Speech Production in People Who Stutter: Testing the Motor Plan Assembly Hypothesis The main purpose of the present study was to test the hypothesis that persons who stutter, when compared to persons who do not stutter, are less able to assemble abstract motor plans for short verbal responses. Subjects were adult males who stutter and age- and sex-matched control speakers, who were ... Research Article
Research Article  |   February 01, 1996
Speech Production in People Who Stutter: Testing the Motor Plan Assembly Hypothesis
 
Author Affiliations & Notes
  • Pascal H.H.M. van Lieshout
    Nijmegen Institute of Cognition and Information and University Hospital, Department of Voice and Speech Disorders Nijmegen, The Netherlands
  • Wouter Hulstijn
    Nijmegen Institute of Cognition and Information and University of Nijmegen The Netherlands
  • Herman F.M. Peters
    University Hospital, Department of Voice and Speech Disorders and University of Nijmegen The Netherlands
  • Contact author: Pascal H. H. M. van Lieshout, University of Nijmegan, NICI/KUN, P.O. Box 9104, 6500 HE Nijmegan, The Netherlands. E-mail: lieshout@nici.kun.nl
Article Information
Speech, Voice & Prosodic Disorders / Fluency Disorders / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   February 01, 1996
Speech Production in People Who Stutter: Testing the Motor Plan Assembly Hypothesis
Journal of Speech, Language, and Hearing Research, February 1996, Vol. 39, 76-92. doi:10.1044/jshr.3901.76
History: Received March 9, 1995 , Accepted June 21, 1995
 
Journal of Speech, Language, and Hearing Research, February 1996, Vol. 39, 76-92. doi:10.1044/jshr.3901.76
History: Received March 9, 1995; Accepted June 21, 1995

The main purpose of the present study was to test the hypothesis that persons who stutter, when compared to persons who do not stutter, are less able to assemble abstract motor plans for short verbal responses. Subjects were adult males who stutter and age- and sex-matched control speakers, who were tested on naming pictures and words, using a choice-reaction time paradigm for both tasks. Words varied in the number of syllables (1, 2, and 3 syllables) and, for the bisyllabic words, also in the number of consonants (one or more) at the onset of the second syllable. Measurements consisted of speech reaction times, word durations, and measures of relative timing of specific motor events in the respiratory, phonatory, and articulatory subsystems.

Results indicated that, in spite of longer speech reaction times for persons who stutter in comparison to control speakers, there was no interaction with word size, a finding that does not lend support to the abovementioned hypothesis. Word durations were found to be longer for persons who stutter, and, in addition, there was an interaction of group with word size. Both findings were associated with longer delays for persons who stutter in the onset of upper lip integrated electromyographic (IEMG) activity and thoracic compression, and a group effect on the order of upper lip and lower lip IEMG onset. Findings are taken to suggest the possibility that persons who stutter may use different motor control strategies to compensate for a reduced verbal motor skill, and although the nature of this reduced skill is unknown, it is speculated that it relates to the processes involved in the integration of sensory-motor information.

Acknowledgments
This research was supported in part by the Netherlands Organization of Scientific Research (NWO), Grant 560-259-031. The authors wish to express their gratitude to Erna Lankhorst for her valuable assistance in the experiments and data analysis, as well as for her active participation throughout the research period. We also wish to thank Martin Nicolasen for his help in getting all systems running. We thank Ed Conture for his valuable comments and suggestions on an earlier version of this manuscript. Finally, we thank Dr. Watson, Dr. Pindzola, and two anonymous reviewers whose comments and suggestions were of great help in improving this manuscript.
Order a Subscription
Pay Per View
Entire Journal of Speech, Language, and Hearing Research content & archive
24-hour access
This Article
24-hour access