Recovery Patterns During Extended Hyperbaric Oxygen Treatment Combined With Steroids in Severe Sudden Sensorineural Hearing Loss: A Multi-Center Study.

Introduction: Severe sudden sensorineural hearing loss (SSNHL) is a challenging otological emergency. Hyperbaric oxygen (HBO₂) treatment is an adjunctive treatment for SSNHL, improving oxygen supply and microcirculation and reducing oxidative stress. While HBO₂ is increasingly used for SSNHL, the temporal patterns of hearing recovery during extended treatment protocols remain poorly characterized. This study investigates the frequency-specific recovery patterns and speech recognition improvements during a 30-session HBO₂ protocol with concurrent steroid treatment in patients with severe SSNHL. Methods: This multi-center, retrospective cohort study included patients diagnosed with severe SSNHL at four medical centers from January 2019 to December 2024. Inclusion criteria included patients who initiated HBO₂ with steroids within five days of onset, completed 30 HBO₂ sessions, and underwent pure-tone audiometry and speech recognition assessments at specified intervals. A total of 103 patients receiving combined HBO₂ and steroid treatment were analyzed using SPSS. Results: Low-frequency hearing (125 Hz, 250 Hz, and 500 Hz) exhibited rapid recovery, with significant enhancements noted after ten sessions of HBO₂ (P < 0.05). In contrast, mid-frequency hearing (1000 Hz and 1500 Hz) and high-frequency hearing (2000 Hz) showed notable improvements after 20 and 30 sessions (P < 0.05), with the 30-session treatment resulting in greater enhancements compared to the 20-session treatment (P < 0.05). Speech recognition rates significantly improved after 20 and 30 sessions of HBO₂ compared to pre-treatment levels (P < 0.05), with the 30-session treatment showing statistically significantly higher rates than the ten-session HBO₂ (P < 0.05). Discussion: Hyperbaric oxygen treatment significantly enhances hearing and speech recognition in severe SSNHL, particularly in the mid-frequency range. Long-term HBO₂ treatment may be a viable option for these patients.