title: Long-term follow-up of thalamic deep brain stimulation for essential tremor - patient satisfaction and mortality.
abstract: BACKGROUND
  Ventral intermediate thalamic nucleus (VIM) deep brain stimulation (DBS) is an effective treatment for tremor, but there is limited data on long-term efficacy and mortality after VIM-DBS. Here we report the analysis of patient satisfaction and mortality in all patients treated in our center 1996-2010 with VIM-DBS for essential tremor (ET).
  
  
  METHODS
  Forty-six consecutive patients were included in this study. Medical records were reviewed, and a follow-up questionnaire was sent to all surviving patients.
  
  
  RESULTS
  Seventy percent of all possible participants (26 patients) answered the questionnaire. Follow-up time for the responding patients was median 6.0 years (2-16). Median self-reported score on visual analogue scale of the initial postoperative effect on tremor was 8.5 (0.1-10), with a significant reduction to 7.4 (0-10) at follow-up (p = 0.001). Patients reported a median score of 10 (0-10) for overall patient satisfaction with VIM-DBS treatment. Eight patients (17%) died after median 8.9 years (0.6-15) after surgery, at median age 77.4 years (70-89). One patient (2%) committed suicide seven months after the operation. Calculated standard mortality ratio among ET patients was 1.3 (CI 0.6-2.6), similar to the general population.
  
  
  CONCLUSIONS
  We found no significant increase in mortality in this cohort of VIM-DBS operated ET patients compared to the general population in Norway. The patients reported high long-term satisfaction and continuing effect of VIM-DBS on tremor even after many years. VIM-DBS therefore seems to be an effective symptomatic long-term treatment of ET. However, one patient committed suicide. Only one other suicide has previously been reported after VIM-DBS. It is therefore still unclear whether VIM-DBS increases suicide risk.
authors.forename: Mari Naumann
authors.initials: MN
authors.lastname: Børretzen
authors.forename: Silje
authors.initials: S
authors.lastname: Bjerknes
authors.forename: Terje
authors.initials: T
authors.lastname: Sæhle
authors.forename: Mona
authors.initials: M
authors.lastname: Skjelland
authors.forename: Inger Marie
authors.initials: IM
authors.lastname: Skogseid
authors.forename: Mathias
authors.initials: M
authors.lastname: Toft
authors.affiliation: Department of Neurology, Oslo University Hospital, PO Box 4950, Nydalen N-0424 Oslo, Norway. espen.dietrichs@medisin.uio.no.
authors.forename: Espen
authors.initials: E
authors.lastname: Dietrichs
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D046690:Deep Brain Stimulation / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D020329:Essential Tremor / Q000401:mortality / Q000523:psychology / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D017060:Patient Satisfaction; D011795:Surveys and Questionnaires; D016019:Survival Analysis; D017741:Survivors / Q000523:psychology; D013788:Thalamus / Q000502:physiology*; D016896:Treatment Outcome