We’ve all (most likely) bumped our heads and brushed it off as nothing to worry about. However, new research shows that repeated head impacts may not be as insignificant as we may think.
In a research article published in Science Advances this past August, researchers found a correlation between routine head-to-head contact in American football players and abnormal changes in the white matter of the brain.
Source: Westshore Rebels & British Columbia Football Conference Media
The study followed players from the University of Rochester over the course of a single season, and had them wear accelerometers in their helmets to measure the force of impact during all practices and games. The participants also underwent brain scans before the season began and after the season ended.
Brain tissue can be divided into two major categories: white matter and grey matter. The grey matter of the brain is primarily responsible for information storage and processing, while the white matter of the brain is crucial in connecting the regions of grey matter to the rest of the body.
Since white matter plays such an important role in transmitting information throughout the body, it varies structurally by the presence of myelin sheaths, which allow the brain to transmit information throughout the body more efficiently.
A measure known as fractional anisotropy, which effectively measures how effectively stretches of white matter can carry neural signals, was used to identify damage sustained to the brain throughout the course of the season.
The findings of this study demonstrate two major facts: there is a significant reduction in the integrity of the white matter of the brain after the repeated head impacts sustained by as little as a single season of football, and that the amount of reduction is related to the amount of rotational acceleration that a player’s brain is exposed to.
One of the major risks associated with repetitive brain trauma are chronic traumatic encephalopathy (CTE), a condition in which a protein develops into clumps in the brain. As it continues to grow and spread throughout the brain tissue, it slowly kills off brain cells.
Some of the symptoms associated with CTE are issues with impulse control, depression, and loss of memory. More information can be found through the Concussion Legacy Foundation website, linked here.
The following infographic shows the four stages of CTE, as proposed by Dr. Ann McKee.
Infographic showing the four proposed stages of CTE development. Source: Concussion Legacy Foundation
The risk of developing CTE was found to increase with the number of years spent playing football, in a study published by the Boston University School of Medicine. It was found that the risk increased by 30% for every year played, meaning that the odds double for every 2.6 years played.
While there’s still a lot of work that needs to be done to further understand the risk factors associated with these repeated impacts, and to what extent it affects cognitive performance, finding that there is a correlation between repetitive head impact and the degradation in the quality of brain tissue is a notable step in establishing the importance of concussion prevention and treatment.
– Sarah Jiang
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