Mild brain-impact changes: Easy come, easy go (as long as players take enough time off)

Concussions or no, collegiate football players who experience repetitive head impacts during a single season sustain alterations to the white matter in their brains. The good news: The damage tends to disappear on diffusion tensor MRI after six months of rest, suggesting remission, according to a small prospective study published online Jan. 14 in Brain Imaging and Behavior.

Michael Mayinger, MD, of Ludwig Maximilian University of Munich in Germany and colleagues evaluated longitudinal changes in the diffusion characteristics of brain white matter in American football players at three time points: prior to the start of the season, after a single season and after six months of no-contact rest.

The team looked at 15 college gridiron athletes and five non-athlete controls, sending all for diffusion MR imaging and computerized cognitive testing at all three timepoints.

The researchers used whole-brain tract-based spatial statistics to compare fractional anisotropy, radial diffusivity, axial diffusivity and trace between all timepoints.

They obtained average diffusion values from statistically significant clusters for each participant.

Of note, no athlete sustained a concussion during the study period.

“After one season of play, we observed a significant increase in trace in a cluster located in the brainstem and left temporal lobe, and a significant increase in fractional anisotropy in the left parietal lobe,” the authors report.

After six months of no-contact rest, there was a significant decrease in trace and fractional anisotropy in clusters that were partially overlapping or in close proximity with the initial clusters, with no significant changes” from the first MRI scan to the third.

Mayinger and colleagues state, in so many words, that these preliminary results suggest it might be wise to keep collegiate football players off the game field (and full-contact-practice field) for periods of time longer than the players might like.

Or, to quote the authors verbatim, collegiate football players “might benefit from periods without exposure to repetitive head impacts.”