Hyperbaric oxygen for idiopathic suddensensorineural hearing loss and tinnitus (Cochrane Review).

Citation: Bennett M, Kertesz T, Yeung P. Hyperbaric oxygen for idiopathic suddensensorineural hearing loss and tinnitus (Cochrane Review). In: The Cochrane Library (Issue 1 2005). Chichester, UK: John Wiley & Sons, Ltd.

Background

Idiopathic sudden sensorineural hearing loss (ISSHL) with or without tinnitus is common and presents a health problem with significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) may improve oxygen supply to the inner ear and it is postulated that application of HBOT to these patients may result in an improvement in hearing and/or a reduction in the intensity of tinnitus.

  Objectives

To assess the benefits and harms of HBOT for treating ISSHL and/or tinnitus.

  Search strategy

We searched the Cochrane ENT Specialist Register (June 2004), CENTRAL (The Cochrane Library Issue 3, 2004), MEDLINE (1966 - 2004), EMBASE (1974 - 2004), CINAHL (1982 - 2004), DORCTHIM (1996 - 2004), and reference lists of articles. Relevant journals were hand searched and researchers in the field were contacted.

  Selection criteria

Randomised studies comparing the effect on ISSHL and/or tinnitus of therapeutic regimens which include HBOT with those that exclude HBOT.

  Data collection & analysis

Three reviewers independently evaluated the quality of the relevant trials using the validated Oxford-Scale (Jadad 1996) and extracted the data from the included trials.

  Main results

Five trials contributed to this review (254 subjects). Pooled data from two trials involving 114 patients did not show any significant improvement in the chance of a 50% increase in hearing threshold on Pure Tone Average (PTA) when HBOT was used (relative risk [RR] with HBOT 1.53, 95% CI 0.85 to 2.78, P=0.16), but did show a significantly increased chance of a 25% increase in PTA (RR 1.39, 95% CI 1.05 to 1.84, P=0.02). There was a 22% greater chance of improvement with HBOT, and the number need to treat (NNT) to achieve one extra good outcome was 5 (95% CI 3 to 20). A single trial involving 50 subjects also suggested significant more improvement in the mean PTA threshold with HBOT, expressed as a percentage of baseline (WMD 37%, 95% CI 22% to 53%, P<0.001).  The significance of any improvement following HBOT in a subjective rating of tinnitus could not be assessed due to poor reporting.

There were no significant improvements in hearing or tinnitus reported in the single study to examine chronic presentation (six months) of ISSHL and/or tinnitus.

  Reviewers' conclusions

For people with early presentation of ISSHL, the application of HBOT significantly improved hearing loss, but the clinical significance of the level of improvement is not clear. We could not assess the effect of HBOT on tinnitus by pooled data analysis. The routine application of HBOT to these patients cannot be justified from this review. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously, and an appropriately powered trial of high methodological rigour is justified to define those patients (if any) who can be expected to derive most benefit from HBOT.