A treatable injury?

Mr. Collins declined to discuss Mr. Nakamura or Mr. Earnhardt, but expressed confidence in UPMC’s ability to treat the head injury.

“This is a treatable injury and we can get kids better from it,” said Mr. Collins, who said UPMC has the busiest clinics of its kind in the country. “It’s rare when we can’t find out what the problem is and treat it effectively. It’s very rare for us to retire anyone from concussion.”

Although medical facilities around the country tout treatments for concussion, former Allegheny County pathologist Bennet Omalu challenged the idea that concussion is even treatable.

“No physician should tell a parent that it is safe for your children to receive repeated blows to the head because we can treat them,” said Dr. Omalu, who is now a forensic pathologist and chief medical examiner at the San Joaquin County Sheriff’s office in California. “That has no reasonable scientific basis. It is wrong to state that concussions can be treated and cured.”

While working in Pittsburgh in 2002, Dr. Omalu linked repetitive head injuries to a degenerative brain disease called chronic traumatic encephalopathy in former Steelers players. Recent research suggests that even repetitive, minor hits to the head could be a problem.

More than a million students play high school football, with up to 67,000 suffering a concussion annually, according to a 2014 study. An equal number are thought to suffer the head injury without seeking medical help, which has drawn the attention of researchers.

At least a dozen studies in recent years suggest that hits to the head that don’t cause symptoms may have long-term consequences. Using the UPMC-developed ImPACT concussion assessment tool and two other screening measures, the study of high school football players unexpectedly found “degraded neurological performance” among players who did not have the classic symptoms of concussion, especially linemen who experienced helmet-to-helmet contact on nearly every play.

Four of eight players who showed no signs of concussion were found to be at least as impaired as those players who had diagnosed concussions, the study found.

“Damage may accumulate over time as a result of injuries that do not produce symptoms that meet the clinical criteria for concussion,” according to the study, which appeared in the Journal of Neurotrauma.

To rest or not to rest?

Not enough evidence exists to link sub-concussive blows to the head to longterm injury, said Mr. Collins, who pointed to the success of UPMC’s concussion center in treating 17year-old Amara Shroba of Redbank, N.J. Doctors nearly universally embrace rest, which was described as the “cornerstone of concussion management,” by the Fourth International Conference on Concussion in Sport in Zurich in 2012.

But rest wasn’t helping Amara, according to her mother, Laura Shroba. She sustained a concussion in March 2014 while playing soccer, and doctors prescribed rest, sometimes called the tincture of time. Instead of improving, her headaches persisted and she became depressed in what her mother described as the start of a “downward spiral.” Her school grades suffered.

Ms. Shroba said the improvements in her daughter’s condition since seeking help at UPMC’s Concussion Clinic have been dramatic. A key part of the treatment: getting Amara active.

“You feel we’ve turned around this ship here,” Mr. Collins said during a clinic visit in July with Amara. “Yeah,” she answered. “I’m still getting headaches, but they’re headaches I can deal with.”

“That spark in her eyes has come back and we got our daughter back,” Ms. Shroba said.

Getting active again was exactly the wrong prescription for 16-year-old Jack Hansberry of Upper St. Clair, who suffered his first concussion while playing football in 2014. The crown of an opposing player’s helmet slammed into his facemask, snapping back his head. He walked off the field and sat down on a bench.

“As soon as I sat down, I knew something was wrong,” he said. “I was crying. I was very emotional. I couldn’t help it.”

Jack said he was so eager to return to school and competitive sports that he ignored advice to rest from

Even without standardized treatment protocols, the consensus is that care for concussion has improved in recent years.

Removing kids from play after a confirmed concussion has become more common, with just 2 percent of high school athletes returning to the game on the day of the injury in 2015, down from more than 8 percent in 2007, according to Dawn Comstock, associate professor in the department of epidemiology at the Colorado School of Public Health.

Dartmouth College ended full-contact hitting and tackling in football practice in 2010 and the rest of the Ivy League teams followed earlier this year. The changes are filtering down to community athletic programs, like the one in the tiny Somerset County borough of Windber, which ended tackle football for youngsters in July.

Despite improvements in concussion care, some believe the measures don’t go far enough.

In a January editorial in the American Journal of Bioethics, University of Minnesota physicians Steven Miles and Shailendra Prasad called for an end to tackle football in all public schools because of the “high prevalence of concussions.”

Students do not “reliably accept information about concussion and often fail to report concussive symptoms,” they wrote.