Evaluation of Speech-Evoked Envelope Following Responses as an Objective Aided Outcome Measure: Effect of Stimulus Level, Bandwidth, and Amplification in Adults With Hearing Loss

Objectives: The present study evaluated a novel test paradigm based
on speech-evoked envelope following responses (EFRs) as an objective
aided outcome measure for individuals fitted with hearing aids. Although
intended for use in infants with hearing loss, this study evaluated the
paradigm in adults with hearing loss, as a precursor to further evaluation
in infants. The test stimulus was a naturally male-spoken token /
susa∫i/, modified to enable recording of eight individual EFRs, two from
each vowel for different formants and one from each fricative. In experiment
I, sensitivity of the paradigm to changes in audibility due to varying
stimulus level and use of hearing aids was tested. In experiment II,
sensitivity of the paradigm to changes in aided audible bandwidth was
evaluated. As well, experiment II aimed to test convergent validity of
the EFR paradigm by comparing the effect of bandwidth on EFRs and
behavioral outcome measures of hearing aid fitting.