Reduced cognitive resiliency ofattention-deficit/hyperactivity disorder against subconcussive head impacts

Abstract

Objective The purpose of this study was to determine the subconcussive head impacts (SHI) effects on neurocognitive function in individuals diagnosed with attention-deficit/hyperactivity disorder (ADHD). Background Athletes diagnosed with ADHD have a heightened risk (2 to 4-fold) for sustaining concussion. However, their response to repetitive SHI remain unclear. Design/Methods In this case-control intervention study, 17 soccer players clinically diagnosed with ADHD who take their prescribed medication daily, were assigned a heading intervention (ADHD-Heading group),individuals who met the ADHD criteria but were non-soccer players, were assigned into a kicking group, (ADHD-Kicking group, n = 15). Whereas 34 soccer players without ADHD diagnosis were randomized into either a heading or kicking intervention, yielding Non-ADHD-Heading group (n = 17) or Non-ADHD-Kicking group (n = 17). To implement SHI, the heading groups executed 10 headers with a standard soccer ball projected at a velocity of 25 mph (equivalent to a long throw-in) over 10 minutes by a JUGS soccer machine, while the kicking groups performed 10 kicks. Neurocognitive function was measured via the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) at pre-intervention baseline, 0h, 2h, and 24h post-intervention. Results The vulnerability to SHI was notable in subjects diagnosed with ADHD particularly in memory, as illustrated by a significant group × time interaction, F(6,96) = 3.796, p = 0.002. Both Kicking groups improved verbal memory over time indicating the brain’s ability to learn, whereas the Non-ADHD-Heading group showed no improvement. The ADHD-Heading group showed a significant decline at 0h and 2h post-heading compared to other groups. As for visual memory, the ADHD-Heading group showed a significant decline at 24h post; however, all other groups displayed improvement. There were no group differences in remaining domains. Conclusions Data suggests neurocognitive vulnerability in athletes diagnosed with ADHD after experiencing SHI, specifically in memory performance. These outcomes can better inform clinicians; overall, promoting a better personalized care in athletes diagnosed with ADHD.