[Impulse noise influence on hearing].

UNLABELLED: Impulse noise from weapons and explosions produces hearing damage among military service. The discovery of otoacoustic emissions (OAE) has given a new possibility of early diagnosis of noise induced hearing loss. The aim of the study was to assess the effects of exposure to impulse noise on TEOAE, SNR and PTA.

MATERIAL AND

METHODS

the study comprised 92 (184 ears, aged 18.5-20 years) soldiers, subjected to impulse noise during one year of military service. The soldiers were divided in to three groups according exposure to noise. Group I the highest exposure 2222, 9 kPa2/s, group II--611, 8 kPa2/s and group III--103-109 kPa2/s. The control group consisted of 60 (120 ears) secondary school students. Hearing evaluation was performed before and after one year of military service, using extended pure tone audiometry, tympanometry, TEOAE and SNR.

RESULTS

after military service significant deterioration of hearing was observed on average 1-2 dB for 0.125-3 kHz and 4-6 dB for 4-12 kHz for all examined soldiers without differences between groups. TEOAE reductions were registered predominantly at frequencies of 3 and 4 kHz, for both ears and SNR mean values reduction for the frequencies of 2, 3 and 4 kHz.

CONCLUSIONS

TEOAE especially in cases where clinical audiometry is less sensitive can monitor small changes in the cochlea. There were no differences between groups and ears.