WASHINGTON — Researchers for the first time have linked troops exposed to even a single roadside bomb blast to serious degenerative brain disease and resulting long-term cognitive failures, suggesting that tens of thousands of returning veterans may face significant long-term health problems.
Investigators from Boston University and the Veterans Affairs Boston Healthcare System on Wednesday published a study that shows chronic traumatic encephalopathy — a brain disease found in athletes who suffer frequent concussions — in autopsies of veterans who had been exposed to detonations of improvised explosive devices.
Unlike the temporary cognitive and memory loss associated with some traumatic brain injuries, CTE manifests itself in the form of psychiatric symptoms, learning deficits, dementia and progressive brain cell death. Researchers called the new findings a major cause for concern for a generation of young veterans.
“We know in its end stages CTE is a very severely debilitating disease that in many ways looks like Alzheimer’s,” said Dr. Ann McKee, study co-author and director of the Neuropathology Service for VA New England Healthcare System. “It’s something that progresses with time, and you wouldn’t want anyone to develop this.”
The study is the first to definitively link the brain disease to head injuries suffered from bomb blasts, although previous studies have hinted at a connection .
Studies of athletes have shown repeated blows to the head can cause the disease, but researchers in the new study said the force of the blast wind — reaching up to 300 miles per hour — from a typical roadside bomb attack also can lead to the long-term impairments.
Veterans advocates called the news sobering.
“It underscores just how much work VA has in store to properly care for these men and women,” said Shane Barker, senior legislative associate for the Veterans of Foreign Wars. “The effects of even a single roadside blast can haunt servicemembers all their lives with chronic and devastating consequences.”
Jacob Gadd, deputy director for health care at the American Legion, called the study “exactly the type of brain injury research that’s needed,” because experts still don’t know the most effective way to treat those injuries.
“These are the signature wounds of these conflicts,” he said. “We need to be studying this, and finding ways to translate the clinical findings into treatments as soon as possible.”
McKee said the findings represent a breakthrough in understanding the mechanics and treatment of brain trauma. Currently, CTE can only be diagnosed after death, following a close examination of protein build-up on the brain. There’s no known repair or cure for the damage.
Study co-author Dr. Lee Goldstein, associate professor at Boston University School of Medicine, called it a first step in finding ways to reverse that damage.
“If we want to treat this, first you have to understand the mechanism,” he said. “Now that we have identified the mechanism, we can work on developing ways to prevent it.”
Goldstein emphasized that not all troops exposed to bomb blasts develop the disease, just like not all servicemembers who experience traumatic events develop post-traumatic stress disorder.
The study compared the brains of four athletes, four combat veterans and four civilians, the latter acting as the control group. The deceased veterans examined in the study suffered only a few roadside bomb blasts, but still showed signs of CTE. McKee said concussions and other head injuries suffered earlier in life — playing sports in high school, for example — may have contributed to developing the disease.
However, researchers experimenting on mice found that even a single powerful blast can trigger build-up of those harmful proteins, indicating the potential for severe, lifelong problems.
The issue for veterans is complicated by the fact that military officials don’t have complete data on roadside blast injuries. A ProPublica report last year found that only about 20 percent of troops who experienced a roadside bomb attack said they were later examined for concussions or other head trauma.
Defense Department statistics estimate that more than 460,000 troops may have suffered some traumatic brain injury from roadside bomb attacks since 2001.
The study notes that some signs of long-term impairment of brain function were seen just two weeks after the trauma occurred, but McKee said the most serious symptoms can take years to develop.
On Wednesday, Veterans Affairs Secretary Eric Shinseki released a statement praising the new findings, calling it an opportunity to “improve patient care and veterans’ quality of life.”
The CTE findings were released in the medical journal Science Translational Medicine on Wednesday.