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.

Specific Language Impairment is not Specific to Language: the Procedural Deficit Hypothesis

“…Intriguingly, non-word repetition has been found to correlate, across subjects, with performance at several tasks probing grammatical processing: sentence repetition (Bishop et al, 1996; Kamhi and Catts, 1986), past tense and third person singular production tasks (Botting and Conti-Ramsden, 2001), and a test of receptive grammar (Botting and Conti-Ramsden, 2001). Similarly, other measures of working memory abilities have also been found to correlate with performance at sentence comprehension (Montgomery, 2000). These data suggest a common neural basis for working memory and grammar, as predicted by the PDH.…”

“…Working memory impairments. SLI is strongly linked to working memory impairments (Botting and Conti-Ramsden, 2001;Fazio, 1996Fazio, , 1998Gathercole and Baddeley, 1993;Kirchner and Klatzky, 1985;Montgomery, 1995aMontgomery, , 1995bMontgomery, 2000Montgomery, , 2003Sininger et al, 1989;Weismer, 1996). In one study children with SLI took almost four times as long to scan a sequence of items in short-term memory (measured by response speed on a Sternberg task) as compared to control children (Sininger et al, 1989).…”

Differences in the cognitive demands of word order, plural, and subject-verb agreement constructions

“…The other half were asked to remember digits while processing the sentences. Specifically, before each sentence they were presented with an orienting asterisk for 500 msec, followed by a random seven-digit string for language impairment are known to have working memory and/or phonological deficits; similar deficits are exhibited by second-language learners in their second language (Bird et al, 2003;McDonald, 2006;Montgomery, 2000aMontgomery, , 2000b. These processing deficits could contribute to poor plural or agreement performance, whereas SVO word order is relatively well maintained.…”

“…Working memory capacity was measured using a syntax-free size judgment task (Cherry & Park, 1993;Montgomery, 2000aMontgomery, , 2000b, in which participants were given a list of items that they were to give back in the order of physically smallest to physically largest object. For example, if given pig, door, butterfly, participants were to say, "butterfly, pig, door."…”

Specific language impairment as systemic developmental disorders

“…Difficulties in functional working memory are likely to exist as well but the relation to children with SLI performances is unclear (Montgomery, 2000(Montgomery, , , 2003 Procedural memory has been hypothesised to be a cause of grammatical disorders (Ullman & Pierpont, 2005). Long-term memory is known to be deficient in dyslexia (Nicolson & Fawcett, 2000), and it could also play a role in SLI.…”