This study examined the influence of phonological working memory on sentence comprehension in children with specific language impairment (SLI). Fourteen children with SLI and 13 with normal language (NL) participated in two tasks. In the first, a nonsense word repetition task (index of phonological working memory), subjects repeated nonsense words varying in length from one syllable to four. In a sentence comprehension task, subjects listened to sentences under two conditions varying in linguistic redundancy (redundant, nonredundant). On the nonsense word repetition task, between- and within-group analyses revealed that subjects with SLI repeated significantly fewer 3-syllable and 4-syllable nonsense words. On the sentence comprehension task, between- and within-group analyses determined that subjects with SLI comprehended significantly fewer redundant (longer) sentences than nonredundant (shorter) sentences. A positive correlation was found between subjects' performance on the nonsense word repetition and sentence comprehension tasks. Results were interpreted to suggest that children with SLI have diminished phonological working memory capacity and that this capacity deficit compromises their sentence comprehension efforts.

In the past 10 years, important new theoretical insights into the range and nature of WM deficits and relation between these limitations and the language difficulties in SLI have occurred. New, robust diagnostic assessment tools and computerized treatment methods designed to enhance children's WM functioning have also been developed. The assessment, diagnosis, and treatment of the language difficulties in SLI should consider the potential influence of WM.

In this study we examined the influence of verbal working memory on sentence comprehension in children with SLI. Twelve children with SLI, 12 normally developing children matched for age (CA), and 12 children matched for receptive vocabulary (VM) completed two tasks. In the verbal working memory task, children recalled as many real words as possible under three processing load conditions (i.e., no-load condition; single-load condition, where words were recalled according to physical size of word referents; and dual-load condition, where words were recalled by semantic category and physical size of word referents). In the sentence comprehension task, children listened to linguistically nonredundant (shorter) and linguistically redundant (longer) sentences. Results of the memory task showed that the children with SLI recalled fewer words in the dual-load condition than their CA peers, who showed no condition effect. The SLI and VM groups performed similarly overall, but both groups showed poorer recall in the dual-load condition than in the other conditions. On the sentence comprehension task, children with SLI comprehended fewer sentences of both types than the CA children and fewer redundant sentences relative to themselves and to the VM children. Results were interpreted to suggest that children with SLI (a) have less functional verbal working memory capacity (i.e., ability to coordinate both storage and processing functions) than their CA peers and (b) have greater difficulty managing both their working memory abilities and general processing resources than both age peers and younger children when performing a "complex" off-line sentence processing task.

Purpose This study investigated the association of 2 mechanisms of working memory (phonological short-term memory [PSTM], attentional resource capacity/allocation) with the sentence comprehension of school-age children with specific language impairment (SLI) and 2 groups of control children. Method Twenty-four children with SLI, 18 age-matched (CA) children, and 16 language- and memory-matched (LMM) children completed a nonword repetition task (PSTM), the competing language processing task (CLPT; resource capacity/allocation), and a sentence comprehension task comprising complex and simple sentences. Results (1) The SLI group performed worse than the CA group on each memory task; (2) all 3 groups showed comparable simple sentence comprehension, but for complex sentences, the SLI and LMM groups performed worse than the CA group; (3) for the SLI group, (a) CLPT correlated with complex sentence comprehension, and (b) nonword repetition correlated with simple sentence comprehension; (4) for CA children, neither memory variable correlated with either sentence type; and (5) for LMM children, only CLPT correlated with complex sentences. Conclusions Comprehension of both complex and simple grammar by school-age children with SLI is a mentally demanding activity, requiring significant working memory resources.

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.