Vocalization Rate and Consonant Production in Toddlers at High and Low Risk for Autism Background Previous work has documented lower vocalization rate and consonant acquisition delays in toddlers with autism spectrum disorder (ASD). We investigated differences in these variables at 12, 18, and 24 months in toddlers at high and low risk for ASD. Method Vocalization rate and number of different consonants ... Research Article
Research Article  |   April 14, 2017
Vocalization Rate and Consonant Production in Toddlers at High and Low Risk for Autism
 
Author Affiliations & Notes
  • Karen Chenausky
    Boston University, Massachusetts
  • Charles Nelson, III
    Boston Children's Hospital, Massachusetts
  • Helen Tager-Flusberg
    Boston University, Massachusetts
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication. ×
  • Correspondence to Karen Chenausky: kchenaus@bu.edu
  • Editor and Associate Editor: Lisa Goffman
    Editor and Associate Editor: Lisa Goffman×
Article Information
Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   April 14, 2017
Vocalization Rate and Consonant Production in Toddlers at High and Low Risk for Autism
Journal of Speech, Language, and Hearing Research, April 2017, Vol. 60, 865-876. doi:10.1044/2016_JSLHR-S-15-0400
History: Received November 20, 2015 , Revised June 7, 2016 , Accepted October 18, 2016
 
Journal of Speech, Language, and Hearing Research, April 2017, Vol. 60, 865-876. doi:10.1044/2016_JSLHR-S-15-0400
History: Received November 20, 2015; Revised June 7, 2016; Accepted October 18, 2016

Background Previous work has documented lower vocalization rate and consonant acquisition delays in toddlers with autism spectrum disorder (ASD). We investigated differences in these variables at 12, 18, and 24 months in toddlers at high and low risk for ASD.

Method Vocalization rate and number of different consonants were obtained from speech samples from a prospective study of infant siblings of children with ASD. Three groups were compared: 18 toddlers at low risk for ASD (low-risk control), 18 high-risk siblings without ASD (HRA−), and 10 high-risk siblings with ASD (HRA+).

Results All groups' mean language scores were within the normal range. HRA+ toddlers showed consistently lower vocalization rate; vocalization rate did not predict number of different consonants at 12 months for HRA+. HRA−, not HRA+, toddlers had the smallest number of different consonants and produced significantly fewer different consonants than predicted by their vocalization rate at 12 months. Consonant-acquisition trajectories differed between groups, with HRA− showing the greatest increase from 12 to 18 months.

Conclusion Lower vocalization rate was not associated with reduced number of different consonants in these toddlers. Between-groups differences in developmental trajectories are discussed in the context of the social feedback loop and differential ability to benefit from adult feedback between groups.

Acknowledgments
Funding was provided by the National Institute of Health (R21DC08637) to H.T-F., the National Institute on Deafness and Other Communication Disorders (1R01DC010290) to H.T-F. and C.A.N., the Simons Foundation (137186) to C.A.N., the Autism Speaks Pilot Grants Program to H.T-F., and the Autism Science Foundation Mini-Enhancement Grant Program to K.V.C. We thank the Infant Sibling Project staff members, past and present, for their hard work in collecting these data. We are deeply grateful for the effort of the dedicated families who have committed years of their lives to the Infant Sibling Project, making this work possible. Thanks also to Melanie Matthies for suggesting the curve-fitting analysis.
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