Brain scientists are reporting new clues on how the disease chronic traumatic encephalopathy (CTE) attacks the brains of athletes and combat soldiers. CTE is a degenerative brain disease caused by concussions and other repeat brain trauma.
The disease can only be diagnosed in autopsy, but there have been reports of emotional changes and Alzheimer's-like symptoms in some athletes prior to their posthumous diagnoses. The disease has been found in former NFL players including, and more recently , all of whom committed suicide.
By studying male athletes with CTE, the researchers found what may provide the earliest signs of the disorder in the living.
"This is the largest study to date of the clinical presentation and course of CTE in autopsy-confirmed cases of the disease," study author Dr. Robert A. Stern, a professor of neurology and neurosurgery at Boston University School of Medicine, said in a statement.
Stern, along with Dr. Ann McKee, a professor of neurology and pathology at BU, co-founded the school's Center for the Study of Traumatic Encephalopathy, sometimes referred to as the NFL's "brain bank" because deceased players' brains are donated there for study.
In May 2012, a study led by McKee and the Center found.
"One of our primary goals is to be able to diagnose this disease in life," Stern said to CBS News' Jericka Duncan.
The researchers examined brains of 36 deceased male athletes who were between the ages of 17 and 98, and had no other confirmed neurological diseases, like Alzheimer's. The majority of the athletes played amateur or professional football, but the study also included hockey players, wrestlers and boxers.
Prior to being known as a disease risk for NFL players, CTE was referred to as "punch-drunk syndrome" or dementia pugilistica, because of the symptoms seen in retired boxers before their deaths.
Researchers interviewed the athletes' family members about their lives and medical histories, specifically looking for some of the reported signs of the disease including dementia-like symptoms and changes in thinking, memory, behavior, mood, motor skills or the ability to carry out daily living activities.
McKee conducted neurological examinations of the brains.
They found 22 athletes had behavior and mood problems as their first symptoms, while 11 had memory and thinking problems first. Three of the athletes showed no symptoms at all.
Those who experienced memory and thinking problems first did so at an average age of 59. When behavior and mood problems came first, the average age was 35.
CTE patients in the mood and behavior group were more likely to be described as "explosive," out of control and violent verbally and physically, compared to those in the memory and thinking group.
Eighty-six percent of those in the mood/behavior group reported depression, compared to only 18 percent of those who had memory symptoms first.
More than 90 percent of those who had mood and behavior symptoms first also experienced memory and thinking declines at some point, but the reverse was only the case for with 55 percent experiencing behavior symptoms and 64 percent experiencing mood symptoms.
"The study itself is relatively preliminary, [but] we found two relatively distinct presentations of the disease," study co-author Daniel Daneshvar, a postdoctoral researcher at Center for the Study of Traumatic Encephalopathy, said to HealthDay. "So little is known about the clinical presentation of CTE that anything we found is not necessarily surprising, simply because there's a dearth of information about CTE."
Last Dec., afrom the Center found 68 of 85 people tested that had a history of repeated head trauma had evidence of the disease.
More thanover concussion-related injuries.
Dr. John Hart, Jr., a neuroscientist at the University of Texas at Dallas, told Reuters the next step is to study current athletes and determine how CTE progresses from head trauma to symptoms to measurable changes on brain scans.
"The whole field has to look at, how do we tie these things together?" said Hart, who wasn't part of the study."There's not just an easy, straightforward answer to what's happening with these folks."