Higher brain activity after concussion

Concussion patients have irregular brain activity within the first 24 hours after their injury but increased levels of brain activity a few weeks later, which suggests that the brain may compensate for the injury during recovery, a new study reports.

Researchers used functional MRI to study the recovery of 12 high school football players with concussion and compared them to 12 uninjured teammates. The concussed players underwent brain scans at 13 hours and again seven weeks after their head injury, and the uninjured players had brain scans at the same time.

At 13 hours, the concussed athletes had typical symptoms such as decreased reaction time and reduced mental abilities. Their brain scans revealed decreased activity in certain areas of the right hemisphere of the brain. This suggests that their reduced mental abilities may be related to underactivation of attentional brain circuits, according to the researchers.

At seven weeks, the concussed players showed improvement in their mental abilities and normal reaction time. Brain scans at that time revealed that the concussed athletes had more activation in the brain's attentional circuits than the uninjured players.

"This hyperactivation may represent a compensatory brain response that mediates recovery," study lead author Thomas Hammeke, a professor of psychiatry and behavioural medicine at the Medical College of Wisconsin, said in a college news release. "This is the first study to demonstrate that reversal in activation patterns, and that reversal matches the progression of symptoms from the time of the injury through clinical recovery."

The study appears in the September issue of the Journal of the International Neuropsychological Society.

"Deciding when a concussed player should return to the playing field is currently an inexact science," study senior author Dr Stephen Rao, director of the Schey Center for Cognitive Neuroimaging at the Cleveland Clinic, said in the news release. "Measuring changes in brain activity during the acute recovery period can provide a scientific basis for making this critical decision."

More information

The American Academy of Family Physicians has more about concussion.