Effects of impact noise on the hearing of military personnel.

UNLABELLED 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 125 dB(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.