Head impact burden and change in neurocognitive function over 2 seasons of youth football participation

Objective To determine the association of repetitive sub-concussive head impacts with neurocognitive outcomes in primary school and high school tackle football players. Methods We 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. Results Average 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. Conclusions Over 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.