title: A randomized double-blind crossover study of phase-shift sound therapy for tinnitus.
abstract: OBJECTIVE
  The purpose of this study was to compare the efficacy of the treatment of tinnitus with a phase-shifting pure tone to that of the same tone treatment without phase shifting.
  
  
  METHODS
  A double-blind crossover randomized controlled trial.
  
  
  METHODS
  This study was conducted at the University Medical Center Groningen.
  
  
  METHODS
  Twenty-two patients with predominantly tonal tinnitus underwent both intervention and control treatments. Each treatment consisted of three 30-minute sessions in 1 week. The control treatment was identical to the intervention treatment, except that the stimulus was a pure tone without phase shifting. Questionnaires, tinnitus loudness match, and annoyance and loudness ratings were used to measure treatment effects.
  
  
  RESULTS
  Pure-tone treatment and phase-shift treatment had no significant effect on tinnitus according to questionnaires (Tinnitus Handicap Index, Tinnitus Reaction Questionnaire, Hospital Anxiety and Depression Scale, and Maastricht Questionnaire), audiological matching procedures, and loudness and annoyance ratings of tinnitus. Furthermore, phase-shift treatment showed no additional significant improvement in comparison with pure-tone treatment. Changes in questionnaire scores due to pure-tone and the phase-shift treatment were correlated.
  
  
  CONCLUSIONS
  On average across the group, both treatments failed to demonstrate a significant effect. Both treatments were beneficial for some patients. However, a positive effect was not demonstrated that could be attributed to the periodic shifting of the phase of the stimulus tone.
authors.affiliation: Department of Otorhinolaryngology/Head & Neck Surgery, University of Groningen, University Medical Center Groningen, The Netherlands. k.m.heijneman@umcg.nl
authors.forename: Karin M
authors.initials: KM
authors.lastname: Heijneman
authors.forename: Emile
authors.initials: E
authors.lastname: de Kleine
authors.forename: Pim
authors.initials: P
authors.lastname: van Dijk
mesh_terms: D000328:Adult; D000368:Aged; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013016:Sound; D014012:Tinnitus / Q000628:therapy*