Speech Rate Normalization and Phonemic Boundary Perception in Cochlear-Implant Users Purpose Normal-hearing (NH) listeners rate normalize, temporarily remapping phonemic category boundaries to account for a talker's speech rate. It is unknown if adults who use auditory prostheses called cochlear implants (CI) can rate normalize, as CIs transmit degraded speech signals to the auditory nerve. Ineffective adjustment to rate information could ... Research Article
Research Article  |   May 25, 2017
Speech Rate Normalization and Phonemic Boundary Perception in Cochlear-Implant Users
 
Author Affiliations & Notes
  • Brittany N. Jaekel
    Department of Hearing and Speech Sciences, University of Maryland, College Park
  • Rochelle S. Newman
    Department of Hearing and Speech Sciences, University of Maryland, College Park
  • Matthew J. Goupell
    Department of Hearing and Speech Sciences, University of Maryland, College Park
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication. ×
  • Correspondence to Brittany N. Jaekel: jaekel@umd.edu
  • Editor: Nancy Tye-Murray
    Editor: Nancy Tye-Murray×
  • Associate Editor: Richard Dowell
    Associate Editor: Richard Dowell×
Article Information
Hearing Aids, Cochlear Implants & Assistive Technology / Speech, Voice & Prosody / Hearing / Research Articles
Research Article   |   May 25, 2017
Speech Rate Normalization and Phonemic Boundary Perception in Cochlear-Implant Users
Journal of Speech, Language, and Hearing Research, May 2017, Vol. 60, 1398-1416. doi:10.1044/2016_JSLHR-H-15-0427
History: Received December 11, 2015 , Revised May 4, 2016 , Accepted October 14, 2016
 
Journal of Speech, Language, and Hearing Research, May 2017, Vol. 60, 1398-1416. doi:10.1044/2016_JSLHR-H-15-0427
History: Received December 11, 2015; Revised May 4, 2016; Accepted October 14, 2016

Purpose Normal-hearing (NH) listeners rate normalize, temporarily remapping phonemic category boundaries to account for a talker's speech rate. It is unknown if adults who use auditory prostheses called cochlear implants (CI) can rate normalize, as CIs transmit degraded speech signals to the auditory nerve. Ineffective adjustment to rate information could explain some of the variability in this population's speech perception outcomes.

Method Phonemes with manipulated voice-onset-time (VOT) durations were embedded in sentences with different speech rates. Twenty-three CI and 29 NH participants performed a phoneme identification task. NH participants heard the same unprocessed stimuli as the CI participants or stimuli degraded by a sine vocoder, simulating aspects of CI processing.

Results CI participants showed larger rate normalization effects (6.6 ms) than the NH participants (3.7 ms) and had shallower (less reliable) category boundary slopes. NH participants showed similarly shallow slopes when presented acoustically degraded vocoded signals, but an equal or smaller rate effect in response to reductions in available spectral and temporal information.

Conclusion CI participants can rate normalize, despite their degraded speech input, and show a larger rate effect compared to NH participants. CI participants may particularly rely on rate normalization to better maintain perceptual constancy of the speech signal.

Acknowledgments
This work was supported by National Institute of Health Grant R01-AG051603 (M.J.G.), P30-DC004664 (C-CEBH), a training award T32-DC000046E (B.N.J.), and the University of Maryland. Special thanks to Matan Simhi for his help with data collection, James R. Sawusch for recording the stimuli, and Christopher Cullen Heffner for help with the statistical analysis. Portions of this work have been presented at the 169th Meeting of the Acoustical Society of America and the 2015 Conference on Implantable Auditory Prostheses.
Order a Subscription
Pay Per View
Entire Journal of Speech, Language, and Hearing Research content & archive
24-hour access
This Article
24-hour access