Cognitive persistence: Development and validation of a novel measure from the Wisconsin Card Sorting Test

Abstract

The Wisconsin Card Sorting Test (WCST) has long been used as a neuropsychological assessment of executive function abilities, in particular, cognitive flexibility or "set-shifting". Recent advances in scoring the task have helped to isolate specific WCST performance metrics that index set-shifting abilities and have improved our understanding of how prefrontal and parietal cortex contribute to set-shifting. We present evidence that the ability to overcome task difficulty to achieve a goal, or "cognitive persistence", is another important prefrontal function that is characterized by the WCST and that can be differentiated from efficient set-shifting. This novel measure of cognitive persistence was developed using the WCST-64 in an adult lifespan sample of 230 participants. The measure was validated using individual variation in cingulo-opercular cortex function in a sub-sample of older adults who had completed a challenging speech recognition in noise fMRI task. Specifically, older adults with higher cognitive persistence were more likely to demonstrate word recognition benefit from cingulo-opercular activity. The WCST-derived cognitive persistence measure can be used to disentangle neural processes involved in set-shifting from those involved in persistence.

Keywords: Persistence; Prefrontal cortex; Set-shifting; Speech recognition; Wisconsin Card Sorting Test.

Figure 1

Diagram of two possible efficient shift trial sequences in which the correct sorting rule changed from color to form. ✓: correct response; ✘: incorrect response. Participants can first detect a rule change upon receiving negative feedback for using the previous sorting rule. Following detection of a rule change, participants performing optimally will switch to one of the two remaining rules, which could be the incorrect rule (Efficient Shift Pattern 1) or the correct rule (Efficient Shift Pattern 2). An efficient error occurs when the participant switches to the wrong rule but then switches to and keeps using the right rule (e.g., the “Number” response in Efficient Shift Pattern 1). Both patterns shown in the diagram are expected as part of the optimal performance strategy after the sorting rule changes.

Figure 2

Special cases arising from participant responses that match on multiple dimensions (indicated in bold). C: color response; F: form response; N: number response. Top panel: The multidimensional response shifts the detection of a rule change, and thus the start of a new sequence, by one trial. Middle panel: The multidimensional response is scored as an efficient error, because the participant subsequently switches to the correct rule. Bottom panel: The multidimensional response shifts the opportunity to determine the new sorting rule by one trial, resulting in an efficient error later in the sequence.

Figure 3

Cingulo-opercular ROIs for (A) adaptive-control effects (red) and (B) error-responses (green). Their overlap (yellow) is shown in (C). ROIs were defined from an independent sample of 18 younger adults and warped into study-specific space.

Figure 4

The relationship between number of efficient shifts and accuracy on the WCST. Solid horizontal lines indicate the median for each category of efficient shifts. The dashed line indicates chance accuracy (25%). Individuals who fall above the median (red) have positive accuracy differences and consequently positive persistence values. Individuals who fall below the median (blue) have negative accuracy differences and consequently negative persistence values. For visualization purposes, data have been randomly jittered ±0.1 along the x-axis to reduce overlap. Persistence scores of exactly 0 are plotted in red.

Figure 5

Middle-aged to older adults with higher cognitive persistence demonstrated significantly larger adaptive-control beta estimates in the dACC.