High school football: Teen brains don’t heal during offseason

"The brain is pretty amazing at covering up a lot of changes," says Thomas Talavage. "Some of these kids have no outward symptoms, but we can see their brains have rewired themselves to skip around the parts that are affected." (Credit: matthewreid/Flickr)

Brain scans of high school football players taken before, during, and after the season raise concerns they don’t fully recover from repeated head hits.

The researchers used an imaging technique called proton magnetic resonance spectroscopy (1H MRS) to study the brains of 25 high school football players and compared them to the brains of teenagers involved in non-contact sports.

“We are finding that the more hits you take, the more you change your brain chemistry.”

The findings suggest repeated head hits in football can cause changes in brain chemistry and metabolism, even in players not diagnosed with concussions. The results are detailed in five papers published in the journal Developmental Neuropsychology.

“We are seeing damage not just to neurons, but also to the vasculature and glial cells in the brain,” says Eric Nauman, professor of mechanical engineering, basic medical sciences, and biomedical engineering at Purdue University.

“I was particularly disturbed that when you get to the offseason—we are looking somewhere between two and five months after the season has ended—the majority of players are still showing that they had not fully recovered.”

Brains rewire themselves

The 1H MRS data provide details about the blood flow, metabolism, and chemistry of neurons and glial cells important for brain function. The data also revealed a “hypermetabolic response” during the preseason, as though the brain was trying to heal connections impaired from the previous season.

“We found that in the preseason for the football players in our study, one part of the brain would be associating with about 100 other regions, which is much higher than the controls,” says Thomas Talavage,  professor of electrical and computer engineering and biomedical engineering and co-director of the Purdue MRI Facility.

“The brain is pretty amazing at covering up a lot of changes. Some of these kids have no outward symptoms, but we can see their brains have rewired themselves to skip around the parts that are affected.”

‘Deviant’ changes in brains

One of the research papers shows that knowing a player’s history of specific types of hits to the head makes it possible to accurately predict “deviant brain metabolism,” suggesting that sub-concussive blows can produce biochemical changes and potentially lead to neurological problems, which indicates a correlation between players taking the heaviest hits and brain chemistry changes.

The data shows that the neurons in the motor cortex region in the brains of football players produced about 50 percent less of the neurotransmitter glutamine compared to controls.

“We are finding that the more hits you take, the more you change your brain chemistry, the more you change your brain’s ability to move blood to the right locations,” Nauman says.

To help prevent concussions, sensors might be integrated into helmets to track hits to the head and to monitor how well the helmet is absorbing the blows.

“Intervention is a big issue,” says Larry Leverenz, clinical professor of health and kinesiology, and an expert in athletic training. “We’d like to get to the point where, now that we know we can observe with imaging how the brain changes with exposure, we can intervene to change the hardware, change the helmets, change techniques, and training regimens.”

2 weeks of rest is not enough

The Purdue Neurotrauma Group has been studying brain changes in high school football players since 2009, research spanning six seasons. The most recent papers are based on data collected during the study’s fourth season.

“Recent proton magnetic resonance spectroscopy studies argue that the recommended two-week window of rest is insufficient for full metabolic recovery after concussion,” Nauman says. “Those returning to play prior to full recovery could incur a second concussion with symptoms and metabolic changes more lasting than the first.”


Researchers also are working to develop helmet technologies that absorb more energy than conventional helmets to better protect the brain.

“The human-health consequences of repeated hits to the head have a significant effect on people’s lives, whether they play the game or their children play or a sibling plays or a friend plays it,” Nauman says.

Researchers at Purdue have formed the Concussion Neuroimaging Consortium with seven other institutions to garner support and funding for research into the neurological effects of contact sports. The other members are Northwestern University, Michigan State University, North Shore University Hospital, Ohio State University, Pennsylvania State University, the University of Nebraska, and the University of Central Florida.

The Indiana Spinal Cord and Brain Injury Research Fund, a part of the Indiana Department of Health, funded the work.

Source: Purdue University