Recent research suggests that some high school football players exhibit measurable brain changes after a single season of play, even in the absence of concussion. The study joins a growing body of evidence that indicates a season of play in a contact sport can affect the brain in the absence of clinical findings, says Christopher T. Whitlow, MD, PhD, MHA, associate professor of radiology at Wake Forest School of Medicine and radiologist at Wake Forest Baptist Medical Center in Winston-Salem, NC.

A news release from the Radiological Society of North America reports that during the study, Whitlow and colleagues aimed to determine if head impacts sustained during a season of high school football produce white matter changes in the brain in the absence of clinically diagnosed concussion.

According to the release, during the study researchers studied 24 high school football players between the ages of 16 and 18. For all games and practices, the players were reportedly 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 during the course of the season. The release notes that the data, along with total impacts, was used to categorize the players into one of two groups. The first group was known as heavy hitters, and the second group was known as light hitters. The participants numbered nine heavy hitters to 15 light hitters. None of the players experienced concussion during the season.

The release adds that all players also underwent pre- and postseason evaluation with diffusion tensor imaging (DTI) of the brain. DTI is an advanced MRI technique that identifies microstructural changes in the brain’s white matter. Diffusion tensor imaging produces a measurement, called fractional anisotropy (FA), of the movement of water molecules along axons. The release notes that in healthy white matter, the direction of water movement is fairly uniform and measures high in FA. However, when water movement is more random, FA values decrease, indicating microstructural abnormalities.

The study’s results suggest that both groups demonstrated global increases of FA over time, which researchers say likely reflected the impact of brain development. Yet, the heavy-hitter group exhibited statistically significant areas of decreased FA postseason in specific areas of the brain, including the splenium of the corpus callosum and deep white matter tracts.

Whitlow explains that, “Our study found that players experiencing greater levels of head impacts have more FA loss compared to players with lower impact exposure. Similar brain MRI changes have been previously associated with mild traumatic brain injury. However, it is unclear whether or not these effects will be associated with any negative long-term consequences.”

Whitlow also emphasizes that the results are preliminary and additional research needs to be conducted.

Photo caption: HITs helmet-mounted accelerometers are used in youth and collegiate football to assess the frequency and severity of helmet impacts.

Photo credit: RSNA

[Source: Radiological Society of North America]