Auditory rate-induced facilitation of acoustic reflex thresholds in younger and middle-aged adults

Objective: Acoustic reflex thresholds (ARTs) improve with an increase in click rates. The goal of this exploratory study was to compare the click-rate induced facilitation (cRIF) of ARTs across younger and middle-aged adults. Design: Cross-sectional Study Sample: The younger adult group (18 to 27 years) included 16 women and 15 men. The middle-aged group (45 to 59 years) included 18 women and 12 men. ARTs were established at the click rates of 50 and 300/sec in each ear. The thresholds obtained at the rate of 300/sec were subtracted from those obtained at the rate of 50/sec to derive the cRIF. Results: A general linear repeated measures model was used by setting up the right and left RIF as repeated variables, sex and age as fixed factors, and right and left ear average hearing loss as covariates. This model revealed a medium-sized significant effect of age group [F (1,55) = 4.97; p =.030; Partial Eta Squared:.083], no effect of sex and ear, and no significant interactions. Conclusions: The reduced cRIF of ARTs suggests a significant deterioration in temporal processing speed in the middle-aged group. Future studies to confirm these preliminary results will be helpful.