This project aims to combine assessment of hearing abilities among subjects of different ages over time, together with information from their communication and health histories. Medical and cognitive data collected from subjects in the longitudinal study will be examined with respect to the audiologic and case history data. The two principal objectives of this project are: A) To study the contribution of medical, genetic, dietary and social factors to age-related auditory dysfunction; and B) To determine to what extent age, independent of other etiologic factors, causes a deterioration in hearing abilities. During the past year, approximately 450 subjects from the BLSA have been tested on all of the new measures in the hearing protocol. These measures include assessment of pure-tone hearing sensitivity, sentence understanding in noise, self-perceived hearing handicap, tympanometry, acoustic reflex thresholds, acoustic reflex magnitude, acoustic reflex adaptation, and acoustic reflex latency (the last five measures are part of the acoustic immittance battery of electrophysiologic tests). We have recently completed a retrospective analysis of gender differences in longitudinal change in hearing sensitivity in a sample screened to exclude otological disorders and evidence of noise-induced hearing loss. We plan to extend these analyses to develop age- and gender- specific nomograms for pure-tone thresholds and to document the natural history of the development of noise- induced hearing loss.
