Brian Duncan doesn’t know why his brain still works as well as it does. Duncan, 67, got his bell rung more than once during his life as a professional football player, an amateur boxer and a bull rider at Texas rodeos. He remembers one time he got slammed into the ground by L.C. Greenwood, a 6-foot, 6-inch defensive end for the Pittsburgh Steelers; so hard that he hallucinated he was back playing high school football. “They use to play a team that had a feed lot behind their football stadium,” Duncan said.
Despite that history, Duncan is one of the lucky athletes whose past punishment has not caught up to him. Duncan and players like him highlight what continues to be a point of ferocious debate among brain researchers the effect of repeat head trauma on both brain structure and the brain’s ability to think, remember and reason. He’s part of a recent study of National Football League (NFL) players that find no link between impaired brain function and either the number of concussions players received or the number of years they played in the NFL.
The football player
However, the study faces criticism from other brain researchers who note; so that these findings run counter to a growing mound of evidence linking brain damage to the number of years a person plays football. “You see the same sentence repeat [in the study], almost as if they’re trying to lull us with a bedtime story ‘They did not find a significant linear association,’ over and over,” said Kristen Dams-O’Connor. She directs the Traumatic Brain Injury Research Center of Mount Sinai, in New York City.
Didehbani stressed that, “none of us believe concussions are good for the brain. Some people do have problems after multiple or even single concussions. But it’s not as simple as playing football equals impairment. It’s not a simple one-to-one.” But experts criticizing the study noted that Didehbani and her colleagues; so only count the years players spent in the NFL in their calculations. Other research has found that the hits a player takes in Pop Warner; so high school and college football all contribute to brain injury, and that those effects stack up over time.
Chris Nowinski is co-founder and CEO of the Concussion Legacy Foundation. He said, “they would argue that they didn’t measure exposure; also so they would argue they should not have published the study as is. They should have gone back to those players; also ask them how long they played football. That is the question, and that is the relationship that has observe in other studies. To me, this study is meaningless without additional data regarding how many years they play.”
Loss of brain function
Dams-O’Connor also criticized the small sample size of 35 players. She note that the study’s own statistics initially show a weak correlation between years played and loss of brain function, although that relationship washes out when corrected for other factors. “They am pretty confident that if the sample size was larger, then that would have a statistically significant association,” Dams O’Connor said. Repeated concussions have been linked to a brain disorder called chronic traumatic encephalopathy (CTE), which is marked by structural degeneration of the brain and abnormal clusters of toxic tau protein clusters.
Didehbani said that research needs to move forward to focus on individual factors that might increase the risk that a person’s brain function would suffer as a result of repeated concussions. “There are a lot of other factors and a lot of unknowns still,” Didehbani said. “We’re kind of jumping the gun a little too early and assuming that playing a contact sport will cause problems down the road. There are other factors we need to look at.”
For his part, Duncan thinks “there’s no question that head trauma causes some people to have some severe, long-term lasting injuries. To say that it’s 100%, that’s not correct, but on the other hand I think it probably is a good thing that awareness was brought to the situation because it’s caused the NFL to recognize these problems,” he added. “There’s still a lot to learn,” Duncan continued. “I don’t think people ought to panic about playing football; but they should be aware of the issues.”