: Lopez-Rios
authors.forename: Mojgan
authors.initials: M
authors.lastname: Hodaie
authors.forename: Robert
authors.initials: R
authors.lastname: Chen
authors.forename: Adrian W
authors.initials: AW
authors.lastname: Laxton
authors.forename: William D
authors.initials: WD
authors.lastname: Hutchison
authors.forename: Jonathan O
authors.initials: JO
authors.lastname: Dostrovsky
authors.forename: Andres M
authors.initials: AM
authors.lastname: Lozano
mesh_terms: D000328:Adult; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications* / Q000503:physiopathology; D014202:Tremor / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery*; D020651:Ventral Thalamic Nuclei / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D055815:Young Adult