Considerations for using the Wisconsin Card Sorting Test to assess cognitive flexibility.

The Wisconsin Card Sorting Test (WCST) is a popular neurocognitive task used to assess cognitive flexibility, and aspects of executive functioning more broadly, in research and clinical practice. Despite its widespread use and the development of an updated WCST manual in 1993, confusion remains in the literature about how to score the WCST, and importantly, how to interpret the outcome variables as indicators of cognitive flexibility. This critical review provides an overview of the changes in the WCST, how existing scoring methods of the task differ, the key terminology and how these relate to the assessment of cognitive flexibility, and issues with the use of the WCST across the literature. In particular, this review focuses on the confusion between the terms 'perseverative responses' and 'perseverative errors' and the inconsistent scoring of these variables. To our knowledge, this critical review is the first of its kind to focus on the inherent issues surrounding the WCST when used as an assessment of cognitive flexibility. We provide recommendations to overcome these and other issues when using the WCST in future research and clinical practice.