Researchers say their newly published study confirms a finding of chronic traumatic encephalopathy in a living patient.
The study, published in Neurosurgery this week, found the presence of tau, a protein that forms around damaged neural cells, in 14 living retired NFL players through a brain scan. Following the death of one of the players, doctors confirmed a CTE diagnosis.
Dr. Bennet Omalu, one of the 12 researchers for the paper, told ESPN's Outside the Lines that the former NFL player was Fred McNeill, who died in 2015.
Dr. Julian Bailes, who participated in the study, told ESPN that the new publication contains the peer review of two co-authors, who confirmed that McNeill had been living with CTE, as OTL reported in February 2016.
CTE can cause symptoms such as depression, impulsive anger, violent mood swings, memory loss and deficits similar in some cases to Alzheimer's disease. CTE has been found in a number of former NFL players after their deaths, including Junior Seau, Dave Duerson and Aaron Hernandez.
"It's not just about the concussions," Bailes said. "It's about years of exposure and subconcussive blows."
McNeill had been studied by UCLA researchers, including Omalu, after he was showing symptoms of the disease. Omalu told OTL in February 2016 that McNeill's case was the first correlation between UCLA's experimental testing and a posthumous examination.
Bailes said the data could improve the potential diagnosis of CTE in players while they are still alive.
"The importance of this one today is that this is the first time to have a scan which shows brain degeneration of CTE in a living person and then to have that person die and it correlates with the autopsy," Bailes said, according to ABC News.
Bailes said this individual study needs further research to verify the correlation between tau and CTE. Omalu told CNN that the research team is raising funds for further research to replicate the study's results but that a commercial test could be available in less than five years.
ESPN's William Weinbaum contributed to this report.