Addressing the ``Replication Crisis'' in Sports Neuropsychology: Validation of the Two-Factor Theory of ImPACT

Abstract

Abstract Purpose The "replication crisis" in psychology and across the broader field of social sciences raises criticism due to a lack of data to show that esoteric research findings can be replicated. The present study replicated and validated the two-factor “memory” and “speed” structure of ImPACT (Schatz & Maerlender, 2013). Methods High school aged athletes (N=18,918, Mean age=15.4, SD=1.2) who completed pre-season baseline ImPACT testing were randomly assigned to one of 5 independent samples of approximately 3,780 athletes. Exploratory factor analyses (FA) for a two-factor solution were conducted with ImPACT composite scores within each of the five groups. Post-Concussion Symptom Scale (PCSS) scores were included, with the expectation they would load on a third, unique factor. Results All five samples met assumptions for FA (KMO Measure of Sampling Adequacy above .600), and all five analyses yielded the same “memory” and “speed” two-factor structure. Visual Motor Speed and Reaction Time loaded on the first "Speed" factor and Verbal and Visual Memory loaded on a second "Memory" factor. The PCSS scores loaded on a third, unique “symptom” factor. Conclusion Replication of the two-factor structure for ImPACT in a five large high school sample further validates the model. Given that both visual and verbal memory involve encoding of information presented visually, use of a “memory” factor may improve interpretation of ImPACT scores. Similarly, similarities between constructs measuring speed of responding (Reaction Time) and speed of processing (Visual Motor Processing Speed) may be best explained using a “speed” factor.