Patterns of Orofacial Movement Velocity Across Variations in Speech Rate To understand the clinical aspects of speech rate control, a clearer picture is needed of how orofacial structures are coordinated across variations in speech rate. To address this problem, patterns of orofacial tangential velocity or speed were analyzed in a group of 9 normal speakers as they produced the utterance ... Research Article
Research Article  |   February 01, 2000
Patterns of Orofacial Movement Velocity Across Variations in Speech Rate
 
Author Affiliations & Notes
  • Michael D. McClean
    Walter Reed Army Medical Center Washington, DC
  • Corresponding author: e-mail: mdmcclean@hotmail.com
  • Contact author: Michael D. McClean, PhD, Audiology and Speech Center, Walter Reed Army Medical Center, Washington, DC 20307–5001. Email: mdmcclean@hotmail.com
Article Information
Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   February 01, 2000
Patterns of Orofacial Movement Velocity Across Variations in Speech Rate
Journal of Speech, Language, and Hearing Research, February 2000, Vol. 43, 205-216. doi:10.1044/jslhr.4301.205
History: Received November 2, 1998 , Accepted June 10, 1999
 
Journal of Speech, Language, and Hearing Research, February 2000, Vol. 43, 205-216. doi:10.1044/jslhr.4301.205
History: Received November 2, 1998; Accepted June 10, 1999

To understand the clinical aspects of speech rate control, a clearer picture is needed of how orofacial structures are coordinated across variations in speech rate. To address this problem, patterns of orofacial tangential velocity or speed were analyzed in a group of 9 normal speakers as they produced the utterance “a bad daba” at fast, normal, and slow speech rates. An electromagnetic system was used to record the movements of the upper lip, lower lip, jaw, and tongue. Measures of the magnitude of peak tangential velocities were obtained across the four structures. Orofacial velocities consistently decreased at slow rates relative to normal rates, whereas at fast rates increased and decreased velocities were observed in an equivalent number of cases. Significant correlations frequently were obtained across speech rate between lip, tongue, and jaw velocities. Upper and lower lip velocities showed consistent positive correlations with one another, whereas marked intersubject differences were observed in the sign of jaw-related correlations. Repeated testing on 3 subjects indicated a high degree of consistency within subjects in the overall patterns of mean velocity for the different structures. Results are discussed in relation to possible motor control differences underlying fast and slow speech, neural coupling of muscle systems, and jaw-related individual differences in speech motor coordination.

Acknowledgments
This research was supported by the Department of Clinical Investigation, Walter Reed Army Medical Center, under Work Unit 2546, and was approved by the Center’s Human Use Committee. All subjects enrolled in the study voluntarily agreed to participate and gave written and informed consent. The opinions or assertions contained herein are the private views of the author and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. Thanks to John Westbury for very helpful discussion on aspects of this research, Chen-Wen Ko for advice on statistical analysis, David Karpinski for assistance with software development, and Mary Cord for assistance with data measurement.
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