The mystery behind the degenerative brain disease chronic traumatic encephalopathy (CTE) grew on Wednesday with the release of the brain autopsy results of former NHL enforcer Todd Ewen.
Family and friends were certain that Ewen – who suffered multiple concussions during a 518-game career with four teams, and died by suicide in September – had CTE. But a study by the Toronto-based Canadian Concussion Centre, which has conducted an in-depth study of his brain the past several months, revealed he did not.
Ewen was 49 years old when he died, and had been experiencing memory loss, chronic pain, diabetes and depression.
"We were very surprised by the results, as we were sure Todd must have had CTE," said Ewen's wife, Kelli, who donated her husband's brain to be studied by the CCC shortly after his death. "We hope that anyone suffering from the effects of concussion takes heart that their symptoms are not an automatic diagnosis of CTE. Depression coupled with other disorders can have many of the same symptoms as CTE."
"These results indicate that, in some athletes, multiple concussions do not lead to the development of CTE," said Dr. Lili-Naz Hazrati, a neuropathologist who helped conduct the examination of Ewen's brain with the CCC research team. "Our findings continue to show that concussions can affect the brain in different ways.
This underlines the need to not only continue this research but also be cautious about drawing any definitive conclusions about CTE until we have more data."
CTE has become synonymous with former NFL players who have experienced debilitating conditions after retirement and died tragically. In recent years, several deceased NHL players – many of them former fighters – have also been found to have had CTE.
"Every time it was announced that a fellow player had CTE, Todd would say: 'If they had CTE, I know I have CTE,'" Kelli Ewen said.
"He was terrified by the thought of a future living with a degenerative disease that could rob him of his quality of life and cause him to be a burden to his family."
It's not known why some athletes who suffered multiple concussions during their careers develop CTE while others do not.
Neuropathologists such as Boston University's Dr. Ann McKee, a leading CTE expert, theorize that some people might have a genetic predisposition to getting the disease, while others might have a genetic resistance.
As it is not yet possible to test for CTE in the living, despite advancements toward that goal, researchers are relying on the slow process of collecting and analyzing deceased athletes' brains to learn more.
Including Ewen's, the CCC has analyzed 20 brains and roughly half have shown signs of CTE or other neurodegenerative diseases.
The centre was founded by Dr. Charles Tator with the goal of examining 50 donated brains as part of the research project.
"We still need to better understand this disease and the effects of concussions on the brain in order to figure out how to identify those who will develop CTE, as well as help people like Todd Ewen who struggle with symptoms from head injuries," said Dr. Carmela Tartaglia, a neurologist who was also part of the CCC research team.
"It's through these analyses that we hope to find answers."