title: Hyperbaric oxygen in tinnitus: influence of psychological factors on treatment results?
abstract: BACKGROUND
  The standard treatment of subjective tinnitus hardly reaches the level of placebo controls. Though the effectiveness of hyperbaric oxygenation (HBO) for subjective tinnitus has never been objectified, it is still advocated by some institutions. We analyzed the effectiveness of hyperbaric oxygen treatment in the context of accompanying factors.
  
  
  METHODS
  We randomized 360 patients suffering from tinnitus into 2 HBO treatment protocols (group A: 2.2 bar for 60 min bottom time and group B: 2.5 bar for 60 min bottom time once a day for 15 days). All patients were asked to fill in a questionnaire (social and medical history, tinnitus characteristics, pre-HBO duration of tinnitus, prior therapy, pretreatment expectation, accompanying symptoms). A subjective assessment of the therapeutic effect was obtained.
  
  
  RESULTS
  Twelve patients (3.3%) experienced complete remission of tinnitus, in 122 (33.9) the intensity lessened, and 44 (12.2%) had a subjectively agreeable change of noise characteristics. No change was found in 157 cases (43.6%) and 25 (6.9%) experienced deterioration. There was no statistically significant difference between groups A and B (p > 0.05). Out of 68 patients with a positive expectation of HBO effects, 60.3% stated that the tinnitus had improved whereas only 47.2 and 19%, respectively, out of patients who underwent therapy with an indifferent (n = 271) or negative expectation (n = 21) reported an improvement. The influence of subjective expectation on the outcome was statistically significant (p < 0.05).
  
  
  CONCLUSIONS
  The therapeutic effects of HBO on subjective tinnitus may be substantially influenced by psychological mechanisms.
authors.affiliation: Division of Thoracic Surgery and Hyperbaric Medicine, University of Medicine, Graz, Austria. christian.porubsky@klinikum-graz.at
authors.forename: C
authors.initials: C
authors.lastname: Porubsky
authors.forename: P
authors.initials: P
authors.lastname: Stiegler
authors.forename: V
authors.initials: V
authors.lastname: Matzi
authors.forename: C
authors.initials: C
authors.lastname: Lipp
authors.forename: A
authors.initials: A
authors.lastname: Kontaxis
authors.forename: H
authors.initials: H
authors.lastname: Klemen
authors.forename: C
authors.initials: C
authors.lastname: Walch
authors.forename: F
authors.initials: F
authors.lastname: Smolle-Juttner
mesh_terms: D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006801:Humans; D006931:Hyperbaric Oxygenation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D013997:Time Factors; D014012:Tinnitus / Q000453:epidemiology* / Q000628:therapy*; D016896:Treatment Outcome