Tongues and Lips Without Jaws A Comparison of Methods for Decoupling Speech Movements Research Article
EDITOR'S AWARD
Research Article  |   August 01, 2002
Tongues and Lips Without Jaws
 
Author Affiliations & Notes
  • John R. Westbury
    Department of Communicative Disorders and Waisman Center University of Wisconsin-Madison
  • Mary J. Lindstrom
    Department of Biostatistics and Medical Informatics University of Wisconsin-Madison
  • Michael D. McClean
    Walter Reed Army Medical Center Washington, DC
  • Corresponding author: e-mail: westbury@wisc.edu
Article Information
Swallowing, Dysphagia & Feeding Disorders / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   August 01, 2002
Tongues and Lips Without Jaws
Journal of Speech, Language, and Hearing Research, August 2002, Vol. 45, 651-662. doi:10.1044/1092-4388(2002/052)
History: Received June 5, 2001 , Accepted April 4, 2002
 
Journal of Speech, Language, and Hearing Research, August 2002, Vol. 45, 651-662. doi:10.1044/1092-4388(2002/052)
History: Received June 5, 2001; Accepted April 4, 2002
Web of Science® Times Cited: 45

Speech-related motions of small markers attached to the tongue, lower lip, and lower jaw of 44 normal young adult talkers of American English were analyzed to estimate the relative accuracy of selected methods for decoupling tongue and lip motions from ongoing jaw motion when all movements are originally measured relative to a common reference frame (such as the head). In general, results of the analysis show that a common "simple subtractio" method that ignores pitching rotation of the jaw yields larger errors in positions and speeds of decoupled tongue and lip markers than methods that do not ignore rotation. When the jaw is widely opened, is moving quickly, and/or when any decoupled marker is relatively far from the origin of a local coordinate system fixed to the jaw, positional and speed errors associated with the subtraction method can exceed 5 mm and 25 mm/s, respectively. We propose a simple procedure for estimating the pitching rotation of the jaw that can be applied when pitch cannot be measured. We then show that decoupled motions of tongue and lower lip markers based on estimated jaw rotation involve less error than those derived from any other decoupling method considered. Careful attention to processing methods should yield more accurate inferences about the nature and degree of coordination between speech-related movements of the tongue and lower lip that are decoupled from, and hence independent of, concurrent movements of the lower jaw.

Acknowledgments
Research support was provided by USPHS/NIH Grants R01 DC00820, R01 CA75097, R01 DC03273, and R01 DC03659. A preliminary report of this research was presented at the Tenth Biennial Conference on Motor Speech: Motor Speech Disorders & Speech Motor Control, San Antonio, TX, February 3-6, 2000. We thank Christine Mooshammer for drawing our attention to selected reference materials, and we thank Jordan Green for insightful comments on earlier drafts.
Order a Subscription
Pay Per View
Entire Journal of Speech, Language, and Hearing Research content & archive
24-hour access
This Article
24-hour access