Study, inspired by quarterback Tua Tagovailoa’s brain injury, identifies a new concussion symptom
Numerous NFL players, including four Eagles, have had concussions this season. Now, researchers believe they have another way to recognize brain injuries in athletes.
Concussions, and the long-term health risks of repeated head injuries, continue to loom like a storm cloud over the NFL.
In an attempt to drive down the number of players who suffer traumatic brain injuries, the league has adopted new kickoff rules and introduced helmets that manufacturers say are safer.
Yet nearly each week of the 2024 season has been marred, so far, by the unsettling sight of players suffering concussions, from Miami Dolphins quarterback Tua Tagovailoa to four members of the Eagles — right tackle Lane Johnson, wide receivers DeVonta Smith and Johnny Wilson, and right guard Mekhi Becton.
A new study, led by Harvard Medical School researchers and neuroscientist Chris Nowinski, has identified a symptom that might help training staff and coaches sooner identify a player who has suffered a concussion.
The study, published Wednesday in the medical journal Diagnostics, focuses on a specific motion: an athlete shaking their head rapidly from side to side, moments after suffering a head impact or collision, a movement that the researchers refer to as Spontaneous Headshake After a Kinematic Event.
Researchers surveyed 347 current and former athletes and found that almost 69% had exhibited a SHAAKE in the past, with 93.3% reporting that they had made the head-shaking motion in connection with a diagnosed concussion at least once.
The participants, who had an average age of 27, reported shaking their heads in response to a range of symptoms that often are associated with concussions: blurred vision, confusion, dizziness, and feeling like they needed to jump-start their brains.
“From our perspective, it’s sad that this has not been recognized as a concussion sign up until now,” said Daniel Daneshvar, the chief of brain injury rehabilitation at Harvard Medical School, and the study’s senior author.
Daneshvar, who also serves as the cochair of sports concussion at Mass General Brigham, said researchers have reached out to medical organizations, professional sports leagues, and players’ unions to discuss having SHAAKE added to existing guidelines for concussion symptoms.
“Now that it’s been shown to likely be a reliable indicator of potential concussions,” he said, “it would be even more sad if someone’s brain injury were missed because a sideline clinician didn’t know that this could be an indicator of a concussion.”
In an emailed statement, Allen Sills, the NFL’s chief medical officer, wrote that the league’s “medical committees regularly review new research, and we have been in touch with the authors of this study.
“As with any new research, we will discuss these findings with our experts and look at our own data to see if these findings can be replicated.”
Sills said that the NFL’s concussion protocol is reviewed annually “to ensure players are receiving care that reflects the most up-to-date medical consensus on the identification, diagnosis, and treatment of concussions.”
The head-shaking motion has long been a staple of popular entertainment. In action movies, comedies, and professional wrestling matches, characters often shake their heads after absorbing a powerful blow; in cartoons, head shakes are sometimes accompanied by stars and fluttering birds.
But the primary inspiration for the SHAAKE study, Nowinski and Daneshvar said, was Tagovailoa.
During a Sept. 25, 2022, game against the Buffalo Bills, the quarterback was shoved by a Bills defender, then tumbled backward and slammed his head against the field.
Tagovailoa stood, shook his head, and nearly collapsed.
After telling medical officials that his fall had been caused by back and ankle injuries, Tagovailoa cleared the NFL’s concussion screening protocol and was allowed to return to the game.
Four days later, during a Thursday Night Football game against the Cincinnati Bengals, Tagovailoa’s head again slammed against the field; this time, his hands jutted out in a fencing response, which sometimes is observed in victims of traumatic brain injuries, and was removed from the game on a stretcher.
(The NFL and the players’ union jointly investigated Tagovailoa’s initial 2022 head injury, and determined that medical staff had followed the league’s concussion protocol before allowing Tagovailoa to return to the game. But the two sides also quickly updated that protocol, so that players who display signs of balance, motor or speech problems would be removed from the game. The union separately fired the independent neurotrauma consultant who had evaluated Tagovailoa.)
“The head shaking is something I’ve recognized as being associated with a concussion for a long time,” said Nowinski, a former professional wrestler, and the cofounder of Concussion Legacy Foundation, which advocates for athletes and military veterans who have suffered brain injuries.
“When it happened with Tua, and they didn’t pull him out of the game, I realized that it’s not actually on the list of possible concussion signs that anyone is looking for.”
Nowinski and the study’s other researchers reviewed extensive medical literature and found no references to a link between head-shaking and concussions.
“It’s frustrating that we didn’t have this [diagnosis symptom] 10 years ago,” he said.
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Tagovailoa suffered another concussion earlier this year, during a Thursday Night Football game against the Bills; again, his hands jutted out in a fencing response.
The Dolphins placed him on injured reserve, and he has missed four games.
On Monday, Dolphins head coach Mike McDaniel said that “medical experts have deemed it safe” for Tagovailoa to return.
“I appreciate your concern. I really do,” the quarterback told reporters. “I love this game. And I love it to the death of me. That’s it.”
Tagovailoa returned to practice Wednesday and might play Sunday against the Arizona Cardinals.
“I hope that he has a positive, healthy experience for the rest of the season,” Nowinski said.
“The doctors have assessed him. Now, it becomes a question of how much risk are you willing to take?”