San Francisco 49ers inside linebacker Chris Borland (50) celebrates after a fumble by New Orleans Saints quarterback Drew Brees (not pictured) in New Orleans, Louisiana in a November 9, 2014 file photo. Borland, a leading rookie then, retired from the NFL over health concerns related to repeated head trauma. (Chuck Cook-USA TODAY Sports)

A study that will be presented at next week’s American Academy of Neurology (AAN) meeting offers one of the most conclusive pieces of evidence yet of a definitive link between brain injury and playing football.

It shows that “more than 40 percent of retired National Football League players … had signs of traumatic brain injury based on sensitive MRI scans called diffusion tensor imaging,” according to a press release from the AAN.

This isn’t the first study of its kind. Last year Frontline reported that researchers with the Department of Veterans Affairs and Boston University found chronic traumatic encephalopathy (CTE), which the Mayo Clinic defines as “brain degeneration likely caused by repeated head traumas” that is “a diagnosis only made at autopsy,” in 96 percent of the NFL players they examined and in 79 percent of football players at various levels of play.

The researchers studied 165 deceased people who had played the sport in high school, college or professionally, and found evidence of CTE in 131 of them.

But this newest study is “one of the largest studies to date in living retired NFL players” and the “first to demonstrate significant objective evidence for traumatic brain injury in these former players,” study author Dr. Francis X. Conidi of the Florida Center for Headache and Sports Neurology and Florida State University College of Medicine said in the release.

“The rate of traumatic brain injury was significantly higher in the players than that found in the general population,” Conidi said in the release.

Heightened awareness of the connection between football and head traumas, the ongoing controversy over the NFL’s handling of the issue and a recent movie, “Concussion,” starring Will Smith, have led to speculation that tackle football as America knows it is doomed in the long run as parents become increasingly concerned about letting their children play.

To conduct the latest study, researchers took brain scans of 40 retired NFL players while giving them concentration and memory tests. The participants had played for an average of seven years and had reported an average of 8.1 concussions. Most were less than five years retired. Said the release:

The MRIs measured the amount of damage to the brain’s white matter, which connects different brain regions, based on the movement of water molecules in the brain tissue. Seventeen players, or 43 percent, had levels of movement 2.5 standard deviations below those of healthy people of the same age, which is considered evidence of traumatic brain injury with a less than one percent error rate. Twelve of the former athletes, or 30 percent, showed evidence on traditional MRI of injury to the brain due to disruption of the nerve axons, those parts of nerve cells that allow brain cells to transmit messages to each other. On the tests of thinking skills, about 50 percent had significant problems on executive function, 45 percent on learning or memory, 42 percent on attention and concentration, and 24 percent on spatial and perceptual function.

“We found that longer careers placed the athletes at a higher risk of [traumatic brain injury],” Conidi said in the release.

The study comes a few months after the NFL released its official 2015 injury report, which shows that instances of head trauma jumped by 32 percent from 2014 to 2015, rising from 206 to 271 reported concussions.

2015 saw the highest number of reported concussions in the past four years, as far back as the report disclosed.

Recently, NFL vice president for health and safety Jeff Miller publicly acknowledged the link between brain injury and football. Last month, The Post reported Miller told Rep. Janice Schakowsky (D-Ill.) at an event convened by a House committee that there was a proven correlation between football and brain injury. It was believed to be the first time that an NFL official acknowledged such a link between football and CTE.

Afterwards, however, prominent NFL figures were far less definitive on the subject, reported The Post’s Mark Maske. At least two influential team owners, including the Dallas Cowboys’ Jerry Jones, said last month they were not certain about the relationship between football and brain diseases such as CTE. And at a news conference, Commissioner Roger Goodell did not directly answer a question about whether he and the league believe such a link exists. By acknowledging a link between football and CTE, legal experts say, the NFL could undermine its position in court, where a proposed settlement between the league and retired players is on appeal, and potentially create an open-ended liability with current and future players.

“I think the most important thing for us is to support the medical [experts] and scientists who determine what those connections are,” Goodell said.

In 2010, the NFL took concrete steps toward protecting players from head injuries by implementing rules disallowing players from tackling by leading with their helmets into another player’s head or neck, according to NFL.com.


In this Sept. 27, 2015, file photo, Miami Dolphins linebacker Zach Vigil (49) and Buffalo Bills linebacker A.J. Tarpley (59) talks at the end of an NFL football game in Miami Gardens, Fla. A.J. Tarpley cites two concussions he sustained last year as the reason he has elected to retire from football after just one season. Tarpley’s agent, Ryan Downey, confirmed his client’s decision on Thursday, April 7, 2016, a day after Tarpley announced the news on his Instagram account. (Wilfredo Lee/AP)

The conversation surrounding player safety in football isn’t new. In fact, it has raged for more than 100 years. In 1905, The Post reported that President Theodore Roosevelt summoned coaches and athletic advisers from Harvard, Princeton and Yale to the White House to discuss “reducing the element of brutality in play.”

More than a century later, and the president of the United States is still discussing safety in football.