PROJECT SUMMARY
Developmental language disorder (DLD) is a highly prevalent impairment in the use and understanding of spoken
and written language that contributes to poor academic outcomes and social-emotional distress. Research
suggests that executive function, a set of skills responsible for controlling and monitoring cognitive resources, is
also impaired in children with DLD. However, executive function task performance is often facilitated by verbal
mediation, or the use of language through internal self-talk to guide behavior. Given evidence that verbal
mediation is limited in children with DLD, it is difficult to discern whether poor performance on executive function
tasks is due to ineffective verbal mediation, weak executive function, or both. The presence of co-occurring
deficits can obscure assessment results and lead to the implementation of ineffective interventions. The long-
term goal of this work is to improve assessment and intervention for children with DLD by addressing the critical
gap in knowledge about the relations between language and executive function skills. The objective of this project
is to dissociate the effects of verbal mediation and executive function on a shifting task in school-aged children
with DLD and typical development (TD). Shifting is the ability to alternate between operations or mental sets,
and it is critical for planning and problem solving in an academic environment. Aim #1 will examine the effect of
verbal mediation on shifting task performance using behavioral measures of switch cost, or the slowing of
response following a shift cue, under conditions that allow or prevent the use of verbal mediation. We hypothesize
that when verbal mediation is prevented, switch costs will increase for children with TD and stay the same or
decrease for children with DLD. This pattern would indicate that ineffective verbal mediation is contributing to
poor shifting task performance in children with DLD. Aim #2 will isolate the effect of executive function on shifting
task performance using temporally sensitive event-related potentials (ERPs) extracted from
electroencephalography (EEG) recorded from the scalp. The project will capitalize on a well-studied ERP marker
of shift detection, the cue-P3. We predict that children with DLD will show increased activation of the executive
system reflected in an equally large brain response (i.e., large amplitude of the cue-P3) when shifting is needed
and when it is not. This pattern would be consistent with previous findings in individuals with a weak executive
control system. The proposed project will provide the PI with training in using EEG methodology, analyzing ERP
data, establishing a productive and independent line of research, and improving grantsmanship and leadership
skills. The proposed research and training activities will take place in an exceptional scientific environment with
a highly accomplished mentorship team. Findings from the proposed work will have a positive impact on clinical
assessment by encouraging systematic appraisal of how verbal mediation affects commonly used tests of
executive function. The outcomes of this study will also impact future research on interventions targeting verbal
mediation strategies for children with DLD and executive function challenges.
