Kinematic Analysis of Lip Closure in Stutterers’ Fluent Speech An analysis of lip and jaw motion was carried out in order to evaluate previous observations on the fluent speech of stutterers and to describe possible effects of speech therapy. A strain gauge system was used to transduce lip and jaw movements during fluent repetitions of “sapapple” in adult stutterers ... Research Article
Research Article  |   December 01, 1990
Kinematic Analysis of Lip Closure in Stutterers’ Fluent Speech
 
Author Affiliations & Notes
  • Michael D. McClean
    University of Toronto
  • Robert M. Kroll
    University of Toronto
  • Nirit S. Loftus
    University of Toronto
  • Requests for reprints should be sent to Michael D. McClean, Army Audiology and Speech Center, Walter Reed Army Medical Center, Washington, DC 20307-5001.
Article Information
Research Articles
Research Article   |   December 01, 1990
Kinematic Analysis of Lip Closure in Stutterers’ Fluent Speech
Journal of Speech, Language, and Hearing Research, December 1990, Vol. 33, 755-760. doi:10.1044/jshr.3304.755
History: Received January 17, 1990 , Accepted June 4, 1990
 
Journal of Speech, Language, and Hearing Research, December 1990, Vol. 33, 755-760. doi:10.1044/jshr.3304.755
History: Received January 17, 1990; Accepted June 4, 1990

An analysis of lip and jaw motion was carried out in order to evaluate previous observations on the fluent speech of stutterers and to describe possible effects of speech therapy. A strain gauge system was used to transduce lip and jaw movements during fluent repetitions of “sapapple” in adult stutterers and nonstutterers. Fifteen movement parameters were measured on lip closure for the initial /p/ sound in a group of 10 normal speakers, 10 stutterers who had no recent speech therapy, and 8 stutterers who had been through an intensive speech therapy program involving modification of speech timing. The no-therapy group and nonstutterers did not differ significantly in terms of any movement parameter. Stutterers who had been through speech therapy showed significant increases in jaw movement duration and time to peak velocity of the upper lip, lower lip, and jaw. The expected timing pattern for lip and jaw velocity peaks on lip closure (UL-LL-J) was the most frequently occurring pattern, but deviations from this pattern were observed in both stutterers and nonstutterers. The occurrence of reversals was most prevalent in the therapy group, and it was associated with increases in jaw movement duration across subjects. It is suggested that for the type of movement studied here, anomalies in stutterers’ fluent speech are likely to be the result of acquired adjustments rather than properties of the speech neuromotor system that underly dysfluency.

ACKNOWLEDGMENT
This research was supported by a grant from the Hospital for Sick Children Foundation, Toronto. We wish to thank Anne Smith, Vincent Gracco, and Christopher Moore for their editorial suggestions on this article.
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