As I mentioned, we definitely do know that more people have persisting symptoms than we initially thought, symptoms like headaches, vestibular issues, which are going beyond the usual—quote, unquote—“recovery time” of a couple of weeks. It's unclear whether that is simply because people are more comfortable reporting it and they don't hide it as much as they may have previously, or whether there is some other factor, extrinsic or intrinsic, that is emerging. That is definitely something on which more research needs to be done.
We do know that women do present with persisting symptoms more frequently than men do, so the fact that Dr. Tator has received only one woman's brain for his research is very interesting. It would be very interesting to see more female brains.
In terms of how long symptoms last, when people end up with persisting symptoms, they can become chronic. That's a huge issue in terms of managing the people in that 15% to 20% who end up with a concussion that has persisting symptoms. That impacts people's lives thereafter. The research we really need is to figure out what sorts of things we can do for those people and what kind of evidence we can find in the research to support people like Dr. Marshall who do rehabilitation with people with persisting symptoms.