Efficacy of hyperbaric oxygen therapy as a supplementary therapy of sudden sensorineural hearing loss in the Slovak Republic

We evaluated the efficacy of hyperbaric oxygen (HBO2 ) therapy used as a supplement to the first-line medical treatment of sudden sensorineural hearing loss (SSNHL). We tested 68 patients suffering from SSNHL within seven days of hearing loss: 21 patients received the standard treatment protocol of our department (control group) and 47 individuals were treated with an additional application of HBO2 therapy. Treatment success was assessed using pre- and post-treatment audiograms. Outcomes of our study showed a statistically significant improvement in auditory threshold in all frequency groups for the HBO2 group (P < 0.001), whereas in the control group the statistically significant mean auditory gain was observed only for the frequency zone 1,000 to 2,000 Hertz (P = 0.01). Furthermore, the rate of hearing gain in the HBO2 group was more than doubled (61.7%) compared to the control group (28.6%). Complete recovery of the hearing gain in the control group was observed only in the first two frequency groups (14.29%; 4.76%; 0.00%), whereas in the HBO2 group complete recovery was seen in all the frequency groups (19.15%; 21.13%; 6.38%) as well as in the whole frequency range (6.38%). The efficiency of both treatment protocols was statistically significant (P < 0.001) in both groups of patients, but supplementation of the therapy with HBO2 demonstrated a statistically significantly increase in the effect of pharmacotherapy (P < 0.001) by 11.5 decibels (dB) up to the final hearing gain of 20 dB. HBO2 is therefore a promising modality of SSNHL treatment, but specific mechanisms of HBO2 in patients with SSNHL are still unknown. Further investigations are warranted to explore the mechanisms of action.