Effect of a Single-Channel Wide Dynamic Range Compression Circuit on Perception of Stop Consonant Place of Articulation Previous studies have shown that altering the amplitude of a consonant in a specific frequency region relative to an adjacent vowel's amplitude in the same frequency region will affect listeners' perception of the consonant place of articulation. Hearing aids with single-channel, fast-acting wide dynamic range compression (WDRC) alter the overall ... Research Article
Research Article  |   October 01, 2000
Effect of a Single-Channel Wide Dynamic Range Compression Circuit on Perception of Stop Consonant Place of Articulation
 
Author Affiliations & Notes
  • Mark S. Hedrick
    University of Tennessee Knoxville
  • Tracie Rice
    University of Tennessee Knoxville
  • Contact author: Mark S. Hedrick, PhD, Department of Audiology & Speech Pathology, The University of Tennessee, 457 South Stadium Hall, Knoxville, TN 37996-0740. Email: mhedric1@utk.edu
    Contact author: Mark S. Hedrick, PhD, Department of Audiology & Speech Pathology, The University of Tennessee, 457 South Stadium Hall, Knoxville, TN 37996-0740. Email: mhedric1@utk.edu×
  • Corresponding author: e-mail: mhedric1@utk.edu
Article Information
Hearing Disorders / Hearing Aids, Cochlear Implants & Assistive Technology / Speech, Voice & Prosody / Hearing / Research Articles
Research Article   |   October 01, 2000
Effect of a Single-Channel Wide Dynamic Range Compression Circuit on Perception of Stop Consonant Place of Articulation
Journal of Speech, Language, and Hearing Research, October 2000, Vol. 43, 1174-1184. doi:10.1044/jslhr.4305.1174
History: Received November 10, 1999 , Accepted June 5, 2000
 
Journal of Speech, Language, and Hearing Research, October 2000, Vol. 43, 1174-1184. doi:10.1044/jslhr.4305.1174
History: Received November 10, 1999; Accepted June 5, 2000

Previous studies have shown that altering the amplitude of a consonant in a specific frequency region relative to an adjacent vowel's amplitude in the same frequency region will affect listeners' perception of the consonant place of articulation. Hearing aids with single-channel, fast-acting wide dynamic range compression (WDRC) alter the overall consonant-vowel (CV) intensity ratio by increasing consonant energy. Perhaps one reason WDRC has had limited success in improving speech recognition performance is that the natural amplitude balances between consonant and vowel are altered in crucial frequency regions, thus disturbing the aforementioned amplitude cue for determining place of articulation. The current study investigated the effect of a WDRC circuit on listeners' perception of place of articulation when the relative amplitude of consonant and vowel was manipulated. The stimuli were a continuum of synthetic CV syllables stripped of all place cues except relative consonant amplitudes. Acoustic analysis of the CVs before and after hearing aid processing showed a predictable increase in high-frequency energy, particularly for the burst of the consonant. Alveolar bursts had more high-frequency energy than labial bursts. Twenty-five listeners with normal hearing and 5 listeners with sensorineural hearing loss labeled the consonant sound of the CV syllables in unaided form and after the syllables were recorded through a hearing aid with single-channel WDRC. There were significantly more listeners who were unable to produce a category boundary when labeling the aided stimuli. Of those listeners who did yield a category boundary for both aided and unaided stimuli, there were significantly more alveolar responses for the aided condition. These results can be explained by the acoustic analyses of the aided stimuli.

Acknowledgments
This study was completed by the second author as a master's thesis under the direction of the first author. Support for this project was provided by a Professional Development Award from The University of Tennessee, Knoxville and in part by a grant from the National Institute on Deafness and Other Communication Disorders, National Institutes of Health (1 R55 DC03682). We thank Unitron for the generous loan of the hearing aid used in this study and Jan Dungan and Linda Reed for their help. Thanks are extended also to Drs. Sam Burchfield, Jim Thelin, Laurel Christensen, Sandra Gordon-Salant, Larry Humes, and four anonymous reviewers for their comments on previous versions of this manuscript.
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