Changes in Normal Speech After Fatiguing the Tongue Detrimental effects of tongue fatigue on speech have been assumed to exist based on neuromotor speech disorders. However, to address whether fatigue is a contributing cause to impaired speech requires an experimental protocol with anuncomplicated population. This study induced tongue fatigue in eight neurologically normal persons and examined changes in ... Research Article
Research Article  |   December 01, 2000
Changes in Normal Speech After Fatiguing the Tongue
 
Author Affiliations & Notes
  • Nancy Pearl Solomon
    University of Minnesota Minneappolis
  • Corresponding author: e-mail: Nancy.P.Solomon-1@tc.umn.edu
  • Contact author: Nancy Pearl Solomon, PhD, Department of Communication Disorders, University of Minnesota, Minneapolis, MN 55455 Email: Nancy.P.Solomon-1@tc.umn.edu
    Contact author: Nancy Pearl Solomon, PhD, Department of Communication Disorders, University of Minnesota, Minneapolis, MN 55455 Email: Nancy.P.Solomon-1@tc.umn.edu×
Article Information
Speech, Voice & Prosodic Disorders / Hearing & Speech Perception / Acoustics / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   December 01, 2000
Changes in Normal Speech After Fatiguing the Tongue
Journal of Speech, Language, and Hearing Research, December 2000, Vol. 43, 1416-1428. doi:10.1044/jslhr.4306.1416
History: Received October 1, 1999 , Accepted February 21, 2000
 
Journal of Speech, Language, and Hearing Research, December 2000, Vol. 43, 1416-1428. doi:10.1044/jslhr.4306.1416
History: Received October 1, 1999; Accepted February 21, 2000

Detrimental effects of tongue fatigue on speech have been assumed to exist based on neuromotor speech disorders. However, to address whether fatigue is a contributing cause to impaired speech requires an experimental protocol with anuncomplicated population. This study induced tongue fatigue in eight neurologically normal persons and examined changes in speech perceptually and acoustically. The fatigue task consisted of repeated cycles of 6 s of sustained maximum voluntary contraction and 4 s of rest until 50% of maximum strength could not be achieved for three consecutive cycles. Participants then produced speech that was weighted heavily with lingual-palatal consonants. Perceptual analyses of the speech revealed a statistically significant deleterious effect of induced tongue fatigue on speech precision and an incomplete reversal of this effect after a recovery period. Acoustically, the first and third spectral moments (mean and skewness) of the spectral energy for /t/, /s/, and /ʃ/ differed significantly after fatigue but in directions opposite to a priori predictions. Tendencies were found for decreased stop-closure duration and increased voice onset time for /t/ after fatigue. Supplemental analyses revealed decreased second formant (F2) frequency for /u/ and /i/ and flattened F2 transition for the diphthong /@@@I/ after fatigue. These results indicate disruption of tongue positioning and transitioning for lingual-palatal consonants during speech after prolonged strenuous tongue exercises.

Acknowledgments
This project was supported in part by a Grant-in-Aid of Research, Artistry and Scholarship from the Office of the Vice President for Research and Dean of the Graduate School of the University of Minnesota. A portion of this research was conducted at the University of Iowa, Department of Speech Pathology and Audiology, while the author was an assistant research scientist with the National Center for Voice and Speech (grant P60-DC00976 from the National Institute on Deafness and Other Communication Disorders). Preliminary data were presented at the 1997 Convention of the American Speech-Language-Hearing Association in Boston, MA.
I extend sincere thanks to my colleagues and students who assisted with many aspects of this study: Donald Robin for conceptual development; Erich Luschei for instrumentation; Paul Milenkovic for consulting regarding the moments analysis; Ariel Dannis and Emily Karam for data collection; John Nichols and Charles Vale for computer support; Jennifer Godwin Hayes for acoustic analyses; Bruce Carter for perceptual studies; and Edward Carney, Rochelle Milbrath, and Sanford Weisberg for statistical analyses. I am also grateful to Donald Robin, Erich Luschei, Geralyn Schulz, and anonymous reviewers for insightful comments on previous versions of this manuscript.
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