Single football season can affect brain of young players

After just one season of playing American football, some teenagers appear to show measurable changes in their brains even when they did not suffer concussion, according to a new study.
"This study adds to the growing body of evidence that a season of play in a contact sport can affect the brain in the absence of clinical findings," said Christopher T Whitlow, associate professor of radiology at Wake Forest School of Medicine in US.
Whitlow and colleagues set out to determine if head impacts acquired over a season of high school football produce white matter changes in the brain in the absence of clinically diagnosed concussion.

The researchers studied 24 high school football players between the ages of 16 and 18.
For all games and practices, players were monitored with Head Impact Telemetry System (HITs) helmet-mounted accelerometers, which are used in youth and collegiate football to assess the frequency and severity of helmet impacts.
Risk-weighted cumulative exposure was computed from the HITs data, representing the risk of concussion over the course of the season.

All players underwent pre- and post-season evaluation with diffusion tensor imaging (DTI) of the brain. DTI is an advanced MRI technique, which identifies microstructural changes in the brain's white matter.
The brain's white matter is composed of millions of nerve fibres called axons that act like communication cables connecting various regions of the brain.

Diffusion tensor imaging produces a measurement, called fractional anisotropy (FA), of the movement of water molecules along axons.
The results showed that both groups demonstrated global increases of FA over time, likely reflecting effects of brain development.
However, the heavy-hitter group showed statistically significant areas of decreased FA post-season in specific areas of the brain, including the splenium of the corpus callosum and deep white matter tracts.
"Our study found that players experiencing greater levels of head impacts have more FA loss compared to players with lower impact exposure," said Whitlow, also a radiologist at Wake Forest Baptist Medical Centre.