Minimal Detectable Change for the ImPACT Subtests at Baseline.

Objective: To establish the minimal detectable change (MDC) of the subtests that comprise the composite scores from remotely administered Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) baselines.

Method: Remote ImPACT baseline data from 172 (male = 45, female = 127) National Collegiate Athletic Association Division I student-athletes from the 2020 and 2021 athletic preseasons were used to calculate the MDC at the 95%, 90%, and 80% confidence intervals (CIs) for all subtest scores used to generate the four core composite scores and the impulse control composite.

Results: The MDCs for the verbal memory subtests at the 95% CI were 10.31 for word memory percent correct, 4.68 for symbol match total correct hidden, and 18.25 for three letters percentage correct. Visual memory subtest MDCs were 19.03 for design memory total percent correct and 4.90 for XO total correct memory. Visual motor speed subtest MDCs were 18.89 for XO total correct interference and 5.40 for three letters average counted correctly. Reaction time (RT) MDCs were 0.12 for XO average correct, 0.95 for symbol match average correct RT, and 0.28 for color match average correct. Impulse control MDCs were 5.97 for XO total incorrect and 1.15 for color match total commissions. One-way repeated measures MANOVA, repeated measures ANOVAs, and Wilcoxon signed-ranks test all suggested no significant difference between any subtests across two remote ImPACT baselines.

Conclusions: The ImPACT subtest scores did not significantly change between athletic seasons. Our study suggests the subtests be evaluated in conjunction with the composite scores to provide additional metrics for clinical interpretation.