COAEs and SSOAEs in adults with increased age

Objective: The purpose of this study was to compare click-evoked otoacoustic emissions (COAEs) of sub jects having similar auditory thresholds but different age ranges. It is well known that elevated hearing thresholds are common with increasing age and that deterioration of outer hair cells is often noted in cases of hearing loss due to increased age. It has also been reported that evoked otoacoustic emissions (EOAEs) decrease with increased age. How· ever, there is still some question whether changes in EOAEs with aging are associated with the increased hearing threshold or whether there is some additional effect of aging that influences EOAEs. Design: COAE input/output functions and synchronized spontaneous OAEs (SSOAEs) were measured in two groups of subjects having similar auditory thresholds, one ranging in age from 19 to 29 yr, the other ranging in age from 40 to 61 yr. Mixed-model ANOVAs were performed to determine whether there were any statistically significant differences in COAEs based on age group. Results: There were no statistically significant differences in COAE level or COAE threshold between age groups. Significant differences in COAEs were found for subjects based on whether they had measurable SSOAEs, regardless of age. Conclusions: Age does not significantly reduce COAE level nor increase COAE threshold. Other factors, such as presence of SSOAEs and hearing loss, undoubtedly have more influence on COAEs than the factor of age.