Concussion Damage in Adolescent Athletes Lingers

November 6, 2017

MRI shows damage to brain tissue among adolescent athletes may continue after they have been cleared to return to sports.

MRI shows lasting changes in the brains of adolescent players with concussion after clinical signs have resolved, according to a study published in Neurology.

Researchers from Canada sought to determine whether multiparametric MRI data would provide insight into the acute and long-lasting neuronal sequelae after a concussion in adolescent athletes.

Seventeen male Bantam-level hockey players between the ages of 11 and 14, who suffered a concussion during the regular season were compared to age-matched controls of non-concussed players. The researchers assessed clinical measures, diffusion metrics, resting-state network and region-to-region functional connectivity patterns, and magnetic resonance spectroscopy absolute metabolite concentrations. Fourteen patients were assessed three months after a diagnosed concussion.

The results showed diffusion abnormalities within multiple white matter tracts, functional hyperconnectivity, and decreases in choline three months after players had sustained concussions. Tract-specific spatial statistics revealed a large region along the superior longitudinal fasciculus with the largest decreases in diffusivity measures, which significantly correlated with clinical deficits.

The region also spatially intersected with probabilistic tracts connecting cortical regions where there were acute functional connectivity changes. Hyperconnectivity patterns at three months after concussion were present only in players with relatively less severe clinical outcomes, higher choline concentrations, and diffusivity indicative of relatively less axonal disruption.

These changes were only visible using high field strength MRI scans and using sophisticated analytical methods, co-author Kathryn Manning, a PhD Candidate at University of Western Ontario’s Centre for Functional and Metabolic Mapping at Robarts Research Institute, said in a release. "On a normal clinical MRI scan, you typically see the structural images of the brain, and for a mild brain injury like a concussion, we aren't able to see the underlying changes we were able to see using these advanced methods.”

Co-author Ravi Menon, PhD, a professor at Western's Schulich School of Medicine & Dentistry and a scientist at Robarts Research Institute added,

"What the MRI shows is that there are still changes occurring in the brain even after the clinical tests have returned to normal. This is potentially of some concern and we'd like to understand this further to determine if these are normal healthy changes or if they are indicative of something that might be going wrong."

The researchers concluded that consequences of early brain injury for ongoing brain development and risk of more serious conditions such as second impact syndrome or neural degenerative processes need to be elucidated.