Provoking and minimising potentially destructive binaural stimulation effects in auditory steady-state response (ASSR) measurements
In Proceedings of the International Symposium on Audiological and Auditory Research, 2020
Abstract
An aided sound-field auditory steady state response (ASSR) has the potential to be used to verify the quality of fit of hearing aids on infants. Each aided ear should ideally be tested independently, but it is suspected that binaural testing may be used by clinics to reduce test time. This study simulates ‘clinically conceivable’ dichotic ASSR sound-field conditions to examine the risk of making false judgements due to unchecked binaural effects. Unaided ASSRs were recorded with a clinical two channel EEG system for 15 normally hearing subjects using a three-band CE-ChirpTM stimulus. It was found that the noise corrected power of a response harmonic can be reduced by up to 10 dB by introducing large ITDs equal to half the time period of the stimulus envelope. This could lead to concluding that a hearing aid fitting is poor, even though the fitting would have passed separate monaural ASSR tests (false referral). No effect was detected for simulated lateralisations of the stimulus, which is beneficial for a proposed aided ASSR approach. Full-scalp ASSR recordings show distinct SNR reductions and topographical changes in response to the large ITDs, and demonstrate the vulnerability of ASSR to montage and inter-subject variation. Findings suggest that multi-harmonic detectors could make binaural measurements robust to artificial reductions of response harmonics cause by large ITDs.
Info
Conference Paper, 2020
In Proceedings of the International Symposium on Audiological and Auditory Research, 2020
UN SDG Classification
DK Main Research Area
Science/Technology
