BOSTON An extensive study of the brains of dead athletes and others shows that most had signs of brain damage after suffering repeated head injuries.
The study published Monday by the Boston University School of Medicine reports on the autopsies of 85 brain donors.
The autopsies revealed extensive evidence of protein tangles clogging brain tissue and causing the destruction of brain cells in football players, wrestlers, hockey players, boxers, and military combat veterans.
The researchers reported in the journal Brain that 68 of the 85 individuals they examined, all of whom had experienced repeated head trauma, had evidence of chronic traumatic encephalopathy.
Co-author Dr. Robert Cantu tells The Boston Globe the study should convince doubters that CTE is a real condition caused by repeat head injuries.
Cantu's colleague, Dr. Ann McKee,that CTE can only be detected after death by staining tau protein deposits in brain tissue - a complex, several-month process that she compared to developing a photograph.
Last year, McKee concluded that Dave Duerson, a former NFL player who committed suicide, had "moderately advanced" brain damage related to blows to the head. Hockey player Derek Boogaard also at the time of his death last year.
In September, the NFL announced a donation of $30 million for medical research to the Foundation for the National Institutes of Health, the fundraising arm of the NIH.
NFL Commissioner Roger Goodell said the research could benefit athletes and potential areas of study may include CTE, concussion management and treatment and disorders from later in life such as Alzheimer's.
Last month, Goodell talked to "CBS This Morning" about the growing concerns surrounding the safety of players (watch video at left).