Sense of Effort and the Effects of Fatigue in the Tongue and Hand Fatigue and increased effort are common symptoms for people with movement disorders and dysarthria, but they are rarely quantified. In an attempt to develop a clinically useful and physiologically meaningful measure of fatigue, we used a task that involves sustaining a target effort level without visual feedback while squeezing a ... Research Article
Research Article  |   February 01, 1996
Sense of Effort and the Effects of Fatigue in the Tongue and Hand
 
Author Affiliations & Notes
  • Nancy Pearl Solomon
    Department of Speech Pathology and Audiology and National Center for Voice and Speech University of Iowa Iowa City
  • Donald A. Robin
    Department of Speech Pathology and Audiology and National Center for Voice and Speech University of Iowa Iowa City
  • Sara I. Mitchinson
    Department of Speech Pathology and Audiology and National Center for Voice and Speech University of Iowa Iowa City
  • Douglas J. VanDaele
    Department of Speech Pathology and Audiology and National Center for Voice and Speech University of Iowa Iowa City
  • Erich S. Luschei
    Department of Speech Pathology and Audiology and National Center for Voice and Speech University of Iowa Iowa City
  • Currently affiliated with the Department of Communication Disorders, University of Minnesota, Minneapolis
    Currently affiliated with the Department of Communication Disorders, University of Minnesota, Minneapolis×
  • Currently affiliated with Cognitive and Rehabilitation Specialists, Westchester, IL
    Currently affiliated with Cognitive and Rehabilitation Specialists, Westchester, IL×
  • Contact author: Nancy Pearl Solomon, PhD, Department of Communication Disorders, University of Minnesota, 115 Shevlin Hall, Minneapolis, MN 55455.
    Contact author: Nancy Pearl Solomon, PhD, Department of Communication Disorders, University of Minnesota, 115 Shevlin Hall, Minneapolis, MN 55455.×
Article Information
Research Issues, Methods & Evidence-Based Practice / Speech / Research Articles
Research Article   |   February 01, 1996
Sense of Effort and the Effects of Fatigue in the Tongue and Hand
Journal of Speech, Language, and Hearing Research, February 1996, Vol. 39, 114-125. doi:10.1044/jshr.3901.114
History: Received February 3, 1995 , Accepted July 17, 1995
 
Journal of Speech, Language, and Hearing Research, February 1996, Vol. 39, 114-125. doi:10.1044/jshr.3901.114
History: Received February 3, 1995; Accepted July 17, 1995

Fatigue and increased effort are common symptoms for people with movement disorders and dysarthria, but they are rarely quantified. In an attempt to develop a clinically useful and physiologically meaningful measure of fatigue, we used a task that involves sustaining a target effort level without visual feedback while squeezing a bulb connected to a pressure transducer. In the first experiment, 12 healthy young adults performed the constant-effort task with the tongue and the preferred hand at 3 submaximal levels of effort. The resulting pressure declined over time as a negative exponential function with a nonzero asymptote. In the second experiment, 6 subjects performed the constant-effort task before and after acutely fatiguing the tongue and hand. The rate of pressure decline was significantly greater after fatigue. One possible mechanism for the characteristic negative exponential function is that It reflects a constant descending drive from higher centers in the CNS to the appropriate motoneuron pools. Thus, this technique may elucidate the contribution of central fatigue to normal and disordered speech.

Acknowledgments
This research was supported by research grants 1-R03-DC01182 and P60-DC00976 from the National Institutes on Deafness and Other Communication Disorders. A portion of this work was presented at the 1992 Conference on Motor Speech in Boulder, CO. We would like to thank Dr. William Clarke for statistical consultation and three anonymous reviewers who provided helpful suggestions for the final version of this manuscript.
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