Early treatment response predicts outcome in patients with idiopathic sudden sensorineural hearing loss treated with hyperbaric oxygen therapy.

Hyperbaric oxygen (HBO₂) therapy is used in the treatment of idiopathic sudden sensorineural hearing loss (ISSNHL). Some patients, however, do not benefit from HBO₂ therapy despite several weeks of treatment. We hypothesized that early treatment response could predict treatment failure. We conducted a retrospective chart review and identified patients diagnosed with ISSNHL and recorded the pure tone average (PTA) levels prior to, after the first week and at completion of HBO₂ therapy. Early treatment response (ETR) was assessed after the first week of HBO₂ therapy, and an increase ⟨10 decibels (dB) in mean PTA level was defined as a negative ETR. Factors associated with no recovery were determined using logistic regression analysis. Overall, 39 patients (22 males; mean age (±SD) 41.9 ±14.3 years) were assessed. At treatment completion, the improvement in hearing was 'very substantial' (≥20 dB) for 21 patients (53.8%), 'substantial' (10-19 dB) for eight (20.5%), 'minimal' (⟨10 dB) for five (12.8%) and absent for five (12.8%) patients. After the first week of HBO₂ therapy, 18 (46.2%) patients displayed negative ETR. Multivariate logistic regression analysis revealed 'negative ETR' as the only significant predictor of treatment failure (odds ratio (95% confidence interval): 6.98 (1.59-30.61), p=0.010) in patients with ISSNHL treated with HBO₂. In conclusion, we found that patients who fail to benefit from an initial set of HBO₂ sessions were less likely to benefit from additional HBO₂ sessions. Further prospective studies are necessary to confirm our findings.