THE FLAWS OF THE FAMOUS 99 PER CENT
Critic says study of NFLers’ brains exaggerates the concussion issue
Scenario: Over the course of a few years, 111 kids at an amusement park are taken to first aid, nearly all complaining of queasy stomachs. Paramedics diagnose 110 with nausea.
Conclusion: more than 99 per cent of kids who ever go to an amusement park get nauseated. Right? Of course not. But this is the kind of unsupported extrapolation many have made since late last month, when the latest study co-authored by a leading brain-disease researcher, Boston University’s Dr. Ann McKee, was released. She and 26 other medical researchers identified chronic traumatic encephalopathy — the neurodegenerative malady known as CTE — in 110 of the 111 donated brains of one-time National Football League players.
“My hope is we’ll stop arguing about whether or not this is a problem, or whether or not it needs to be addressed,” said McKee, director of BU’s CTE Center.
The world’s foremost experts on traumatic brain injuries agree the matter needs to be addressed, and urgently. International experts just won’t go as far as to chain-link concussions to CTE. After the fifth International Consensus Conference on Concussion in Sport held last autumn in Berlin, experts reached the following consensus conclusion, released publicly in April, which stops far short of definitively linking traumatic head hits to brain diseases.
“There is still much to learn on the potential association between concussion/recurrent head trauma and long-term effects.
“There continues to be a need for additional research to fully understand the cause-effect relationship established between concussion and CTE.”
Does such a cause-effect relationship exist? If so, to what degree? And how prevalent is CTE in all retired NFL players? No researchers can say.
By her own admission, McKee has not yet studied a random sample of former football players, but rather a “convenience sample” consisting of only the donated brains of one-time players, nearly all of whom exhibited varying degrees of brain-disease symptoms before dying.
What about the brains of all those former NFL players who exhibited no such brain maladies in later life? Or brains randomly selected from the general population? What if the brains of those who never played football or any contact sports also exhibit seriously high levels of CTE? And to what degree, if any, did substance abuse exacerbate CTE in the brains of those McKee and the others examined?
To ask these questions is not to undermine the groundbreaking work of McKee and her researchers this decade, especially the work of her partner Dr. Chris Nowinski, founder of the Concussion Legacy Foundation and co-founder of McKee’s brain bank. For years, he has been the sharpest critic of feet-dragging pro sports leagues and the loudest advocate for the wide implementation of safer, more conservative protocols for concussion diagnosis and return-to-play at all levels of contact sports.
Nowinski and McKee have undoubtedly saved lives and aided the concussion recoveries of countless athletes because of their tireless advocacy in raising awareness of concussions and CTE. It’s just that not all experts in their field concur with all of their conclusions.
Dr. Lili-Naz Hazrati is a Toronto neuropathologist. She is an associate professor at University of Toronto and works at both Toronto’s Hospital for Sick Children and the Canadian Concussion Centre. She has examined dozens of brains of former professional athletes.
In a phone interview from Toronto, Hazrati told Postmedia she has not found nearly the high incidence of CTE as McKee and the others. What’s more, Hazrati said she’s troubled by the study’s lumping of brains showing minuscule traces of CTE (stages 1 and 2) with much more severe Stage 3 or 4 cases, and that as a result of the shocking 99 per cent prevalence figure, she is concerned media and the public are inferring an unsupported conclusion that not only football, but all contact sports, are extremely dangerous for all participants.
“When you look at their numbers (in the study), quite a bit of their CTE diagnoses are just, like, that tiny little spot,” Hazrati said. “Stage 1 means that they’ve looked through the whole brain and have found one tiny little spot where there are a few cells positive with tau protein (a primary CTE marker). In that whole brain there are very limited amounts of tau, and in one small area.
“If they call that CTE, fine — but then they bunch it with the ones with more severe, advanced CTE, and they call the whole bunch CTE. It’s like counting burn patients but even including me, who has a little burn at the very tip of my finger, and also everyone who has been burned somehow even any little bit, and lumping us all in with the severely burned.”
Nowinski, one of the study’s authors, takes great exception to Hazrati’s comments on this particular issue.
“I think Dr. Hazrati is severely mischaracterizing the study,” Nowinski wrote in an email to Postmedia. “Only 11 of 177 cases (six per cent) were Stage 1, so while a neuropathologist can complain that they think they have a better minimum criteria for diagnosis, it has no implication on the overall findings.
“A burn on the tip of your finger, which is an injury and does not turn into a progressive disease, is a completely inappropriate analogy for early-stage CTE. Cancer is more accurate.”
In her own examinations of brains of deceased professional athletes, Hazrati said she has detected less prevalence of CTE, and less severe cases, than her American counterpart.
“What I’m seeing, in ballpark numbers, is 30 per cent of our cases have some CTE pathology,” said Hazrati, who underscored that her research receives no funding of any kind from any professional sports body. “Most are basically very low-stage pathology. I’ve got CFL players, I’ve got hockey players and I’ve got brains from some other athletes — rugby players, wrestlers, boxers, sports like that. So it’s a mix, but they’re all professional athletes.
“We don’t see that volume of advanced cases that have been reported (by McKee). Only 30 per cent of our brains have CTE, and about 30 per cent don’t have anything.”
Bottom line, Hazrati said: “None of these post-mortem brain autopsies are going to solve the CTE (mystery) at all. You cannot solve the cause of CTE by looking at brains of deceased people.”
As yet, there is no way to detect CTE in the living.
“That first step is not solved yet — whether there’s a definitive link to concussions,” Hazrati said. “So how can you even think about who’s the most susceptible, who’s not, what age is the worst? Just looking at these brains (posthumously), you cannot say any of that. It’s just impossible at this point.”
Hazrati isn’t the only neuroscientist whose findings appear at odds with those of McKee and company.
For instance, Dr. William Stewart — a lead neuropathologist at a hospital in Glasgow, Scotland, with diagnostic and research specialties in forensic neuropathology, especially traumatic brain injuries — co-authored a study published earlier this year. That study examined the long-term health of those who suffered repeated concussions in elite-level rugby, a sport arguably as dangerous as football.
Researchers compared the cognitive function of 52 living, retired former male Scottish international rugby players — who had suffered an average of 14 concussions apiece — against 29 non-rugby players of similar age.
“There were no significant associations between number of concussions and performance on cognitive tests,” the study found. What’s more, although “persisting symptoms attributed to concussion” were more common in rugby players who suffered more than nine concussions, “these symptoms were not perceived to affect social or work functioning.”
Until researchers are able to study large random samples of football players, including those without symptoms — as well as non-football players in the general population who were never concussed — it will be hard for any claims of widespread afflictions to hold up to scrutiny.
Hazrati said we should all be careful to read closely what studies have found, and not connect more dots than medical scientists have provided. It might help, then, to bear in mind that analogy of nauseated kids at amusement parks.
“That describes it pretty well, yes,” Hazrati said.
That first step is not solved yet — whether there’s a definitive link to concussions … So how can you even think about who’s the most susceptible, who’s not?