When Dale Earnhardt Jr. started having problems with his vision and balance last summer, he went to the doctor to find out what was going on.
It didn't take long for Earnhardt to be diagnosed with a concussion, one he had likely sustained weeks earlier in a crash at Michigan International Speedway.
Earnhardt, NASCAR's most popular driver and one of the sport's most influential figures, wouldn't drive a race car competitively again in 2016. It wasn't until December that he was medically cleared to race in 2017, and he will make his return in February's season-opening Daytona 500.
With safety continuing to be a focus for NASCAR _ there hasn't been a death in any of the sport's three national series since Dale Earnhardt Sr. was killed at Daytona in 2001 _ concussions, like they are in other sports, are a significant concern.
"It is a very serious and scary thing because you really just don't know enough about them," driver Clint Bowyer said this week at the Charlotte Motor Speedway media tour.
Earnhardt Jr. helped raised that awareness, making a case of how important it is for drivers to get themselves checked if they think they are experiencing concussion symptoms.
"Dale has been doing this a long time, he's had a lot of bad wrecks and everybody is different," Bowyer said, adding that he has had concussions before. "I really do believe that everybody is different on how they react to them and not everybody has the same impact or the same crashes. Some people are more fortunate than others. But I think you'll know when you're not good and you don't need to be in that race car.
"Talking to him, there was no question in his mind he didn't need to be in that race car. As big and dominant of a force he is and what he means to this sport, I thought it showed just how serious a concussion can be and I'm glad he spoke up and said, 'Hey, I've got a problem and I need to get out for all of our sakes.' "
NASCAR has a concussion protocol that begins with a baseline neuro-cognitive assessment that drivers take every year. If a driver is injured during a race, the driver must go to the hospital if a board-certified emergency room doctor in the infield medical center has concerns about a head injury. The driver goes through a series of tests at the hospital and must be cleared by a neurologist before returning to racing.
Earnhardt's concussion, however, was missed that day in Michigan. That's part of a reason not every driver supports how NASCAR handles concussions.
Brad Keselowski, the 2012 Cup champion, has been critical of the protocol system, saying doctors don't understand the sport enough to decide whether potentially concussed drivers should be able to race or not. Keselowski sided with driver Matt DiBenedetto last fall when DiBenedetto wasn't medically cleared to for a Cup race after sustaining a concussion during an Xfinity Series race the previous day.
Keselowski said he has read of potential breakthroughs that might include better, more definitive ways to diagnose concussions.
"That piece, to me, is potentially the future of the sport and the path we need to go down and explore," Keselowski said. "Not just for our sport but for all sports."
There is little doubt, however, that drivers are thinking more about concussions and what impact they might have on their future.
While not specifically mentioning concussions, Carl Edwards cited health concerns as among the reasons for his recent decision to step away from the sport. Earnhardt said Wednesday that his time away last season forced him to think about his life after racing.
"We all process it and deal with it differently," said Cup champion Jimmie Johnson. "I've firmly believed ... that the day you're thinking about it is the day you need to step down. And that shows up at a different point in time for all competitors. We've made some amazing headway in driver safety and concussion-related injuries, and the way I process it and internalize it, I'm good with where I'm at right now. That could change some day."
