The normalization of auditory brainstem responses in normal hearing persons

Auditory evoked potentials are the combined electrical activity of the auditory system that represents the neural activity from the 8th nerve to cortex in response to acoustic stimulus. Auditory brainstem responses (ABR) are the most commonly used potentials. There is not certainty in the national or international standards of ABR scales, so there is the necessity that each clinic form their own standard scales. This study was conducted to define the clinical normalization of the auditory brainstem responses of the people with normal ears in different age and gender groups at The Department of Otorhinolaryngology, Faculty of Medicine, Fırat University, to determine if there is a significant difference between wave latencies and inter-peak latencies according to age and gender groups and to be an important reference source in the future.In the study, 100 people, between the ages of 10 to 60, who have no systematic and otologic illness were included. Five groups were created and each group consists of 20 people, 10 of whom were males; 10, females. Immitansmetric evaluation, pure-tone and speech audiometry, and ABR tests were administered to the people in the study. For data analysis, independent-samples t-test and one-way ANOVA were used and the following results were obtained:There is not a significant difference (p>0.05) in latencies, interpeak latencies (IPL), amplitudes and amplitude ratios (AR) related to 11 and 21 click rates at 70 dB nHL, 50 dB nHL ve 30 dB nHL stimulus intensity.Significant differences (p<0.05) considering the gender were found in latencies, IPL, amplitudes and AR both in 11 and 21 click rates at 70, 50 ve 30 dB nHL stimulus intensity.As regards the age groups of both male and female, it was found that there is a significant difference (p<0.05) in latencies, IPL, amplitudes and AR in 70, 50 ve 30 dB nHL stimulus intensity at 11 and 21 click rates.Differences (p<0.05) were found between ears in 70, 50 ve 30 dB nHL stimulus intensity at 11 and 21 click rates.As a result, differences were found between latencies and IPL regarding the age and gender in 70, 50 ve 30 dB nHL stimulus intensity among the ages 10 - 60.Key words: Auditory brainstem response, normalization, young-adult