Research on executive function in a neurodevelopmental context: Application of clinical measures

In pursuit of evidence to support the hypothesis that executive dysfunction (EDF) contributes to the manifestations of learning disabilities, we encounter conceptual and methodological issues. EDF cannot be documented without establishing that there is adequate processing of the information content (linguistic or visuospatial) of the task purported to demand executive function. Because there are no content-free tasks, it is necessary to assess, in pairs or dyads, content-sharing tasks that differ in their executive demands. We give preference to research tasks that readily translate into clinical applications: Referring to the executive function candidate as Task B, we review approaches such as subtracting z scores (Task A minus Task B discrepancy) and deriving residual values of Task B from a normative regression of Task B on Task A. We report greater success in operationalizing EDF within the linguistic content domain than within the visuospatial content domain.