Role of Fundamental Frequency Differences in the Perceptual Separation of Competing Vowel Sounds by Listeners With Normal Hearing and Listeners With Hearing Loss This study compared the ability of listeners with normal hearing and listeners with moderate to moderately-severe sensorineural hearing loss to use fundamental frequency differences (ΔF0) in the identification of monotically presented simultaneous vowels. Two psychophysical procedures, double vowel identification and masked vowel identification, were used to measure identification performance as ... Research Article
Research Article  |   December 01, 1997
Role of Fundamental Frequency Differences in the Perceptual Separation of Competing Vowel Sounds by Listeners With Normal Hearing and Listeners With Hearing Loss
 
Author Affiliations & Notes
  • Kathryn Hoberg Arehart
    University of Colorado at Boulder
  • Catherine Arriaga King
    University of Colorado at Boulder
  • Kelly S. McLean-Mudgett
    University of Colorado at Boulder
Article Information
Hearing & Speech Perception / Hearing Disorders / Speech, Voice & Prosody / Hearing / Research Articles
Research Article   |   December 01, 1997
Role of Fundamental Frequency Differences in the Perceptual Separation of Competing Vowel Sounds by Listeners With Normal Hearing and Listeners With Hearing Loss
Journal of Speech, Language, and Hearing Research, December 1997, Vol. 40, 1434-1444. doi:10.1044/jslhr.4006.1434
History: Received August 5, 1996 , Accepted June 6, 1997
 
Journal of Speech, Language, and Hearing Research, December 1997, Vol. 40, 1434-1444. doi:10.1044/jslhr.4006.1434
History: Received August 5, 1996; Accepted June 6, 1997

This study compared the ability of listeners with normal hearing and listeners with moderate to moderately-severe sensorineural hearing loss to use fundamental frequency differences (ΔF0) in the identification of monotically presented simultaneous vowels. Two psychophysical procedures, double vowel identification and masked vowel identification, were used to measure identification performance as a function of ΔF0 (0 through 8 semitones) between simultaneous vowels. Performance in the double vowel identification task was measured by the percentage of trials in which listeners correctly identified both vowels in a double vowel. The masked vowel identification task yielded thresholds representing signal-to-noise ratios at which listeners could just identify target vowels in the presence of a masking vowel. In the double vowel identification task, both listeners with normal hearing and listeners with hearing loss showed significant ΔF0 benefit: Between 0 and 2 semitones, listeners with normal hearing showed an 18.5% average increase in performance; listeners with hearing loss showed a 16.5% average increase. In the masked vowel identification task, both groups showed significant ΔF0 benefit. However, the mean benefit associated with ΔF0 differences in the masked vowel task was more than twice as large in listeners with normal hearing 9.4 dB) when compared to listeners with hearing loss (4.4 dB), suggesting less ΔF0 benefit in listeners with hearing loss. In both tasks, overall performance of listeners with hearing loss was significantly worse than performance of listeners with normal hearing. Possible reasons for reduced ΔF0 benefit and decreased overall performance in listeners with hearing loss include reduced audibility of vowel sounds and deficits in spectro-temporal processing.

Acknowledgments
This research was supported by grants from the Deafness Research Foundation and the Council for Research and Creative Work at the University of Colorado at Boulder. Portions of these results were reported at the Convention of the Acoustical Society of America, Indianapolis, Indiana, May 1996. Portions of the results were also the bases for theses submitted by the second and third authors to the University of Colorado in partial fulfillment of the requirements for the Master of Arts degree. The authors extend thanks to Tom Eberhard for technical and programming assistance and to Darby Hart, A. Nichole Kingham, Amanda Serles, and Jennifer Sible for assistance in data collection.
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