Changes in Speech Production Associated With Alphabet Supplementation Purpose This study examined the effect of alphabet supplementation (AS) on temporal and spectral features of speech production in individuals with cerebral palsy and dysarthria. Method Twelve speakers with dysarthria contributed speech samples using habitual speech and while using AS. One hundred twenty listeners orthographically transcribed speech samples. ... Research Article
Research Article  |   December 01, 2008
Changes in Speech Production Associated With Alphabet Supplementation
 
Author Affiliations & Notes
  • Katherine C. Hustad
    Department of Communicative Disorders and Waisman Center, University of Wisconsin–Madison
  • Jimin Lee
    Department of Communicative Disorders and Waisman Center, University of Wisconsin–Madison
  • Contact author: Katherine C. Hustad, Department of Communicative Disorders and the Waisman Center, University of Wisconsin–Madison, 1500 Highland Avenue, Madison, WI 53705. E-mail: kchustad@wisc.edu.
Article Information
Speech, Voice & Prosodic Disorders / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   December 01, 2008
Changes in Speech Production Associated With Alphabet Supplementation
Journal of Speech, Language, and Hearing Research, December 2008, Vol. 51, 1438-1450. doi:10.1044/1092-4388(2008/07-0185)
History: Received September 11, 2007 , Accepted March 19, 2008
 
Journal of Speech, Language, and Hearing Research, December 2008, Vol. 51, 1438-1450. doi:10.1044/1092-4388(2008/07-0185)
History: Received September 11, 2007; Accepted March 19, 2008
Web of Science® Times Cited: 18

Purpose This study examined the effect of alphabet supplementation (AS) on temporal and spectral features of speech production in individuals with cerebral palsy and dysarthria.

Method Twelve speakers with dysarthria contributed speech samples using habitual speech and while using AS. One hundred twenty listeners orthographically transcribed speech samples. Differences between habitual and AS speech were examined for intelligibility, rate, word duration, vowel duration, pause duration, pause frequency, vowel space, and first and second formant frequency (F1 and F2) values for corner vowels.

Results Descriptive results showed that intelligibility was higher, rate of speech was slower, and pause duration and pause frequency were greater for AS than for habitual speech. Inferential statistics showed that vowel duration, word duration, and vowel space increased significantly for AS. Vowel space did not differ for male and female speakers; however, there was an interaction between sex and speaking condition. Changes in vowel space were accomplished by reductions in F2 for /u/. Vowel space accounted for more variability in intelligibility than rate for AS; the opposite was true for habitual speech.

Conclusion AS is associated with temporal and spectral changes in speech production. Spectral changes associated with corner vowels appear to be more important than temporal changes.

Acknowledgments
This research was funded by National Institute on Deafness and Other Communication Disorders Grant R03 DC005536. We thank Caitlin Dardis, Kelly McCourt, and Joy Taylor-Wade for assistance with data collection and data analysis. We also thank Gary Weismer for assistance with acoustic analyses and for feedback on sections of this article. Portions of these data were presented at the 2006 American Speech, Language, and Hearing Association Annual Convention in Miami, Florida.
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