On Friday, Team USA will take on France in the Women's World Cup quarterfinal. But meanwhile, first on "CBS This Morning," former soccer stars Michelle Akers and Brandi Chastain reveal how they're raising awareness of a debilitating brain disease known as chronic traumatic encephalopathy, or CTE.

CTE is most often associated with football players who have repeated blows to the head and suffer from symptoms like memory loss. Now, these women are helping to launch a landmark study of former female soccer players.



Michelle Akers discusses the landmark study CBS News

"I was the one, the target. So I won every punt by the goalkeepers ... " said Akers, who scored both goals in Team USA's first championship in 1991. "As far as headers went … usually 50 a game."

Chastain, who helped lead the team to another title in 1999, had a similar experience. "Oh, I did a lot of heading the ball," she said. "And very proudly so and very determined and very aggressive."

Two decades after Akers and Chastain were celebrated for those championship plays, the former teammates are still close friends. Akers has suffered from migraines for decades -- and both women, now in their early 50s, wonder if their occasional memory lapses are out of the ordinary.

Chastain said that sometimes she "can't remember some details of a place we went ... or somebody's last name … But then my friends seem to reassure me that they, too, are experiencing that … So I'm thinking, 'Okay, maybe I'm all right.'"

"One of the difficulties is, 'how do you determine what's not normal and what is?'" Akers added.

Brandi Chastain reflects on her soccer career CBS News

Akers' questions mounted after she saw a 2017 documentary by British soccer legend Alan Shearer, who underwent testing to see if he had any early signs of CTE.

"I was watching that and going 'oh my gosh' …" Akers said. "That could be me … and it stopped me in my tracks."



To help find answers, Akers and Chastain have joined a long-term study into possible cognitive effects of those headers and collisions. The study, led by neurology professor Robert Stern, is run out of Boston University School of Medicine. Stern said that Akers and Chastain are now at the age where if there was going to be "worsening difficulty," it would become more visible.

The concern, Stern added, is the "subtler repeated hits" to the head – what's known as "sub-concussive trauma." The study will follow 20 former high-level female soccer players, 40 or older. Baseline testing includes an MRI of the brain and evaluation of cognitive function.

The findings could impact soccer all the way to college and youth levels. "I am concerned that this game played by hundreds of millions across the globe might be played in a way right now that could lead to later life brain disease," Stern said. "That's pretty scary."

Now a youth soccer coach, mother of two and a new grandmother, Chastain is determined to protect young players from unnecessary headers. "I have absolutely done a 180° on that," she said, adding "Heading five-story punted balls, no, not gonna happen. We're not doin' that."

"We can't ignore this anymore," she said. "It's not something we can just say, 'okay, tough it out.' it's not that."

While raising her 14-year-old son, Cody, and cheering on the next generation of soccer superstars, Akers is wondering about her own future. "As I'm getting older … I want to have a great life. I'm planning on that …" she said. "And if not, then I need to, like, prepare."

If she could go back and do it again, Akers said she "would not be heading a million balls like that."

"There's no way on earth I would do that again," she added.

FIFA, the world soccer federation, says it is actively studying and monitoring player health. The organization said that "to our very best knowledge, there is currently no true evidence of the negative effect of heading or other sub-concussive blows" – but Stern said that there have been MRI studies showing subtle brain damage linked to competitive heading.

To learn more about head impacts go to: https://concussionfoundation.org/ and http://www.sternneurolab.org/cte-research.