Individual susceptibility to noise-induced hearing loss: an old topic revisited.

The wide range in susceptibility to noise-induced hearing loss has intrigued researchers and hearing conservationists alike. Some of these differences in variability have been attributed to various intrinsic factors such as eye color, gender, age, etc. However, a review of controlled research shows that the influence of these intrinsic variables is relatively small and cannot explain the wide range of hearing loss observed in demographic studies. Furthermore, uncontrolled variables or unrecognized drug and noise interaction may obscure the relation between noise exposure and hearing loss. With the growing understanding of the physiology of the auditory system, new possibilities are emerging that may explain the range of susceptibility. A review of the role of acoustic reflex effectiveness, cochlear efferent function, and history of noise exposure provide a perspective for future strategies in predicting susceptibility to noise-induced hearing loss.