15 Executive Functions

Rehabilitation for people recovering from stroke focuses on restoring the ability to perform the activities required for living independently. For the most part, clinical neurorehabilitation concentrates on interventions designed to treat motor and language impairments. The difficulties an individual may experience from impairments of high-level cognitive functions, typically labeled executive functions) are not always apparent in clinical settings and are often not the focus of therapy. Part of the reason executive functions may be somewhat overlooked in clinical care is that executive functions have been defined in a number of contexts ranging from experimental cognitive studies to neuropsychological assessments. There is no commonly agreed set of cognitive abilities or neural structures uniquely identified as supporting executive functions. Rebecca Elliot (2003) provides a good summary of why the term executive functions is not a unitary concept. In this chapter, we will attempt to integrate across the behavioral, cognitive, and neural descriptions of executive functions in an effort to identify gaps in our knowledge that, if filled, could be helpful in translating research findings into clinical practice. In general, cognitive psychologists describe executive functions as (i) the ability to exhibit flexible adaptive behavior, (ii) the use of appropriate problem-solving strategies as required for maintaining and updating goals, (iii) the capacity to monitor the consequences of actions, and (iv) the ability to use prior knowledge to correctly interpret future events (Miyake & Shah, 1999). Cognitively, the term executive functions also derives in part from the idea of top-down control by a central executive, as proposed in models of working memory (Baddeley, 2001) or of attentional control (Posner & Petersen, 1990). From