CHAPEL HILL, N.C. -- Zoya Johnson, a former gymnast at the University of North Carolina at Chapel Hill, had her last concussion two years ago -- and six others before that. She fell on her neck from the high bars.
As an athlete and a student, being concussed kept her from studying, from falling asleep. She struggled with nausea and dizziness. Today, Johnson still takes seizure medication during the day, and other medicine to help her sleep.
"I didn't realize I had so many until I learned what a concussion was," she said here at the annual conference  of UNC's Collegiate Sport Research Institute -- and even after she found out, it wasn't her last. "I didn't realize I had five until I had [my sixth]."
It was clear at a panel discussion here on head trauma in college athletics that despite growing attention being paid to the issue, there's still a lot that people don't know -- and aren't doing -- about it.
For instance, how many concussions does it take to cause long-term cognitive problems? How much does sports culture -- which rewards toughness and fighting through adversity and pain -- have to do with the prevalence of head trauma, and what can be done to shift it? When concussion tests have reliability and validity issues (as they do), how can a coach or athletic trainer confidently return a concussed athlete to the field?
Data on head trauma are lacking, but given what we already know -- that head trauma sustained through contact sports can cause short-term problems like Johnson's but also long-term dementia and depression -- do we really need any more data before intervening?
As put by Lewis Margolis, an associate professor of maternal and child health at UNC: "Aren't we engaged in a large, immoral national experiment about this problem, and when will we step back and say, 'Stop'?"
The National Collegiate Athletic Association, facing a rising risk of litigation and following the lead of the National Football League, has taken some steps to try to prevent head trauma. In 2010 it mandated that all institutions develop concussion management plans, and it has adjusted some rules to discourage dangerous forms of contact. (For example, it moved the kickoff line 15 yards forward, which has resulted in more touchbacks -- and thus fewer collisions on returns -- while not affecting the frequency of scoring.)
But the association is still skirting responsibility and needs to be held accountable, said Ramogi Huma, founder of the National College Players Association.
"There's a lot the NCAA can do in policy," Huma said. "By avoiding it, they are a cancerous part of the culture."
The Ivy League in 2012 limited contact in practices  to try to reduce head trauma, and is working with the Big Ten Conference to gather data  on concussions. It will take years before any conclusions can begun to be drawn, but any steps that might help are worthwhile, said Huma, who has pushed the NCAA and other conferences to adopt similar policies but been largely ignored.
A good chunk of discussion focused on a factor that's not easily addressed by tests or making athletes sit out a play when their helmet comes off during a play (which the NCAA now does): culture.
"If there's something that's not keeping you off the field, you're going to play through it," Huma said. "Anything less is an embarrassment."
Jason Mihalik, an assistant professor of exercise and sport science at UNC, recalled hearing some coaches tell concussed students to just take the concussion test and get back out on the field.
"The testing itself is not the answer," he said. "There are many other things that go into it." Identifying the symptoms and knowing your athlete -- recognizing that a smart quarterback calling the same play three times in a row is probably a sign that something's wrong -- are also crucial.
Johnson said her fellow athletes didn't even take the tests seriously until she started speaking up about how concussions were affecting her personally.
Athletic trainers or physicians on the sidelines are charged with testing the athletes and deciding whether they're O.K. to go back to playing. But when coaches hold huge power at institutions, and the institutions or even the athletics department are hiring the trainers, conflicts of interest could result in pressure on the trainers to give a go-ahead when they shouldn't, Huma said.
In multiple cases last year, athletes showed obvious signs of concussions -- vomiting on the field and falling down repeatedly -- but were not removed from the game.
"I think there's a need for independent doctors," Huma said. "The person who at the end of the day decides whether or not the player returns should not have a conflict of interest."
However, Mihalik noted that physicians in general don't get a lot of training in concussions.
"I would argue that a coach that is there all the time that knows the athletes might be better equipped to identify the subtle nuances of a concussion," he said.
When people think about head trauma, football is most often the main sport (and perhaps the only sport) that comes to mind. Athletes do sustain more concussions in football than in any other sport, simply because there are more athletes playing the game. But the rate of concussions per athlete is worse in ice hockey, and head trauma can occur in any contact sport (as well as in those that wouldn't be considered contact sports, like gymnastics).
UNC -- which Mihalik said goes above and beyond what's required by the NCAA's concussion management plans -- does pre-season baseline testing for 20 of its 29 sports. Then, when an athlete is concussed, officials can measure their test results against the non-concussed results.
Huma, who played football at the University of California at Los Angeles, said he doesn't know if he'll let his two sons play football once they're older.
"No, I shudder to think of all the hits I took and gave," he said, comparing the risks to Russian roulette. "I don't think anyone knows how this is going to turn out."