Matt Dunigan has been known to forget where he placed his car keys, though the 51-year-old former quarterback can vividly recall his final game in the Canadian Football League, down to the last few mind-numbing hits.

It's Friday night in August of the 1996 season, his Hamilton Tiger-Cats hosting the B.C. Lions.

The gritty, 5-foot-10½, bow-legged signal-caller surveys the field before absorbing a hit that sends his body and head bouncing off the turf. As the football comes free, a woozy Dunigan instinctively scrambles after it only to be slammed to the turf again. He leaves for the sideline with a team trainer's assistance. After a quick turnover, though, he is back on the field at Ivor Wynne Stadium, yet again dispatched to the turf like a ragdoll on successive incomplete passes.

"I didn't need six neurosurgeons telling me it was over with," says Dunigan, who played in five Grey Cup championship games, winning twice.

These days, Dunigan is a popular CFL analyst, a member of the Canadian Football Hall of Fame and a concussion crusader, lending his name to Canadian efforts to study the repercussions of traumatic brain injury. Dunigan last year agreed to donate his brain and spinal cord to be studied after his death by researchers with the upstart Canadian Sports Concussion Project.

The Dunigan name may lack cachet outside of Canadian football circles, but he did grow up in the shadow of Texas Stadium outside Dallas and starred at Louisiana Tech, which a decade earlier had served as a launching pad for NFL great Terry Bradshaw. By his unofficial count, Dunigan sustained at least a dozen concussions that caused him to sit out snaps during a 14-year CFL career.

The last, on that August night, didn't just leave him seeing stars and fighting cobwebs. It led to a hell hole that plagued him for months and lingers to a lesser degree to this day. In the days after, on the outside he looked fit and ready to dominate a huddle, but his head wasn't right. He couldn't complete a thought. His personality turned dour and angry, so much so that his wife and college sweetheart, Kathy, feared leaving him alone with their three young children.

"I couldn't put sentences together for the first two weeks," Dunigan says. "My lips were moving, but I wasn't digesting much information at all. It just wasn't happening. I didn't say a lot. I would go to practice. People would be, 'Hey, you look good, what is wrong?'

"After 16 years, I am still running the gamut of post-concussion symptoms. That is something I continue to deal with. I don't use it as a crutch. It is just my opponent in today's world."

He is not alone in his fight. Concussion-related issues exist both in the CFL and for those playing in the National Football League. Grown men bang heads in both leagues, though anecdotally the CFL game appears home to fewer violent hits and a smaller percentage of former players suffering the effects of traumatic brain injuries.

Unlike the NFL, which faces a class-action lawsuit brought by nearly 3,000 players or their family members, the Canadian league isn't hounded by a pack of aggressive attorneys. At least three former players, however, who spent some time in the CFL have signed on as plaintiffs in the NFL suit -- Raghib "Rocket" Ismail, Sean Salisbury and Mike Schad.

"As a society, we don't litigate as much as you down there," says Leo Ezerins, executive director of the CFL Alumni Association. "The other side of it is the CFL is another professional football league in North America, but it is far away from [the NFL]. As an example, we generate let's say $200 million amongst eight teams, and the NFL is almost $9 billion."

Perhaps then it is no surprise that the early research approach to the brain injury dilemma in Canada is as different as the two pro football leagues' financial statements.

While two research teams -- one centered at Boston University and the other, the Brain Injury Research Institute, led by Drs. Julian Bailes and Bennet Omalu -- have been acquiring and studying post-mortem the brains of NFL veterans and other athletes for a decade, the Toronto-based Canadian Sports Concussion Project only two years ago began to attract funding and gain research ethical board approval.

The Canadian group just recently announced a $25 million fundraising campaign in support of its concussion studies. Research leaders note the CFL Alumni Association has assisted in raising funds and acquiring brains to study, though the CFL itself hasn't contributed. By contrast, the NFL, after having at first failed to fully acknowledge the long-term effects of concussions, donated $1 million in 2010 to the Boston University research group.

Despite their late start, the Canadian researchers have developed a relationship with the Boston group and have had access to some of its findings related to the brain disease known as chronic traumatic encephalopathy, which is characterized by an abnormal build-up in the brain of a protein called tau. Researchers believe one of the causes of CTE is repetitive concussions, the likes of which are particularly seen in such contact sports as football, hockey and boxing. CTE is known to result in memory impairment, emotional instability, depression and, in some instances, dementia.

The Boston group links a former athlete's name to a study only when family members allow for it to be made public, but the group's director, Dr. Robert Cantu, told "Outside the Lines" that researchers have to date autopsied more than 80 brains of athletes and identified CTE in 68 of them. Such a high percentage is not unexpected, he cautions, because many of the athletes had previously exhibited CTE symptoms, or at times even violent or suicidal behavior. "The brains that we have are of people that have had a lot of trouble," Cantu says.

Of the six brains of former CFL players studied so far, Canadian Sports Concussion Project researchers have found that three had CTE. The sample size is relatively modest, but the medical team remains puzzled that half showed no signs in light of the fact that all of the players had had a history of multiple concussions.

"One difficult part of this type of research, which is really retrospective research where somebody dies and the family is good enough to donate the brain to our project, is we have to scramble for the clinical details," says Dr. Charles Tator, the neurosurgeon overseeing the 15 doctors and scientists attached to the Toronto-based project. "Very often if it is an older person that dies, the clinical details are not available to any great extent. So it is an estimate of how many concussions they had, and that is why we also want to do prospective research where we can collect this data directly ourselves before [the athlete's] death."

Toward that end, Canadian researchers have begun the clinical aspect of their project, which to date has seen five retired CFL players put through a series of two-day exams, including neuro-psychological testing and MRIs. The idea is to not only gather clinical data on younger retired players, but also to diagnose CTE in its early stages in hopes that the condition is reversible.

Another of the long-term aims is to determine if CTE is less prevalent among former CFL players than their NFL counterparts, which might be a step toward providing definitive proof that the Canadian game is safer. The league has generally been thought to be a more open, less-physical game because of a host of rule variances.

Matt Dunigan's son, Dolan, showed exceptional quarterbacking skills at a young age, but the former pro pulled his son out of football after Dolan suffered concussions. Dunigan Family

Among those most commonly cited:

• Three downs vs. four per offensive series, which translates to less reliance on the physical running game.

• Defensive linemen required to line up one yard from the offensive line vs. head-to-head in the NFL.

• Larger fields, less time between plays and fewer timeouts per half lending the league to smaller, less physically imposing athletes.

"I can tell you it is culturally different in the CFL and the NFL," says Robert W. Turner, an author and sociology professor at the University of North Carolina who played in the USFL, the CFL and briefly in the NFL with the San Francisco 49ers in the 1980s. "Your practice day is a whole lot shorter. You almost do no hitting during the season in practice. And your offseason, you are totally off. You're not playing any football whatsoever. Is the game equally as aggressive? Absolutely, yes. But your time actually combating compared to the NFL is less."

With safety in mind, the CFL's board of governors put in a rule this season that a play is to be blown dead immediately if a ball carrier loses his helmet. The ball is placed at the spot where the helmet came free. If the helmet comes off a non-ball carrier, he can no longer participate in the play and, if he does, his team incurs a 10-yard penalty.

The place occupied by the game in the countries' sporting cultures is also night and day.

"I am a Canadian, and I played college ball in the U.S., the [CFL] game is more wide open so you don't have as much contact," says Ezerins, the alumni leader and a member of the Canadian Sports Concussion Project. "And then it is not nearly as intense. You just don't realize how much football teams are playing professionally and in college. Or how much more football is played and practiced in a career in the U.S. vs. Canada. Now hockey, that is a different story."

But don't try telling Dunigan, the old quarterback, or his family that football north of the border is a soft game played by a bunch of semi-serious guys. He was, in his words, "a slow, white Irishman" who rarely took a knee or ducked out of bounds to avoid a hit.

"There are good days and bad days," Dunigan says, assessing his physical and mental status. "There are issues with equilibrium. There are headaches. It is mood swings. It is depression."

His wife, Kathy, suggests the concussions stole a part of his outgoing personality. The funny guy she first set eyes on at Louisiana Tech had turned very serious. Even today, they live with the fallout of what transpired on football fields two and three decades ago.

"Everything is a struggle for him," she says. "He is 51 and I am 50, so it is hard to say what part of that may be related to aging. He is more forgetful now, for sure. He'll tell me, 'I told you that. I showed you that.' And I am like, 'No you didn't.' His speech is fine. He still has really bad headaches, but a lot of people do. I still think they are from the concussions because he didn't have them before.

"He gets involved working in the yard. He just goes somewhere in his head where he likes mindless things. I mean pruning bushes, trimming and mowing, those things he just doesn't have to think. He is really good with those mindless tasks. He really enjoys that. It takes a load off of him."

Yet Dunigan, a proud dad, didn't sit mindlessly when he witnessed his teenage son have his bell rung one too many times. Four years ago, Dolan Dunigan was a high school freshman quarterback, well on his way to 6-foot-5, with a head for the game and a rifle of an arm like his dad. Not to mention, unfortunately, a history of concussions.

After seeing his son motionless on the sideline after a hit, the teenager's eyes rolling back in his head, Dunigan pulled the plug on his son's promising football career -- sending him full time to baseball and the pitcher's mound.

"That is one of the most difficult things I had to do as a parent was to tell my kid what he couldn't do as opposed to encourage him to do the things that he wanted to do," Dunigan says. "At the time, he was doing things at the quarterback position that you can't teach. I thought he had a bright future.

"It kills me every time I look at him, but it's also fortunate that I had the education and understanding of what people potentially can go through. Hopefully, we'll get to the point that no parent has to be faced with that kind of decision."