conventional audiometry, extended high-frequency audiometry, and dpoae for early diagnosis of nihl

background noise most frequently affects hearing system, as it may typically cause a bilateral, progressive sensorineural hearing loss at high frequencies. objectives this study was designed to compare three different methods to evaluate noise-induced hearing loss (conventional audiometry, high-frequency audiometry, and distortion product otoacoustic emission). material and methods this was a cross-sectional study. data was analyzed by spss (ver. 19) using chi square, t test and repeated measures analysis. study samples were workers from tile and ceramic industry. results we found that conventional audiometry, extended high-frequency audiometry, low-tone distortion product otoacoustic emission and high-tone distortion product otoacoustic emission had abnormal findings in 29 %, 69 %, 22 %, and 52 % of participants. most frequently affected frequencies were 4000 and 6000hz in conventional audiometry, and 14000 and 16000 in extended high-frequency audiometry. conclusions extended high-frequency audiometry was the most sensitive test for detection of hearing loss in workers exposed to hazardous noise compared with conventional audiometry and distortion product otoacoustic.