Age correction factor in noise-induced hearing loss: a quantitative model.

This paper considers the factors of presbyacusis and noise exposure in relation to permanent hearing loss and provides a quantitative model from which an age correction factor in occupational hearing loss may be derived. The rationale for a presbyacusis correction is provided in terms of physiological and audiometric data. The additivity hypothesis is considered and constraints on this approach are presented. A quantitative model for assessing the age component in occupational hearing loss is then derived from empirical functions. The model is based on the concept of a variable ratio for partitioning the effects of presbyacusis and noise exposure. Consideration is given to the application of the model in medico-legal cases of occupational hearing loss in which the degree of hearing impairment must be assessed.