In September, Miami Dolphins quarterback Tua Tagovailoa was hit in two separate games over five days. He slammed his head on the turf so severely in both instances that they became a flash point for criticism of the N.F.L.’s, and the team’s, handling of concussions and prompted pro football to amend its policy regarding benching players after head hits.
But last week Tagovailoa took a third hit, after which he gathered himself and played the next snap, an illustration of the difficulties that the league faces with its evolving concussion strategy.
In the game against the Green Bay Packers, Tagovailoa was sacked from behind as he tried to shovel a pass out to a Dolphins receiver. His momentum swung him around, and Tagovailoa fell backward, his head smacking the field again. Tagovailoa did not display the obvious loss of motor skills that he had in the previous instances — loss of consciousness, trouble standing, involuntary hand movements — but he threw three interceptions on three consecutive possessions in the second half of the Miami loss.
Not until Monday, the day after the game, did Tagovailoa report concussion symptoms to team personnel, who placed him under league-mandated observation and out of play.
“I totally didn’t realize that Tua went through that,” Raheem Mostert, the Dolphins running back, said of the concussion. “But it also kind of made sense toward the end of the game. You know, I was asking myself in the huddle, like, ‘What are we doing? What’s going on?’”
Head Injuries and C.T.E. in Sports
The permanent damage caused by brain injuries to athletes can have devastating effects.
The N.F.L. and the players’ union said in a joint statement on Saturday that they had reviewed the game and that the play involving Tagovailoa did not immediately merit taking him out of the game. “The review established that symptoms of a concussion were neither exhibited nor reported until the following day at which time the team medical personnel appropriately evaluated and placed Mr. Tagovailoa in the concussion protocol,” the league and union said.
The league mandates that nearly 30 medical professionals are on hand for every game. They include athletic trainers and neurotrauma consultants on the sidelines and medical experts scanning the field from press boxes in order to spot any potential head injuries that might be missed below.
But concussions can cause much subtler symptoms, including headaches, sluggishness and difficulty sleeping, some of which are not present immediately after a trauma. The absence of obvious symptoms makes the type of instant diagnosis that is urged in the N.F.L. difficult without the adoption of updated tools that can measure concussion symptoms with a higher degree of specificity.
“Basically, anything that your brain controls can be disrupted by a concussion,” said Dr. Uzma Samadani, a neurosurgeon who was an unaffiliated neurotrauma consultant for four years at Minnesota Vikings games and who developed an eye-tracking device to more definitively diagnose concussions. “Is it possible to make an objective assessment of someone’s total capacity of brain function on the sideline that rapidly? It’s very difficult.”
In recent weeks, the players themselves have been the ones alerting football staff to potential concussions. In early November, Los Angeles Rams quarterback Matthew Stafford reported the onset of concussion symptoms days after he was sacked four times in a loss to the Tampa Bay Buccaneers. He was placed in concussion protocols again that month after experiencing leg numbness that doctors could not attribute to one particular injury.
In a Monday night game on Dec. 12, New England Patriots receiver Nelson Agholor frantically waved down a referee to stop play so that his teammate DeVante Parker could be evaluated after a hit. Parker had been lined up to play the next down but was eventually diagnosed with a concussion.
“I can tell you there’s been a sea change over the last decade in the willingness and the understanding of players to speak up about their symptoms,” said Dr. Allen Sills, the N.F.L.’s chief medical officer. Around 40 percent of the league’s concussion evaluations involved some form of self-reporting, he added.
Sills noted that today’s players have “grown up with a concussion protocol,” often having had their high schools and colleges institute policy changes. “They’re much more familiar with and have a much greater understanding of the protocols and players than maybe a generation ago,” he said.
While self-reporting symptoms can be key to diagnosing concussions, studies have found that players can be reluctant to speak up for a variety of reasons. Those include the risk of going against football’s next-man-up culture and the loss of compensation in a sport without guaranteed contracts.
The N.F.L. uses a series of physical and cognitive exams to assess players for concussions, but experts in brain injuries say that there remains no objective tool to identify a concussion. Elite athletes, even with diminished mobility, can often handle the physical tests designed to gauge their balance and motor skills.
“Unfortunately, even today with all of our technology, we don’t have a blood test or an X-ray scan or an M.R.I. scan to reliably diagnose concussion. We’re still very reliant upon self-report of symptoms and identification of symptoms as kind of the cornerstone of our diagnosis,” Sills said.
Still, as science evolves, other diagnostic tools are gaining wider acceptance outside of football in evaluating concussions. Dr. Nsini Umoh, a traumatic brain injury program director at the National Institute of Neurological Disorders and Stroke, points to CT scans and the Banyan Brain Trauma Indicator test — a blood test that measures two proteins that appear in instances of brain bleeding — as advancements that are gaining common usage.
The N.F.L. has partnered with the Canadian Football League since 2015 on new testing and funds concussion research through various initiatives but has yet to adopt any of the new tools. “Before we’ll put a tool as part of our concussion protocol, we and the Players’ Association together need to be convinced that it’s going to improve our diagnostic accuracy because players don’t want false positives,” Sills said.
The league and its players’ union must jointly agree to adopt changes to the concussion protocol, including new diagnostic tools. Advocacy from players has been key in certain changes to the policy in the past.
The N.F.L.P.A.’s lobbying prompted the 2012 addition of independent neurological evaluators on the sidelines and in booths, and the union has pushed for the use of better helmets and searched for ways to better review back-of-head hits.