Bite Block Vowel Production in Apraxia of Speech Purpose This study explored vowel production and adaptation to articulatory constraints in adults with acquired apraxia of speech (AOS) plus aphasia. Method Five adults with acquired AOS plus aphasia and 5 healthy control participants produced the vowels [i], [ɛ], and [æ] in four word-length conditions in unconstrained and ... Research Article
Research Article  |   August 01, 2008
Bite Block Vowel Production in Apraxia of Speech
 
Author Affiliations & Notes
  • Adam Jacks
    University of Texas at Austin
  • Contact author: Adam Jacks, who is now at the Department of Communication Disorders, Texas State University, San Marcos, TX 78666, and the Research Imaging Center, The University of Texas Health Science Center, San Antonio, TX 78229. E-mail: adamjacks@txstate.edu.
Article Information
Speech, Voice & Prosodic Disorders / Apraxia of Speech & Childhood Apraxia of Speech / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   August 01, 2008
Bite Block Vowel Production in Apraxia of Speech
Journal of Speech, Language, and Hearing Research, August 2008, Vol. 51, 898-913. doi:10.1044/1092-4388(2008/066)
History: Received September 4, 2006 , Revised March 21, 2007 , Accepted November 8, 2007
 
Journal of Speech, Language, and Hearing Research, August 2008, Vol. 51, 898-913. doi:10.1044/1092-4388(2008/066)
History: Received September 4, 2006; Revised March 21, 2007; Accepted November 8, 2007
Web of Science® Times Cited: 13

Purpose This study explored vowel production and adaptation to articulatory constraints in adults with acquired apraxia of speech (AOS) plus aphasia.

Method Five adults with acquired AOS plus aphasia and 5 healthy control participants produced the vowels [i], [ɛ], and [æ] in four word-length conditions in unconstrained and bite block conditions. In addition to acoustic and perceptual measures of vowel productions, individually determined idealized vowels based on each participant’s best performance were used to assess vowel accuracy and distinctiveness.

Results Findings showed (a) clear separation of vowel formants in speakers with AOS; (b) impaired vowel production in speakers with AOS, shown by perceptual measures of vowel quality and acoustic measures of vowel accuracy and contrastivity; and (c) incomplete compensation to bite block compensation both for individuals with AOS and for healthy controls.

Conclusions Although adults with AOS were less accurate overall in vowel production than unimpaired speakers, introduction of a bite block resulted in similar patterns of decreased vowel accuracy for the two groups. Findings suggest that feedback control for vowel production is relatively intact in these individuals with AOS and aphasia. Predominant use of feedback control mechanisms is hypothesized to account for characteristic vowel deficits of the disorder.

Acknowledgments
This research was completed as part of a doctoral dissertation project at the University of Texas at Austin in the Department of Communication Sciences and Disorders, directed by Thomas P. Marquardt. I gratefully acknowledge Thomas P. Marquardt, Donald A. Robin (University of Texas Health Science Center at San Antonio), and Frank H. Guenther (Boston University and Massachusetts Institute of Technology) for providing helpful comments on a draft of this article. I also greatly appreciate the assistance of Sarah Key-Delyria in providing acoustic reliability measures for the study. Finally, this work would not have been possible without the 10 participants who volunteered to be part of this study.
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