Scientists working with active and recently retired National Football League players have found a way to track brain injury from concussions and any self-repair over time.
The researchers used positron emission tomography imaging—commonly called PET scanning—to look for a marker of injury and repair in the brains of the players.
“We now believe we have a useful tool to monitor the brains of NFL players and athletes in other contact sports,” says Jennifer Coughlin, assistant professor of psychiatry and behavioral sciences at Johns Hopkins University.
The research, published online by the journal JAMA Neurology, builds on anecdotal evidence and a few scientific studies suggesting that athletes with repeated concussive head injuries are at higher risk for a neurodegenerative disease called chronic traumatic encephalopathy. CTE is associated with memory deficits, confusion, poor decision-making and, eventually, onset of dementia.
Because CTE is often only diagnosed at autopsy, however, and because similar symptoms may occur in people without repeated head injuries, researchers are looking for better methods to visualize tissue damage in the living brain.
Coughlin and her research team measured TSPO, a biomarker of brain injury they were able to see on PET scans.
“We can now begin to follow it over time to see if the brain is repairing itself or not,” Coughlin says.
“With further research using this technology, we may better understand the relationship between concussion and brain damage,” she says. “Further understanding may help inform players of associated risk and will allow us to test preventive and therapeutic interventions that may improve the lives of players.”
12 NFL players
According to Centers for Disease Control and Prevention estimates, anywhere from 1.6 million to 3.8 million concussions happen each year in the United States in sports or recreational activities.
In early 2015, the Johns Hopkins research team published PET imaging results showing high levels of the TSPO biomarker in the brains of nine elderly former NFL players compared to control participants. Since they initially studied elderly players many years into retirement, however, the researchers were unable to say if the findings were also linked to aging and vascular disease, independent of any football injuries.
In the new study, the researchers compared PET imaging data from 11 men who had never had concussion to scans of 12 NFL players, all still playing or retired within 12 years. The players—average age, 31—all reported having had at least one concussion. Controls were matched to the players by body mass index, age, and education level.
The researchers found more TSPO in players than controls in eight of 12 brain regions. These regions included the hippocampus, a region involved in memory.
The researchers also looked at MRI scans for evidence of structural changes in the brains of study participants. They found no brain tissue loss in players compared with controls, but did find some evidence of white matter damage in the players’ brains.
“We suspect that when the brain moves during a hard hit, it causes a shearing injury of the white matter fibers that travel across the brain,” Coughlin says.
The researchers say creatine supplements—taken by athletes to improve performance—may interfere with the imaging results. More study of this effect is needed before they can study participants taking creatine, they note.
Other researchers contributing to the study were from Johns Hopkins, Boston University, the University of Sydney, and Florida International University. The Brain and Behavior Research Foundation, the Alexander Wilson Schweizer Fellowship, the National Institute of Environmental Health Sciences and the GE/NFL Head Health Challenge funded the research.
Source: Johns Hopkins University