When I was 4, I suffered a mild to moderate brain concussion. I remember stepping onto the stairs leading down to the basement with my toy plastic rake and tripping over it. I also remember careening down the stairway towards a cement support pillar and hitting it with my head. My next memory is of being in an ambulance and seeing my grandfather there with me. Then waking up in a hospital bed wondering where I was.
I’ve sometimes wondered since what was happening to my brain during all of those blacked out moments. So I was interested to see a new study published that looks at the brain activity within the first 24 hours of a concussive injury and beyond. The data suggests that the brain may compensate for the injury during the recovery time.
To examine the organic recovery from sports concussions, 12 concussed high school football athletes plus 12 uninjured teammates were assessed at 13 hours and again at seven weeks following concussion injury.
Attention Deficit and Surplus
Athletes with concussions showed the typical post-concussive symptoms, which include decreased reaction times and lowered cognitive abilities. Imaging via functional magnetic resonance imaging (fMRI) showed less activity in selective areas of the brain’s right hemisphere, suggesting that the lower cognitive function of concussion patients is related to the underactivation of attentional brain circuits.
In the follow up, seven weeks after the injuries, concussed athletes showed improvement of cognitive abilities and normal reaction time. But fMRI scans at that time showed the post-concussed athletes actually 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 lead author Dr. Thomas 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.”
3.8 Million Brain Injuries Each Year
“Deciding when a concussed player should return to the playing field is currently an inexact science,” said senior author Dr. Stephen Rao. “Measuring changes in brain activity during the acute recovery period can provide a scientific basis for making this critical decision.”
An estimated 3.8 million people sustain a traumatic brain injury annually. Ttraumatic brain injury is a contributing factor to a third of all injury-related deaths in the United States, and over three-quarters of the TBI’s that occur are concussions or other forms of mild TBI.
So the hyperactivation discussed in the study may have something to do with my more vivid memories of what happened after I found myself in the hospital. Perhaps not. What is clear is that more research into when exactly the brain begins to recover is needed.
Thomas A. Hammeke, Michael McCrea, Sarah M. Coats, Matthew D. Verber, Sally Durgerian, Kristin Flora, Gary S. Olsen, Peter D. Leo, Thomas A. Gennarelli and Stephen M. Rao. Acute and Subacute Changes in Neural Activation during the Recovery from Sport-Related Concussion. Journal of the International Neuropsychological Society, available on CJO2013. doi:10.1017/S1355617713000702.