Effect of Tongue Exercise on Protrusive Force and Muscle Fiber Area in Aging Rats Purpose Age-related changes in tongue function may contribute to dysphagia in elderly people. The authors' purpose was to investigate whether aged rats that have undergone tongue exercise would manifest increased protrusive tongue forces and increased genioglossus (GG) muscle fiber cross-sectional areas. Method Forty-eight young adult, middle-aged, and old ... Research Article
Research Article  |   June 01, 2009
Effect of Tongue Exercise on Protrusive Force and Muscle Fiber Area in Aging Rats
 
Author Affiliations & Notes
  • Nadine P. Connor
    University of Wisconsin, Madison
  • John A. Russell
    University of Wisconsin, Madison
  • Hao Wang
    University of Wisconsin, Madison
  • Michelle A. Jackson
    University of Wisconsin, Madison
  • Laura Mann
    University of Wisconsin, Madison
  • Keith Kluender
    University of Wisconsin, Madison
  • Contact author: Nadine P. Connor, University of Wisconsin Clinical Science Center, Room K4/711, 600 Highland Avenue, Madison, WI 53792-7375. E-mail: connor@surgery.wisc.edu.
Article Information
Swallowing, Dysphagia & Feeding Disorders / Special Populations / Older Adults & Aging / Speech / Research Articles
Research Article   |   June 01, 2009
Effect of Tongue Exercise on Protrusive Force and Muscle Fiber Area in Aging Rats
Journal of Speech, Language, and Hearing Research, June 2009, Vol. 52, 732-744. doi:10.1044/1092-4388(2008/08-0105)
History: Received May 23, 2008 , Accepted July 25, 2008
 
Journal of Speech, Language, and Hearing Research, June 2009, Vol. 52, 732-744. doi:10.1044/1092-4388(2008/08-0105)
History: Received May 23, 2008; Accepted July 25, 2008
Web of Science® Times Cited: 21

Purpose Age-related changes in tongue function may contribute to dysphagia in elderly people. The authors' purpose was to investigate whether aged rats that have undergone tongue exercise would manifest increased protrusive tongue forces and increased genioglossus (GG) muscle fiber cross-sectional areas.

Method Forty-eight young adult, middle-aged, and old Fischer 344/Brown Norway rats received 8 weeks of tongue exercise. Protrusive tongue forces were measured before and after exercise. GG muscle fiber cross-sectional area was measured in exercised rats and was compared with cross-sectional areas in a no-exercise control group.

Results A significant increase in maximum tongue force was found following exercise in all age groups. In addition, a trend for increased GG muscle fiber cross-sectional area and a significant increase in variability of GG muscle fiber cross-sectional area was identified postexercise.

Conclusion The findings of this study have implications for treatment of elderly persons with dysphagia using tongue exercise programs. Specifically, increases in tongue force that occur following 8 weeks of progressive resistance tongue exercise may be accompanied by alterations in tongue muscle fiber morphology. These changes may provide greater strength and endurance for goal-oriented actions associated with the oropharyngeal swallow and should be investigated in future research.

Acknowledgments
This study was supported by National Institute on Deafness and Other Communication Disorders Grants R01DC005935 and R01DC008149. We are grateful for the assistance of Kyungah Lee, Scott Speer, Kiara Marlega, Emily Bethea, Aaron Johnson, Glen Leverson, Alejandro Munoz del Rio, Karen Williams, Rachel Nelson, Sarah Cain, Hayley Gallaher, and Lisa Vinney in the completion of this work. Michelle Ciucci and JoAnne Robbins provided valuable comments on an earlier draft of this article.
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