Hyperbaric oxygen therapy for acute noise-induced hearing loss: evaluation of different treatment regimens.

INTRODUCTION Impulse noise from firearms is a common cause of acute acoustic trauma (AAT), which is characterized by high-frequency hearing loss and tinnitus. Various treatment modalities have been proposed, some combining medical treatment with hyperbaric oxygen (HBOT) in various ways. We have reviewed the therapeutic effect of primary protocols, with or without HBOT, used in our hospital. METHODS Sixty-eight soldiers for all of whom pre-AAT audiometry tests were available, were treated with one of three different regimens. Group 1 received oral medication only. Group 2 received HBOT twice a day for 3 days then once a day (7 days), combined with intravenous medication (5 days) followed by oral treatment. Group 3 received HBOT once a day and oral medication for 10 days. Medical treatment consisted of methylprednisolone and piracetam in all groups. Control audiometry was performed after 10 days. Average Hearing Gain (AHG) and Average Residual Hearing Loss (ARHL) were calculated. RESULTS The mean AHG in Group 1 was +5.58 ± 3.58 dB (mean ± SD); in Group 2 it was +20.62 ± 17.68 dB; and in Group 3 +17.0 ± 14.0 dB (P = 0.001, Kruskal-Wallis test). The mean ARHL without HBOT was -14.7 ± 8.27 dB (Group 1), and respectively -2.36 ± 10.69 dB (Group 2) and -5.0 ± 8.0 dB (Group 3) in the HBOT groups (P = 0.001, Kruskal-Wallis test). CONCLUSION These results indicate a significant benefit for the combination of HBOT and medical therapy over medical treatment alone. Which of the two HBOT regimens is the more effective, remains to be determined.