Verbal Mediation During Shifting in School-Aged Children With Developmental Language Disorder

Children with developmental language disorder (DLD) often exhibit deficits in executive function. These deficits may be linked to less effective verbal mediation or the use of self-directed language to guide task performance. This study examined the role of verbal mediation during an executive shifting task.

Twenty-seven children aged 8-12 years (15 with DLD, 12 with typical development [TD]) completed a cued local-global task with verbal mediation (baseline) and without (articulatory suppression). Shifting performance was measured as accuracy and reaction time. Trial-type contrasts for mixing costs (general task demands) and switching costs (trial-level shifting) were examined. Analyses controlled for age and selective attention.

Children with DLD responded more slowly than their peers with TD but achieved comparable accuracy. All children were slower and less accurate during articulatory suppression compared to baseline. A significant three-way interaction for accuracy indicated that mixing costs were larger for children with DLD than TD at baseline, but they were the same under articulatory suppression. Two-way interactions for reaction time indicated that mixing costs were larger in the DLD group than the TD group and larger during articulatory suppression than baseline.

The detrimental effect of articulatory suppression was greater for children with TD than children with DLD, which suggests that language ability contributed to executive function task performance. Verbal mediation may play a larger role in sustaining task goals than in making trial-level switching decisions during shifting tasks. There is a need to further explore verbal mediation mechanisms contributing to executive function in DLD.