Acoustic and Perceptual Correlates of Stress in Nonwords Produced by Children With Suspected Developmental Apraxia of Speech and Children With Phonological Disorder Previous research (L. Shriberg, D. Aram, & J. Kwiatkowski, 1997b, 1997c) has suggested that accuracy in producing linguistic stress reliably distinguishes between children with suspected developmental apraxia of speech (sDAS) and children with phonological disorder (PD). The current investigation tested this hypothesis by examining acoustic correlates of stress in trochaic ... Research Article
Research Article  |   February 01, 2003
Acoustic and Perceptual Correlates of Stress in Nonwords Produced by Children With Suspected Developmental Apraxia of Speech and Children With Phonological Disorder
 
Author Affiliations & Notes
  • Benjamin Munson
    University of Minnesota, Minneapolis
  • Elissa M. Bjorum
    University of Minnesota, Minneapolis
  • Jennifer Windsor
    University of Minnesota, Minneapolis
  • Contact author: Benjamin Munson, Department of Communication Disorders, University of Minnesota, 115 Shevlin Hall, 164 Pillsbury Drive, SE, Minneapolis, MN 55455.
    Contact author: Benjamin Munson, Department of Communication Disorders, University of Minnesota, 115 Shevlin Hall, 164 Pillsbury Drive, SE, Minneapolis, MN 55455.×
  • Corresponding author: E-mail: Munso005@umn.edu
Article Information
Speech, Voice & Prosodic Disorders / Apraxia of Speech & Childhood Apraxia of Speech / Hearing & Speech Perception / Acoustics / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   February 01, 2003
Acoustic and Perceptual Correlates of Stress in Nonwords Produced by Children With Suspected Developmental Apraxia of Speech and Children With Phonological Disorder
Journal of Speech, Language, and Hearing Research, February 2003, Vol. 46, 189-202. doi:10.1044/1092-4388(2003/015)
History: Received February 22, 2002 , Accepted August 9, 2002
 
Journal of Speech, Language, and Hearing Research, February 2003, Vol. 46, 189-202. doi:10.1044/1092-4388(2003/015)
History: Received February 22, 2002; Accepted August 9, 2002
Web of Science® Times Cited: 15

Previous research (L. Shriberg, D. Aram, & J. Kwiatkowski, 1997b, 1997c) has suggested that accuracy in producing linguistic stress reliably distinguishes between children with suspected developmental apraxia of speech (sDAS) and children with phonological disorder (PD). The current investigation tested this hypothesis by examining acoustic correlates of stress in trochaic (strong-weak) and iambic (weak-strong) nonwords produced by 5 children in each of these 2 groups. Four measures relating to stress production were examined: vowel duration, fundamental frequency (f0) at vowel midpoint, timing of the f0 peak relative to vowel onset, and intensity at vowel midpoint. In addition, perceptual judgments of accuracy of stress production were obtained. No group differences in the production of stress were found; however, listeners judged that the nonword repetitions of children with sDAS matched the target stress contour less often than did the repetitions of children with PD. Multiple regression analyses found that mean vowel duration, as well as the relative duration and relative f0 of stressed and stressless syllables, predicted listeners’ judgments of stress, although these variables only accounted for a small proportion of variance (21.8%). Thus, children with sDAS were able to produce acoustic differences between stressed and stressless syllables, but these differences were not consistently perceptible to listeners.

Acknowledgment
Elissa Bjorum is now at Saint Paul Public Schools, St. Paul, MN. Portions of this article were completed as part of the second author’s M.A. thesis in the Department of Communication Disorders at the University of Minnesota. The thesis was co-advised by the first and third authors. This work was supported by the Clark Starr/Bryng Bryngelson fund in the Department of Communication Disorders at the University of Minnesota and by the University of Minnesota College of Liberal Arts. We generously thank Janet Jacobs and Leslie Glaze for assistance in recruiting participants. We also thank Heather Mathews and Tara Gibbs for assisting with acoustic analyses and Kathryn Kohnert for assistance in preparing production prompts.
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