Dr. Ann McKee (Chris O'Meara/AP)

Dr. Ann McKee has studied the brains of 54 former NFL players, more than any other person, but that hasn’t stopped some from criticizing her statements. (Chris O’Meara/AP)

“I’m really wondering where this stops,” said Dr. Ann McKee, a neuropathologist at Boston University. “I’m wondering if, on some level, every single football player doesn’t have this.

McKee and her research are featured in the Frontline documentary “League of Denial” that aired Tuesday evening on PBS stations. Dr. McKee, who grew up in Wisconsin, is a Green Bay Packers fan. She has discovered evidence of chronic traumatic encephalopathy in the brains of former NFL players.

In August, having seen the trailer for “League of Denial,” the President of ESPN characterized Dr. McKee’s speculation as “sensational.” ESPN investigative reporter Mark Fainaru-Wada, who co-wrote both the documentary “League of Denial” and the book of the same title with his brother, Steve Fainaru, doesn’t entirely agree.

“She’s looked at more brains than anybody. She’s now up to 54 brains that have been studied of former NFL players; 52 of those have been shown to have CTE,” he said. “To suggest that Ann McKee is being sensationalistic is a tough sell, given her background on the issue.”

Dr. McKee’s research is central to the documentary and the book. McKee’s conclusions, and the conclusions of Dr. Bennet Omalu, Dr. Julian Bailes, and various other neurologists and neurosurgeons were disputed for years by the National Football League’s doctors, as Steve Fainaru recounts.“It started with former Commissioner Paul Tagliabue, who, in 1994, where there was a series of high profile concussions, called it “a pack journalism issue,” an issue that was a media creation, that it was a very small problem, relatively speaking, in the NFL,” he said.

Commissioner Tagliabue subsequently created the Mild Traumatic Brain Injury committee. It was first led by Dr. Elliot Pellman, a rheumatologist, and subsequently by Dr. Ira Casson, who earned the nickname “Dr. No” by repeatedly denying any connection between repetitive head trauma and the brain injuries suffered by NFL players.

“They attacked independent scientists, many of whom had worked in the league or loved professional football and were trying to warn the league that it was facing a major health crisis and needed to deal with the problem,” Steve Fainaru said. “That was their systematic effort over a period of nearly two decades.”

Why do some players develop CTE, and some do not? What is the role of prevalence? Is steroid use a factor? All of these things need to be answered.
– Dr. Kenneth Podell
The NFL declined to speak to Steve Fainaru and Mark Fainaru-Wada. The league also declined Only A Game’s request for an interview, providing instead a statement from Jeff Miller, the NFL’s Senior Vice President of Health and Safety Policy. The statement begins: “For more than two decades, the NFL has been a leader in addressing the issue of head injuries in a serious way.”

Steve Fainaru recognized the statement when I shared it with him.

“I think in many ways the best response to this assertion that the league is making is the response of the league itself,” he said. “So after 16 years of doing this groundbreaking research, as they describe it, under pressure from Congress and journalists from the New York Times and ESPN, and after being publicly embarrassed over what they were doing, they blew up the committee and disavowed that work. So for the NFL to make this assertion now and go back and say that they’ve been doing the leading research into concussions and long term brain damage is refuted by their own people at this point. So it’s sort of curious to us why they’re taking that position.”

Both the documentary and the book feature a historical perspective. One of the criticisms of the documentary has been that it leans too heavily on familiar stories of former players who have suffered from depression and dementia, lost their families and their money, and, in some cases, committed suicide.

One of those players, former Pittsburgh Steeler Mike Webster, died in 2002. He was 50. His doctors testified that football had damaged his brain. After a long and expensive fight, the league extended medical benefits to Webster, while simultaneously maintaining publicly that there was no connection between multiple concussions suffered by its players and depression, dementia, or suicide.

It’s probably impossible to watch the documentary or read League of Denial without concluding that the NFL has been guilty of hypocrisy for the past 20 years.

But Neil Genzlinger, who reviewed the documentary for Monday’s New York Times, fears that most viewers were not surprised, let alone shocked.

“Because of what we’ve seen with tobacco, as some of the Congress people pointed out, equating this NFL thing to what tobacco went through, no behavior surprises you when the idea is ‘You gotta protect the bottom line,’” Genzlinger said.

Genzlinger faults the film for failing to produce what he refers to as “a smoking gun.” For him, that would have been a secret memo acknowledging that the NFL knew their game was causing brain damage and didn’t care.

Dr. Kenneth Podell, a neuropsychologist with the Houston Methodist Hospital, also has problems with what’s not in the documentary. He feels “League of Denial” leaves the impression that concussions and sub-concussive impacts entirely explain the disease in the brains of former NFL players.

“Is there a relationship between repetitive hits and potentially developing chronic traumatic encephalopathy? There probably is,” he said. “So what is the role of genetics? Why do some players develop CTE, and some do not? What is the role of prevalence? Is steroid use a factor? All of these things need to be answered.”

What you should know now is that your child could develop a brain injury from playing football. It’s not just on the pro level. It’s on every level of football.
– Harry Carson, retired linebacker

Dr. Podell, who acknowledges that he’s an NFL fan, suggests that the necessarily expensive research into those questions will take many years. Meanwhile, he points out, the league has recently instituted rule changes and sideline protocols designed to limit the number of concussions and to more conservatively treat players who’ve suffered them. Still, he doesn’t regard the game as he once did.

“Do I see it a little bit differently now? Yes. Am I worried about head injuries? Absolutely,” Podell said. “But you also have to remember that society loves football, and the majority of people want to see the game stay the way it is, and until society changes its views, it’s going to be a very difficult thing to change.”

Among the former NFL players who’d like to see those views change is Harry Carson, former linebacker for the New York Giants and a member of the Pro Football Hall of Fame. Appearing in League of Denial, Carson, who has seen numbers of his contemporaries fall victim to depression and dementia in their retirement, offers advice to the parents of children with football dreams.

“What you should know now is that your child could develop a brain injury from playing football,” he said. “It’s not just on the pro level. It’s on every level of football. The question is, do you want it to be your child?”