Noise-induced hidden hearing loss: evaluation of peripheral and central auditory pathway

Abstract

Introduction: There are studies that emphasize the importance of evaluation entire auditory pathway in workers exposed to occupational noise, since both peripheral and central portions can be affected by otoaggressive agents, such as noise. Recently, animal studies have showed that exposure to noise may cause hidden hearing loss (synaptopathy), a change that would occur due to the loss of presynaptic structures of the inner hair cells and neurodegeneration of spiral ganglion neurons. In hidden hearing loss, conventional audiometry would be within normal range, since the inner and outer hair cells would be functioning normally. Therefore, it is necessary that this type of alteration be confirmed in humans, identifying which procedures would be more sensitive for the detection of hidden hearing loss and other changes in the peripheral and / or central auditory pathway due to noise, which would be imperceptible in the case of audiological monitoring exclusively performed by means of conventional audiometry, which is the standard currently used. Objective: To compare the audiological results of normal hearing individuals exposed and non-exposed to noise, matched by age, using different procedures to evaluate the peripheral and central auditory pathway. Methods: Sixty workers (male) from the University of São Paulo participated in the study, divided into two groups: Group 1 composed of workers exposed to noise and Group 2 composed of workers who were not exposed to noise. The following procedures will be performed: meatoscopy, immitanciometry, conventional and high frequency tonal audiometry, logoaudiometry, temporal resolution evaluation with the Gap-in-Noise (GIN) test, speech recognition in noise with the Sentence List test (LSP), Distortion Product Evoked Otoacoustic Emissions (DPOAE), Brainstem Auditory Evoked Potential (BAEP) with and without contralateral noise, Stable State Auditory Evoked Potential (PEAEE), and Long Latency Auditory Evoked Potential (LLAEP) with and without contralateral noise. After the collection, the data obtained will be compared between the groups. (AU)