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OBJECTIVE To determine the association of repetitive subconcussive head impacts with functional outcomes in primary and high school tackle football players. SETTING Youth football fields and an outpatient sports neurology clinic. PARTICIPANTS A total of 112 primary school (n = 55, age 9-12 years) and high school (n = 57, age 15-18 years) football players. DESIGN A prospective cohort study. MAIN MEASURES Helmet-based sensors were used to record head impacts during practices and games during the 2016 football season. Impact g-forces were summed to yield a measure of cumulative impact. History of self-reported premorbid medical diagnoses was obtained preseason. Players completed assessments of a variety of outcomes both pre- and postseason: neuropsychological test performance, symptoms, vestibular and ocular-motor screening, balance, parent-completed attention-deficit hyperactivity disorder (ADHD) symptoms, and self-reported behavioral adjustment. RESULTS Average cumulative impact was 3700 (standard deviation = 2700) g-forces for the season and did not differ between age groups (P = .594). Cumulative impact did not predict pre- to postseason change scores on any outcome measures (all P > .05). Instead, younger age group and reported history of premorbid ADHD predicted change scores on several cognitive testing measures and parent-reported ADHD symptoms, while reported history of premorbid anxiety and depression predicted change scores on symptom reporting. CONCLUSIONS In youth tackle football, subconcussive head impacts sustained over the course of a single season may not be associated with neurocognitive functional outcomes. The absence of a significant association may reflect the relatively short follow-up interval, and signals the need for studies across multiple seasons.

ObjectiveTo determine the association of repetitive sub-concussive head impacts with neurocognitive outcomes in primary school and high school tackle football players.MethodsWe conducted a prospective cohort study of 35 primary school players age 9–12 and 20 high school players age 15–18 who each participated in 2 consecutive seasons of tackle football from 2016 to 2017. Helmet-based sensors were used to record head impacts during contact practices and games, which were summed as a cumulative impact for the 2 football seasons. Players were also divided into high intensity and low intensity groups based on whether they sustained high g-force impacts in both seasons. Players completed assessments on a variety of outcomes before the 2016 season and after the 2017 season: neuropsychological test performance, symptom ratings, vestibular-ocular function, balance, parent-completed ADHD symptoms, and self-reported behavioral adjustment.ResultsAverage cumulative impact was 6,920 (SD 4,553) g-forces combined for the 2 seasons and did not differ between age groups (p = 0.66). Twenty-one players (38%) were classified as high intensity based on individual impacts. After correcting for multiple comparisons, neither cumulative impact nor impact intensity predicted change scores from pre-2016 season to post-2017 season on any outcome measures. Instead, younger age group and history of ADHD predicted worse change scores on several cognitive measures and ADHD symptom reporting.ConclusionsOver 2 consecutive seasons of primary and high school tackle football participation, cumulative head impact burden and intensity of impacts were not found to be associated with changes in cognition, balance, vestibular-ocular function, or behavioral adjustment.