During the conflicts in Iraq and Afghanistan, about one-fifth of US service members experienced a head injury, according to recent estimates from the US Department of Defense, and more than 80 percent of those were considered mild.
But even seemingly mild injuries can lead to severe long-term struggles, including difficulty returning to previous work, family, and social activities, new research shows.
“Symptoms of post-traumatic stress and depression have always been thought to develop months to years later,” says David L. Brody, associate professor of neurology at Washington University in St. Louis.
“We don’t know what causes these symptoms, whether they result from the brain injury itself, from the stress of war, or some combination of factors. But regardless of their origin, the severity of these psychological symptoms soon after injury was the strongest predictor of later disability.”
Published in the journal Brain, the findings raise questions about how best to treat US troops who suffer head injuries.
“I was surprised by how severe the level of disability was 6 to 12 months after these seemingly mild injuries, especially given that virtually all of these patients returned to duty soon after their concussions,” says Brody, the study’s senior author.
First week after injury
The study is the first to evaluate active-duty service members with blast-related mild concussions very early, in the first week after injury, and to combine that with follow-up evaluations of the same patients months later. Most studies of traumatic brain injury in military personnel have focused on those injured severely enough to be evacuated from war zones.
In partnership with the US military, investigators at Washington University in St. Louis and the Naval Medical Center Portsmouth in Virginia evaluated traumatic brain injury from blast exposure in active-duty military personnel stationed in Afghanistan in 2012.
The study included 38 patients diagnosed with mild blast-related brain injury and 34 service members without brain injury who volunteered to serve as controls. Those in the study ranged in age from 19-44, with a median age of 26 in the study group and 28 in the control group.
Early assessments of service members were made in Afghanistan within the first week after injury. To evaluate mental health, investigators used a standard military questionnaire for assessing symptoms of post-traumatic stress disorder, such as experiencing repeated, disturbing memories or dreams, feelings of emotional numbness, difficulty concentrating and feelings of anger or hyper-alertness.
Follow-up mental health assessments were conducted with standard interviews 6-12 months later. At later evaluations, 63 percent of patients in the brain injury group were classified as moderately disabled, compared with 20 percent of the control group.
Patients were classified as moderately disabled if they were unable to work as they did before injury; unable to continue previous social and leisure activities; or had mental health problems that disrupted relationships with family and friends.
The remaining 37 percent of the brain injury group were considered to have a good recovery.
“When we were able to connect the dots, we saw that injuries that might have been considered trivial seemed to have a big impact on how these patients did later on,” says first author Christine L. MacDonald, who conducted the study while at Washington University and is now at the University of Washington.
The results were unexpected because the vast majority of past research on traumatic brain injury in military personnel and civilians has focused on cognitive function and physical symptoms such as headaches.
“Most previous studies have hypothesized that things such as duration of loss of consciousness, duration of post-traumatic amnesia, and how well patients could perform tasks of thinking, memory, attention, balance, and coordination would be the predictors of later disability,” Brody says.
“We looked at these factors. And they were not strongly correlated with how well patients did long term.”
The findings suggest that care for brain injuries among military personnel should be broadened to include psychological evaluations earlier in the process, MacDonald says.
Similar to the decision criteria for civilians returning to sports, school, or work after concussions, the criteria used to determine whether a service member should return to active duty now are focused on cognitive function and clinical symptoms and do not include assessments of mental health.
“We hope to contribute to the discussion about what should be done for these patients when they come in with seemingly mild concussions,” MacDonald says. “We need to investigate whether there are new approaches to early care that will improve their quality of life over the long term.”
Brody and MacDonald credit a partnership with the study’s principal investigator in Afghanistan, Lt. Cmdr. Octavian Adam of the US Navy, for making the study possible. Adam is a neurologist at Naval Medical Center Portsmouth and was deployed to provide care for US troops.
“We wouldn’t have been able to do the study if Lt. Cmdr. Adam hadn’t reached out to us to collaborate,” MacDonald says. “The logistical complexities of conducting a study in an active war zone were extraordinary.”
As such, Brody and colleagues are planning a similar study of civilian concussions, looking at mental health measures immediately following mild head injuries in patients who come to the emergency room. Those patients will be followed to determine long-term outcomes.
“The lessons that we learn from military trauma apply quite readily to civilian trauma,” Brody says. “Still, there may be unique aspects of military brain injury that are not true in the civilian world.
“It could also be that this is a general phenomenon that has not been carefully addressed in civilian or military populations.”
The Congressionally Directed Medical Research Program funded the work.