Secondary hyperbaric oxygen therapy for idiopathic sudden sensorineural hearing loss in the subacute and chronic phases.

This study investigated the efficacy of hyperbaric oxygen therapy (HBOT) as a secondary treatment for patients with idiopathic sudden sensorineural hearing loss (ISSNHL) in the subacute and chronic phases. Forty-eight ISSNHL patients (HBOT group) who had received primary conventional treatment within 4 weeks after onset and underwent HBOT between 4 and 20 weeks post-onset were retrospectively compared with 44 ISSNHL patients (control group) with primary conventional treatment alone. Mean hearing gain was slight, with gains of 5.2 +/- 8.9 dB in the HBOT group and 2.0 +/- 7.6 dB in the control group. However, no significant difference was recognized between the two groups. In the HBOT group, no significant difference was observed in hearing gain among patients with HBOT initial time at 4-7, 8-11, 12-15 or 16-20 weeks after onset. Meanwhile, hearing gain was significantly higher in patients with profound hearing loss than in the other patients. We conclude that the effectiveness of secondary HBOT for ISSNHL patients in either subacute or chronic phase remains unproven, and thus, the decision administer HBOT should be made with caution.