Abstract:
This study examines the relationship between ABR thresholds and behavioural pure-tone thresholds in individuals with normal hearing and those with SNHL and CDHL. 73 ears from 57 participants, including 26 individuals with SNHL, 20 with CDHL, and 11 with normal hearing, were assessed. The findings show that the threshold difference between click-evoked ABR thresholds and behavioural thresholds (PTA1 & PTA2) is similar for normal-hearing and CDHL individuals but less for the SNHL group, and also differences reduced as SNHL severity increased. Significant differences in ABR and behavioural thresholds were observed between normal and SNHL groups, and between SNHL and CDHL groups, but not between normal-hearing and CDHL groups. In general, SNHL group of any degree showed significant different from normal and any degree of CDHL group. Degree of CDHL did not differ significantly with other, whereas SNHL did show differences between them but not significant. Frequency-specific analyses indicated significant differences between SNHL and both normal and CDHL groups, with no differences between normal and CDHL groups. Significant correlations were found between click ABR thresholds and all pure-tone thresholds for SNHL and CDHL groups, with normal-hearing individuals showing significant correlations only with PTA2. The threshold difference for 500Hz TB ABR is similar for normal hearing and SNHL groups, with no significant correlation between thresholds. The study concludes that while ABR thresholds correlate well with behavioural thresholds in SNHL individuals due to cochlear mechanisms, this correlation is weaker in normal hearing and CDHL groups. This suggests that different correction values should be used for different types of hearing loss, with a reduced correction factor for severe SNHL population. Additionally, click-evoked ABR thresholds should be correlated with PTA2 in normal and SNHL populations, and with PTA1 in CDHL populations, with 2 kHz thresholds providing the best correlation for both normal and SNHL groups.
