One-day measurement to assess the auditory risks encountered by noise-exposed workers

Background: Noise is one of the most pervasive hazardous factors in the workplace. Despite regulations, noise-induced hearing loss is a common disease. To prevent such a scourge, pure-tone air-conduction audiometry (PTA) is the reference test even though it can hardly be used as an early indicator. Objective: In this study, we compare the efficacy of PTA and that of efferent reflexes (ER) measured with DPOAEs associated with a contralateral acoustic stimulation to assess a one-day auditory fatigue. Design and Sample: The history of noise exposure, PTA, and ER detection were obtained from 46 selected volunteer workers in 7 different companies whose LEX,8h was 85 dB(A). The workers were tested before and at the end of the workday. Results: After only one single workday, the noise impact on the ER thresholds measured from DPOAEs was larger than that measured with PTA. Such measurements are objective, easy to carry out, and do not need a sound-attenuated booth. The study showed a soft age-related susceptibility to noise as well. Conclusion: Workers’screening by the periodic detection of ER thresholds from DPOAEs associated with contralateral stimulations helps detect early changes in hearing status before development of noise-induced hearing loss. It can be easily used in a hearing conservation program.