The first one, he thinks, came when he was pushed into the boards head-first in atom hockey - he would have been 10 or 11.
Six more concussions - "at least, could be more" - followed over the next decade, including one while playing in the Quebec Major Junior Hockey League that briefly resulted in respiratory arrest and was followed a day later by a disorienting overnight train ride home.
"I cried non-stop from Moncton to Amqui, which is about five hours. I didn't stop because I wasn't sad any more, just because I was too exhausted," former Drummondville Voltigeurs winger Kevin Mailhiot said.
He potted 25 goals as a 16-year-old rookie in the Q and was touted as a potential first-round NHL pick. That was before his career went off the rails, part because of concussions.
Mailhiot, now 24 and a law school grad, told his story this weekend at a well-attended concussion seminar in a downtown Montreal hotel, sponsored by Hockey Canada and the Dr. Tom Pashby Sports Safety Fund as part of an itinerant series of workshops that are being held from Whitehorse to St. John's this year.
If the national minor hockey body has been criticized in the past for not being more aggressive in getting the word out about concussions, it's hard to make that charge now.
"I didn't come here kicking and screaming, and I like to think I keep up on what's happening in sports medicine … but I'm stunned by what I've heard here today," said Richard Michaud, a minor hockey official from Rivière-du-Loup, Que., whose association counts 370 teams and more than 5,000 players.
The audience, which included trainers, doctors, minor hockey coaches, officials from major junior teams, and more than a few hockey parents, heard a range of presentations from several of Canada's leading sports clinicians and concussion researchers, including renowned University of Toronto neurosurgeon Charles Tator.
Their messages, in a nutshell: You don't have to lose consciousness to suffer a concussion (they can be tricky to diagnose, and are often accompanied by neck, nasal and dental injuries); any time one is suspected the player must be immediately withdrawn from the game or practice; no player should ever return to full contact until he or she is completely asymptomatic and cleared by a doctor; children suffer greater damage than adults; helmets can't protect against the injury, full face shields don't hurt; and the evidence on mouthguards is inconclusive.
"You don't suck it up and try to play through a concussion, if you do, it will get worse, we need to convince athletes this is different from other injuries," said Jamie Kissick, a former Ottawa Senators team doctor.
The main benefit of the conference, said Hockey Quebec president Michael Brind'Amour, is in improving the knowledge of parents, players and coaches.
"Can we do more? We can always do more and we must," said Brind'Amour, who was impressed enough that he hopes to stage similar conferences in each of his organization's 14 regions.
And if parents and coaches can benefit from greater education about concussion, so can the country's broader medical community, including family physicians.
"You know now more about concussions than most doctors in Canada," Kissick told the audience at one point during the question-and-answer session.
The more considerable challenge, however, is to provoke a dramatic cultural and attitude shift in hockey circles regarding concussions and how to avoid them.
"It'll probably take 10 years," Michaud said. "But we'll get there."