Spatiotemporal Stability of Lip Movements in Older Adult Speakers Although the intelligibility of healthy older adults normally seems unimpaired, age-related changes occur in sensorimotor components of the speech system and in such global parameters as speech rate. In order to clarify the effect of these changes on the variability of speech movements, we examined oral peripheral abilities, speech rate, ... Research Article
Research Article  |   February 01, 1998
Spatiotemporal Stability of Lip Movements in Older Adult Speakers
 
Author Affiliations & Notes
  • Amy B. Wohlert
    Purdue University West Lafayette, IN
  • Anne Smith
    Purdue University West Lafayette, IN
  • Contact author: Amy B. Wohlert, PhD, Department of Audiology and Speech Sciences, Purdue University, 1353 Heavilon Hall, West Lafayette, IN 47907. Email: wohlert@purdue.edu
Article Information
Special Populations / Older Adults & Aging / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   February 01, 1998
Spatiotemporal Stability of Lip Movements in Older Adult Speakers
Journal of Speech, Language, and Hearing Research, February 1998, Vol. 41, 41-50. doi:10.1044/jslhr.4101.41
History: Received February 10, 1997 , Accepted September 29, 1997
 
Journal of Speech, Language, and Hearing Research, February 1998, Vol. 41, 41-50. doi:10.1044/jslhr.4101.41
History: Received February 10, 1997; Accepted September 29, 1997

Although the intelligibility of healthy older adults normally seems unimpaired, age-related changes occur in sensorimotor components of the speech system and in such global parameters as speech rate. In order to clarify the effect of these changes on the variability of speech movements, we examined oral peripheral abilities, speech rate, and speech kinematics in a group of 10 adults age 76–83, compared to a group of 10 young adults. Participants repeated a short phrase 15 times at habitual, fast, and slow rates. The resulting lip displacement signals were time- and amplitude-normalized, and successive standard deviations along the movement waveforms were summed to produce a spatiotemporal index (STI) representing individual variability in movement pattern. Participants tended to show greatest variability at slow rate, less variability at fast rate, and least variability at habitual rate. For the older adults, STI at habitual rate was significantly higher (more variable) and speech durations were longer than those of young adults. Perioral strength and tactile acuity were poorer in these older adults than in young adults. We conclude that as sensorimotor abilities change in old age, speakers are less consistent in the spatiotemporal organization of speech movements, reflecting decreased stability of speech motor control.

Acknowledgments
This work was partially funded by a grant to Amy Wohlert from the Purdue University Gerontology Program and a grant (DC02527) to Anne Smith from the National Institutes of Health. We wish to thank Janna Berlin and Tisha Kauffman for their assistance in testing participants and analyzing data and Goangshiuan Ying for development of the analysis programs.
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