Computational Neural Modeling of Speech Motor Control in Childhood Apraxia of Speech (CAS) PurposeChildhood apraxia of speech (CAS) has been associated with a wide variety of diagnostic descriptions and has been shown to involve different symptoms during successive stages of development. In the present study, the authors attempted to associate the symptoms of CAS in a particular developmental stage with particular information-processing deficits ... Article
Article  |   December 01, 2009
Computational Neural Modeling of Speech Motor Control in Childhood Apraxia of Speech (CAS)
 
Author Affiliations & Notes
  • Hayo Terband
    Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
  • Ben Maassen
    Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
  • Frank H. Guenther
    Boston University, Boston, MA; Harvard University, Cambridge, MA; and Massachusetts Institute of Technology, Cambridge, MA
  • Jonathan Brumberg
    Boston University
  • Contact author: Hayo Terband, Medical Psychology/Pediatric Neurology Centre/ENT, Radboud University Nijmegen Medical Centre, P.O. Box 9101, Nijmegen, 6500HB, the Netherlands. E-mail: h.terband@kno.umcn.nl.
  • Ben Maassen is now also at the University of Groningen and University Medical Centre Groningen, Groningen, the Netherlands.
    Ben Maassen is now also at the University of Groningen and University Medical Centre Groningen, Groningen, the Netherlands.×
Article Information
Speech, Voice & Prosodic Disorders / Apraxia of Speech & Childhood Apraxia of Speech / Speech, Voice & Prosody / Speech
Article   |   December 01, 2009
Computational Neural Modeling of Speech Motor Control in Childhood Apraxia of Speech (CAS)
Journal of Speech, Language, and Hearing Research, December 2009, Vol. 52, 1595-1609. doi:10.1044/1092-4388(2009/07-0283)
History: Received December 22, 2007 , Revised October 11, 2008 , Accepted February 9, 2009
 
Journal of Speech, Language, and Hearing Research, December 2009, Vol. 52, 1595-1609. doi:10.1044/1092-4388(2009/07-0283)
History: Received December 22, 2007; Revised October 11, 2008; Accepted February 9, 2009
Web of Science® Times Cited: 35

PurposeChildhood apraxia of speech (CAS) has been associated with a wide variety of diagnostic descriptions and has been shown to involve different symptoms during successive stages of development. In the present study, the authors attempted to associate the symptoms of CAS in a particular developmental stage with particular information-processing deficits by using computational modeling with the Directions Into Velocities of Articulators (DIVA) model. The hypothesis was that the speech production system in CAS suffers from poor feed-forward control and, consequently, an increased reliance on the feedback control subsystem.

MethodIn a series of computer simulations, the authors systematically varied the ratio between feed-forward and feedback control during production attempts in the acquisition of feed-forward motor commands. The simulations were evaluated acoustically on 4 selected key symptoms of CAS.

ResultsResults showed that increasing the reliance on feedback control causes increased severity of these 4 symptoms of CAS: deviant coarticulation, speech sound distortion, searching articulation, and increased variability.

ConclusionsThe findings support the idea that the key symptoms found in CAS could result from an increased reliance on feedback control due to poor feed-forward commands. Two possible root causes of degraded feed-forward control in CAS are discussed: reduced somatosensory information and increased levels of neural noise.

Acknowledgment
This study was funded by the Netherlands Organization for Scientific Research (NWO) and in part by National Institutes of Health Grant R01 DC02852 and Center of Excellence in Learning, Science, and Technology (CELEST), a National Science Foundation Science of Learning Center (Grant NSF SBE-0354378).
Order a Subscription
Pay Per View
Entire Journal of Speech, Language, and Hearing Research content & archive
24-hour access
This Article
24-hour access