ABSTRACT
Assessment of executive function has historically been confined to laboratory-based performance tests. While such tests offer the advantages of strong internal validity, control over extraneous variables, and potential to fractionate and examine components of executive function separately such as planning versus working memory, they are necessarily limited in ecological validity, or predictive value of functioning in the everyday environment. Fundamentally, executive functions are necessary for organization of goal-directed behavior in this everyday, ‘‘real world,’’ environment. Thus, in addition to assessing these functions with clinical performance measures, it is essential to also capture actual behavioral manifestation of executive function or dysfunction. This chapter focuses on measurement of executive function through assessment of individuals’ behavior in their everyday environment. First, the concept of ecological validity is discussed in relationship to assessment of executive function. This is followed by descriptions of fivemeasures that capture individuals’ executive functioning via their everyday behavior. We review the Dysexecutive Questionnaire (DEX) (Wilson, Alderman, Burgess, Emslie, & Evans, 1996), Frontal Behavior Inventory (Kertesz, Davidson, & Fox, 1997), Behavior Rating Inventory of Executive Function (BRIEF) (Gioia, Isquith, Guy, & Kenworthy, 2000), Frontal Systems Behavior Scale (Grace & Malloy, 2001), and the Executive Function Index (EFI) (Spinella, 2005). As articulated in previous chapters, the term ‘‘executive function’’ is an umbrella
construct for a collection of interrelated functions that are responsible for purposeful, goal-directed, and problem-solving behavior. The executive functions may be defined as the control or self-regulatory functions that organize and direct all cognitive
activity, emotional response, and overt behavior. We view executive function as a broad umbrella term within which a set of interrelated subdomains can be defined that manifest behaviorally. Although authors vary in which functions are viewed as executive function domains, they typically include: initiation of goal-directed behavior, inhibition of competing actions or stimuli, planning and selection of relevant task goals, organization of behavior to solve complex problems, flexible shifting of problem-solving strategies when necessary, and monitoring and evaluation of problem-solving behavior. In support of these behaviors, workingmemory capacity plays a fundamental role in holding information actively ‘‘on-line’’ in the service of problem solving (Pennington, Bennetto, McAleer, & Roberts, 1996). Importantly, the executive functions are not exclusive to cognition; emotional control is also relevant to effective problem-solving activity and should be considered in any definition. Deficits in various subdomains of the executive functions are central character-
istics of many developmental and acquired neurological disorders across the life span, yet their measurement can be complex and challenging. Given the central importance of the executive functions to the direction and control of dynamic ‘‘real world’’ behavior, reliance on clinic-based test performance measures potentially can yield a limited, incomplete assessment (Gioia & Isquith, 2004; Silver, 2000). While performance tests attempt to tap executive functions in explicit and specific ways, multiple confounds can limit their ecological validity and generalizability. Burgess (1997) argues that neuropsychological tests alone are inadequate for assessing executive function because they artificially and ambiguously fractionate an integrated system. Performance-based measures tap individual components of the executive function system over a short time frame and not the integrated, multidimensional, relativistic, priority-based decision making that is often demanded in real-world situations (Goldberg & Podell, 2000; Shallice & Burgess, 1991). The structured and interactive nature of the typical assessment situation may
reduce demands on the executive functions, and thereby reduce the opportunities to observe critical processes associated with the executive functions (Bernstein & Waber, 1990). That is, in many testing situations, the examiner provides the structure, planning, organization and guidance as well as the cueing and monitoring necessary for an individual’s optimal performance. In this manner, executive control is provided by the examiner (Kaplan, 1988; Stuss & Benson, 1986). As a result, individuals with substantial executive dysfunction can often perform adequately on well-structured tests when the examiner is allowed to cue and probe for more information, relieving the individual of the need to be appropriately inhibited, flexible, strategic in planning, and goal directed. Given the challenges of executive function assessment in the laboratory and the
inherent limitations to applicability in the everyday environment, increasing attention is being given to alternative methods of evaluation that offer enhanced ecological validity (Silver, 2000). Assessment methods that reliably tap the individual’s everyday executive problem-solving in natural settings offer a complementary approach to clinical performance-based assessment. The challenge in assessing executive dysfunction is not only to find appropriate performance measures (tests), as Lezak (1995) and others suggest, but also to evaluate the functional, real-world impact of executive dysfunction as expressed in everyday activities. In this chapter,
Executive functions and
we address behavioral assessment of executive functions as a time and cost efficient measurement method that complements traditional performance-based test methodology. We approach this problem from an ecological perspective, examining measures that capture the everyday behavior of the individual. We briefly discuss ecological validity in assessment of executive function, followed by a review of the assessment tools that use everyday behavior as the primary data source.
