ADHD May Associate With Reduced Tolerance to Acute Subconcussive Head Impacts: A Pilot Case-Control Intervention Study

Objective: To test our hypothesis that individuals with ADHD would exhibit reduced resiliency to subconcussive head impacts induced by ten soccer headings. Method: We conducted a case-control intervention study in 51 adults (20.6 ± 1.7 years old). Cognitive assessment, using ImPACT, and plasma levels of neurofilament-light (NF-L), Tau, glial-fibrillary-acidic protein (GFAP), and ubiquitin-C-terminal hydrolase-L1 (UCH-L1) were measured. Results: Ten controlled soccer headings demonstrated ADHD-specific transient declines in verbal memory function. Ten headings also blunted learning effects in visual memory function in the ADHD group while the non-ADHD counterparts improved both verbal and visual memory functions even after ten headings. Blood biomarker levels of the ADHD group were sensitive to the stress induced by ten headings, where plasma GFAP and UCH-L1 levels acutely increased after 10 headings. Variance in ADHD-specific verbal memory decline was correlated with increased levels of plasma GFAP in the ADHD group. Conclusions: These data suggest that ADHD may reduce brain tolerance to repetitive subconcussive head impacts.