Hyperbaric oxygen therapy for idiopathic sudden sensorineural hearing loss: a cohort study of 10 versus more than 10 treatments

Abstract

Introduction: Current treatment of idiopathic sudden sensorineural hearing loss (ISSNHL) includes a combination of corticosteroids and hyperbaric oxygen therapy (HBOT) without established dose. The objective of this study was to investigate whether > 10 HBOT treatments offers improved outcome over 10 treatments. Methods: A retrospective chart review was performed of patients treated with HBOT for ISSNHL between 2013 and 2022 at the Royal Brisbane and Women’s Hospital. Pure tone average results from 500, 1,000, 2,000, 4,000 hertz (PTA4) were obtained pre-treatment, after treatment 10, and six weeks post-treatment. Results: There were 479 patients treated for ISSNHL: 144 having audiograms six weeks post-treatment, 140 of whom also had an audiogram after treatment 10. At six weeks post treatment 22% (32/144) had normal hearing (PTA4 < 25 dB), and 69% (99/144) had a PTA4 gain ≥ 10 dB. At the treatment 10 audiogram, 83/140 (59%) were improved. From these, 5/21 (24%) with 10 treatments and 14/57 (25%) with > 10 treatments had a further PTA4 gain of ≥ 10 dB occurring after treatment 10. For those 57/140 (41%) not improved at treatment 10, 7/26 (27%) with 10 treatments and 12/31 (39%) with > 10 treatments were improved at six weeks post-treatment with 5/7 (71%) and 8/12 (67%) of the 10 and > 10 groups respectively having ≥ 10 dB gain in PTA4 occurring after treatment 10. Overall, there was no significant difference in mean (SD) hearing gain from treatment 10 to six weeks post treatment between the 10 treatments and > 10 treatments groups: 4.73 (8.90) versus 5.93 (11.25) dB, P = 0.53. Conclusions: In conjunction with steroids, 10 treatments of hyperbaric oxygen therapy appear to offer equivalent benefit to > 10 treatments. Similar improvements in PTA4 and hearing recovery occur after 10 HBOT treatments independent of ongoing HBOT. A prospective trial comparing 10 versus > 10 treatments for ISSNHL with outcome measured beyond treatment completion is warranted.