Relation of working memory to off-line and real-time sentence processing in children with specific language impairment

Abstract

In this study we examined the influence of working memory on the off-line and real-time sentence comprehension/processing of children with specific language impairment (SLI). A total of 12 children with SLI, 12 normally developing children matched for chronological age (CA), and 12 children matched for receptive syntax (RS) completed three tasks. In the working memory task, children recalled as many words as possible under three processing load conditions varying in the number of mental operations (i.e., no load, single load, dual load). In the off-line comprehension task, children listened to linguistically nonredundant and redundant sentences. In the real-time sentence processing task, children monitored sentences for the occurrence of a target word appearing at the beginning, middle, or end of a test sentence and pushed a response pad as quickly as possible upon hearing the target. In the memory task, SLI children recalled fewer words in the dual-load condition relative to CA peers, who showed no condition effect. The SLI and RS groups performed similarly overall; however, both groups recalled fewer words in the dual-load condition than in the other conditions. In the off-line task, the SLI group comprehended fewer sentences of both types relative to the CA controls and fewer redundant sentences relative to themselves and to the RS controls. A significant correlation between working memory and sentence comprehension was found for the SLI group and control groups. For the on-line task, between-group analyses revealed that the SLI group yielded an overall slower word recognition reaction time than the CA and RS groups. Working memory and sentence processing were not correlated for any group. Results were interpreted to suggest that SLI children have a more limited functional working memory capacity than their CA peers. Children with SLI also appear to have greater difficulty managing their working memory resources relative to both age peers and younger children when performing a conventional off-line sentence comprehension task but not a real-time sentence processing task.