Predicting Lexical Density Growth Rate in Young Children With Autism Spectrum Disorders Purpose The purpose of this longitudinal correlational study was to test whether an environmental variable and 4 child variables predicted growth rate of number of different nonimitative words used (i.e., lexical density). Method Thirty-five young (age range = 21–54 months) children with autism spectrum disorders (ASD) who were ... Research Article
Research Article  |   November 01, 2006
Predicting Lexical Density Growth Rate in Young Children With Autism Spectrum Disorders
 
Author Affiliations & Notes
  • Paul J. Yoder
    Vanderbilt University, Nashville, TN
  • Contact author: Paul Yoder, 230 Appleton Place, Vanderbilt University, Nashville, TN 37203-5701. E-mail: paul.yoder@vanderbilt.edu.
Article Information
Special Populations / Autism Spectrum / Research Articles
Research Article   |   November 01, 2006
Predicting Lexical Density Growth Rate in Young Children With Autism Spectrum Disorders
American Journal of Speech-Language Pathology, November 2006, Vol. 15, 378-388. doi:10.1044/1058-0360(2006/035)
History: Received September 21, 2005 , Accepted July 1, 2006
 
American Journal of Speech-Language Pathology, November 2006, Vol. 15, 378-388. doi:10.1044/1058-0360(2006/035)
History: Received September 21, 2005; Accepted July 1, 2006
Web of Science® Times Cited: 15

Purpose The purpose of this longitudinal correlational study was to test whether an environmental variable and 4 child variables predicted growth rate of number of different nonimitative words used (i.e., lexical density).

Method Thirty-five young (age range = 21–54 months) children with autism spectrum disorders (ASD) who were initially nonverbal or low verbal participated in the study. Lexical density was measured at 3 times: at entry into the study as well as 6 months and 12 months after entry into the study. Growth curve analysis was used to test the associations. The predictive value of the putative predictors in the model was tested after controlling for initial expressive language impairment.

Results Initial frequency of intentional communication and diversity of object play were predictors of lexical density growth above and beyond initial expressive language impairment (both pseudo R2s = .14).

Conclusions Intentional communication and diversity of object play may represent important prelinguistic goals for young children with ASD. These skills not only have been shown to be malleable through treatment, but they also provide a context for linguistic input from others that may facilitate language development.

Acknowledgments
This work was supported by National Institute on Deafness and Other Communication Disorders Grant R01CD03581 and the core grant support to the Vanderbilt University Kennedy Center (National Institute of Child Health and Human Development Grant HD15052). The author extends his heartfelt thanks to the families who entrusted their children to our care. The author is especially grateful to his very competent colleague, Wendy Stone. Her input and support were important to completing this project. Gratitude is offered to the team leaders: Melanie Jarzynka, Melanie Jacobs, and Tom Lamb. Thanks are also given to Lisa Stepp, Melanee Horton, Dawn Garcia, Lauren Radovich, Lindsey Hancock, Monica Smith, Nicolette Bainbridge, and Cornelia Taylor for data collection and coding.
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