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 pursued two types of retrospective analyses. In the first analysis, we are examining risk factors for apparent age-related hearing loss in men and women participants in the BLSA. Subjects included in this analysis exhibited significant deterioration in hearing during the course of data collection, but had no known cause for hearing impairment. Of the three modifiable risk factors examined, only blood pressure had an association with hearing loss, independent of age, in the women. In the second analysis, we are comparing longitudinal changes in hearing thresholds with age among men, women, and men with apparent noise-induced hearing loss (on the basis of a notched audiometric configuration). We plan to develop and distribute a noise exposure questionnaire to these participants in order to identify important sources of incidental noise exposure in this population of predominantly white collar workers.
