Rotation and Translation of the Jaw During Speech A two-dimensional rigid-body model of jaw movement was used to describe jaw opening and closing gestures for vowels and for bilabial and alveolar consonants. Jaw movements were decomposed into three components: (a) rotation about the terminal hinge axis, (b) the horizontal translation of that axis, and (c) the vertical translation ... Research Article
Research Article  |   September 01, 1990
Rotation and Translation of the Jaw During Speech
 
Author Affiliations & Notes
  • Jan Edwards
    Hunter College of the City University of New York
  • Katherine S. Harris
    The Graduate Center of the City University of New York and Haskins Laboratories
  • Requests for reprints should be sent to Jan Edwards, Hunter College, School of Health Sciences, Brookdale Health Science Center, 425 E. 25th Street, New York, NY 10010.
Article Information
Research Issues, Methods & Evidence-Based Practice / Speech, Voice & Prosody / Research Articles
Research Article   |   September 01, 1990
Rotation and Translation of the Jaw During Speech
Journal of Speech, Language, and Hearing Research, September 1990, Vol. 33, 550-562. doi:10.1044/jshr.3303.550
History: Received September 28, 1989 , Accepted April 6, 1990
 
Journal of Speech, Language, and Hearing Research, September 1990, Vol. 33, 550-562. doi:10.1044/jshr.3303.550
History: Received September 28, 1989; Accepted April 6, 1990

A two-dimensional rigid-body model of jaw movement was used to describe jaw opening and closing gestures for vowels and for bilabial and alveolar consonants. Jaw movements were decomposed into three components: (a) rotation about the terminal hinge axis, (b) the horizontal translation of that axis, and (c) the vertical translation of that axis. Data were collected for 3 subjects in two separate recording sessions. Multiple regression analysis was used to examine the relationships among the three jaw movement components. For 2 subjects, but not for the third, an interdependence between jaw rotation and the first principal component of jaw translation, horizontal translation, was observed. For these 2 subjects, the first degree of freedom of jaw movement corresponded to a combination of rotation and the first principal component of jaw translation. For the third subject, the first degree of freedom of jaw movement corresponded to rotation alone. The results of this study, like those of Westbury (1988), indicate that an accurate description of jaw movement during speech requires the recording of two points of jaw movement.

ACKNOWLEDGMENTS
This article is based on a doctoral dissertation by the first author which was supported by NINCDS grant NS 13617 to Haskins Laboratories. We would especially like to thank Tom Baer for his help on working through the geometry of the model and Osamu Fujimura for relating this problem to the analysis of the X-ray microbeam data, as well as for their careful reading of many versions of the dissertation. We would also like to thank Win Nelson, for his help on the curve-fitting algorithm; Nell Sedransk, for help with the statistical analysis; and David Kussovitsky, D.D.S., for constructing and attaching the dental appliances. Finally, we thank David Ostry, John Westbury, and a third anonymous reviewer for their thoughtful reviews of this paper.
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