2018 Sat Poster 6478

Saturday, November 3, 2018 | Poster Session II, Metcalf Small | 3:15pm

Deviant vocabulary development in children with Autism Spectrum Disorder
E. Jimenez, E. Haebig, T. Hills

Children diagnosed with autism spectrum disorder (ASD) have core impairments in social communication and have restricted interests and repetitive behaviors. Additionally, the majority of young children with ASD have early language delays. Although these early delays are well- documented, it remains unclear whether language skills are simply delayed or if they are deviant. That is, do early language profiles of children with ASD correspond to the dimensional account or the distinct category account of language (Elli Weismer et al., 2011)? The current study aimed to expand on previous studies (e.g., Charman et al., 2003; Luyster, Lopez, & Lord, 2007; Rescorla & Safyer, 2012) to provide a large-scale comparison of early language profiles between typically developing (TD) toddlers and young children with ASD. Specifically, we sought to examine the composition of word classes (i.e., nouns, predicates, and closed class words) and semantic categories (i.e., animals, toys, sound effects and animal sounds) in the early TD and ASD language profiles.

To investigate these aims, we examined early expressive vocabularies using data collected from the MacArthur-Bates Communicative Development Inventory (CDI; Fenson et al., 2006), obtained from the National Database for Autism Research (Payakachat, Tilford, & Ungar, 2016) and the Wordbank repository (Frank et al., 2016). The current study included 250 children with ASD (mean expressive vocabulary: 209.1, range: 1-680; mean age: 45 months, range: 11-173) and 7,707 TD children (mean expressive vocabulary: 200.05, range: 1-680; mean age: 20.02 months, range: 8-30). For each child, we computed the percentage of words that each group of children produced for each word class (i.e., nouns, predicates, and closed class words). Additionally, we computed the percentage of words within each child vocabulary across 3 CDI categories (sound effects and animal sounds, animals, and toys), which were based on significant findings presented by Charman and colleagues (2003).

To address our research questions, we conducted a series of linear regression analyses with the following independent variables: group, vocabulary size, and group x vocabulary size. Results revealed that children with ASD produced a smaller percentage of nouns, and that the percentage of nouns in a vocabulary decreased across all children as they learned more words, but that this reduction was less steep in the ASD group. When examining predicates, we found that children with ASD produced a significantly higher percentage of predicates. Also, as vocabulary size increased, the percentage of predicates increased; however, the slope was less steep for children with ASD. Lastly, children with ASD produced a significantly higher percentage of closed class words and the trajectory of growth of the percentage of closed class words differed between groups. Figure 1 depicts the word type trajectories. When addressing our research question about word categories, differences were only found for the sound effects and animal sounds category. Children with ASD produced a significantly greater percentage, but the trajectory of growth differed between the groups. The current findings lend support to the distinct category account of language development in children with ASD.

References

Charman, T., Drew, A., Baird, C., & Baird, G. (2003). Measuring early language development in preschool children with autism spectrum disorder using the MacArthur Communicative Development Inventory (Infant Form). Journal of Child Language, 30(1), 213-236.

Ellis Weismer, S., Gernsbacher, M., Stronach, S., Karasinski, C., Eernisse, E., Venker, C. E., & Sindberg, (2011). Lexical and grammatical skills in toddlers on the autism spectrum compared to late talking toddlers. Journal of Autism and Developmental Disorders, 41(8), 1065-1075.

Fenson, L., Marchman, V., Thal, D., Dale, P., Reznick, J.S., & Bates, E. (2007). MacArthur-Bates communicative development inventories: Users guide and technical manual, (2 nd edn.). Baltimore, MD: Brookes Publishing.

Frank, M. C., Braginsky, M., Yurovsky, D., & Marchman, V. A. (2017). Wordbank: An open repository for developmental vocabulary data. Journal of Child Language, 44(3), 677-694.

Luyster, R., Lopez, K., & Lord, C. (2007). Characterizing communicative development in children referred for autism spectrum disorders using the MacArthur-Bates Communicative Development Inventory (CDI). Journal of Child Language, 34(3), 623-654.

Payakachat, N., Tilford, J. M., & Ungar, W. J. (2016). National Database for Autism Research (NDAR): Big data opportunities for health services research and health technology assessment. PharmacoEconomics, 34(2), 127-138.

Rescorla, L., & Safyer, P. (2013). Lexical composition in children with autism spectrum disorder (ASD). Journal of Child Language, 40(1), 47-68.