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Health

How Football Messes With the Teenage Brain

Even for those who don't get concussions.
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With 1:05 left in the second quarter of the Carolina Panthers' Nov. 17 meeting with the New Orleans Saints, Panthers linebacker Luke Kuechly ran headfirst into Saints running back Tim Hightower's charging shoulder. Kuechly stumbled, fell, tried to get up, and finally sat down on the 47-yard line.  The image of Kuechly sobbing in the back of the medical cart, uncertain about his future, went viral, drawing more attention to the relationship between NFL-sized hits and brain disorders such as dementia, ALS, and chronic traumatic encephalopathy (the latter of which took the life of former New York Giant Tyler Sash at age 27).

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Photo: Grant Halverson/Getty Images

But how early can these hits affect the developing brains of younger athletes? A research team from the University of Texas Southwestern Medical Center and Wake Forest University hopes to find out using state-of-the-art brain imaging technology to get inside players' helmets.

The team first started analyzing the brains of football players in 2012, focusing on a select group of 16- to 18-year-old varsity athletes from Winston-Salem Forsyth County Schools in North Carolina. The researchers conducted pre-season and post-season MRI and magnetoencephalography (MEG) scans, tracking changes to gray and white brain matter. Gray matter controls general cognition, muscle control, sensory perception, and a host of other bodily functions; white matter serves as the connective tissue between gray matter areas, and has recently been correlated to the brain's ability to learn new motor tasks, such as juggling.

Lead researcher Elizabeth Davenport says the team focused on players with no history of concussions or neurological diseases to find out how non-concussive hits (which can fly under the radar) can affect developing brains.

The players wore helmets equipped with six accelerometers that measured linear and rotational acceleration and recorded data from each hit. Meanwhile, the researchers filmed all of the practices and games, and then matched each hit to the corresponding helmet.

Davenport's team recently finished compiling the data from that 2012 season. The MRI analyzed pre-season and post-season diffusion imaging metrics, which display the location and orientation of the brain's white matter (the squishy stuff that carries nerve impulses between gray matter areas of the brain). She found a startling correlation.

"If you imagine a wire [the white matter] that goes through your brain, if it's stretched or frayed, you're going to see a difference in the way that water or electrical signal travels," Davenport says. The greatest disruptions in those electrical signals were found in the players who took the most hits to the helmet.

Researchers still don't know how subconcussive head impacts affect the brain long-term, and Davenport says longitudinal studies are needed to answer that question.

But the methodology may nevertheless have real-world applications. In the study, a weighted scale indicated a player's exposure to head impacts, with harder hits counting for more than softer ones. Just as a baseball coach keeps a pitch count to avoid injuring their pitcher's shoulder, football coaches could someday use the helmet accelerometer technology to bench players who surpass a quota of hard hits. Unfortunately, it won't be anytime soon: Davenport says that widespread use of helmet accelerometers is likely years, if not decades away.