fMRI Study Records Brain Activation During Concussion Recovery

Researchers for the first time have documented irregular brain activity within the first 24 hours of a concussive injury, as well as an increased level of brain activity weeks later—suggesting that the brain may compensate for the injury during the recovery time.

The findings were published in the September 2013 issue of the Journal of the International Neuropsychological Society. Thomas Hammeke, PhD, professor of psychiatry and behavioral medicine at the Medical College of Wisconsin (Milwaukee, USA), is the lead author.

To assess the natural recovery from sports concussion, 12 concussed high school football athletes and 12 uninjured teammates were evaluated at 13 hours and again at seven weeks following concussive injury. The concussed athletes showed the predicted postconcussive symptoms, including decreased reaction time and diminished cognitive capabilities. The use of functional magnetic resonance imaging (fMRI) revealed diminished activity in select areas of the right hemisphere of the brain, which suggests the poor cognitive performance of concussion patients is related to that underactivation of attentional brain circuits.

The concussed athletes, seven weeks post-injury, showed improvement of cognitive abilities and normal reaction time. However, imaging at that time showed the postconcussed athletes had more activation in the brain’s attentional circuits than did the control athletes. “This hyperactivation may represent a compensatory brain response that mediates recovery,” said Dr. Hammeke. “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.”

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

Annually, an estimated 3.8 million people sustain a traumatic brain injury (TBI) in the United States alone. TBI is a contributing factor to one-third of all injury-related deaths in the United States. More than three-quarters of the TBIs that occur are concussions or other forms of mild TBI, many of which may go undiagnosed.

Related Links:
Medical College of Wisconsin
Cleveland Clinic