Articulatory Movements in Adolescents Evidence for Protracted Development of Speech Motor Control Processes Research Article
Research Article  |   December 01, 2002
Articulatory Movements in Adolescents
 
Author Affiliations & Notes
  • Bridget Walsh
    Purdue University West Lafayette, IN
  • Anne Smith
    Purdue University West Lafayette, IN
  • Contact authors: Bridget Walsh and Anne Smith, Department of Audiology and Speech Sciences, 1353 Heavilon Hall, Purdue University, West Lafayette, Indiana 47907. E-mail: bridget@purdue.edu, asmith@purdue.edu
Article Information
Development / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   December 01, 2002
Articulatory Movements in Adolescents
Journal of Speech, Language, and Hearing Research, December 2002, Vol. 45, 1119-1133. doi:10.1044/1092-4388(2002/090)
History: Received April 9, 2002 , Accepted July 26, 2002
 
Journal of Speech, Language, and Hearing Research, December 2002, Vol. 45, 1119-1133. doi:10.1044/1092-4388(2002/090)
History: Received April 9, 2002; Accepted July 26, 2002
Web of Science® Times Cited: 83

In order to contribute to a more comprehensive model of speech motor development, we examined the movement trajectories of the upper lip, lower lip, and jaw to determine (a) if there are changes in articulatory motor control in late adolescence; b) if there are sex differences during this developmental period, perhaps related to differences in craniofacial growth rates; (c) if control of jaw motion is adultlike earlier than control of the upper and lower lip; and (d) if control of spatial and temporal aspects of articulatory movement co-develop in adolescence. Participants were 12-, 14-, and 16-year-olds, and young adults (mean age 21.2 years), with 15 males and 15 females per group. A measure reflecting spatiotemporal consistency in trajectory formation for repeated productions of a phrase was calculated for the upper lip, lower lip, and jaw movements. Overall trajectory variability was higher for adolescents compared to young adults. Jaw trajectories were less variable than upper lip or lower lip trajectories, but all effectors showed parallel decreases in variability as age increased, suggesting that control of jaw movement does not reach adult performance before control of the lips. Separate temporal and spatial measures revealed that adolescents had significantly longer movement durations, lower velocities, smaller displacements, and greater variability on these measures than young adults. There were no sex differences on any measure examined, suggesting that peripheral growth factors do not account for this protracted developmental time course. These results provide initial evidence of significant changes in speech motor control processes during adolescence.

Acknowledgment
This paper is based on a thesis submitted by the first author in partial fulfillment of the requirements for the degree of Master of Science in the Department of Audiology and Speech Sciences at Purdue University and was supported by grant DC02527 from the National Institute on Deafness and Other Communication Disorders.
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