ABSTRACT Exposure to high levels of noise cause sensorineural hearing loss that could be detected early. This study, conducted in 2009, investigated electroacoustic responses for Transient Evoked Otoacoustic Emission (TOAE) and for Distortion Product Otoacoustic Emission (DPOAE) in workers exposed to noise levels equal to or above 85dB(A). Meatoscopy, immittance measures, TOAE and DPOAE were performed in 270 male metallurgy workers between 18 and 30 years. Workers were assigned to GI - 160 workers exposed for one to five years, or GII - 110 workers exposed for more than five years. Concerning TOAE, in GI, 82% passed and 5.62% failed bilaterally; in GII, 80% passed and 7.3% failed bilaterally. For DPOAE, in GI 96.9% passed and 0.6% failed bilaterally; in GII, 97.3% passed and 0.9% failed bilaterally. There were statistically significant differences between the groups for DPOAE in 4 kHz and 5 kHz. Results showed that responses to TOAE were absent in a greater number than those to DPOAE in this group, even when hearing thresholds obtained in pure tone audiometry were normal. Thus, TOAE is an important tool to detect disorders in cochlear physiology due to occupational exposure to noise, and can be useful for implementing earlier measures of protection.
hearing; workers; otoacoustic emissions
