麻豆传媒

CHICAGO, Ill. – High school football players exhibited changes in white matter and brainwave formation after one season of play, even in the absence of clinical concussion, researchers reported here.

In 24 players from a high school football team (mean age 16.9) with no history of concussion, a Spearman's rank correlation analyses revealed a statistically significant association between the number of abnormal SKI Tortuosity voxels and abnormally increased magnetoencephalographic (MEG) delta power voxels, according to of the University of Texas Southwestern Medical Center in Dallas, and colleagues.

There was also a strong correlation between diffusion tensor imaging (DTI) axonal water fraction (AWF) and MEG delta power, they said in a presentation at the Radiological Society of North America annual meeting.

"We saw changes in these young players' brains on both structural and functional imaging after a single season of football. It's important to understand the potential changes occurring in the brain related to youth contact sports," Davenport stated, adding that the findings could offer clues as to the early stages of chronic traumatic encephalopathy (CTE).

"We are attempting to find out when and how that [CTE] process starts, so that we can keep sports a healthy activity for millions of children and adolescents," she said in a press statement.

The players were outfitted with the Head Impact Telemetry System (HITs) during all practices and games. The biomechanical metric (RWE) was computed.

All players received pre- and post-season MRI. Whole-brain DTI images were acquired using a 2D single-shot EPI sequence. DTI-derived metrics were calculated using the.

Diffusion kurtosis imaging-derived metrics were computed using the . In the pre- and post-season, each participant had 8 minutes of eyes-open, resting-state MEG data collected, and brain space delta wave power was computed.

Changes (post-season minus pre-season) for each metric were computed for each player, and then used to determine the total number of abnormal voxels (2 standard deviations above or below the group mean), the authors explained.

They noted that "tortuosity is expected to be sensitive to the myelinated axonal fraction where FA is a measure of general anisotropy. The relationship of Tortuosity with delta waves may indicate a correlation between the number of myelinated axons and delta waves."

Davenport said her group plans to expand the study with researchers from other institutions joining in. "Without a larger population that is closely followed in a longitudinal study, it is difficult to know the long-term effects of these changes," she said. "We don't know if the brain's developmental trajectory is altered, or if the off-season time allows for the brain to return to normal."

"These head impacts are something that we are taking a great interest in," noted of Stanford University in Stanford, Calif. "It is something I think about ... because I have a 6-year-old son who is interested in things like karate and football."

Wintermark pointed out that the study only covered a year of play, so "we don't know if these changes are reversible. We see something on imaging, but we don't know if this persists or goes away. I would also want to see if these brain changes correlate with any kind of neuropsychological testing -- did they perform worse in math, were their grades different?"

He also cautioned about putting too much emphasis on the imaging results alone. "One thing we always have to remember with imaging is that these techniques show something, but it is not necessarily the 'truth' ... we have to wonder, 'What does it mean?'"

"This study is a good step in exploring how these brain injuries accumulate, but it is not a final answer," Wintermark added.

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