Hearing loss and tinnitus in acute acoustic trauma

Despite extensive educational and protective measures, acute acoustic trauma continues to be a major problem in young military recruits. This retrospective study concern conscripts from eastern Austria who were referred to the Central Military Hospital for acute acoustic trauma (AAT) during the last 18 months. The study was designed to provide information on the profile of hearing loss and the presence of tinnitus after AAT. At the time when AAT occurred, hearing protection was not used in the majority of cases. In more than 75% of the ears hearing loss was registered in the high-frequency region (above 2 kHz). In the remaining 25% the speech frequency range under 2 kHz was also affected. Interestingly, the degree of hearing loss was independent of the type of firearm used, the number of shots and the use of hearing protection (ear plugs). Hearing loss occurred asymmetrically due to one-sided noise, whereas the distribution of tinnitus was symmetrical. The majority of patients experienced both, tinnitus and hearing loss as a consequence of AAT. Yet, in 6.2% of the subjects tinnitus was the only symptom. These results strongly suggest that tinnitus is as important a symptom of AAT as is hearing loss. Therefore, we believe that a tinnitus match should be performed in every patient with suspected AAT.