Prevalence of Invalid Performance on the ImPACT in Division I Football Players

J Int Neuropsychol Soc. 2011 Mar;


Szabo, A. J., T. Stratton, P. Long, L. Dent, C. Wells and J. Gunstad.



Objective: Many student-athletes are assessed using computerized test batteries due to the ease of administration and relatively complete screen of cognitive functions. The widely-used ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing) describes two types of suspicious assessments: “sand-bagging”, or faking bad with the possible intent of not appearing impaired post-concussion, and invalid responses due to a lack of attention to testing. No study has determined the prevalence of these responses. Participants and Methods: For the current study, baseline measures from a division I collegiate football team were examined to determine the frequency of invalid profiles. Baseline testing was conducted during pre-season practices in group format. A total of 290 baseline assessments were collected over three seasons and some athletes are represented more than once. Average age was 20.3 ± 1.37 years. Results: Analyses revealed that 73.8% of assessments were valid, as 12.1% of assessments suggested invalid responding and 22.1% sandbagging. One measure (i.e. Visual Memory Composite) identified 17% of the profiles as invalid. Approximately 72.9% of assessments were valid prior to education on the importance of concussion and 76.3% after. Conclusions: In summary, although most student-athletes produce valid results on IMPACT testing, the current findings raise concern about valid responding and sand-bagging during baseline assessments. This pattern may complicate interpretation of post-concussion testing and place athletes at risk for subsequent injury. Future studies should develop strategies to improve effort during testing and indices to clarify invalid scores.

Links to full article: