Abnormal brain activity points to damage in former players

Football is a rough game that takes a visible toll on the body. Now, researchers say that toll could have a serious mental impact as well.

Led by Adam Hampshire, Imperial College (London, U.K.), with the assistance of Western Psychology professor Adrian Owen, a recent study showed former National Football League (NFL) players face a risk of subtle neurological deficits that don’t show up on normal clinical tests. These deficits may affect their ability to plan and organize their everyday lives.

Although the former players in the study were not diagnosed with any neurological condition, brain-imaging tests revealed unusual activity that correlated with how many times they had left the field with a head injury during their careers.

“The NFL alumni showed some of the most pronounced abnormalities in brain activity that I have ever seen, and I have processed a lot of patient data sets in the past,” Hampshire said. “The critical fact is, the level of brain abnormality correlates strongly with the measure of head impacts of great enough severity to warrant being taken out of play. This means it is highly likely damage caused by blows to the head accumulate toward an executive impairment in later life.”

Previous research found former NFL players experienced higher rates of neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease.

The study, published recently in Scientific Reports, involved 13 former NFL players who believed they were suffering from neurological problems affecting their everyday lives, as a consequence of their careers. The players, along with 60 healthy volunteers, were given a test that involved rearranging coloured balls in a series of tubes in as few steps as possible. Their brain activity was measured using functional magnetic resonance imaging (fMRI) while they did the test.

Owen, Western’s Canada Excellence Research Chair in Cognitive Neuroscience and Imaging, said being able to brain scan the NFL players set this study apart. Because of the multiple concussions these players suffered during their careers, they comprise a rather unique population for study.

While the NFL players performed worse on the test than the healthy volunteers, the difference was modest. More strikingly, however, the scans showed unusual patterns of brain activity in the frontal lobe.

“We found severe abnormalities in the frontal lobes of these players, a region of the brain I have studied for more than 20 years. The frontal lobes are crucial for planning, attention, concentration and many aspects of memory,” Owen said. He noted the difference between the two groups was so significant a computer program learned to distinguish NFL alumni and non-alumni at close to 90 per cent accuracy.

“Of the thousands of people who have participated in our cognitive studies, we can literally pick out the NFL players, based on their (abnormal) pattern of brain activity alone,” Owen said.

The most “amazing finding,” Owen continued, was the severity of the abnormality correlated with the number of times the players had been carried off the field during their professional careers.

Hampshire suggested the fMRI could be used to reveal hidden neurological problems not picked up by standard clinical tests on NFL players. Brain-imaging results could be useful to retired players who are negotiating compensation for neurological problems that may be related to their careers. Players could also be scanned each season to detect problems early.

“Researchers have put a lot of time into developing tests to pick up on executive dysfunction, but none of them work at all well,” Hampshire said. “It’s not unusual for an individual who has had a blow to the head to perform relatively well on a neuropsychological testing battery, and then go on to struggle in everyday life.

“The results tell us something very interesting about the human brain, which is, after damage, it can work harder and bring extra areas online in order to cope with cognitive tasks. It is likely that in more complicated real-world scenarios, this plasticity is insufficient and, consequently, the executive impairment is no longer masked. In this respect, the results are also of relevance to other patients who suffer from multiple head injuries.