Two of the four deceased CFL players whose brains were donated to the Canadian Sports Concussion Project suffered from a neurological disease linked to concussions, preliminary results show.

The brains of Bobby Kuntz, Jay Roberts, Peter Ribbins and Tony Proudfoot, who all suffered from repeated concussions, were examined as part of the project at the Krembil Neuroscience Centre in Toronto Western Hospital.

The results show that Kuntz and Roberts suffered from a neurological disease known as chronic traumatic encephalopathy (CTE), an abnormal buildup of a protein in the brain.

Kuntz, a former linebacker for the Toronto Argonauts and Hamilton Tiger-Cats, and Roberts, an Ottawa Rough Riders tight end, also displayed other degenerative changes.

"While both of these men appeared to have pathological signs of CTE, they also suffered from other serious neurological and vascular-related diseases," said Dr. Lili-Naz Hazrati, a neuropathologist who performed the autopsies.

The study, the first of its kind, was conducted at Toronto Western by a collection of concussion experts, including Dr. Charles Tator, Dr. Richard Wennberg and scientists from several other Canadian institutions.

Patients who suffer from CTE can experience memory impairment, emotional instability, erratic behaviour, depression and problems with impulse control. The condition can also advance into dementia.

"There are still so many unanswered questions surrounding concussion and the long-term consequences of repeated head injuries," Tator said. "We are trying to determine why some athletes in contact sports develop CTE and others don't, as well as how many concussions lead to the onset of this degenerative brain disease Also, we need to develop tests to detect this condition at an early stage and to discover treatments."

Kuntz died in February 2011 at age 79 after a long battle with Parkinson's disease and diffuse Lewy body disease — a condition that overlaps with Parkinson's and Alzheimer's disease. Roberts, 67, passed away in October 2010 after suffering from dementia and lung cancer.

The results from the autopsies done on Ribbins and Proudfoot did not show signs of CTE. Ribbins, a receiver and defensive back with the Winnipeg Blue Bombers, died at age 63 of Parkinson's disease. Proudfoot, an all-star defensive back with the Montreal Alouettes, lost his battle with amyotrophic lateral sclerosis (ALS) this year at 61.

Dr. Hazrati emphasized the exact link between concussions and neurodegeneration need to be examined by further research.

"Right now we have more questions than answers about the relationship between repeated concussions and late brain degeneration," he said. "For example, we are still trying to understand why these two players acquired CTE and the other two did not."

Ribbins and Proudfoot played in an era when tackling by leading with the helmet was common. Known as a hard-hitting defensive back during his 12-year career, Proudfoot experienced repeated head trauma, according to the CFL's Alumni Association.

Mary Kuntz, wife of the late Bobby Kuntz, believes more players who donate their brains for research will help athletes in the future.

"We've always had questions about Bob's health, because there were so many conflicting medical opinions," she said. "We knew there must have been some effect from all of the concussions over the years, and this was an affirmation that concussions did have a part in his health problems.

"Young players should know the risks of concussions. When you are young, you can't believe what can happen to you when you are older, but we have lived though it. What is good about this study is that there will be more evidence and information for players."

"We were very happy to be involved in this and it has brought us a sense of closure."

Jay Roberts's son Jed and his sisters recognized the earlier signs of their father's memory loss after he recounted the same stories.

"My dad had numerous concussions, although they were undocumented, and I think he knew there was something was wrong, which is why he wanted to help find answers that would hopefully protect future football players," said Jed, a former CFL player with the Edmonton Eskimos. "I think it is really important that we create awareness around this issue, so that players can live healthy, productive lives beyond the game."

Follow Tony Care on Twitter at: http://twitter.com/#!/tcare66