Study: NFL players with concussion histories showed reduced cognitive performance

A large study looking at over 353 former National Football League (NFL) players found that players with a history of concussions and concussive symptoms had reduced cognitive function long after retiring.

The study, led by Mass General Brigham investigators from McLean Hospital and Spaulding Rehabilitation Network, compared former players against men of the same age and found that players who had concussions during their NFL careers scored worse on assessments of episodic memory, sustained attention, processing speed and vocabulary.

The study required 353 former players — who had on average retired from the NFL 29 years ago — to complete hour-long online tests. Concussion information and details about players’ symptoms was self-reported. Researchers then compared the players’ test scores to the scores of 5,000 male volunteers who did not play football. The comparison found that while younger former players outperformed nonplayers on some tests, older retired players were more likely to perform worse.

“It is well-established that in the hours and days after a concussion, people experience some cognitive impairment. However, when you look decades out, the data on the long-term impact have been mixed,” said study senior author Laura Germine, director of the Laboratory for Brain and Cognitive Health Technology at McLean Hospital and associate professor of psychiatry at Harvard Medical School, in a press release. “These new findings from the largest study of its kind show that professional football players can still experience cognitive difficulties associated with head injuries decades after they have retired from the sport.”

To find out which players had experienced concussion symptoms while playing, the researchers asked them if they had experienced symptoms such as headaches, nausea, dizziness, memory problems, or visual problems.

Players were also asked to think back on their careers and report if they had ever lost consciousness while playing, and if they were diagnosed with a concussion by a medical professional at any point.

The results of these assessments showed that players who said they had experienced concussion symptoms during their career demonstrated worsened cognitive function overall.

To put these results in perspective, when looking at visual memory scores between former players with the highest versus the lowest reported concussion symptoms, they found their difference in cognitive function was comparable to that of a typical 35 year old and 60 year old.

“Former players can support their cognitive health as they age by taking proactive steps and continuing to consult with their providers and educate themselves on symptoms of head injury,” said Ross Zafonte, principal investigator of Harvard University’s Football Players Health Study, of which this new study is a part of, in a press release.

Neither the number of diagnosed concessions nor the length of a player’s football career appeared to impact the results.

To understand how playing football contributes to the decline in cognitive function later in life, researchers conducted a follow-up analysis that compared the former NFL players to more than 5,000 males from the general population who were not football players.

This comparison concluded that the NFL players’ cognitive function generally worsened to a higher degree as they aged, more than the non-players.

A previous study published in 2010 reported on the prevalence of concussions in the sport, finding that there are approximately 140 concussions reported each NFL season, plus it’s estimated that one player suffers a concussion every five games.

“For researchers and providers, these findings support efforts to develop ways to enhance diagnosis and define long-term sequalae of concussion,” said Zafonte.

“Football today is very, very different from 30 years ago, 20 years ago, even 10 years ago,” Germine said. “A lot of changes have been made to improve concussion detection, to prevent concussions and injury in general, and to address player health at the time that a concussion occurs. Could more be done? Yes.”

Germine said that the league should emphasize detecting a head impact at the time of a concussion, track symptoms, and if a player has multiple concussions, they should be treated in conjunction with each other, not as separate medical events.

Player education also matters, she said.

Teams and medical staff should be “making sure that players are well-educated in … the long-term differences that are associated with brain injury and with concussions, so that it’s not just about this game, this moment, but about it as something that one needs to do to maintain one’s healthy functioning and brain health in the long term,” Germine said.

Former players should also be aware that the impacts of concussions can follow them even for decades after they leave the field, Germine added.

“The story is not over here. We are looking 30 years later, and we’re seeing differences, right?” she said. “We have to be taking care of players. They have to be able to take care of themselves and their brain health in the long term.”

Part of the article was reported by CBS News.