Repetitive Head Impacts in Youth Football: Description and Relationship to White Matter Structure.

Background: Few studies have examined white matter with diffusion tensor imaging in 8- to 12-year-old collision sport (CS) athletes.

Hypothesis: Youth CS athletes will demonstrate change in brain fractional anisotropy (FA) after a season of CS compared with an age-matched noncollision sport (NCS) cohort, and the number, magnitude, and location of hits will correlate with changes in the brain determined via FA for CS athletes.

Study Design: Prospective cohort study.