Nonverbal EF and language in children with DLD (Everaert et al., 2023)
Purpose: Developmental language disorder (DLD) is characterized by persistent and unexplained difficulties in language development. Accumulating evidence shows that children with DLD also present with deficits in other cognitive domains, such as executive functioning (EF). There is an ongoing debate on whether exclusively verbal EF abilities are impaired in children with DLD or whether nonverbal EF is also impaired, and whether these EF impairments are related to their language difficulties. The aims of this study were to (a) compare nonverbal performance of preschoolers with DLD and typically developing (TD) peers, (b) examine how nonverbal EF and language abilities are related, and (c) investigate whether a diagnosis of DLD moderates the relationship between EF and language abilities.
Method: A total of 143 children (nDLD = 65, nTD = 78) participated. All children were between 3 and 6.5 years old and were monolingual Dutch. We assessed nonverbal EF with a visual selective attention task, a visuospatial short-term and working memory task, and a task gauging broad EF abilities. Vocabulary and morphosyntax were each measured with two standardized language tests. We created latent variables for EF, vocabulary, and morphosyntax.
Results: Analyses showed that children with DLD were outperformed by their TD peers on all nonverbal EF tasks. Nonverbal EF abilities were related to morphosyntactic abilities in both groups, whereas a relationship between vocabulary and EF skills was found in the TD group only. These relationships were not significantly moderated by a diagnosis of DLD.
Conclusions: We found evidence for nonverbal EF impairments in preschool children with DLD. Moreover, nonverbal EF and morphosyntactic abilities were significantly related in these children. These findings may have implications for intervention and support the improvement of prognostic accuracy.
Supplemental Material S1. Group comparison on raw and norm scores of each language measure separately.
Supplemental Material S2. Correlations between the latent language factors and the separate EF tasks and the latent EF factor.
Supplemental Material S3. Correlations between the EF tasks.
Supplemental Material S4. Correlations of the latent factors with demographic variables.
Supplemental Material S5. Comparison of demographic variables of children who completed the HTKS and those who did not for both groups.
Supplemental Material S6. Baseline regression models.
Everaert, E., Boerma, T., Selten, I., Gerrits, E., Houben, M., Vorstman, J., & Wijnen, F. (2023). Nonverbal executive functioning in relation to vocabulary and morphosyntax in preschool children with and without developmental language disorder. Journal of Speech, Language, and Hearing Research, 66(10), 3954–3973. https://doi.org/10.1044/2023_JSLHR-22-00732