The brain of former National Hockey League player Derek Boogaard showed signs of early chronic traumatic encephalopathy, researchers report, shedding light on the neurological condition that may affect some athletes who sustain brain injuries during play.
Boogaard died at age 28 from a drug overdose in May, and his brain was autopsied by Dr. Ann McKee, a neuropathologist at the Bedford VA Medical Center and co-director of the Center for the Study of Traumatic Encephalopathy at Boston University. Earlier this year she also found evidence of the condition in the brain of former Chicago Bears safety David Duerson, who killed himself in February.
It's believed that repeated head trauma, such as concussions, contributes to the progressive condition, which causes brain degeneration and is characterized by a buildup of an abnormal brain protein called tau.
"Tau is a structural protein--it's like the scaffolding of the brain cells," says Dr. Christopher Giza, an associate professor of pediatric neurology and neurosurgery at UCLA's David Geffen School of Medicine. "In an abnormal state it clumps together and changes the structure of the brain cell."
But abnormal tau deposits can be seen only via an autopsy. Symptoms of chronic traumatic encephalopathy can include confusion, slow reaction time, aggression, anxiety, depression, problems controlling impulses, loss of memory and confusion, and they can progress over time.
"There's no question that there's a cumulative effect, but it seems that some people can sustain the same exposure and not develop the disease, or at least not manifest it," says Dr. Charles Bernick, associate director of the Cleveland Clinic's Lou Ruvo Center for Brain Health in Las Vegas. "But when does this start, and how early do these changes occur? Does the age when you start an activity matter? There are many questions that need to be answered."
Genetics may play a part and could explain why some people are more susceptible to the effects of head trauma than others. Bernick is currently involved in research with boxers and mixed martial artists to see what affects head trauma has on brain activity.
"If you follow an athlete over time and get periodic tests of the abilities and reaction time and processing speed," he says, "the hope is that you can identify people who may be at an abnormal trajectory and really starting to change more than what's normal for their age. The problem is in some athletes that may be too late--the changes may already be happening in the brain."
But by noticing early changes via PET scans or MRIs, he added, doctors and scientists may be able to intervene sooner. However, unknowns remain, such as how much head trauma is too much, and could subconcussive injuries still rack up damage.
How this news will shake down in the athletic world isn't known. Obviously athletes want to be safe without giving up too much of the sports they enjoy.
"If there's one good thing that comes out of this tragedy," Giza says, "it's that by stimulating research we will better understand this. When I grew up people didn't pay any attention to concussions. But there's more concern now as people are trying to find out if [CTE] is caused by repeated injury, if there's some way to avoid it--maybe there's a way to mitigate some of the problems."