Noise-induced hearing loss caused by gunshot in South Korean military service.
BACKGROUND
Noise-induced hearing loss 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 South Korean males in military service. Considering the significant lack of awareness on this serious issue as well as the absence of proper protective gear, an in-depth analysis is desperately needed.


METHODS
All 3650 soldiers performed regular periodic gunfire exercise without any hearing protective measures. Seven patients with hearing impairment after periodic gunfire visited the aeromedical squadron; all were right-handed males. Six were tested with the K-2 rifle and one was tested with a K-5 revolver. History taking, physical examination, pure-tone audiometry, and impedance audiometry were conducted. In the next periodic gunfire exercise, all 3650 soldiers performed gunfire with unilateral hearing protection.


RESULTS
The average outcome of postexposure air conduction thresholds was 6.5 dB in the right ear and 33.1 dB in the left ear. After medical treatment, hearing impairment was much improved; however, tinnitus was not diminished. In the next periodic gunfire exercise, the result of a supplement of unilateral earplug protection proved its effectiveness on acoustic trauma caused by gunfire noise.


CONCLUSIONS
Asymmetry in hearing loss is related to the position of the head during gunfire. A unilateral hearing protection device was enough to protect hearing from gunfire noise. At the same time, it can effectively prevent a potential firearm accident that can be caused by trainees mishearing the instruction of a firearm instructor if both earplugs are worn. Thus, providing a unilateral earplug for protection against acoustic trauma must be taken into serious consideration.
Moon
In Seok
IS
Republic of Korea Air Force, 20th Fighter Wing Aeromedical Squadron, P.O. Box 384-21, Seokpo-ri, Heami-myeon, Seosan-si, Chungcheongnam-do, South Korea.
D000328:Adult; D004430:Ear Protective Devices; D005389:Firearms; D006317:Hearing Loss, Noise-Induced / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D006801:Humans; D007723:Korea; D008297:Male; D008487:Medical History Taking; D008887:Military Medicine; D008889:Military Personnel; D009623:Noise, Occupational / Q000009:adverse effects* / Q000517:prevention & control; D011187:Posture