The effects of exposure to multiple occupational health stressors on distortion product otoacoustic emissions

Abstract

Mineworkers are exposed to combinations of stressors, since they spend most of the working shift performing physical work under noisy, hot, humid and dusty conditions, in some cases with exposure to chemicals. Such combined exposure confounds the evaluation of impacts from individual stressors. Studies have demonstrated that exposure to noise combined with physical work can have synergistic impacts. Similarly, exposure to noise and chemicals accelerates and exacerbates the development of noise-induced hearing loss (NIHL). Furthermore, exposure to heat is believed to influence the biochemical properties of cochlear outer hair cells (OHCs) and heat stress structurally modifies the OHCs, making them stiffer through an increase in F-actin5. This experiment aimed to simulate some conditions in a mining environment (noise, heat/humidity, physical work) and to measure the effects of individual, and combinations of occupational health (OH) stressors on the functioning of the inner ear, using Distortion Product Otoacoustic Emissions (DPOAEs).