The stability of ImPACT baseline test performance over a 3-year period in high school athletes

Abstract

PurposeAnnual baseline assessment using computerized neurocognitive tests have been recommended by governing healthcare bodies for the management of sport-related concussion but is supported by limited evidence. The current study examined the stability of ImPACT performance across three-successive years in adolescent athletes.MethodThis prospective cohort included 229 (117 male, 112 female) high school student-athletes from 2 private high schools. ImPACT was administered in a controlled group setting (1–17 participants) at years 1 (T1; n = 229), 2 (T2; n = 101) and 3 (T3; n = 47). Repeated measures analyses of variance (ANOVA 4 × 3) were used to examine performance on ImPACT's Verbal Memory (VEM), Visual Memory (VIS), Visual Motor Speed (VMS), and Reaction Time (RT) composite scores. Paired t-tests were used for post-hoc analyses. Two-way mixed intraclass correlation coefficients (ICC [3,1]) with 95% confidence intervals (CI) were calculated between time points. Group mean and within-subject differences between each time point for ImPACT scores were analyzed using manufacturer provided reliable change indices (RCI). All analyses were performed with alpha = 0.05.ResultsA significant main effect was observed for VMS (F [2,92] = 27.90, p = 0.001) across time. Participants significantly improved on VMS between T2 and T1 (t [100] = 4.15, p = 0.001), T3 and T2 (t [46] = 7.19, p = 0.001), and T3 and T1 (t [46] = 3.85, p < 0 .001). Weak (VEM: ICC = 0.37, CI = 0.19, 0.55) to strong (VMS: ICC = 0.83, CI = 0.74, 0.90) ICCs were observed for ImPACT scores. No group mean differences exceeded the 80% CI for ImPACT's RCI, although within-subject differences for at least 1 score exceeded the 80% CI between T2 and T1 (24%–39%), T3 and T2 (26%–45%), and T3 and T1 (32%–51%).ConclusionsOverall, statistically significant improvement was observed for VMS, however, the magnitude of the change may not be clinically meaningful. Similar to previous research, reliability of ImPACT scores ranged from weak to strong. Our results support annual baseline assessment of young athletes for progression of neurocognitive functioning.