From Planning to Articulation in Speech Production: What Differentiates a Person Who Stutters From a Person Who Does Not Stutter? The main purpose of the present study was to differentiate between people who stutter and control speakers regarding their ability to assemble motor plans and to prepare (and execute) muscle commands. Adult males who stutter, matched for age, gender, and educational level with a group of control speakers, were tested ... Research Article
Research Article  |   June 01, 1996
From Planning to Articulation in Speech Production: What Differentiates a Person Who Stutters From a Person Who Does Not Stutter?
 
Author Affiliations & Notes
  • Pascal H. H. M. van Lieshout
    Nijmegen Institute of Cognition and Information, and University Hospital, Department of Voice and Speech Disorders, 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, PhD, NICI, P.O. Box 9104, 6500 HE Nijmegen, The Netherlands. E-mail: lieshout@nici.kun.nl
Article Information
Speech, Voice & Prosodic Disorders / Fluency Disorders / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   June 01, 1996
From Planning to Articulation in Speech Production: What Differentiates a Person Who Stutters From a Person Who Does Not Stutter?
Journal of Speech, Language, and Hearing Research, June 1996, Vol. 39, 546-564. doi:10.1044/jshr.3903.546
History: Received June 5, 1995 , Accepted November 6, 1995
 
Journal of Speech, Language, and Hearing Research, June 1996, Vol. 39, 546-564. doi:10.1044/jshr.3903.546
History: Received June 5, 1995; Accepted November 6, 1995

The main purpose of the present study was to differentiate between people who stutter and control speakers regarding their ability to assemble motor plans and to prepare (and execute) muscle commands. Adult males who stutter, matched for age, gender, and educational level with a group of control speakers, were tested on naming words and symbols. In addition, their ability to encode and retrieve memory representations of combinations of a symbol and a word, was tested in a recognition task, using manual reaction times and sensitivity scores, as defined in signal detection theory, as performance measures. Group differences in muscle command preparation were assessed from electromyographic recordings of upper lip and lower lip. Results indicated no interaction between group and word size effects in choice reaction times or a group effect in the ability to recognize previously learned symbol-word combinations. However, they were significantly different in the timing of peak amplitudes in the integrated electromyographic signals of upper lip and lower lip (IEMG peak latency). Findings question the claim that people who stutter have problems in creating abstract motor plans for speech. In addition, it is argued that the group differences in IEMG peak latency that were found in the present study might be better understood in terms of motor control strategies than in terms of motor control deficits.

Acknowledgments
The Netherlands Organization for Scientific Research (NWO) is gratefully acknowledged for funding this project. The authors wish to express their gratitude to C. Berkeljon, B. Frumau, and A. Sanderman for their valuable assistance with the experiments and data analysis, as well as their active participation throughout the research period. They also wish to thank C. Bouwhuisen (NICI) and Martin Nicolasen (Academic Hospital Nijmegen, ENT clinic) for their help in getting all systems running. The authors would like to thank Dr. Watson, Dr. Smith, Mr. Dembowski, and an anonymous reviewer for their helpful comments and suggestions on an earlier version of this manuscript.
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