ImPACT and performance validity: Examination of standard and experimental validity indicators

Journal of the International Neuropsychological Society. 2018 Nov;

24(s1):53.

Peterson, J., Bolton, C., Lowe, J., Barnhart, D., Kibble, C., Pyykkonen, B. and Kutnar, K..

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Abstract:

Objective: Performance validity indicators are embedded in the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery, but only two studies to date have investigated their effective- ness at identifying intentionally poor performance. The present study evaluated the ImPACT’s standard validity indicators, examined experimental validity indicators described in the literature, and extended previous research by applying these indicators to the same sample to allow comparisons. Participants and Methods: 48 undergraduates completed the ImPACT in a simulation design that included full-effort, uncoached, and coached groups. Uncoached and coached participants were both instructed to complete the measures as if they were concussed so as to artificially deflate their baseline scores, but coached participants were warned that the test could recognize individuals exaggerating poor performance. Results: Chi square analyses demonstrated that all indicators identified participants intentionally performing poorly at rates better than chance. The ImPACT’s five standard validity indicators identified 65.6% of the participants who were instructed to perform poorly. This rate is consistent with previous findings. Both the experimental Word Memory Correct Distractors score (sensitivity = .97, specificity = .94) and a combination of nine indices (sensitivity = .84, specificity = 1.00) were more effective than the five standard validity indicators at identifying participants who were instructed to perform poorly. Conclusions: Either including four additional indicators along with the ImPACT’s current five indicators or using one of the experimental indicators, the Word Memory Correct Distractors score, could improve the ImPACT’s ability to identify invalid performance.

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