A Maximum-Force-Dependent Protocol for Assessing Labial Force Control A protocol based on target levels, referenced to maximum voluntary closing force (MVCF), was used to assess static force control in the perioral musculature. Twenty normal-speaking subjects were instructed to produce rapid and accurate isometric force trajectories to end-point target levels and maintain force on-target for 5 sec while viewing ... Research Article
Research Article  |   June 01, 1993
A Maximum-Force-Dependent Protocol for Assessing Labial Force Control
 
Author Affiliations & Notes
  • James D. Amerman
    University of Missouri-Columbia
  • Contact author: James D. Amerman, PhD, Communicative Disorders Program, University of Missouri-Columbia, 317 Lewis Hall, Columbia, MO 65211.
Article Information
Healthcare Settings / Research Issues, Methods & Evidence-Based Practice / Speech / Research Articles
Research Article   |   June 01, 1993
A Maximum-Force-Dependent Protocol for Assessing Labial Force Control
Journal of Speech, Language, and Hearing Research, June 1993, Vol. 36, 460-465. doi:10.1044/jshr.3603.460
History: Received August 28, 1991 , Accepted December 7, 1992
 
Journal of Speech, Language, and Hearing Research, June 1993, Vol. 36, 460-465. doi:10.1044/jshr.3603.460
History: Received August 28, 1991; Accepted December 7, 1992

A protocol based on target levels, referenced to maximum voluntary closing force (MVCF), was used to assess static force control in the perioral musculature. Twenty normal-speaking subjects were instructed to produce rapid and accurate isometric force trajectories to end-point target levels and maintain force on-target for 5 sec while viewing a computer monitor. Each lip was assessed on a number of quantitative force control measures at 10, 20, 50, and 75% of MVCF. The 10% and 20% target levels were included so that static force control could be evaluated within the presumed physiological operating range for normal speech. Results of the target-level scaling procedure revealed that the upper lip was more stable in controlling force at all four targets. The use of MVCF-based target scaling is discussed in relation to absolute nonscaled force analysis methods applied to the perioral motor system.

Acknowledgments
A portion of this research project was presented at the 1989 ASHA Convention in St. Louis. Thanks to Terry Goins, Dana Fritz, and Ellen Lowe for their evaluation and analysis contributions to a preliminary version of this paper. Also, Martha M. Parnell deserves credit for her review and editing expertise. Finally, Pam Allard was instrumental throughout the processing and finalizing of the manuscript.
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