gms | German Medical Science

The aim of this investigation was to examine the ability of auditory steady-state response (ASSR) thresholds obtained in infancy to predict behavioural hearing levels in children with normal hearing and varying degrees of permanent hearing loss.

Auditory steady-state response testing has been used to provide frequency-specific estimates of hearing in babies in Australia for over fifteen years. This retrospective clinical study investigated the relationship between ASSR thresholds determined in the first three months of life, and subsequently obtained behavioural hearing levels in children with normal acuity, children with sensorineural hearing loss and children with auditory neuropathy/dys-synchrony type hearing loss. Findings for 575 babies obtained from seven paediatric diagnostic centres are included. ASSR thresholds were established using carrier tones at octave frequencies from 500 Hz to 4 kHz. Behavioural hearing thresholds were determined (approximately 8 months after the ASSR evaluation) using conditioned response procedures.

In children with sensorineural hearing loss (n=271) there was a strong correlation between ASSR and behavioural hearing thresholds at each of the test frequencies. Hearing aid fittings (at a mean age of 4 months) based on ASSR findings produced successful outcomes in 268 of 271 cases (98%). (Three subjects were under-amplified as their hearing deteriorated after the initial ASSR evaluation). In children with auditory neuropathy type hearing loss however, there was only a weak correlation between behavioural and ASSR thresholds. In these cases (n=19), ASSRs could only be recorded at very high sensation levels, and as such, the results were generally not useful as a guide for hearing aid configuration. Children identified with severe/profound hearing loss were typically referred to the Melbourne Cochlear Implant Clinic in the first 10 months of life, and all of those meeting the candidature criterion were implanted prior to the age of 18 months.

ASSR testing provided an accurate basis for early intervention in this cohort of babies with sensorineural hearing loss. In children with auditory neuropathy type hearing loss the technique was less successful as a predictor of behavioural hearing levels, although the abnormal findings in these cases did identify affected children as being in need of further evaluation.