Multichannel Compression, Temporal Cues, and Audibility Although multichannel compression systems are quickly becoming integral components of programmable hearing aids, research results have not consistently demonstrated their benefit over conventional amplification. The present study examined two confounding factors that may have contributed to this inconsistency in results: alteration of temporal information and audibility of speech cues. Recognition ... Research Article
Research Article  |   April 01, 1998
Multichannel Compression, Temporal Cues, and Audibility
 
Author Affiliations & Notes
  • Pamela E. Souza
    Department of Speech and Hearing Sciences University of Washington, Seattle
  • Christopher W. Turner
    Department of Speech Pathology and Audiology University of Iowa, Iowa City
  • Contact author: Pamela E. Souza, PhD, Department of Speech and Hearing Sciences, University of Washington, 1417 NE 42nd Street, Seattle, WA 98105. Email: psouza@u.washington.edu
Article Information
Hearing & Speech Perception / Acoustics / Hearing Disorders / Hearing Aids, Cochlear Implants & Assistive Technology / Audiologic / Aural Rehabilitation / Hearing / Research Articles
Research Article   |   April 01, 1998
Multichannel Compression, Temporal Cues, and Audibility
Journal of Speech, Language, and Hearing Research, April 1998, Vol. 41, 315-326. doi:10.1044/jslhr.4102.315
History: Received December 19, 1996 , Accepted October 8, 1997
 
Journal of Speech, Language, and Hearing Research, April 1998, Vol. 41, 315-326. doi:10.1044/jslhr.4102.315
History: Received December 19, 1996; Accepted October 8, 1997

Although multichannel compression systems are quickly becoming integral components of programmable hearing aids, research results have not consistently demonstrated their benefit over conventional amplification. The present study examined two confounding factors that may have contributed to this inconsistency in results: alteration of temporal information and audibility of speech cues. Recognition of linearly amplified and multichannel-compressed speech was measured for listeners with mild-to-severe sensorineural hearing loss and for a control group of listeners with normal hearing. In addition to the standard speech signal, which provided both temporal and spectral information, the listener's ability to use temporal information in a multichannel compressed signal was directly tested using a signal-correlated noise (SCN) stimulus. This stimulus consisted of a time-varying speech envelope modulating a two-channel noise carrier. It preserved temporal cues but provided minimal spectral information. For each stimulus condition, short-term level measurements were used to determine the range of audible speech. Multichannel compression improved speech recognition under conditions where superior audibility was provided by the twochannel compression system over linear amplification. When audibility of both linearly amplified and multichannel-compressed speech was maximized, the multichannel compression had no significant effect on speech recognition score for speech containing both temporal and spectral cues. However, results for the SCN stimuli show that more extreme amounts of multichannel compression can reduce use of temporal information.

Acknowledgments
This research was supported by the American Speech-Language-Hearing Foundation and by NIDCD Grant #00377. The authors would like to thank Tim Trine, Jim Chan, and Eduardo Solessio for assistance in developing the compression algorithm. The authors also thank Ed Burns, Rich Folsom, Lynne Werner, Judy Dubno, and Jayne Ahlstrom for comments on an earlier version of this paper. The assistance of Larry Humes, Amy Horwitz, and an anonymous reviewer is gratefully acknowledged.
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