Active Research

Principal Investigator: Dawn Konrad-Martin, Ph.D.

Objective: To determine whether physiological estimates of frequency tuning based on response delays of tone-burst-evoked otoacoustic emissions (OAE) predict psychophysical tuning measures in young and elderly subjects. This research also aims to determine the extent that age and actual or simulated losses in sensitivity and frequency tuning alter the accuracy, speed and confidence with which listeners are able to identify time-gated words.

Background: Diminished frequency tuning caused by hearing loss can reduce spectral contrasts within the cochlear excitation pattern evoked by speech, even for hearing-impaired listeners fitted appropriately with hearing aids. Such distortions in the speech signal place greater demands on the cognitive resources of older adults, reducing speech processing accuracy and speed.

Findings: Results will determine whether proposed OAE measures can predict behavioral tuning with sufficient accuracy to be clinically useful for identifying peripheral sources of speech-understanding deficits. Methods developed from this research will help differentiate speech-understanding deficits arising from abnormal frequency tuning and slowed perceptual encoding, which likely require different remediation strategies (e.g., sharpening of spectral peaks within the speech signal or slowing of the temporal stream).