Effects of impact noise on the hearing of military personnel

ABSTRACT: Shooting is an activity that exposes military personnel to noise impact, which may cause irreversible effects on hearing. OBJECTIVE: To evaluate impact noise on the hearing of military personnel that practice shooting. STUDY DESIGN: A case-control retrospective study. METHODS: 115 military personnel were enrolled; 65 had been exposed to impact noise and 50 were non-exposed. Firearm noise levels were evaluated, subjects answered a questionnaire and underwent threshold tonal audiometry and otoacoustic emissions testing. RESULTS: The average noise level was 125dB(C). Most subjects (78%) believe that noise may cause hearing loss; nearly all (92.3%) used ear noise protectors while shooting, but most (32.3%) had never received guidance for using this equipment. There were significant differences between the two groups in relation to changes suggesting impact noise-induced hearing loss. CONCLUSION: The differences between groups show that noise-exposed military personnel are more likely to develop hearing loss. The goal of a hearing conservation program for this population should be to preserve hearing and educate these individuals about the importance of using hearing protection correctly.