No significant improvement in hearing with the addition of hyperbaric oxygen to a pharmacological regime for the treatment of sudden idiopathic sensorineural hearing loss.

Clinical Bottom Line:
1. No significant improvement in the proportion of patients gaining over 50% hearing return was demonstrated.
2. Similarly, there was no significant proportion of patients obtaining 25% improvement or better.

Appraised by: Mike Bennett, Dept of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney, Monday, 23 November, 1998

Clinical Scenario: A patient with sudden onset of sensorineural hearing loss of unknown origin.
Three-part Question: In adult patients with sudden idiopathic sensorineural hearing loss, does the addition of hyperbaric oxygen therapy to a standard treatment regime result in any additional benefit?
Search Terms: Hyperbaric oxygenation, deafness, hearing loss, noise induced.

The Study:
Non-blinded randomised controlled trial with intention-to-treat.
Adults with sudden sensorineural hearing loss where no cause was known.
Control group (N = 30; 30 analysed): Multiple drug therapy consisting of heparin, betamethasone, nicotinic acid, flunarizine, citidinephosphocoline, dextran, vitamins, neurotropic and antiviral drugs- doses not given.
Experimental group (N = 34; 34 analysed): Pharmacotherapy as for control group plus oxygen at 2.5ATA for 60 minutes daily for 15 sessions over 3 weeks.

The Evidence:
Time to Outcome
Relative benefit increase
Absolute benefit increase
Return of hearing greater than 50%
3 weeks
95% CI

-34% to 79%
-0.15 to 0.34
NNT=7 to INF NNH=3 to INF

Return of hearing greater than 25%
3 weeks
95% CI

-11% to 70%
-0.06 to 0.40
NNT=16 to NF
NNH=3 to INF

1. No details given on randomisation, blinding or exclusions from analysis.
2. Small study with no power, significance levels or confidence intervals given.
3. Trends apparent for some improvement with the addition of hyperbaric oxygen, but do not reach statistical significance.
4. No details given on outcome measures.

Expiry date: June 2020
References: 1. Cavallazzi G, Pignataro L, Capaccio P. Italian experience in hyperbaric oxygen therapy for idiopathic sudden sensorineural hearing loss. In Proceedings of the International Joint Meeting on Hyperbaric and Underwater Medicine. Marroni A, Oriani G, Wattel F, eds. Grafica Victoria, Bologna 1996:647-649.