Relationship between Executive Function and Language Skills in Youth with Autism Spectrum Disorder

Background: One of the most important skill sets for youth to master is executive functioning (EF). Strong EF skills are related to social competence, academic achievement, and positive life outcomes (Center on the Developing Child, 2011). Many EF processes are dependant upon language which plays an integral part in top-down processes that allow for the regulation of thoughts, feelings and behaviour (Vygotsky, 1978; Zelazo, 2015). For example, consider the critical importance of using self-talk to help calm yourself down when you’re upset instead of yelling and throwing things. Among typically developing (TD) children, language consistently predicts the development of EF (Faja et al., 2016). However, only two studies have examined this relationship in ASD. Joseph et al. (2005) found no relationship between EF and language concluding that perhaps youth with ASD are not using language to support EF. However, Akbar and colleagues (2013) demonstrated that 62% of the variability in working memory ability was explained by language in their sample of youth with ASD. Therefore, more research into the relationship between EF and language in youth with ASD is necessary.

Objectives: We examined relative impact of language ability to predict variability in EF skills across a sample of youth with ASD.

Methods: Twenty-five youth with ASD, aged 6 to 16 years (M=10 yrs) completed a measure of receptive language, Peabody Picture Vocabulary Test-Fourth Edition (PPVT), and a measure of their expressive language skills, Expressive Language Index (ELI) from the Clinical Evaluation of Language Fundamentals- Fifth Edition. Set-shifting, working memory and inhibition were each assessed using subtests from the NIH Toolbox and Weschler Intelligence Scale for Children-5th Edition. Additionally, parents completed the Behaviour Rating Inventory of Executive Function- Second Edition as a measure of participants’ EF-related behaviour.

Results: To examine how well language ability predicted EF, we created regression models of EF using our language measures as predictors. Our first model explained 61.1% of the variance in our working memory task with ELI making the only unique contribution to the variability in scores. In contrast, our second model predicted 36.2% of the variance in inhibition with PPVT-4 making the only unique contribution. Finally, while the third model explained 20.4% of the variance in our set-shifting task, neither ELI nor PPVT made unique contributions. However, language did not predict EF when the parent-reported measure of EF was used in the model.

Conclusions: Our results lend further support to the hypothesis that language ability predicts EF skills for youth with ASD. This suggests that youth with ASD are capable of using language in service of EF processes. While many students with ASD may not have strong EF skills (Demetriou et al., 2017), these findings suggest that they seem to use language in EF process in the same way that TD kids do. More importantly, this work may suggest that parents, clinicians and educators may need to focus on strengthening the language-based strategies used during EF processes to support the development of these skills.