Effects of Head Impact Exposure in High School Football Athletes on Cognitive Performance and Symptom Prevalence

Abstract

Context: High school football players may sustain hundreds of head impacts (HI) each season. Impacts to the head raise concern about their cumulative effects and long term consequences on neurocognitive function. Tackling training interventions have been shown to reduce overall head impacts and burden, but the effects of these interventions to both decrease head impacts and burden and preserve neurocognitive ability are not clear. Objective: To evaluate the effects of one season of football on neurocognitive scores as measured by the ImPACT test battery on high school football (FB) players involved in a helmetless tackling training program compared to low contact sport athletes (CON). Design: quasi-experimental, prospective cohort. Setting: Three high schools on O'ahu. Patients and Participants: 165 FB (15.3 ± 1.1 yrs) and 139 CON (15.4 ± 1.3 yrs) male participants aged 14 to 18 years old. Main Outcome Measures: ImPACT scores and symptom prevalence compared between FB and controls as well as HI and burden subgroups. Results: A difference was observed between overall FB postseason and CON baseline ImPACT scores (p=0.001). FB Verbal Memory (p=0.043) and Visual Motor Speed (p=0.018) scores were lower than CON. FB HI subgroups (p=0.047) and FB burden (p=0.028) subgroups were both different compared to CON. No univariate tests across the subgroup HI or burden analyses were significant. Post hoc testing revealed statistically significant (p<0.05) differences between groups in HI and burden subgroup analyses. Conclusion: Differences were found between FB and CON as well as HI and burden subgroups and CON, however, the effect size differences were minimal and thus, were not likely clinically significant. Therefore, football players who participated in helmetless tackling training interventions were not different from athletes who participate in non- or limited contact sports at their respective schools. FB ImPACT scores were also similar to the CON scores when grouped by differing amounts of head impacts or head impact burden. Helmetless tackling training participants may have been protected from neurocognitive changes due to overall reduced HI and burden.