A - 04 Associations of Concussion and Contact Sport Exposure History With Brain Microstructure Using Quantitative Susceptibility Mapping

Abstract Purpose The goal of this work was to characterize the association of prior concussion and years of contact sport exposure with quantitative susceptibility mapping (QSM) MRI. We hypothesized that concussion and contact sport exposure would be independently associated with lower susceptibility in white matter regions. Method Active and otherwise healthy athletes aged 18–26 (N = 200; 124 male) completed semi-structured head injury and exposure history interviews, a clinical battery consisting of measures of symptoms and neurocognitive functioning, and an MRI session to obtain QSM, an extension of susceptibility weighted imaging. Linear models assessed the association of number of prior concussions and years of contact sport exposure with QSM and clinical measures. Results Higher general symptom severity and psychological symptoms were observed in athletes with a greater history of concussion (ps < 0.001), but not years of contact sport exposure (ps > 0.10). No associations between concussion or years of exposure with cognitive performance were observed (ps > 0.10). Voxel-wise analyses found that individuals with more prior concussions also had lower magnetic susceptibility in two predominately white matter clusters, including the superior longitudinal fasciculi and forceps major (ps < 0.01). No associations of susceptibility and contact sport exposure were observed. Finally, lower susceptibility in the identified regions was associated with worse psychological symptoms, worse concussion-related symptoms, and worse performance on a composite measure of fluid cognition tasks (rsex ≥ 0.15; ps < 0.05). Conclusions Current results suggest that more prior concussions in otherwise healthy collegiate-aged athletes are associated with decreases in susceptibility that are in turn associated with more severe symptoms and worse cognitive performance.