Brain, Biology and Behavior, Center for


Date of this Version


Document Type



Published in Archives of Clinical Neuropsychology 32 (2017), pp 259-266.

doi 10.1093/arclin/acw108

PMID: 28431031


Copyright © 2016 Kathryn L. Higgins, Robert L. Denney, & Arthur Maerlender. Published by Oxford University Press. Used by permission.


The Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) is a computerized neuropsychological test battery commonly used to assess cognitive functioning after a concussion. It is recommended that application of ImPACT utilizes a baseline administration so athletes have an individualized baseline with which to compare post-injury results should they sustain a concussion. It has been suggested that athletes may provide suboptimal effort, called “sandbagging,” in order to return to their baseline cognitive scores, and thus to play, more quickly. This research examines ImPACT baseline scores when high school athletes were asked to attempt to “sandbag,” and compares those scores with scores obtained when they were asked to give their “best effort.” Fifty-four high school student athlete volunteers participated in the study. In contrast to previous research that just looked at the cut-score invalidity indicators built into ImPACT, this research developed a regression equation to predict sandbagging. A logistic regression equation developed with four variables that demonstrated the largest effect size between “best effort” and “sandbagged” baselines showed a 99.7% classification accuracy for the “best effort” and “sandbag” groups.