Sex Differences On The Impact Validity Indices At Baseline

Abstract Objective In the context of sports-related concussion (SRC) evaluations, some athletes have been known to “sandbag” baseline testing in order to improve chances of return-to-play post-concussion. To circumvent this problem, the ImPACT, a widely used computerized program in SRC evaluations, contains five embedded validity indices (VIs). Building on nascent research demonstrating the ImPACT VIs’ validity in detecting sandbagging, this exploratory study seeks to identify the distinguishing characteristics of those who sandbag. With this in mind, the present study aimed to examine sex differences in performance on the ImPACT VIs at baseline. Method Participants included 1,254 college students (70% male; 77.3% Caucasian) divided into two groups: males (n = 881) and females (n = 373). All participants completed the ImPACT individually. Primary outcomes of interest included the five ImPACT VIs: Impulse Control Composite, X’s and O’s Total Incorrect, Word Memory Learning Percent Correct, Design Memory Learning Percent Correct, and Three Letters Total Letters Correct. Results Independent samples t-tests revealed significant sex differences on Word Memory Learning Percent Correct and Design Memory Learning Percent Correct (p = .007 to .009; d = 0.16), with males performing worse. The three remaining VI’s were not significantly different between groups (p = .080 to .331, d = −0.08 to 0.06). Conclusion Significant sex differences were found on two of the five ImPACT VIs; however, effect sizes were small. Our results suggest that while sex may play a role in sandbagging, other factors are also likely at play. Identifying a subgroup of males and females with poor performance on these validity indices and exploring their characteristics will help to further clarify these findings.