Promoting hearing health and the combined risk of noise-induced hearing loss and ototoxicity

Abstract

The ototoxicity of therapeutic drugs has been a concern in the field of audiology for many years. In comparison, only recently has the ototoxicity of chemicals found in the environment from contaminants in air, food or water, and in the workplace become a concern for audiologists and other health professionals. Studies have shown that some toxins can reach the inner ear through the bloodstream. They were found in the inner ear fluids and have caused damage to some of the inner ear structures and functions. The damage, however, is not always restricted to the cochlea. The onset, site, mechanism and extent of ototoxic damage caused by these toxins vary according to risk factors that include type of chemical, interactions, exposure level and duration of exposure as is the case with therapeutic drugs. Noise exposure has been reported to potentiate or interact synergistically with several toxins. Moreover, it makes the detection and diagnosis of the ototoxicity effect more challenging. The new evidence has prompted the proposal of new guidelines and standards on hearing loss prevention. In this paper, the implications of the studies on the effect of environmental and occupational toxins exposure on the auditory system are discussed. Recent guidelines and legislative developments and alternative strategies for preventing auditory effects of exposure to ototoxic chemicals are examined.

• solvents
• metals
• asphyxiants
• pesticides