The ASSR: Clinical application in normal-hearing and hearing-impaired infants and adults, comparison with the click-evoked ABR and pure-tone audiometry

The objective of this study was to investigate the clinical application of the ASSR (GSI Audera). It was completed in two parts: Study 1. Correlation between the ASSR-based threshold estimations and the conventional pure-tone thresholds in adults; and Study 2. Correlation between the average of the 2-4 kHz ASSR-based threshold estimations and c-ABR thresholds in children. The ASSRs were recorded in awake adults and sleeping infants with a range of hearing loss at Us of 0.5 to 4 kHz and MFs between 46 and 95 Hz. The results show that in hearing-impaired adults (thresholds > 40 dBHL) good correlations can be observed between the behavioural thresholds and the ASSR-based threshold estimations. For the normal- to near-normal-hearing adults, a significant correspondence exists between the ASSR-based threshold estimations and FPTA. In children, strong correlations were found between the c-ABR and the 24 kHz ASSR-based threshold estimation average. These studies illustrate that the GSI Audera ASSR can accurately predict the behavioural audiogram in hearing-impaired subjects. In subjects with normal hearing the individual ASSR-based threshold estimations scatter too much. Instead the average of the ASSR-based threshold estimations corresponds well with the FPTA.