The most dangerous game?

“I have two daughters, both play soccer, and I’m very comfortable with that,” Sommers said. “I don’t think I’d let a son of mine play football.”

Von Puttkammer, still recovering from the trauma of her fourth concussion, falls very much in line with Sommers.

“I’ve considered it with football, and I wouldn’t let my son play, because it just seems dangerous,” Von Puttkammer said. “It’s hard, because most of my teammates haven’t had concussions. After a kid got a first concussion, I would probably say let’s pick a sport that’s less intense on your head, but probably not until that point.”

Unfortunately, the first concussion can often be the most significant. According to Cordeiro, those who have had a prior concussion are more likely to get concussions, and the symptoms associated with each successive concussion get longer and more detrimental.

“For most athletes, if they have a concussion hopefully their symptoms will be gone after seven to 10 days,” said Cordeiro, who still can’t read with background noise or run for more than 15 minutes two years after receiving a second concussion during a triathlon. “But for some people, they last longer, and it’s typically those people who have had head injuries before.”

There also comes the difficult decision of whether or not athletes should be hanging up the cleats after multiple concussions. For Von Puttkammer, the thought never crossed her mind until she was recovering from her fourth.

“I never have considered giving up snowboarding or soccer until now,” she said. “Unless I play in a women’s league when I’m older, I probably wouldn’t risk it. This has been pretty life−altering — I haven’t been able to do anything but school and sitting for three months. And as an active person, that’s frustrating.”

According to Cordeiro, every person is an individual case, and there’s no clear−cut line of whether an athlete should be allowed to continue to play a sport.

“We have team physicians here, we have a team neurologist at Tufts Medical, we have Dr. [Robert] Cantu, who’s one of the leading concussion experts, right down the street, and even if you sent an athlete to those doctors and said, ‘They’ve had three concussions or four concussions before, would you keep them out?,’ you’d get differing opinions. It’s a decision they have to make together as a team,” she said.

But there is a light at the end of the tunnel. Athletes are getting better and better at self−reporting their concussions, which is leading to more precautions and safer treatments. It also means more accurate data for researchers in the lab, as they try to break down the confusing world of one of the human body’s most difficult injuries to understand.

“We need to look at the question of why is this happening more,” Cordeiro said. “Until we can answer that, we’re really not going to know what direction to go into. Because we have all the data, we have all the numbers. People are focusing on it now, which is really the most exciting part, but we’re still a ways off from finding the answer.”