Canadian skier Justin Dorey won't participate in this month's PyeongChang Olympics like he did in Sochi in 2014, when he finished 12th in the inaugural freestyle halfpipe event there. Though he was just 25 at the time, Dorey retired shortly after. He'd had enough concussions.

Like athletes in all sports, winter Olympians are confronting the realities of traumatic brain injuries, and perhaps unsurprisingly in sports that reward the abandon necessary to go higher and faster, the risks they face are significant. Bobsled, luge and skeleton racers hurtle down slippery courses at 80 to 90 mph. Snowboarders and skiers fly a dozen feet in the air before crashing down to icy halfpipes unforgiving to mistakes, or wrestle for room on tight courses that seem made to spark collisions.

Even seemingly benign winter sports — say, curling — carry a greater concussion risk than similarly contact-averse sports merely because they are played on ice. Canadian curler Brad Gushue, who won a gold medal at the 2006 Olympics, suffered a severe concussion when he slipped on the ice in a televised match. American Olympic cross-country skier Erik Bjornsen suffered a reported concussion in a collision in 2014.

Of the 15 sports listed that will be contested in these Olympics, an American has suffered at least one publicly reported concussion in 12 of them.

Complicating matters is the once-every-four-years nature of Olympic sports. When professional athletes in other sport suffer head injuries, they usually get paid while they recover. For aspiring Olympians, one ill-timed concussion can end a decades-long dream.

Dorey remembered being reluctant to speak up about a head injury, and he knew his teammates were, too. While most governing bodies of Olympic sports have issued guidance or concussion protocols in recent years, awareness has not resolved the issue.

"With how serious our team and everybody has gotten about concussions in the last few years, there's a chance if you mention or say something the wrong way that you'll be sidelined even if you shouldn't be, just because they want to protect you and also protect themselves from responsibility," Dorey said.

"The associations can hold the athlete back, even if they're willing to take the risk. It creates a system in which athletes aren't always honest."

Scary symptoms

Dorey's first handful of concussions came from mountain biking as a kid. He used to black out for a few hours, ask people who he was and where he was, then feel everything click back into place. When, in his 20s, he began suffering concussions during his halfpipe runs, the symptoms started to change.

After one fall in 2012, when he was in his early 20s, Dorey felt something he had never felt before: abject panic.

"I've never had a panic attack, but it was like what I would imagine that would feel like. I just had this crazy anxiety, this fear and panic the world was going to end," Dorey said.

"Since that one, the symptoms started shifting less from memory stuff to more anxiety, irritability, nightmares. I've been able to focus pretty well, but — I don't really know how to describe them. Nightmares. A lot more emotional."

He continues to deal with those symptoms to this day.

For two-time Olympic bobsled medalist Elana Meyers Taylor, symptoms such as those started in 2015. She remembers the exact date of the crash that did it: Jan. 16, in a race in Germany. Not long after, her coach told her who would be joining her in her sled, the kind of decision she worked with, not against.

"I went crazy on him," Meyers Taylor said. "And he's just like, 'What the heck just happened?' I'm crying and just screaming. Just really bizarre stuff. They were like, 'Okay, something's really wrong. She's got to come get checked out.' "

Meyers Taylor passed the concussion protocol that day but struggled through traditional eight-hour workdays at her job with the International Olympic Committee that summer. The symptoms didn't stop. She wasn't the same person.

Eventually, she had to step away from racing to treat the symptoms, working with the Neurolife Institute in Atlanta, where American skeleton athlete Katie Uhlaender also has sought treatment. After a few months away from racing, Meyers Taylor began to feel like herself again. She and Uhlaender will represent the United States in PyeongChang.

Inherent risks

While concussions do not have to end Olympic dreams — skeleton slider John Daly said most people who are put through the protocol by USA Bobsled and Skeleton sit out for a month and a half at most — every week matters, particularly in an Olympic cycle. One competition, one race or one chance for someone else can alter the chances of making a team dramatically.

Even if the U.S. Olympic Committee or the winter sports federations could find a way to foster better disclosure, athletes who have just suffered a traumatic brain injury are not exactly in peak condition to make a decision that could affect their mental health and cognitive function for the rest of their lives. Caution and competitiveness rarely coexist in harmony.

Absent a simple solution to the problem of accurate concussion reporting, some athletes are pushing for improved safety equipment. American Alpine skier Ted Ligety started his own equipment company, Shred, in 2007. His helmets employ the Rotational Energy System, a newer technology aimed at deflecting the energy from an impact around the head, rather than into it.

But even the most researched helmets do not prevent concussions, which can occur as a product of direct impact to the head but also due to whiplash-like incidents that rattle brains regardless of what is protecting the skull itself.

After Gushue's gruesome televised fall spooked curlers, companies began pushing protective gear such as padded baseball caps and headbands. But for Gushue, a freak slip on ice was not so much a curling problem as a gravity problem.

"Really, for the amount of time I've spent on curling ice and fallen — once — compared to walking out into my driveway in the middle of winter, I've fallen much more in my driveway going to my car than I have on curling ice," Gushue said. "We aren't going to see people wearing helmets walking to their cars. At least I hope not."

Certainly, the concussion risk for Olympic curlers is minimal compared to the risks accepted by those in more high-flying or high-speed sports such as bobsledding, skiing and snowboarding. And those who have already accepted the risks of their sports must avoid letting awareness translate to fear.

"I think that if it's in your mind, you're going to attract it," said figure skater Adam Rippon, who considers himself lucky that he has experienced just one mild concussion in his career, though many skaters he knows have endured worse blows and lengthy recoveries. "You'll probably end up getting a concussion since you'll be on the defense."

Winter sports athletes who spend their lives pushing limits in pursuit of medals seemingly have made their risk-reward choice. But as awareness of the dangers involved grows, the consequences of those choices are becoming much clearer.

"You're going to hit your head. It's there," said American bobsled coach Sepp Plozza said. "It's [more of a concern] than it was, but it's more because everyone pays more attention to it. And it's important, because the head and the brain — you can't fix it. A broken bone takes four weeks, and you're good to go. Brain damage is something serious."

Barry Svrluga and Adam Kilgore contributed.

Read more coverage: