Comparison of Contralateral Suppression of Otoacoustic Emissions between Children with APD and Children with ADHD

Abstract

The study aimed to investigate the difference between transient evoked otoacoustic emissions without and with a contralateral acoustic stimulus in typically developing children, children with auditory processing disorder (APD) and children with attention-deficit/hyperactivity disorder (ADHD). The study also aimed to determine the association between contralateral suppression of TEOAEs and speech perception in noise in the above three groups of children. The three participant groups [typically developing children (n = 72), children with APD (n = 19) & children with ADHD (n = 14)] were evaluated using TEOAEs without and with contralateral acoustic stimulus (CAS), ‘Speech perception-in-noise test in Kannada’ [SPIN-K (Vaidyanath & Yathiraj, 2012)], and ‘Kannada word identification-in-white-noise’ (WIWN-K) without and with CAS. Additionally, the absolute suppression amplitude (ASA), calculated from the difference in amplitude of TEOAEs without and with CAS as well as the difference in scores of WIWN-K with CAS and WIWN-K without CAS was computed. The obtained data were not normally distributed and hence were subjected to non-parametric statistical analyses. The TEOAEs without and with CAS and the ASA had no significant age effect, and no significant gender difference in the typically developing children. Further, no significant ear difference was observed in all three participant groups. However, a comparison of TEOAEs without and with CAS within each participant group indicated a significantly higher TEOAE amplitude without CAS. Comparison between the participant groups indicated that the typically developing children had significantly higher TEOAE amplitude without CAS than the two clinical groups. In contrast, the ASA was not significantly different between the typically developing children and the 2 two clinical groups. However, the ASA in the children with ADHD was significantly higher than that obtained in the children with APD. Unlike the TEOAEs, a significant age effect was observed for SPIN-K, WIWN-K without CAS, but not for WIWN-K with CAS in the typically developing children. In this group, a developmental trend was observed where the SPIN-K and WIWN-K without CAS scores improved with an increase in age. As seen for the TEOAEs, no significant gender difference occurred in the typically developing children. Further, no significant ear difference was seen in the three word-identification-in-noise tasks in all the three groups. For the difference in scores of WIWN-K with CAS and WIWN-K without CAS, a significant age effect and no gender difference was observed in the typically developing children. A significant ear difference was present only in the children with APD. In all the three groups, significantly higher scores were obtained for WIWN-K with CAS than WIWN-K without CAS. In contrast, the 11 year olds typically developing children exhibited no significant difference between WIWN-K without and with CAS. A significant positive correlation between ASA and WIWN-K with CAS, and ASA and difference in scores was obtained in the typically developing children and in children with APD. However, no significant correlations were found in the children with ADHD. From the findings of the study, it is evident that the medial olivocochlear inhibition plays a facilitatory role in speech-in-noise perception. Further, as the absolute suppression amplitude was able to differentiate the two clinical groups, it is recommended to be used as a quick objective measure to differentiate children with APD from children with ADHD, when they report of difficulty hearing in the presence of noise.