Pamela Souza1, Gregory Ellis1, Frederick Gallun2, Richard Wright3
1Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, USA
2Department of Otolaryngology-Head and Neck Surgery, Oregon Health and Sciences University, Portland, OR, USA
3Department of Linguistics, University of Washington, Seattle, WA, USA
Clinical hearing aid fittings depend primarily on the pure-tone audiogram, and audiologists can choose among well-validated prescriptions to create an appropriate frequency-gain response for each listener. However, there are no definitive guidelines to guide other aspects of the hearing aid response such as compression speed and strength of digital noise reduction. This presentation describes a series of studies in which a “cue profile” test based on synthetic speech sounds is used to assess a hearing-impaired listener’s use of specific speech cues. The resulting profile quantifies how well individual listeners can utilize higher-precision spectro-temporal information, or whether they rely on lower-precision temporal (envelope) cues to consonant identification. We review consequences of different cue profiles for perception of speech with different types of signal processing (fast- vs slow-acting WDRC and strategies designed to preserve the speech envelope). Aided speech recognition is influenced by the amount of hearing loss, the cue profile, and extent of envelope modification in the signal. Listeners with more temporal-reliant cue profiles tend to have poorer aided speech recognition. Those listeners receive greatest benefit when modulation cues are preserved, compared to listeners with more spectral-reliant cue profiles. These data suggest that better understanding of how different amplification strategies interact with the listener’s auditory abilities may allow clinicians to target strategies of greatest benefit to an individual.
Acknowledgements: US National Institute on Deafness and Other Communication Disorders.