A single season of high school football may be enough to cause microscopic changes in the structure of the brain, according to researchers.
The study, conducted by researchers at the University of California, Berkeley, Duke University, and the University of North Carolina at Chapel Hill, was published recently in Neurobiology of Disease.
The researchers used a new type of magnetic resonance imaging (MRI) to take brain scans of 16 high school players, ages 15 to 17, before and after a season of football. They found significant changes in the structure of the grey matter in the front and rear of the brain, where impacts are most likely to occur, as well as changes to structures deep inside the brain. All participants wore helmets, and none received head impacts severe enough to constitute a concussion.
“It is becoming pretty clear that repetitive impacts to the head, even over a short period of time, can cause changes in the brain,” says study senior author Chunlei Liu, a professor of electrical engineering and computer sciences and a member of the Helen Wills Neuroscience Institute at UC Berkeley, in a media release. “This is the period when the brain is still developing, when it is not mature yet, so there are many critical biological processes going on, and it is unknown how these changes that we observe can affect how the brain matures and develops.”
“There is a lot of emerging evidence that just playing impact sports actually changes the brain, and you can see these changes at the molecular level in the accumulations of different pathogenic proteins associated with neurodegenerative diseases like Parkinson’s and dementia,” Liu adds. “We wanted to know when this actually happens — how early does this occur?”
In their study, the researchers used a new type of MRI called diffusion kurtosis imaging to examine the intricate neural tangles that make up gray matter. They found that the organization of the gray matter in players’ brains changed after a season of football, and these changes correlated with the number and position of head impacts measured by accelerometers mounted inside players’ helmets.
The changes were concentrated in the front and rear of the cerebral cortex, which is responsible for higher-order functions like memory, attention and cognition, and in the centrally located thalamus and putamen, which relay sensory information and coordinate movement, explains the release, from the University of California at Berkeley.
“Although our study did not look into the consequences of the observed changes, there is emerging evidence suggesting that such changes would be harmful over the long term,” Liu states.
Tests revealed that students’ cognitive function did not change over the course of the season, and it is yet unclear whether these changes in the brain are permanent, the researchers say.
“The brain microstructure of younger players is still rapidly developing, and that may counteract the alterations caused by repetitive head impacts,” comments first author Nan-Ji Gong, a postdoctoral researcher in the Department of Electrical Engineering and Computer Sciences at UC Berkeley.
However, the researchers still urge caution — and frequent cognitive and brain monitoring — for youth and high schoolers engaged in impact sports.
“I think it would be reasonable to debate at what age it would be most critical for the brain to endure these sorts of consequences, especially given the popularity of youth football and other sports that cause impact to the brain,” Liu concludes.
[Source(s): University of California – Berkeley, Science Daily]