Background Idiopathic sudden sensorineural hearing loss (ISSNHL) is defined as a 30-decibel (dB) loss in hearing over three contiguous frequencies within 3 days. The cause remains unknown, and there is currently no consensus in the literature as to how it is best treated. Conventional treatment in our unit comprises steroids, pentoxyphiline and dextran, with the potential addition of hyperbaric oxygen therapy (HBOT).

Methods A prospective randomised trial was performed on all soldiers diagnosed with ISSNHL in our institution from 1 January 2007 to 31 December 2016. Participants were randomly allocated to one of two groups. Group A was treated with conventional treatment plus HBOT. Group B was treated with conventional treatment only. Data collection included age, gender, clinical symptoms, pure-tone audiometry results and treatment outcome.

Results 60 participants were enrolled (53 male, 7 female) with ages ranging from 18 to 65 years (mean age of 30.3). No significant differences were observed in the baseline characteristics between the two groups, including gender, age, site, associated symptoms, duration of symptoms and severity of hearing loss. Hearing recovery using Siegel’s criteria on days 8 and 13 showed no significant differences between treatment groups. However, the hearing recovery on day 180 was significantly better in those who received the conventional treatment plus HBOT (P<0.05). Additionally, no significant side effects were observed in either group.

Conclusions HBOT plus existing conventional treatment was associated with a better outcome than conventional treatment alone. We would recommend the addition of HBOT is recommended as a first-line treatment modality for all soldiers presenting with ISSNHL.