Acute acoustic trauma among soldiers during an intense combat

Background: During military actions, soldiers are constantly exposed to various forms of potentially harmful noises. Acute acoustic trauma (AAT) results from an impact, unexpected intense noise ≥140 dB, which generates a high-energy sound wave that can damage the auditory system. Purpose: We sought to characterize AAT injuries among military personnel during operation "Protective Edge," to analyze the effectiveness of hearing protection devices (HPDs), and to evaluate the benefit of steroid treatment in early-diagnosed AAT injury. Research Design: We retrospectively identified affected individuals who presented to military medical facilities with solitary or combined AAT injuries within 4 mo following an intense military operation, which was characterized with an abrupt, intensive noise exposure (July-December 2014). Study Sample: A total of 186 participants who were referred during and shortly after a military operation with suspected AAT injury. Interventions: HPDs, oral steroids. Data Collection and Analysis: Data extracted from charts and audiograms included demographics, AAT severity, worn HPDs, first and last audiograms and treatment (if given). The Student's independent samples t testwas used to compare continuous variables. All testswere considered significant if p valueswere#0.05. Results: A total of 186 participants presented with hearing complaints attributed to AAT: 122, 39, and 25 were in duty service, career personnel, and reservists, with a mean age of 21.1, 29.2, and 30.4 yr, respectively. Of them, 92 (49%) participants had confirmed hearing loss in at least one ear. Hearing impairment was significantly more common in unprotected participants, when compared with protected participants: 62% (74/119) versus 45% (30/67), p < 0.05. Tinnitus was more common in unprotected participants when compared with protected participants (75% versus 49%, p 5 0.04), whereas vertigo was an uncommon symptom(5%versus 2.5%, respectively, p.>0.05). In the 21 participants who received steroid treatment for early-diagnosed AAT, bone-conduction hearing thresholds significantly improved in the posttreatment audiograms, when compared with untreated participants (p < 0.01, for 1-4 kHz). Conclusions: AAT is a common military injury, and should be diagnosed early to minimize associated morbidity. HPDs were proven to be effective in preventing and minimizing AAT hearing sequelae. Steroid treatment was effective in AAT injury, if initiated within 7 days after noise exposure.