Hyperbaric oxygen therapy for idiopathic sudden sensorineural hearing loss and tinnitus: a systematic review of randomized controlled trials.

BACKGROUND Idiopathic sudden sensorineural hearing loss (ISSHL) and tinnitus are common. Hyperbaric oxygen therapy (HBOT) may improve hearing loss and/or reduce the intensity of tinnitus. METHODS We performed a systematic search of the literature for randomized controlled trials, and made pooled analyses of pre-determined clinical outcomes where possible. RESULTS Six trials contributed to this review (304 subjects). Pooled analysis suggested a significantly increased chance of a 25 per cent improvement in hearing threshold on pure tone average with HBOT (relative risk (RR) 1.39, 95 per cent confidence interval (CI) 1.05-1.84, p = 0.02; number-needed-to-treat 5, 95 per cent CI 3-20), but not a 50 per cent increase (RR 1.53, 95 per cent CI 0.85-2.78, p = 0.16). The significance of any improvement in tinnitus following HBOT could not be assessed due to poor reporting. CONCLUSIONS HBOT improved hearing, but the clinical significance of the level of improvement is not clear. Routine application of HBOT to patients with ISSHL is not justified by this review. More research is needed.