And we move now to this month's "Your Brain Health Matters."

Chronic traumatic encephalopathy, or CTE, is a degenerative brain disease associated with repeated hits to the head.

And right now doctors can only diagnose it after death, but researchers are looking for ways to recognize the effects of repeated head impacts while athletes are still alive.

At UNLV, Dr.

Jeffrey Cummings and researcher Brooke Conway Kleven are analyzing data from two long-term studies involving former football players and professional fighters.

They're studying changes in cognition and behavior, along with brain imaging and proteins found in the blood.

(Dr.

Jeff Cummings) Charlie Bernick, who is at the Cleveland Clinic Lou Ruvo Center for Brain Health, has done a fabulous job of studying longitudinally fighters from the UFC and boxers, because we know that these kind of contact sports can give rise to chronic neurological disease.

The observations of the football players happened about simultaneously.

We started that trial eight-- that study eight years ago.

We're looking at the cognition.

How does that look?

Does it look like Alzheimer's or something else?

We're looking at the behavior because we know that athletes can have these rage attacks that are known to occur.

And then the exciting thing that Brooke has been analyzing is the blood biomarkers that we have collected in the study, because they're the most likely aspect of the study to be able to reveal who has these different forms of neurological disease coming from their athlete experience.

(Brooke Conway Kleven) Most of the blood tests we look at are different proteins in the blood that can measure either, one, the amount of structural damage that has happened to the neurons or the amount of injury or inflammation to the surrounding supporting tissue in the brain.

-When are you doing these tests?

-We do it at different time points.

So with the football players, it's baseline and then eight years later.

With the professional athletes study, we do it every year.

So unlike with the football players that they have to be former--no longer playing--with the professional athletes study, we have a lot that are currently actively fighting.

So we do once-a-year blood work, MRI, cognitive measures, behavioral, and measure-- monitor them annually.

So that's something very interesting with that study because we not only get to see once they're done having the exposure, but how does it look when we back up even further and actually see while they're currently having the exposure, when they then transition out of the exposure, and then long term how do those outcomes look?

So this gives us a very long range of being able to observe that.

-And I think you told me before we started recording that you've taken it up to another level where you're beginning before a fight camp and then immediately after a fight?

-Yes.

One of the benefits of the longitudinal study is we can see over a longer period of time how things change, but that doesn't give us a very good idea of what's happening clearly with the exposure.

So what we're looking at more acutely with UFC is in fighters as they're leading up to a fight, we're doing every two weeks throughout this camp leading up to their fight so we can see fluctuations of these blood markers while they're sparring, while they're training, and then after their fight.

So, theoretically, how do they fluctuate over time, and does it look the same as whether they're concussed and/or symptomatic or not?

-Those blood tests are not yet a standalone test for CTE.

But when researchers combine them with brain imaging, cognitive testing, and years of observation, they can begin to identify patterns associated with repeated head impacts.

And some of their findings are challenging common assumptions about CTE.

-We are starting to see that the behavioral explosivity may not necessarily be directly related to CTE like we thought it was.

And a lot of the studies have been showing that the cognitive impairment actually has a greater relationship with the likeliness of CTE than the explosive behaviors.

And that, in my mind, is a very big finding because traditionally in the media, everybody always talks about suicide or domestic abuse and how that's caused from the sport and it's related to CTE.

But a lot of these recent findings from diagnosed CTE actually leans that, yes, neurobehavioral dysregulation is very much associated with head impact in itself but not necessarily with CTE.

-And one other very interesting difference has been that Parkinsonism has often been related to chronic traumatic encephalopathy.

And what we see is some of the boxers get a Parkinson's disease-like syndrome, and that is very rare in the football players.

So we can see that there are differences clinically emerging from the different types of head impact that athletes get.

-Conway Klevin says this research could also help protect members of the military who can experience repeated head impacts or blast exposure.

Her long-term goal is to develop objective measures that could help determine when someone has experienced too much exposure, even if that person is not showing symptoms.