Influences of Length and Syntactic Complexity on the Speech Motor Stability of the Fluent Speech of Adults Who Stutter The purpose of the present study was to investigate the impact of utterance length and syntactic complexity on the speech motor stability of adults who stutter. Lower lip movement was recorded from 8 adults who stutter and 8 normally fluent controls. They produced a target phrase in isolation (baseline condition) ... Research Article
Research Article  |   April 01, 2000
Influences of Length and Syntactic Complexity on the Speech Motor Stability of the Fluent Speech of Adults Who Stutter
 
Author Affiliations & Notes
  • Jennifer Kleinow
    Purdue University West Lafayette, IN
  • Anne Smith
    Purdue University West Lafayette, IN
Article Information
Speech, Voice & Prosodic Disorders / Fluency Disorders / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   April 01, 2000
Influences of Length and Syntactic Complexity on the Speech Motor Stability of the Fluent Speech of Adults Who Stutter
Journal of Speech, Language, and Hearing Research, April 2000, Vol. 43, 548-559. doi:10.1044/jslhr.4302.548
History: Received May 4, 1998 , Accepted August 19, 1999
 
Journal of Speech, Language, and Hearing Research, April 2000, Vol. 43, 548-559. doi:10.1044/jslhr.4302.548
History: Received May 4, 1998; Accepted August 19, 1999

The purpose of the present study was to investigate the impact of utterance length and syntactic complexity on the speech motor stability of adults who stutter. Lower lip movement was recorded from 8 adults who stutter and 8 normally fluent controls. They produced a target phrase in isolation (baseline condition) and the same phrase embedded in utterances of increased length and/or increased syntactic complexity. The spatiotemporal index (STI) was used to quantify the stability of lower lip movements across multiple repetitions of the target phrase. Results indicated: (a) Adults who stutter demonstrated higher overall STI values than normally fluent adults across all experimental conditions, indicating decreased speech motor stability; (b) the speech motor stability of normally fluent adults was not affected by increasing syntactic complexity, but the speech motor stability of adults who stutter decreased when the stimuli were more complex; (c) increasing the length of the target utterance (without increasing syntactic complexity) did not affect the speech motor stability of either speaker group. These results indicate that language formulation processes may affect speech production processes and that the speech motor systems of adults who stutter may be especially susceptible to the linguistic demands required to produce a more complex utterance. The present findings, therefore, support the hypothesis that linguistic complexity is one factor that contributes to the disruptions of speech motor stability characteristic of stuttering.

Acknowledgments
This work was supported by a grant from the National Institutes of Health, NIDCD R01 DC00559. We would like to acknowledge Lisa Goffman and William Murphy for their help on this project.
Order a Subscription
Pay Per View
Entire Journal of Speech, Language, and Hearing Research content & archive
24-hour access
This Article
24-hour access