CTE: What we know about the progressive, degenerative disease
Former Pittsburgh Steelers great Mike Webster showed many of the signs of what we know now associate with chronic traumatic encephalopathy (CTE): depression, memory loss and dementia.
The origins of CTE trace back nearly a century when it was labeled pugilistic dementia, a syndrome first observed in boxers. Webster's death at age 50 in 2002 and the diagnosis of CTE that followed by Bennet Omalu, who worked at the Allegheny County Coroner's Office at the time, brought the disease to the forefront. Omalu's work was chronicled in the movie Concussion.
Since then, more than 100 brains of former NFL players --- and about 200 athletes overall --- have shown signs of CTE. Former New England Patriots tight end Aaron Hernandez was the latest former player diagnosed with the disease by Boston University's CTE Center.
Former NFL player Bubba Smith had brain disease CTE when he died
What causes CTE?
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CTE is a progressive and degenerative disease that is linked to repeated concussions and other traumatic brain injuries (TBI). The impact can cause parts of the brain to atrophy, although it can often take several years between the damage brought on by the trauma to manifest as CTE.
This sort of brain deterioration from head impact has been chronicled since the 1920s in boxers. Back then it was called being “punch drunk” and eventually became known as pugilistic dementia.
Recent studies show that even less forceful hits to the head — collisions that don’t result in a concussion — can also put a person at higher risk of CTE.
Who are the biggest names?
The death of Hall of Fame linebacker Junior Seau from suicide in May 2012 and his subsequent diagnosis of CTE shook the sports world.
Webster, Frank Gifford, John Mackey, Kenny Stabler and Lou Creekmur are among the other members of the Pro Football Hall of Fame who were diagnosed with CTE after their respective deaths.
Former Vikings linebacker Fred McNeill was identified as subject of breakthrough CTE study. The first confirmed case of CTE found in a living person was discovered in the brain of an unnamed player four years before his death, according to a study published in the journal Neurosurgery in November. And multiple mediaoutlets confirmed on Nov. 16 that the unnamed player was McNeill, who died in 2015 at age 63.
Researchers at the VA-BU-CLF CTE Brain Bank, a partnership among the Department of Veterans Affairs, Boston University and the Concussion Legacy Foundation, published an update to their long-running study in July that showed 110 of 111 former NFL players whose brains were donated for research showed signs of CTE.
Boston University neuropathologist Ann McKee, a co-author of the study, also examined Hernandez's brain, which showed he had Stage 3 or 4 of the disease. (Stage 4 is the most advanced.) The fact that Hernandez, at age 27, had one of the advanced stages of CTE after a three-year NFL career that was cut short by murder charges was somewhat of an unexpected finding.
But CTE is not just a football and boxing phenomenon. BMX star Dave Mirra, pro wrestler Chris Benoit, former NHL player Bob Probert and MLB's Ryan Freel also showed signs of CTE after their deaths.
BMX star Dave Mirra's brain showed signs of CTE
How is it diagnosed?
The only scientifically accepted way to detect CTE remains a postmortem examination of the brain.
Brain tissue is dissected and tests are conducted to look for deposits of certain proteins that are evident in those who suffer from CTE.
Researchers are attempting to develop tests — mostly using existing imaging devices like magnetic resonance imaging (MRI) and positron emission tomography (PET) — to diagnose CTE in living subjects.
How have the NFL and others responded?
NFL officials have been criticized for questioning the research that showed a link between football and CTE for years, even as thousands of former players filed lawsuits that claimed the league has long known about the connection.
Jeff Miller, the NFL’s senior vice president of health and safety, became the first league official to acknowledge the link, although it was limited to one particular study conducted by McKee.
"You asked the question whether I thought there was a link and I think certainly based on Dr. McKee’s research that there’s a link, because she’s found CTE in a number of retired football players," Miller said in a congressional roundtable in March.
The NFL said in a statement that Miller’s comments “accurately reflect the view of the NFL.”
The NFL is among the leagues that have continued to tweak concussion protocol over the years to prevent potentially concussed players from returning to action before they’re healthy and instituted penalties for targeting the head. The NFL also agreed to a billion-dollar settlement that covers about 20,000 retired players.
The NFL has backed an initiative that has led to the adoption of return-to-play standards in all 50 states for youth athletes.
What it would mean for the NFL to be able to diagnose CTE in the living
Is there a treatment?
A major barrier researchers face once a validated test is available for those suffering from CTE is finding ways to treat it.
“It will take a great effort from the medical community,” McKee told USA TODAY Sports in February.
Many of those suspected of having CTE are now treated with drugs aimed at Alzheimer’s patients.
“We have no idea if those drugs will have long-term benefits for those with CTE,” Nathan Urban, associate director of the University of Pittsburgh Brain Institute, said.