Quidditch is a fast-paced, co-ed, full-contact combination of dodgeball, rugby and basketball. Above, John Sheridan tries to score points by throwing a quaffle ball through the other team's hoop.
While a day or two of complete rest may be necessary for kids after a concussion, any more could leave them feeling isolated and anxious, says Angela Lumba-Brown, a pediatric emergency medicine physician who helped shape new guidelines.
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UCLA researchers are using a radioactive tracer, which binds to abnormal proteins in the brain, to see if it is possible to diagnose chronic traumatic encephalopathy in living patients. Warmer colors in these PET scans indicate higher concentrations of the tracer.
Marines based in Okinawa, Japan, fire an M136 AT-4 rocket launcher as part of a weapons training exercise on the Kaneohe Bay Range Training Facility, in 2014.
Lance Cpl. Matthew Bragg/U.S. Marines/DVIDS
U.S. Marines fire the Carl Gustav rocket system during live-fire training last October. With each firing, the shooter's brain is exposed to pulses of high pressure air emanating from the explosion that travel faster than the speed of sound.
Sgt. Aaron Patterson/3rd Marine Division/DVIDS
Aaron Hernandez (81), of the New England Patriots, lost his helmet during this play against the New York Jets in 2011. Hernandez killed himself in 2017, and researchers found that he had had one of the most severe cases of CTE ever seen in someone his age.
Professional fighter Gina Mazany practices during a training session at Xtreme Couture Mixed Martial Arts in Las Vegas. She well remembers her first concussion — which came in her first fight. "I was throwing up that night," Mazany says.
Bridget Bennett for NPR
Players who headed a lot of balls — an average of 124 in two weeks — were three times more likely to get a concussion compared to soccer players who rarely headed.
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Minnesota Vikings quarterback Teddy Bridgewater lies unconscious after sustaining a particularly nasty hit to the head during a game against the St. Louis Rams in 2015. The NFL reports there were 271 diagnosed concussions last year.