Omalu compared a region of the brain of a normal, middle-aged individual to a football player's. His analysis showed an accumulation of brown staining in the football player's brain.
The brown blotches mark the accumulation of tau protein -- an abnormal substance that can emerge within the brain after repeated blows to the head. It's known to kill off brain cells, ultimately leading to cognitive dysfunction, even dementia, Omalu said. It's rare to find accumulation in the brain of a 90-year-old -- but at the time it was almost unheard of in a man of 50.
Omalu said that scientific papers have suggested that as few as three major head impacts can result in the abnormalities.
"One individual may just have one major impact to the head. Another individual may have two, another individual may have 1,000 before they will develop this disease," Omalu said.
In the absence of any title for his discovery, he called the disease chronic traumatic encephalopathy, or CTE. He wrote up his findings and sent them to the prestigious academic journal Neurosurgery.
But there was a swift reaction. Several doctors on a committee convened by the NFL to study brain trauma demanded its retraction. But the journal was satisfied with Omalu's work and refused.
"I thought it was my responsibility as a physician. I've seen something unique to report to the general scientific community," Omalu said.
A few months later, Omalu would receive the body of another storied football player. His findings were the same.
"This is how diseases are discovered and identified. So I published the second case. Oh, newspapers, some doctors went to the press. In fact they were insinuating I was practicing voodoo medicine," Omalu told "Nightline." "They called me names -- preposterous, unscientific methods. But again, you seek the truth, and the truth will set you free."
Bailes was the first and most senior clinician in the country to support Omalu's research.
"I reviewed Dr. Omalu's publication, the first one, the sentinel case of Mike Webster. It obviously struck a chord with me because I felt that I knew Mike very well professionally and personally," he said. "The letter of retraction demanded by the NFL was also unusual, and I thought inappropriate, and I thought they had missed the point."
There was now no stopping Omalu. A third body was delivered to his laboratory. Omalu noticed that all of his cases displayed common symptoms, including memory loss, insomnia, alcohol use, drug use and diminished executive functioning, or the loss of the ability to engage in complex mental functioning like business investments and money management. They were paranoid, exhibited manic depressive episodes, breakdown in social relationships and had criminal tendencies, he said.
Since the discovery, Omalu has gone on to study the brains of 7 other retired pro football players postmortem. Along with Bailes, he is beginning to understand how these microscopic injuries may occur at the point of collision.
"Two major things -- one is the helmet and the cranium suddenly stop, but nonetheless the brain continues forward, hits the inside of the skull, it bounces back and hits the back of the skull and maybe reverberated a second time. In addition, there is rotator effects where there is a rotation, and that also is a very common way that fibers get torn," Bailes said.