The news comes on the heels of a new book and accompanying PBS documentary, League Of Denial, which brought awareness of the NFL’s concussion crisis to an even broader audience.
The new study, published in the journal Scientific Reports, does not diagnose any player with chronic traumatic encephalopathy (CTE), the neurodegenerative disease most associated with football head trauma, or any other brain disease. Rather, it suggests that players could be at risk for further cognitive problems down the road. Subjects were hooked up to a functional magnetic resonance imaging (fMRI) machine, which measured their brain activity while they performed a cognitive task: rearranging a series of balls in as few steps as possible. The 13 retired NFL players involved in the study performed slightly worse on the cognitive test than 60 control, non-football playing subjects. And the players showed significantly higher levels of abnormal activity in the frontal lobe, the area of the brain responsible for executive functions like reasoning, planning, executing tasks. Adam Hampshire, senior lecturer in restorative neurosciences at the Imperial College (U.K.) Department of Medicine, and lead author of the study, says the retired NFL players showed “some of the most pronounced abnormalities in brain activity that I have ever seen.”
Their brains, says Hampshire, are doing too much work. The control group showed low activity levels in the frontal lobe while performing the task, while the football players used more mental energy to complete the test successfully. The football players also showed lower levels of connectivity between the frontal lobe and other regions of the brain. What’s more, the level of abnormal brain activity in the NFL players directly correlated with how often they reported leaving a game because of head injury. The more they got knocked out of the game, the more dysfunction in their brains. “This is really critical,” says Hampshire.
According to the researchers, this is the first study to tie together a neuropsychological test, and an fMRI reading, in a cohort of NFL alumni. It has limits: the players all believed they were suffering from neurological problems, so they were a self-selecting population. Still, the work is noteworthy. “What this is really saying is that we may be able to develop a method to track the long term side effects of head impacts in football,” says Hampshire. “We should scan these guys season by season, year by year, to see if we can detect early warning signs that this kind of damage is accumulating. It’s important for each player to know if they’re at risk.”