The effects of increasing the stimulus rate on auditory brainstem response waves latency in old population with normal hearing

The auditory system changes by increasing age in both central and peripheral parts. The purpose of this study was to investigate the effect of the increasing the stimulus rate on auditory brainstem response (ABR) waves latency in old population with normal hearing. In this cross-sectional study click ABR test performed on 20 young normal-hearing subjects with mean age of 20.8 years old and 10 old normal-hearing subjects with mean age of 66.4 years old. ABR results with different stimulus rates were compared between two groups. ABR peak latencies and interpeak intervals were prolonged with increasing the click repetition rate. Peak latencies were slightly prolonged in older adults and the I-V interval did not differ with age but prolongation of III-V interval were significantly differs in older population compared to young adults. Using high click rates may sensitize the ABR to the identification of lesions of auditory nerve or brainstem, but before that, we need to know the normal range of different age groups, so that we can decide about probability of a retrocochlear lesion.