Poor executive functioning in children born very preterm: Using dual-task methodology to untangle alternative theoretical interpretations.

Two alternative theoretical explanations have been proposed for the difficulties with executive functioning observed in children born very preterm (VP; ⩽32 weeks): a general vulnerability (i.e., in attentional and processing capacities), which has a cascading impact on increasingly complex cognitive functions, and a selective vulnerability in executive-level cognitive processes. It is difficult to tease apart this important theoretical distinction because executive functioning tasks are, by default, complex tasks. In the current study, an experimental dual-task design was employed to control for differences in task difficulty in order to isolate executive control. Participants included 50 VP children (mean age=7.29 years) and 39 term peer controls (mean age=7.28 years). The VP group exhibited a greater dual-task cost relative to controls despite experimental control for individual differences in baseline ability on the component single tasks. This group difference also remained under a condition of reduced task difficulty. These results suggest a selective vulnerability in executive-level processes that can be separated from any general vulnerability.