Over the course of its history, the field of neuropsychology has shifted its focus to meet the demands of the medical landscape. Before the advent of neuroimaging, neuropsychologists were relied on to determine brain lesion location and to diagnose brain-behavior pathologies. As time progressed, neuroimaging was able to provide faster and more consistent lesion identification and neuropsychology began to adapt its skills and services for other related fields, such as education, law, and rehabilitation. As a result, some neuropsychological methods were adapted to assess broader cognitive functions in a variety of populations and the general public; however, these assessments have been heavily rooted in the field’s diagnostically focused past, which creates limitations in the ecological validity of this approach. Ecological validity can be generally defined as a measure’s ability to predict functional performance or mimic activities of everyday living (i.e., performance at work, driving). For example, batteries of neuropsychological tests and questionnaires have been used to infer level of function and general performance at work or school. These batteries were developed due their statistical associations with different populations, concordance with neurological theories and constructs, and general face validity. However, very few assessments resembled any activity a person would perform in daily life. For many measures, ecological validity was defined by correlating performance with everyday functioning (verdicality; Franzen & Wilhelm, 1996). In contrast, another approach to ecological validity involved designing measures to resemble or mimic an everyday function (verisimilitude; Franzen & Wilhelm, 1996). The major difference between the two approaches determines the primary goal of designing the measure at the onset. It must be decided if the measure will prioritize construct validity at the onset and subsequently infer a link to everyday function, or vice versa. Many researchers interested in predicting functional outcome have relied on verisimilitude, as it more closely resembles “real-world” performance; however, it often comes at a cost of interpretability within the context of current neuropsychological frameworks and models.
Methodological issues and controversies in research on cognitive disorders