The effect of amplification on cortical synchrony in children with auditory neuropathy spectrum disorder

Objective: The benefit of hearing aids as a clinical intervention strategy for children with Auditory Neuropathy Spectrum Disorder (ANSD) remains controversial. The goal of this study was to determine whether amplification through hearing aid use increased cortical phase synchrony in children with ANSD. Design: Using inter-trial coherence (ITC) of the EEG signal as a measure of cortical phase-locking, we examined differences in cortical phase synchrony in children with ANSD using both cross-sectional and longitudinal designs. Study Sample: Participants in the cross-sectional and longitudinal portions of the study included 58 and 16 children with clinical diagnoses of ANSD, respectively. Results: Results in the cross-sectional portion of the study revealed no significant difference in ITC between unaided and aided children. Overall, longitudinal data revealed no significant increase in ITC over time with hearing aid use. However, half of the subjects in the longitudinal sample showed a significant decrease in ITC from the unaided to the aided conditions. Conclusions: Overall, our results suggest that hearing aids may not be a beneficial intervention strategy for increasing cortical neural synchrony in all cases of ANSD and that amplification may actually reduce cortical phase-locking in some children with ANSD. The clinical implications of these findings are discussed.