Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 51, Issue 2 B124-B131, Copyright © 1996 by The Gerontological Society of America
Effect of aging on the click-rate induced facilitation of acoustic reflex thresholds
VW Rawool
Communication Disorders and Special Education, Bloomsburg University, Pennsylvania 17815, USA.
Acoustic reflex thresholds are known to improve with an increase in the
click-repetition rates from 50/sec to 300/sec. In the current study this
improvement was used to evaluate auditory processing in older subjects.
Acoustic reflex thresholds were obtained from 16 human adult ears within
each of the following four groups: young male, young female (18-28 years),
older male and older female (50-65 years). The probe tone frequency was 226
Hz and the intensity of the probe tone was 85 dB SPL (sound pressure
level). Clicks were delivered ipsilaterally to each ear at repetition rates
of 50, 100, 150, 200, and 300/sec. The mixed MANOVA revealed a significant
effect for the repetition rate and a significant age and rate interaction.
Rate integration in dB was computed by subtracting the highest acoustic
reflex threshold from the lowest threshold of each ear. Statistical
analyses revealed reduced rate integration in the older subjects,
suggesting less efficient processing of faster stimuli within the acoustic
reflex pathway.
