Forrest Petz is a 39-year-old former mixed martial arts fighter from Cleveland. He says in his 11 years in the sport he took his share of hits, sometimes seeing stars.

“You get hit and it’s like a flash goes off," says Petz,"like somebody took your picture, and ‘poof!'”

He recounts one punch in particular, a left hook in a 2007 fight that flattened him and sent him for a loop.

“Next thing I know I’m sitting back stage," says Petz, "and I don’t remember why I’m sitting there."  

The concussion temporarily knocked out his short term memory. He says, "I don’t remember fighting, I don’t remember anything.”

Petz wonders if that punch, and the others he took in his career will come back to haunt him.

“Hopefully I skated through this thing without any lasting effects," he muses. "But only time will tell, right?”
 
An app tests fighters' brain and motor skills
Petz is one of 500 former and active fighters taking part in the Cleveland Clinic’s Professional Fighters Brain Health Study.

He’ll be visiting a lab where he’ll be put him through a battery of tests.

Jay Alberts is director of the Concussion Center and biomedical engineering at Cleveland Clinic’s Lerner Research Institute.

Alberts created an app that allows researchers, athletic trainers and doctors to easily measure brain processing speeds and motor functions in athletes.

He tested some of it on me.

In one test I slide my finger over the iPad trying to link numbers and letters. It’s a bit overwhelming, but the data allows Alberts to measure the speed of my mental processing and the speed of my movements.

This and other tests allow Alberts to untangle a complex set of symptoms in someone with brain injuries.

“So now we can determine: Do you have more of a movement problem, or do you have more of a thinking or set switching problem?"

"If you have more of a movement problem, let’s treat your movement; let’s not treat your cognitive issues. If you’ve got more of a cognitive problem, let’s treat your cognitive issues."

Alberts says the boxing brain study allows clinic researchers to determine how changes in biomechanical and cognitive functioning reflect very specific changes in brain function.

Boxing leads to brain shrinkage
The answers are coming from the world capital of boxing, Las Vegas, where Charles Bernick directs the Cleveland Clinic’s center for brain health.

He took brain scans of more than 200 professional fighters over the course of four years and tied changes to structures in the brain to slower processing speed, recall and reaction times.

“We can actually see a correlation between the anatomical changes and how somebody is performing," Bernick says.

He says nestled deep inside the brain called the thalamus acts as the brain’s central relay station. It shrank in fighters taking the most punches over time.

Bernick says the loss of motor and cognitive functions in the fighters can be linked to shrinkage of the thalamus and other parts of the brain. 

The force of repeated punches tears down the tissues. He says blows that spin the fighter's head are especially harmful because the brain floating in the skull actually starts moving and twisting, "stretching these fibers that cross throughout the brain and injuring them.”

Inflammation, bruising and bleeding inside the brain also take their toll.

Helping athletes outside the ring
Bernick has devised a simple formula to calculate a fighter’s risk of long-term brain damage.

His Fight Exposure Score is based on the total number of professional fights, the number of fights per year and the person’s age.

The higher the score, the more likely someone is to have brain shrinkage and cognitive impairment.

Bernick says this simple assessment tool could be helpful outside of boxing.

“The hope," says Bernick, "is that what we find in studying combat athletes can apply to football players, soccer players and so-on.”

In Cleveland, Jay Alberts says the boxing study will help to refine his brain-injury app to diagnose patients without using an MRI.

He's trying to identify a bio-mechanical signature "that you can evaluate someone relatively quickly and identify their level of neurological function.”

The boxing brain study has major funding from the top professional fighting promoters who say they’ll use the results to help make the sport safer.