Auditory steady-state response thresholds in infants and young children with auditory neuropathy spectrum disorder

Abstract

Auditory neuropathy, renamed by consensus at a recent international conference as auditory neuropathy spectrum disorder (ANSD), is a specific form of hearing loss defined by normal otoacoustic emissions, but severely abnormal or completely absent auditory brainstem responses. We investigated the distribution of auditory steady-state response (ASSR) thresholds in 9 infants and young children with ANSD. The large variability of ASSR thresholds indicated the heterogeneous nature of this disorder. Correlation values showed a significant positive relationship (p<0.05) between ASSR and conditioned orientation response audiometry (COR) thresholds at 500-4000Hz. To estimate the functional gains obtained from the use of hearing aids, we examined the dB difference between unaided and aided thresholds of ASSR and COR. The average functional gains estimated by the ASSR thresholds were up to 15 dB at 500-4000Hz, which were slightly lower than those estimated by the COR thresholds. ASSR testing is considered to be useful for hearing aid validation when behavioral test methods are inconclusive. ASSR may be useful for the estimation of residual auditory capacities and hearing aid benefits in infants and very young children with ANSD.