This is part of Collision Course, a Spectator investigation on concussion and football. See more series content.

It's not often that a scientific article in a neuroscience journal plays a central role in two lawsuits.

More than 200 former CFL players in a class-action lawsuit, and former Tiger-Cat Arland Bruce in a separate case, are suing the CFL, its nine teams and the CFL's former commissioner, accusing the league of negligence in relation to brain injuries.

What's unusual is that the class-action lawsuit also names 81-year-old neurosurgeon Charles Tator and a Toronto neuroscience research institute as defendants.

Both lawsuits include allegations that raise concerns about the relationship between the CFL and the Canadian Sports Concussion Project, which is led by Tator and the Krembil Neuroscience Centre in Toronto. The allegations have not been proven in court.

The statement of claim in the Arland Bruce lawsuit goes a step further and raises concerns about the relationship between the Canadian Sports Concussion Project, the CFL and the CFL Alumni Association.

Both lawsuits take aim at an article published in May 2013 in a scientific journal called Frontiers in Human Neuroscience.

The article was titled "Absence of chronic traumatic encephalopathy in retired football players with multiple concussions and neurological symptomatology."

The paper reports on the findings from the post-mortem examinations of six donated brains from deceased CFL players.

Tator was one of nine co-authors listed on the highly-technical scientific paper. Eight of the nine were associated with various departments of the University of Toronto, including the Krembil Neuroscience Centre.

Also named as one of the co-authors was Leo Ezerins, executive director of the CFL Alumni Association and a former Tiger-Cat.

The Arland Bruce lawsuit alleges the CFL and the CFL Alumni Association provided funding to the Canadian Sports Concussion Project and researchers at the Krembil centre.

The lawsuit also alleges this put Ezerins in a conflict of interest because he was the head of the CFL Alumni Association and a member of the Canadian Sports Concussion Project at the same time.

Ezerins, Tator and the Krembil Neuroscience Centre were originally named as defendants in the Bruce lawsuit, but they were recently released.

What's most curious about the scientific paper is its title.

Although it states clearly "Absence of" chronic traumatic encephalopathy (CTE) in former players, the paper reports that in fact, evidence of CTE was found in three of the six brains.

The other three brains showed evidence of Parkinson's disease, Alzheimer's disease and Amyotrophic Lateral Sclerosis — in other words, all six brains showed evidence of neurodegenerative disease.

The paper includes a frightening chart of symptoms for each player compiled from medical records and interviews with family members.

All six of the players had short-term memory problems. All six had some type of speech or language problems. All six had suffered multiple concussions.

Five of the six showed signs of progressive dementia, four of the six suffered from delusions, and three of the six experienced hallucinations.

"I couldn't believe what I was reading," said Robyn Wishart, a Vancouver-based lawyer who is representing the plaintiffs in both lawsuits against the CFL.

"When is absence ever 50 per cent?

"I don't know how that ever got published," Wishart added.

Tator declined to comment on the lawsuit's allegations because the matter is still before the court. Tator also declined to comment on the "Absence of CTE" scientific article cited in the lawsuit.

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The Bruce lawsuit alleges the article's authors concluded that there was no provable connection between concussion and sub-concussive injuries and CTE in CFL players, which is "against the weight of the medical evidence."

The authors "knew or ought to have known" the link between CTE and concussive head trauma was "statistically more significant than the link between smoking and lung cancer," according to allegations in the Bruce lawsuit.

The suit also alleges Ezerins interfered with an independent project involving cognitive testing of 25 former Ticats in 2011 and that he "ultimately stopped the researchers" at McMaster University from interpreting the test results.

(That project has no connection to the current Spectator concussion research.)

At the time, Ezerins told the Spectator, "We're really protecting the sport and protecting the CFL. It's a very important issue and we want to make sure it doesn't reflect poorly on the game of football, that we have the proper perspective."

The lawsuit also alleges Ezerins stated the "stories of concussion and its long-term effects do not represent the majority of former football players."

Ezerins' conduct in interfering with the Tiger-Cat study was "reprehensible," the lawsuit alleges.

The statements of claim for both lawsuits also allege that former CFL commissioner Mark Cohon claimed in 2011 that "unreported concussions were far less of a problem in the CFL."

A Harvard University study released in May raises questions about how the league would know if that's true.

The Harvard analysis compared the health-related policies and practices of North America's professional sports leagues, including the CFL.

The 258-page report notes that the concussion rate in the CFL is actually slightly higher than the NFL's rate. In fact, the CFL's rate of concussions per game was the highest of the leagues studied.

In a further irony, the report notes that the CFL's concussion rate had to be estimated from other sources because "research has not revealed any injury-tracking system in use by the CFL."

The CFL did not accept an invitation to review the Harvard analysis prior to its publication and did not provide any comments to the researchers.

- Collision Course: How we did it

- Collision Course: What happens in a concussion?

- Collision Course: A Spectator report on the science of hard head knocks