Exposure to occupational noise: otoacoustic emissions test alterations

Exposure to occupational noise may cause injuries to the inner ear, and the distortion product otoacoustic emissions (DPOAE) may identify initial auditory alterations, thus assisting NIHL early diagnosis. AIM: The goal of this study was to evaluate DPOAE as a method to diagnose early physiopathological alterations caused by occupational noise exposure. STUDY DESIGN: Transversal. METHODS: 74 workers of the University of São Paulo, in the capital city of the State, participated in this investigation. They were divided in two age-matched groups and with tonal audiometric values within the acceptable limits: 37 were exposed to occupational noise and 37 were not exposed. RESULTS: Risk estimates (Odds Ratio) of absent DPOAE was 12 fold higher for the group exposed to occupational noise (CI 95% 3.1 - 45.9), in the frequencies of 3. 4 and 6 kHz. CONCLUSIONS: DPOAE may be useful in the identification of physiopathological hearing alterations caused by exposure to occupational noise, even in individuals with tonal audiometric responses within acceptable limits.