Speaker
Description
Objective physiological tests are needed to assess hearing abilities of children who are not developmentally mature enough for behavioural hearing tests. One such physiological test to assess hearing sensitivity is the envelope following response (EFR). EFRs are scalp-based recordings of neural activity at the brainstem level that follows the envelope of sounds, such as naturally spoken vowels. Although EFRs have shown promise for inferring hearing acuity, low amplitude responses can be obscured by the electrophysiologic noise floor, reducing measurement accuracy and certainty in clinical decision-making. Past studies in our lab have shown that EFR amplitude is influenced by phase differences between pairs of vowel harmonics. Phase differences can be manipulated to increase EFR amplitudes based on a cochlear model of an average ear, however, the success of this approach is highly variable across participants.
To improve the optimization accuracy per individual, the present study aims to assess the utility of otoacoustic emissions (OAEs) to personalise the adjustment of harmonics phases. OAEs are low level sounds emitted by the inner ear (cochlea) in response to acoustic stimuli and they faithfully reflect cochlear mechanical processing. OAEs could thus aid in the estimation of stimulus travel time and individualized phase accumulation. By measuring each participant’s OAEs at the same frequency regions as the EFR stimulus, we will be able to design individualized EFR stimuli with optimal harmonic phase relationships for each vowel. If successful, this would be a first step towards a more time-efficient and individualized hearing test using vowel sounds. In addition, this work will also improve our understanding of how EFRs are initiated in the cochlea.
| Keyword-1 | Envelope following response |
|---|---|
| Keyword-2 | Otoacoustic emissions |
| Keyword-3 | Vowel harmonics |