Visuo-spatial processing and executive functions in children with specific language impairment.

BACKGROUND Individual differences in complex working memory tasks reflect simultaneous processing, executive functions, and attention control. Children with specific language impairment (SLI) show a deficit in verbal working memory tasks that involve simultaneous processing of information. AIMS The purpose of the study was to examine executive functions and visuospatial processing and working memory in children with SLI and in their typically developing peers (TLD). Experiment 1 included 40 children with SLI (age = 5; 3-6;10) and 40 children with TLD (age = 5; 3-6;7); Experiment 2 included 25 children with SLI (age = 8;2-11; 2) and 25 children with TLD (age = 8; 3-11; 0). It was examined whether the difficulties that children with SLI show in verbal working memory tasks are also present in visuo-spatial working memory. METHODS & PROCEDURES In Experiment 1, children's performance was measured with three visuo-spatial processing tasks: space visualization, position in space, and design copying. The stimuli in Experiment 2 were two widely used neuropsychological tests: the Wisconsin Card Sorting Test-64 (WCST-64) and the Tower of London test (TOL). OUTCOMES & RESULTS In Experiment 1, children with SLI performed more poorly than their age-matched peers in all visuo-spatial working memory tasks. There was a subgroup within the SLI group that included children whose parents and teachers reported a weakness in the child's attention control. These children showed particular difficulties in the tasks of Experiment 1. The results support Engle's attention control theory: individuals need good attention control to perform well in visuo-spatial working memory tasks. In Experiment 2, the children with SLI produced more perseverative errors and more rule violations than their peers. CONCLUSIONS Executive functions have a great impact on SLI children's working memory performance, regardless of domain. Tasks that require an increased amount of attention control and executive functions are more difficult for the children with SLI than for their peers. Most children with SLI scored either below average or in the low average range on the neuropsychological tests that measured executive functions.