A quarter of Americans have had a concussion, and we’re still far from understanding its consequences.

At the end of the third quarter of the fantastic Notre Dame at Texas college football season opener on September 4, there were about 30 seconds left.

Irish wide receiver Torii Hunter Jr. leapt up to catch what looked like a touchdown pass that would have given Notre Dame the lead. But Texas defensive back DeShon Elliott slammed into Hunter with a hit that at least appeared to to make direct contact with his helmet. The ball fell to the ground and Hunter didn’t get up.

After several minutes of checking to ensure he could still move his arms and legs, the medical team helped him to his feet and walked him to the locker room. The redshirt junior team captain is now in what’s known as the concussion protocol, which means that he’s supposed to return to baseline levels of cognitive performance and balance before slowly ramping up physical activity again.

It’s unclear whether or not Hunter will be cleared to play in the Irish home opener against Nevada on September 10.

We now pay a lot more attention to head injuries in football and other sports, as we’re more aware now of the potential long term consequences than we have ever been. But that doesn’t mean we are anywhere close to figuring out what to do about these injuries.

Hunter’s return is unclear in part because every individual hit to the head is unique, as is the recovery process. But the issue is also something much larger: We still don’t understand nearly as much as we would hope to about brain injuries, despite the fact that they are astonishingly common.

“Part of the biggest problem that we have is that we still don’t know exactly what a concussion is,” Dr. Chad Asplund, medical director of athletics sports medicine at Georgia Southern University, tells Business Insider. We know how concussions happen and we’ve observed a number of different symptoms triggered by brain trauma, but we still don’t know exactly at what point these injuries (or smaller sub-concussive hits) lead to permanent damage.

Almost a quarter of Americans report having suffered a concussion, according to a recent NPR-Truven Health Analytics Health Poll.

therudedogshow@hotmail.comA quarter of Americans have had a concussion, and we’re still far from understanding its consequences.