The role of working memory in the comprehension of syntactically complex sentences in children with and without developmental language disorder: a literature review

Working memory (WΜ) components are investigated as correlates of complex sentence comprehension (cSC) in children, under the consideration of WM as a cognitive system of limited capacity. The present study aims to investigate the relationship between WM components and cSC in children of typical language development (TLD) as well as in children with Developmental Language Disorder (DLD), by systematically reviewing relevant studies. First, different tasks that are used to assess three distinct WM components are presented and task purity considerations on each of them are taken into account. Second, syntactically complex sentence types that are considered to constrain the already limited resources of WM are presented. Then, the systematic methods of the PRISMA-P protocol are followed. Based on them, six databases were thoroughly searched. After an initial screening stage and a final evaluation stage, twenty-eight studies were found to meet the inclusion criteria. Narrative synthesis was performed on the included studies. In TLD children, results on the role of verbal short-term memory (vST) and verbal working memory (vWM) in cSC are inconclusive, either supporting or questioning the capacity-limit approach. In DLD children, verbal working memory (vWM) has an important effect on cSC, rather than verbal short-term memory (vSTM). This suggests that a processing-execution component is important in DLD children’s cSC. For both children groups, a component serving as an interface between vSTM/vWM and long-term memory (vSTM/vWM-LTM) seems to play an important role; however, it is greatly understudied. Based on the results, future research directions and educational implications are suggested.