Modified Card Sorting Test (MCST)

Background

The Modified Card Sorting Test (MCST) was introduced in 1976 by Hazel E Nelson at The National Hospital for Nervous Diseases in London. The test is shoter, easier variation of the classic Wisconsin Card Sorting Test (WCST) designed for patients who might be overly stressed by the original procedure.

The task was first used to study patients with brain leisons by Brenda Milner in 1963. The first computerized version was created by Heaton, Curtiss, and Tuttle (1993).

Task Procedure

The participant is presented cards drawn one at a time from a deck of 48 cards. The cards depict symbols that vary in shape, color, and quantity.

Shapes - cross, triangle, star, or circle Colors - red, blue, green, or yellow Quantities - one, two, three, or four

The participant must guess the sorting rule by selecting one four reference cards that match the target card based on color, shape, or quantity of symbols. After each sort, a feedback message indicates whether the sort was correct or incorrect, enabling the participant to deduce the rule. After 6 consecutive correct responses, the sorting rule changes. The participant is notified of the rule change and discover the new rule through trial and error.

The key differences from the original procedure are:

• Response cards sharing more than one attribute with the stimulus card were removed, leaving 48 rather than 64 cards in the deck.
• The first rule is determined by whichever category the respondent chooses first.
• The number of consecutive correct responses before a rule change was reduced from 10 to 6.
• Respondents are notified when the rule is changing.
• The test ends when the three categories are completed twice, or when all 48 response cards have been used.
• Perseverative errors are scored based on matching the preceding response rather than category.

What it Measures

The MCST is not diagnostic of any single condition, but rather a general assessment of frontal lobe function and prefrontal cortex integrity.

Psychological domains

• Executive Functioning
• Abstract reasoning: Identify and apply abstract categories
• Learning: Discover changing sorting rules through trial and error
• Cognitive Flexibility: Shift to a new rule when the previous rule no longer applies
• Perseveration: Failure to shift to a new rule despite error feedback
• Working Memory: Track previous rules and feedback while formulating hypotheses

Main Performance Metrics

• Perseverative Errors: Difficulty disengaging from the old rule (executive dysfunction)
• Categories Completed: Number of successfully discovered and applied rules
• Failure to Maintain Set: Forgetting a rule after discovering it (attentional problems, impulsivity)
• Total Errors: General efficiency
• Learning To Learn: Faster discovery of new rules over the course of the test

Psychiatric Conditions

MCST Performance tends to be impaired in patients with the following conditions.

• Schizophrenia
• Traumatic Brain Injury (TBI)
• Parkinson’s Disease
• Eating Disorders
• Obsessive-Compulsive Disorder (OCD)
• Dementia
• Attention Deficit Hyperactivity Disorder (ADHD)
• Autism Spectrum Disorder