Neurocognitive Function and Head Impact Burden over Two Seasons of Youth Tackle Football.

This prospective cohort study sought to determine the association of repetitive sub-concussive head impacts with neurocognitive outcomes in youth tackle football players. The study sample included 166 youth tackle football players over two seasons: 70 primary school players ages 9-12 and 96 high school players ages 15-18. Helmet-based sensors recorded head impacts during practices and games, and impacts were summed to provide a cumulative measure of impact for each season. Participants also were stratified by "high intensity" and "low intensity" groups based on whether they sustained high or low g-force impacts. Participants completed assessments on a variety of neurologic, cognitive, and behavioral outcomes before and after each football season. In the subgroup of 55 players who participated in both seasons, the average combined cumulative impact for primary school and high school players was 7127 (standard deviation [SD] 4670) and 6558 (SD 4438) g-forces, respectively. Neither cumulative impact nor impact intensity predicted change scores from pre-season 1 to post-season 2 on any outcome measures. Instead, younger age group and history of attention deficit hyperactivity disorder (ADHD) predicted worse change scores on several cognitive measures and an ADHD symptom reporting scale. In the full 166-player cohort, a computerized test of processing speed declined over time, while the remaining 22 outcome measures either did not change or improved over time. Minimal changes were observed in neurocognitive outcomes associated with participation in youth tackle football over the course of two seasons, and there was no correlation with the number and severity of head impacts sustained over that time. However, longer prospective follow-up times will be beneficial.