The growing evidence of a link between head trauma and long-term, degenerative brain disease was amplified in an extensive study of athletes, military veterans and others who absorbed repeated hits to the head, according to new findings published in the scientific journal Brain.
The study, which included brain samples taken posthumously from 85 people who had histories of repeated mild traumatic brain injury, added to the mounting body of research revealing the possible consequences of routine hits to the head in sports like football and hockey. The possibility that such mild head trauma could result in long-term cognitive impairment has come to vex sports officials, team doctors, athletes and parents in recent years.
Of the group of 85 people, 80 percent (68 men) – nearly all of whom played sports – showed evidence of chronic traumatic encephalopathy, or CTE, a degenerative and incurable disease whose symptoms can include memory loss, depression and dementia.
Among the group found to have CTE, 50 were American football players, including 33 who played in the professional league. Other sportsmen included boxers, hockey players and other players of contact sports.
The study was conducted by investigators at the Boston University Center for the Study of Traumatic Encephalopathy and the Veterans Affairs Boston Healthcare System, in collaboration with the Sports Legacy Institute.
The investigators also created a four-tiered system to classify degrees of CTE, hoping it would help doctors treat patients. The volume of cases in the study “allows us to see the disease at all stages of severity and how it starts and spreads in the brain, which gives us an idea of the mechanism of the injury,” said Ann McKee, the main author of the study.
Despite the breadth of the findings, the study, like others before it, did not prove definitively that head injuries sustained on the field caused CTE. To do that, doctors would need to identify the disease in living patients by using imaging equipment, blood tests or other techniques. Researchers have not been able to determine why some athletes who performed in the same conditions did not develop CTE. “It’s a gambler’s game to try to predict what percentage of the population has this,” said Chris Nowinski, a co-author of the study. New York Times