Brain Imaging Shows Damage to Youth Football Players

MRI and magnetoencephalography show brain changes after only one season of play among school-aged football players with a history of concussion and high impact exposure, according to two studies presented today at RSNA.

Researchers in the United States performed the two studies to determine whether intradefault mode network (DMN) connectivity changes occur when youth participate in contact sports and to determine if history of previous concussion modulates connectivity changes in the magnetoencephalography (MEG) measured DMN.

Twenty high school football players, mean age 16.9, participated in the first study. Five players had experienced at least one concussion, and 15 had no history of concussion. All 20 wore helmets outfitted with Head Impact Telemetry System (HITS) throughout the season. The players underwent eight-minute pre- and post-season MEG scans. Researchers then analyzed the MEG power associated with the eight brain regions of the DMN:

• Inferior parietal L&R

• Medial orbitofrontal L&R

• Posterior cingulate L&R

• Superior frontal L&R

The results showed the players who had a history of concussion had significantly lower DMN correlations from pre-season to post-season, and a negative change in correlation. Players with no history of concussion had, on average, a positive change. No significant differences were found in age, BMI, or head impact exposure between the two groups.

"The brain's default mode network changes differently as a result of previous concussion," co-author Elizabeth M. Davenport, PhD, a postdoctoral researcher in the Advanced NeuroScience Imaging Research (ANSIR) lab at UT Southwestern's O'Donnell Brain Institute, in Dallas, Texas, said in a release. "Previous concussion seems to prime the brain for additional changes. Concussion history may be affecting the brain's ability to compensate for subconcussive impacts."

For the second study, 26 football players aged 9 to 13 also wore HITS for an entire football season; players with previous concussions were excluded from the study. The 26 participants were equally divided into high and low concussion exposure groups. A third group of 13 non-contact sport controls was established. All subjects underwent pre- and post-season resting functional MRI (fMRI) scans and researchers analyzed connectivity within the DMN sub-components.

The algorithm discriminated between high-impact exposure and non-contact with 82%accuracy, and low-impact exposure and non-contact with 70%accuracy. The results suggest an increasing functional change with increasing head-impact exposure.

"Over a season of football, players are exposed to numerous head impacts. The vast majority of these do not result in concussion," study co-author Gowtham Krishnan Murugesan, a PhD student in biomedical engineering and member of the ANSIR lab, said in the same release. "This work adds to a growing body of literature indicating that subconcussive head impacts can have an effect on the brain. This is a highly understudied area at the youth and high school level."

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