Detection and Grading of Early-Stage Cochlear Damage in Land Hunters by Comparison of Extended High-Frequency Audiograms with Conventional High-Frequency Audiograms.

Abstract

Background and ObjectivesFirearms used by hunters produce intermittent loud noises. These sounds, which are above the safe limits set by the World Health Organization, can cause cochlear damage. Detection of cochlear damage at an early stage, before clinical complaints appear, will enable serious treatment measures.Subjects and MethodsA total of 105 male hunters without hearing complaints and 45 controls who were not exposed to loud noise were compared and investigated. Extended high-frequency audiograms and conventional audiograms were used to compare the groups.ResultsThe problem detection rates of conventional high-frequency audiometry, extended high-frequency audiometry, and both tests together were 59.1, 78.1, and 82.9%, respectively. There was no statistical difference between audiometric values at the extended high-frequency and at the acoustic notch at 4 kHz. When the extended high-frequency audiogram was grouped, values at the frequencies of 16, 14, and 12 kHz were affected before that at the acoustic notch at 4 kHz.ConclusionsThe results of our study indicate that hearing at extended high frequencies was affected before that at conventional high frequencies in individuals exposed to intermittent loud sounds. The first affected extended high frequencies were 16, 14, and 12 kHz. Although there was no statistically significant relationship between values at the notch and at extended high frequencies, the presence of a notch at 4 kHz, provided that 8 kHz is normal, may indicate a later stage of damage.