# Evaluation of Hearing Thresholds in Infants With Autism Spectrum Disorder Using Auditory Brainstem and Steady-State Responses

## TL;DR

This study compares two hearing tests in infants with autism and speech delays, finding that both tests show lower hearing thresholds in these children.

## Contribution

The study is the first to directly compare ABR and ASSR hearing tests in children with autism and speech delays.

## Key findings

- Children with ASD had significantly lower hearing thresholds compared to controls using both ABR and ASSR tests.
- ASSR provided additional threshold information not captured by ABR in this population.
- Strong correlation was found between ASSR thresholds at different frequencies.

## Abstract

Introduction

In recent years, most studies on the hearing abilities of children with autism spectrum disorder (ASD) have used the auditory brainstem response (ABR) test alongside other audiological assessments, while only a few have explored the auditory steady-state response (ASSR) test. Moreover, these two electrophysiological methods have not yet been directly compared in this population. This study aims to compare click ABR and chirp ASSR in children with ASD and speech delays to determine whether differences in hearing thresholds can be identified.

Methods

Children with ASD and speech delays referred to Karamandaneio Children’s Hospital between December 13, 2019, and December 6, 2023, were retrospectively identified as cases. Children diagnosed with speech delays but without ASD, who were referred to the same hospital during the same period, were included as controls.

Results

This study evaluated 30 children (21 males and nine females, totaling 60 ears). Of these, 20 children had been diagnosed with both ASD and speech delay, while 10 were non-ASD children with speech delay and normal hearing, serving as the control group. The participants were aged 19-68 months (median age = 38.5). All ears that responded to the click ABR also responded to each chirp frequency tested by the ASSR. This finding highlights the additional information provided by the ASSR compared to the ABR for threshold estimation, as no instances were observed where a response was obtained for the ABR stimulus but not the ASSR. Click ABR thresholds showed a statistically significant association with chirp ASSR threshold averages at 1,000, 2,000, and 4,000 Hz (rho = 0.316, p = 0.014), as well as at 2,000 and 4,000 Hz (rho = 0.277, p = 0.032). The strongest positive correlation was observed between the two chirp ASSR threshold averages (rho = 0.971, p < 0.001).

Conclusions

The results suggest that participants diagnosed with ASD exhibit statistically significantly lower mean scores for both click ABR and chirp ASSR threshold averages, with the effect being slightly more pronounced for the chirp ASSR thresholds than for the click ABR.