What is a concussion?
Most people have a vague understanding of the injury, but what actually happens in the brain after a concussion is not well-known.
A concussion is caused by a movement in the brain so violent that the actual shape of the brain changes, according to Patrick Kiernan, a research assistant at Boston University.
But researchers continue to debate the severity and scope of sports-induced brain damage, especially at the youth level.
Dr. Bennet Omalu, made famous for his CTE research recently portrayed in the movie "Concussion," wrote a December 2015 op-ed in the New York Times entitled: "Don't Let Kids Play Football."
"The human brain becomes fully developed at about 18 to 25 years old," Omalu wrote. "We should at least wait for our children to grow up, be provided with the information and education on the risk of play, and let them make their own decisions."
"No adult, not a parent or a coach, should be allowed to make this potentially life-altering decision for a child."
Young athletes are more at risk because their brains are still developing, said Cliff Robbins, the program manager for education and research with the Concussion Legacy Foundation. The foundation collaborates with Boston University's CTE Program.
"In addition to fixing all the things that's going on, [the brain] is undergoing really large changes in development," Robbins said. "Damage from the initial injury may recover, but there's no way to understand how that has disrupted the long-term development."
Robbins said high-impact concussions are higher risks to brain development than CTE in youth sports. But, Robbins said, the lab has found the beginning of CTE in athletes as young as 17 who died of other causes.
And although the risk of concussion certainly exists in other contact sports, studies show football has especially damaging impacts, and that players could sustain thousands of hits to the head in one season, said Robbins.
But few studies have pinpointed the risk of youth football on later cognitive functioning and overall wellbeing.
"The research is so early," said Karen Postal, a clinical instructor at Harvard Medical School and a neuropsychologist for the NFL and the NFL Players' Association.
In her role with the NFL, Postal consults with players who can request to be seen by her. The NFL selects two neuropsychologists whom the league considers to be neutral for each state to offer their services to players. The NFL then pays a share of the cost of an assessment. Postal says that since she started in this role in 2012 she has yet to have a player request an assessment from her.
The biggest issue she said she sees with studies on CTE deals with selection bias. In most of these studies, the only brains donated to "brain labs" for CTE research are coming from former NFL football players who exhibited erratic behavior shortly before their deaths. Postal said that this causes the data to not fairly represent the entirety of professional football players.
But Boston University's Kiernan said that although the research is inconclusive, the facts point to a problem.
He said the brain bank, founded in 2008, confirmed over 175 cases of CTE, including 90 out of 94 NFL players examined. "While we cannot say precisely how prevalent CTE is yet, this evidence collected in a very short amount of time suggests that CTE is not a rare disease."
Although the science on the long-term effects of concussions may be inconclusive, there is currently a wealth of research that shows what happens to the brain immediately after receiving a concussion, said Postal.
"The type of force that you need to get a concussion is the equivalent of driving a car into a brick wall at 25 miles per hour," she said.
"There's an immediate change in how the cells in the brain are working. The cells start going wild," said Postal. "When they discharge, they use up sugar, [which is] the fuel in the brain. At the same time, there is a restriction of blood flow to the brain."
Postal said she allows her two sons, ages 12 and 13, to play full-contact football for a local league in Massachusetts. Postal also has a seven-year-old daughter who currently plays flag football, but Postal said she will probably play tackle when she's older.
"It's wonderful exercise," she said. "I would never say 'I'm going to keep you from playing these...team sports for fear of getting a concussion.'"
Although she said a first or second concussion wouldn't lead her to pull her kids from the sport, Postal said she would begin to reevaluate her children's involvement if any of them ever got a third concussion.
"If you go back to playing too quickly after getting a concussion, your risk for getting another concussion increases," Postal said.
Think of the brain as a piñata at a birthday party. With every swing of the bat, a piñata becomes more damaged. After just one hit, the cardboard still looks intact and there is no visible damage. But as the piñata takes on more and more hits, the exterior eventually becomes irreparably damaged.
The brain of an athlete who has sustained multiple concussions reacts very similarly to a piñata. After one concussion, he or she probably will not suffer any visible long-term side effects. But after five or six concussions, the athlete could experience irreversible brain damage.
Many young athletes will experience at least one sports-related concussion over the course of their careers.
On May 2, the medical journal JAMA Pediatrics published a study led by Dr. Zachary Kerr. The report found that during the 2012-2014 seasons, "1,429 sports-related concussions were reported among youth, high school, and college-level football athletes."
In the study, which included about 250 teams across the three levels, high school football players had the highest number of reported concussion symptoms. Youth football players had the highest likelihood of returning to play in less than 24 hours among the three levels.
But, the study warned, "puberty and brain development [in youth players] may affect concussion-related outcomes."
Published May 27, 2016