Noise Induced Hearing Loss Caused by Gunshot in Military Service

Moon, In Seok

Abstract

BACKGROUND AND OBJECTIVES
Noise induced hearing loss (NIHL) is a preventive disease and yet the effective treatment modality has not been established. Acute acoustic traumas caused by an exposure to gunshot noise are common in young Korean males in the military service. Considering the significant lack of awareness on this serious issue as well as the absence of proper protection gears, an in-depth analysis is desperately needed.
SUBJECTS AND METHOD
3,650 soldiers performed a regular gunshot exercise without any hearing protective measures. Out of 3,650 soldiers, 8 patients with hearing impairment after the regular gunfire visited aeromedical squadron. They were all right-handed males: 7 had been tested with K-2 rifle and 1 had been tested with K-5 revolver. History taking, physical examination, pure-tone audiometry, and impedence audiometry were performed. In the next round of gunshot practice, all soldiers performed gunfire with unilateral hearing protection.
RESULTS
The average outcome of postexposure air conduction thresholds were 6.5 dB in the right ear and 33.1 dB in left ear. After medical treatment, hearing impairment was much improved ; however, tinnitus was not diminished. In the next round of gunshot practice, the supplement of unilateral earplug protection proved its effectiveness on acoustic trauma caused by gunfire noise.
CONCLUSION
Asymmetry of hearing loss was related to head position during gunfire. Unilateral hearing protection device was enough to protect hearing from acoustic trauma caused by gunshot. At the same time, it can effectively prevent a potential firearm accident that can be caused by trainees' mishearing the instruction of firearm instructor if both earplugs are worn. Thus, providing unilateral earplug protection against acoustic trauma must be taken into serious consideration.