ASSR and ABR tests in early diagnosis of hearing loss: A STROBE observational study

The ABR (auditory brainstem response) and ASSR (auditory steady-state response) electrophysiological tests are fundamental for accurate early diagnosis of hearing loss in young children, and are included in objective hearing assessment, particularly in neonatal post-screening. The main aim of the present study was to compare hearing thresholds obtained by ASSR, ABR and behavioral audiometry at different frequencies. The secondary aims were to compare these in the severe to profound hearing loss group, and to determine the sensitivity and specificity of ASSR and ABR in the diagnosis of hearing loss in young children so as to improve diagnostic strategy.

A retrospective observational study was carried out between January 2017 and June 2020, following STROBE guidelines. Data from 112 children (218 ears) aged 2 months to 4 years tested by ASSR, ABR and behavioral audiometry were analyzed.

Hearing thresholds were comparable between ABR and ASSR, including in the severe to profound deafness group. Sensitivity and specificity of ASSR were 0.922 and 0.892 respectively, and for ABR 0.907 and 0.730.

In most cases, hearing thresholds were comparable between ASSR and ABR, and especially in the severe to profound deafness group. ASSRs are now part of the systematic diagnostic work-up, providing information complementary to ABR. The accuracy of the ASSR test has been improved by incorporating corrective factors from pediatric databases. Considering children's limited sleep time, the excellent correlation between ABR and ASSR at 2000-4000Hz suggests that assessment should begin with ABR and continue with ASSR at 1000 then 500Hz in order to broaden the frequency range studied. Diagnosis of moderate hearing loss remains a challenge, with high rates of improvement and loss to follow-up; incorporating bone-conduction ASSR or ABR could facilitate management by rapidly ruling out any additional conduction factor.