MARY LOUISE KELLY, HOST:
The 27-year-old gunman accused of killing four people in a Park Avenue building in Manhattan claimed he had CTE. That's chronic traumatic encephalopathy. That is a neurological condition caused by head injuries often associated with football. The condition is only diagnosed after death by an examination of the brain. NPR health correspondent Rhitu Chatterjee is here to tell us more. Hey there, Rhitu.
RHITU CHATTERJEE, BYLINE: Hi, Mary Louise.
KELLY: OK, so how do injuries to the brain, how do they cause this condition? How do scientists diagnose it?
CHATTERJEE: So it's a chronic condition, as you said, caused by head injuries. But those injuries have to have happened over many years. I spoke with Dr. Ann McKee. She directs the CTE Center at Boston University and neuropathology at VA Boston. And she and her colleagues have analyzed over 1,700 brains, and she says it's not just concussions that cause CTE.
ANN MCKEE: It's the asymptomatic hits. The hits that aren't realized by the individual. They play right through them, they don't notice them, they think nothing of them. It's those hits that give rise over time to CTE.
CHATTERJEE: And, you know, those hits repeatedly damage the brain in very specific ways. And researchers like McKee look for that damage during a postmortem exam.
MCKEE: The diagnosis in the brain depends on a particular pattern of tau protein deposited around small blood vessels and in the crevices of the brain.
CHATTERJEE: You know, it usually starts in the frontal lobe. That's the part of the brain involved in judgment and decision-making. But as the person gets older, even after they've stopped playing their sport, the disease progresses on its own. And the person develops severe cognitive decline, memory issues, almost, say, like, you know, Alzheimer's-like symptoms.
KELLY: But, Rhitu, you're talking about as people get older. You're talking about...
CHATTERJEE: That's right.
KELLY: ...Hits over many years, over time. What about symptoms in sometimes very young athletes in the early stages?
CHATTERJEE: Yeah, so in the early stages, McKee told me that CTE usually manifests in mood and behavior changes.
MCKEE: And it's often irritability, inattention, but other things like poor impulse control, poor judgment. There can be depression, which can lead to suicidal thoughts.
CHATTERJEE: Now, in general, the vast majority of people with depression and suicidal thoughts aren't violent. They're more likely to be the victims of violence. But for people with CTE, McKee says violent tendencies can also be in the mix. She says individuals who have CTE symptoms are often disturbed by their own inability to control their thoughts and behaviors. But here's the tricky thing. Not everyone with head injuries and those symptoms that we talked about has CTE. Because McKee and our colleagues examined the brains of former athletes, some of whom had the disease and some didn't, but both groups had the same behavioral symptoms. So someone who suspects they may have CTE may not actually have it. It could be something else.
KELLY: It sounds like there's so much still to learn. I assume it would be really helpful if they could figure out does someone have CTE, and if they can figure that out while the person is still alive. Are researchers working on that?
CHATTERJEE: Exactly. And in fact, McKee told me that they're very close to being - they being researchers in general - are very close to being able to diagnose that condition while someone's alive. And it will likely be a blood test to look for specific proteins, like the tau protein she mentioned earlier. But in the meantime, she says, anyone who has CTE-like symptoms should seek treatment because the symptoms are treatable. And one place she recommends contacting is the Concussion Legacy Foundation, which can connect people to a clinic or facility near them.
KELLY: Get them hooked up with some help. NPR's Rhitu Chatterjee, thanks for your reporting.
CHATTERJEE: My pleasure.
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