Wisconsin card sort

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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.

1 Method
2 Clinical use
3 Use in research
4 Reference
5 External links

[edit] Method

Initially, a number of stimulus cards are presented to the participant. He or she is then given a stack of additional cards and asked to match each one to one of the stimulus cards, thereby forming separate piles of cards for each. The participant is not told how to match the cards; 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.^[1] Since the early 1990s, however, computerized versions of the task have been available, the most recent version being the windows-compatible version 4.0.^[2] 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 the following results:

Number of categories achieved
Number of trials
Number of errors
Number of perseverative errors
Percentage perseverative errors

[edit] Clinical use

Clinically, the test is widely used by psychiatrists, neurologists and neuropsychologists in patients with acquired brain injury, neurodegenerative disease, or mental illness such as schizophrenia. 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.^[3] Having achieved the first category they often continue to sort the cards according to the first rule long after that rule has been superseded. A recent factor analysis of the WCST has shown these perseverative errors to be the most useful outcome measure in assessing caseness.^[4] A more sophisticated description of deficits of this type is "executive dysfunction".

[edit] Use in research

The WCST has been used in neuroimaging paradigms such as PET and MRI. As predicted by the acquired brain injury literature, completing the task involves activation primarily of the dorsolateral prefrontal cortex.^[5]^[6] The test's use in neurodegenerative diseases such as motor neurone disease and multiple sclerosis 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.

The test is also widely used in research into schizophrenia e.g.^[7]^[8]

[edit] Reference

^ E. A. Berg. (1948). A simple objective technique for measuring flexibility in thinking J. Gen. Psychol. 39: 15-22.
^ Psychological Assessment Resources. Computerised Wisconsin Card Sort Task Version 4 (WCST). Psychological Assessment Resources; 2003.
^ Milner B. Effect of Different Brain Lesions on Card Sorting. Archives of Neurology 1963; 9: 90-100.
^ Greve KW, Stickle TR, Love J, Bianchini KJ, Stanford MS. Latent structure of the Wisconsin Card Sorting Test: a confirmatory factor analytic study. Archives of Clinical Neuropsychology 2005; 20: 355-364.
^ Berman KF, Ostrem JL, Randolph C et al. Physiological activation of a cortical network during performance of the Wisconsin Card Sorting Test: a positron emission tomography study. Neuropsychologia 1995; 33: 1027-1046.
^ Cabeza R, Nyberg L. Imaging cognition II: An empirical review of 275 PET and fMRI studies. J Cogn Neurosci 2000; 12: 1-47.
^ Cannon TD, Glahn DC, Kim J, Van Erp TG, Karlsgodt K, Cohen MS, Nuechterlein KH, Bava S, Shirinyan D., Dorsolateral Prefrontal Cortex Activity During Maintenance and Manipulation of Information in Working Memory in Patients With Schizophrenia, Arch Gen Psychiatry 2005;62:1071-1080.
^ 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. 2006 Jan 26;6:3.