Wisconsin Card Sorting Test
The Wisconsin Card Sorting Test (WCST) is a neuropsychological test of "set-shifting", i.e. the ability to display flexibility in the face of changing schedules of reinforcement. The WCST was written by David A. Grant and Esta A. Berg. The Professional Manual for the WCST was written by Robert K. Heaton, Gordon J. Chelune, Jack L. Talley, Gary G. Kay, and Glenn Curtiss.
Initially, a number of stimulus cards are presented to the participant. The participant is told to match the cards, but not how to match; however, he or she is told whether a particular match is right or wrong. The original WCST used paper cards and was carried out with the experimenter on one side of the desk facing the participant on the other. Since the early 1990s, however, computerized versions of the task have been available, the most recent version being the Microsoft Windows-compatible version 4.0. The latter has the advantage of automatically scoring the test, which was quite complex in the manual version. The test takes approximately 12–20 minutes to carry out and generates a number of psychometric scores, including numbers, percentages, and percentiles of: categories achieved, trials, errors, and perseverative errors.
 Clinical use
Clinically, the test is widely used by neuropsychologists, clinical psychologists, neurologists and psychiatrists in patients with acquired brain injury, neurodegenerative disease, or mental illness such as schizophrenia. It has been considered a measure of executive function because of its reported sensitivity to frontal lobe dysfunction. As such, the WCST allows the clinician to assess the following "frontal" lobe functions: strategic planning, organized searching, utilizing environmental feedback to shift cognitive sets, directing behavior toward achieving a goal, and modulating impulsive responding. The test can be administered to those from 6.5 years to 89 years of age.
Although successful completion of the test relies upon a number of intact cognitive functions including attention, working memory, and visual processing, it is loosely termed a "frontal lobe" test on the basis that patients with any sort of frontal lobe lesion generally do poorly at the test. In particular, patients with lesions of the dorsolateral frontal lobe make a higher number of perseverative errors than control participants. A recent factor analysis of the WCST has shown these perseverative errors to be the most useful outcome measure in assessing cases. A more sophisticated description of deficits of this type is "executive dysfunction".
 Use in research
The WCST has been used in neuroimaging paradigms such as PET and fMRI. As predicted by the acquired brain injury literature, early PET studies have shown the task involves significant activation of the dorsolateral prefrontal cortex. However, more recent fMRI studies have shown that the ventrolateral prefrontal cortex (Konishi et al., 1998, Nature Neuroscience) together with the caudate nucleus (Monchi et al., 2001, J. Neuroscience) may be the regions most important for the set-shifting process required in the WCST. These regions are also associated with working memory functions (Frank et al., 2001). The test's use in neurodegenerative diseases such as motor neurone disease has identified at least a subgroup of these patients for whom there is some subtle degree of cognitive dysfunction, in contrast to the traditional view that these were pure disorders of the motor system.
 Legal ownership of trademark
The trademark "Wisconsin Card Sorting Test" was registered in 2000 with the United States Patent and Trademark Office (Reg. #2320931, Ser # 75-588988) by Wells Print and Digital Services of Madison, Wisconsin. Although filed in 1998, the trademark application states the mark has been in use in commerce since at least 1970. The trademark covers "psychological testing materials, namely printed tests, printed cards, and printed instruction manuals in the field of psychological evaluation." This trademark does not cover the computer implementation of the test, distributed by Psychological Assessment Resources, Inc., sometimes referred to as simply WCST.
- Monchi, O., Petrides, M. Petre, V., Worsley, K., & Dagher, A. (2001). Wisconsin card sorting revisited: Distinct neural circuits participating in different stages of the task identified by event-related functional magnetic resonance imaging. The Journal of Neuroscience, 21(19), 7733-7741.
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- Psychological Assessment Resources. Computerised Wisconsin Card Sort Task Version 4 (WCST). Psychological Assessment Resources; 2003.
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- Rossi A, Daneluzzo E, Tomassini A, Struglia F, Cavallaro R, Smeraldi E, Stratta P., The effect of verbalization strategy on Wisconsin Card Sorting Test performance in schizophrenic patients receiving classical or atypical antipsychotics. BMC Psychiatry. 1290 Jan 26;6:3.