Cognitive processing and comprehension in developmental language disorder (Montgomery et al., 2018)

<b>Purpose: </b>We assessed the potential direct and indirect (mediated) influences of 4 cognitive mechanisms we believe are theoretically relevant to canonical and noncanonical sentence comprehension of school-age children with and without developmental language disorder (DLD). <b>Method:</b> One hundred seventeen children with DLD and 117 propensity-matched typically developing (TD) children participated. Comprehension was indexed by children identifying the agent in implausible sentences. Children completed cognitive tasks indexing the latent predictors of fluid reasoning (FLD-R), controlled attention (CATT), complex working memory (cWM), and long-term memory language knowledge (LTM-LK).<b>Results: </b>Structural equation modeling revealed that the best model fit was an indirect model in which cWM mediated the relationship among FLD-R, CATT, LTM-LK, and sentence comprehension. For TD children, comprehension of both sentence types was indirectly influenced by FLD-R (pattern recognition) and LTM-LK (linguistic chunking). For children with DLD, canonical sentence comprehension was indirectly influenced by LTM-LK and CATT, and noncanonical comprehension was indirectly influenced just by CATT.<b>Conclusions: </b>cWM mediates sentence comprehension in children with DLD and TD children. For TD children, comprehension occurs automatically through pattern recognition and linguistic chunking. For children with DLD, comprehension is cognitively effortful. Whereas canonical comprehension occurs through chunking, noncanonical comprehension develops on a word-by-word basis.<br><b>Supplemental Material S1. </b>Description of each cognitive task and reliability information.<br><b>Supplemental Material S2.</b> Summary scores on all cognitive measures for the children with developmental language disorder (DLD) and typically developing (TD) controls, and Cohen’s <i>d</i> (standardized mean difference) between the groups.<br><b>Supplemental Material S3.</b> Pearson correlations among the individual cognitive processing measures in the GEM (Gillam–Evans–Montgomery) model (groups combined). <br>Montgomery, J. W., Evans, J. L., Fargo, J. D., Schwartz, S., &amp; Gillam, R. B. (2018). Structural relationship between cognitive processing and syntactic sentence comprehension in children with and without developmental language disorder. <i>Journal of Speech, Language, and Hearing Research.</i> Advance online publication. https://doi.org/10.1044/2018_JSLHR-L-17-0421<br>