The Effects of Dexamethasone Following an Acute Acoustic Trauma

An acute acoustic trauma (AAT) results when the unprotected ear is exposed to very high sound pressure levels, usually as the result of an industrial or milita~ accident. A study was performed to evaluate the effects of a corticosteroid (dexamethasone) on the hearing loss from a series of blast waves that would simulate an AAT. Groups of chinchillas were exposed individually to ten 160-dB peak SPL reverberant blast waves fim a conventional shock tube at a rate of one blast per minute. Immediately following the exposure, the animals were injected with dexamethasone alone (I -2 mgkg IV) or in combination with Dimethyl Sulfoxide (DMSO, 1 mlkg). Groups of animals showed the well-known extreme variability in hearing losses as noted in earlier studies (I). The median permanent [hreshold shifts (PTS) in the various groups of animals showed a dose-dependent effect up to 16 dB, with increasing dosages of dexamethasone associated with lower levels of PTS in the frequency region most affected by the noise exposure.