Introduction and objective: Clinical and experimental research with the Wisconsin Card Sorting Test (WCST) has shown inconsistencies which bring into question the specificity of the test as a marker of frontal dysfunction. The aim of the present review is to evaluate the causes and the consequences of those criticisms for the assessment of both prefrontal function and the executive system of attention.
Development: Clinical evidence confirms that, in its present form, the WCST can not discriminate between lesions in frontal and non frontal brain regions. Moreover, functional neuroimaging studies have shown rapid and widespread activation of frontal and non frontal brain regions during WCST performance. On the one hand, these studies strongly suggest that the concept of anatomically 'pure' tasks is deceptive, but they also provide us with evidence that inconsistencies in WCST research might be motivated by problems with the internal validity and reliability of the original test as a measure of attentional set shifting ability. In contrast, recent studies have successfully employed WCST analogues to link precise cognitive processes with anatomically and functionally well defined prefrontal areas.
Conclusions: It is deemed necessary to apply the new technical and methodological developments to generate more valid and reliable neuropsychological tests, that yield a better correspondence between anatomy and function. This will make possible future progress in the clinical assessment of higher brain functions.