In a new study, a group of researchers has discovered that playing a single season of football in high school may cause microscopic changes in the structure of teenage brain.
Researchers at University of California, Berkeley collaborated with scientists from the University of North Carolina and Duke University, whose findings were published in the recent issue of Neurobiology of Disease. Using a new type of magnetic resonance imagining (MRI), the researchers took brain scans of sixteen high school football players, aged between 15 and 17, before and after a season of the game.
They discovered important alternations in the structure of brain’s grey matter, both in front and rear, where impacts are most likely to happen and changes to structure deep inside the brain. All the 16 participants wore helmet during the game and none received head impacts that could cause a concussion.
Researchers reported that this one of the first studies on how impact sport an affect human brain during the teenage years. According to Chunlei Liu, senior author of the study, the study revealed that repetitive head impacts, even over short time period, can give rise to certain changes in the brain.
At this critical age, the brain is not mature yet, still developing, and undergoing critical biological processes, according to the researchers, it is still not known how outer changes can affect how the human brain develops and attains maturity.
One hit to the head might not cause a major problem. However, supporting evidence reveals that repeated blows to the cranium of the brain due to blast injuries in military combat and playing sports such as football and hockey may result into higher risk of brain disorders and long-term cognitive decline, even without any concussion.
Over the years, researchers noticed signs of a newly identified cognitive disorder called chronic traumatic encephalopathy (CTE) among retired soldiers and college as well as professional football players. Although the disease is still not well understood, it causes pathogenic tau protein buildup in the brain with symptoms including cognitive decline, mood disorders, and eventually brain motor impairment.
According the researchers, the new study raised concerns regarding whether repetitive hits to the head can cause damage to the brain in youth, especially teenage player, and how the changes can be detected at an early stage.
There has been a lot of emerging evidence showing how playing impact sports can cause changes in the brain, Liu said. Further, these changes can be observed at molecular level in accumulation of various pathogenic proteins linked with brain disorders such as dementia and Parkinson’s.
A Matter of Grey and White
The white matter of the brain consists of long neural threads that pass messages across different regions of the brain, whereas grey matter comprise of neuronal cell bodies, giving brain its characteristic wrinkles.
Recent MRI scans have shown that playing football in high school, at least a season or two, mitigate the white matter. The research team extend their research to the changes in gray matter due to repeated blows to the head.
Using diffusion kurtosis imaging, a new type of MRI, the researchers examined the intricate neural cell bodies that make up the grey matter, after the participants played a season of football. They discovered that changes in organization of the grey matter correlated with number and position of hits to the head, calculated by ‘accelerometers’ fixed inside the players’ helmets.
These changes were intense in cerebral cortex, both in front and rear, and also in the thalamus and putamen. These parts of the brain are responsible for functions such as attention, memory, cognition, coordinate movement, and sensory information.
Though it is not yet clear if these changes in the brain will be permanent, there is evidence suggesting the changes may become harmful to the brain over the long term, according to the researchers.