Clinical aplications of distortion product otoacoustic emissions on individuals with occupational noise-induced hearing loss

Abstract

The aim of this study was to study the registers of the otoacoustic emissions – product of distortion (EOAPD), in subjects that presented neurosensorial hearing loss from the exposition to occupational noise. For this study, 89 workers (135 ears) from a textile industry, aged 20 to 60 years old, were selected. These workers presented neurosensory losses in at least one audiometric frequency, from 3 to 6 KHz. Besides the clinical anamnesis, the audiometry, the measurement of medium ear function, otoacoustic emissions registers were obtained – product of distortion with L1=65 dBNPS and L2=55 dBNPS. It was observed that the orders of commitment of the audiometric frequencies were 6k, 4k, 8k and 3kHz. The occurrence of responses present in the EOAPD test was statistically significant on the f2 level from 2,5kHz to 6 kHz. This indicates a statistical correlation between hearing loss and the EOAPD test on high frequencies. The result indicated that the ears whose audiometric limits were, in maximum, 30 dBNA showed responses present in the EOAPD test with L1=65 dBNPS and L2=55 dBNPS. Therefore, the higher the audiometric limits and the number of frequencies committed, the shorter the amplitude of the responses to the EOAPD test. So, the EOAPD demonstrates to be sensible in helping on the clinical following of hearing losses together with the tonal audiometry.