The Dallas Morning News
February 21, 2023
On Sept. 25, Tua Tagovailoa banged his head on the turf after being knocked to the ground in a game against the Buffalo Bills. Stumbling to his feet, the Miami Dolphins quarterback was evaluated for a concussion but returned to the field for the second half.
Tagovailoa was carried off his next game Sept. 29 on a stretcher, hospitalized with a concussion that many believed wasn’t his first. The incident sparked an investigation into how the Dolphins handled Tagovailoa’s Sept. 25 injury and prompted the NFL to add ataxia, or lack of coordination, to its concussion protocol.
It can be difficult to decide when a concussed football player can safely return to the field, be it an NFL quarterback or a high school athlete. A UT Southwestern Medical Center researcher wants to give doctors a measurable way to determine whether youth football players have recovered from a concussion to make that critical decision-making process easier.
In a study published in the journal Brain and Behavior, Elizabeth Davenport and her team identified a brain wave that increased in concussed youth football players compared with nonconcussed players.
More research is needed to find out whether doctors could someday use this brain wave to measure concussion recovery, according to Benjamin Dunkley, an assistant professor at the University of Toronto and scientist at the Hospital for Sick Children. But it’s a promising start.
“It’s exciting that this aligns with some of our previous work in adults, as well as some of the animal models that are used to study [traumatic brain injury],” said Dunkley, who was not involved with the research.
NASCAR and high school football
Concussions can be caused by a blow that makes the head and brain move back and forth. They can cause dizziness, headaches, memory problems and more.
Davenport’s interest in brain injury started with the racetrack. Her father drove for NASCAR when she was very young, and she helped treat crash victims while working as an EMT for a year.
In 2011, she joined radiology professor Dr. Joseph Maldjian’s lab at Wake Forest University as a graduate student, two years after the NFL first publicly acknowledged that concussions could lead to long-term problems for players. Davenport and Maldjian began thinking about concussion-related brain injuries in another, younger group of athletes.
“The NFL was just the tip of the iceberg, where there’s 2,000, 3,000 players,” said Davenport, now an assistant professor of radiology at UT Southwestern. “But then, at the youth level, there’s millions of players.”
Maldjian moved to UT Southwestern in 2015, and Davenport followed in 2016.
An analysis of concussion rates in 20 high school sports from 2013 to 2018 found that boys’ football had the highest concussion rate: 10.4 concussions per 10,000 athletes.
Concussions typically are diagnosed using symptom checklists and behavioral tests that examine a player’s memory, motor function or cognition, Davenport said. She said these tests can be subjective and players sometimes don’t tell doctors their symptoms.
Sitting out a game can be costly for young players who have devoted their lives to the sport.
“It’s very simple to say, if you think you’re hurt, sit it out,” she said. “But for a lot of these kids, and even for the pro players, it can mean scholarships, it can mean life-changing opportunities for them.”
Without looking inside the brain, Davenport said, it’s tough to know how long concussion recovery can take.
Texas high school football players who had concussions may not practice or compete until they have a written statement from a physician confirming that they can safely return to the field, according to Texas state law. They must also complete a return-to-play protocol established by the school district’s Concussion Oversight Team.
Abnormal brain waves
Davenport looked into previous concussion research and found a specific brain wave that spiked during unusual circumstances: delta waves.
“They’re these nice, slow waves that happen in the brain,” Davenport said.
As we grow older, Davenport said delta waves become less common, except in deep sleep. It’s unusual to see them in the brains of awake adults.
Davenport examined research from two University of California San Diego professors that found concussed combat veterans had higher levels of delta waves. In veterans whose concussion symptoms lasted longer than expected, the delta waves were localized to the brain area where they had their symptoms. Davenport wondered whether delta waves might increase in youth football players after they had concussions as well.
She and her team collected data on 24 male student athletes from North Carolina aged 14 to 17. Eight played noncontact sports such as swimming. The remaining 16 were football players. Eight of them experienced a concussion during the season, and the other eight did not.
Davenport and her team scanned the players’ brains before and after the season using an imaging technique called magnetoencephalography, or MEG, to get a clear picture of delta waves in the brain. They also scanned the concussed players’ brains within 72 hours of their concussion.
‘A herculean effort’
Davenport found that the football players with concussions had, by the end of the season, significantly higher delta wave levels than both the noncontact sport athletes and the football players who didn’t have concussions.
The study adds to existing evidence that delta waves increase following a concussion, and it’s one of only a few that looks at concussions in adolescents and children, said Dunkley at the University of Toronto. He said completing studies with a larger athlete population will be necessary to see how delta waves look in different brains.
Dunkley said he believes that delta waves could be useful to diagnose concussions along with other potential markers. Those include using MEG to see how different brain areas communicate or testing patients’ blood or saliva. An FDA-approved blood test was developed by medical device company Abbott Laboratories to help clinicians evaluate patients for traumatic brain injury, for example.
Davenport is recruiting male and female athletes from the Dallas area who play contact sports to begin a longer concussion study starting this spring. She wants to monitor delta waves in athletes’ brains after a concussion and for a month after their season ends.
“We want to follow up with them and see, when do your symptoms go away and then when do your delta waves go away,” she said. “And do those coincide?”
Tracking players for a month after their concussions will take “a herculean effort,” Davenport said. The scanners used by her team to measure delta waves are also used by clinical patients, and timing is critical. If a player suffers a concussion during a Friday night game, Davenport needs to get them scanned first thing Monday morning.
She’s prepared to make it happen.
“We proved with this first small study [that] ‘hey, we can do this,’” she said. “We applied for more funding, and we’re going to expand and better test our theory.”