PTSD and Brain Injury: Double Trouble for Veterans

Liam Davenport

January 08, 2015

Veterans with deployment-related mild traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD) experience persistent mild cognitive impairment and psychological distress, new research shows.

Crucially, veterans with mild TBI, which is often associated with a blast from an improvised explosive device in the field, alongside PTSD perform worse on cognitive measures than those with either condition alone or than healthy individuals.

In addition, the combination of mild TBI and PTSD is associated with significantly more distress than PTSD alone, which is, in turn, linked to more distress than mild TBI alone.

"The take-home message is that we need to validate to the veteran that the problems they are experiencing are real, but [also] to reassure them that their cognitive abilities are within normal limits and they can still be successful," study author Walter High, MD, Department of Physical Medicine and Rehabilitation, University of Kentucky, Lexington Veterans Affairs Medical Center, said in a release.

"There are strategies to rehabilitate and exercise their memory," Dr High added.

This approach was endorsed by lead researcher Hannah Combs, a doctoral student in the Department of Psychology, University of Kentucky, Lexington.

Speaking to Medscape Medical News, she suggested that veterans with mild TBI who are experiencing cognitive impairments should be offered some of the strategies made available to those with more severe TBI.

"It's really more about taking the complaints a little more seriously and not chalking it up to just a change of scene with some psychiatric distress, and [recognizing] neurologically something is going on," she said.

The study was published online October 28 in the Journal of Neurotrauma.

Common Combo

Discussing the genesis of the study, Combs said: "We decided to investigate the cognitive impairment associated with mild TBI when it is combined with PTSD because, in the literature, far less is known about when both of those problems are combined."

"Most of our veterans returning from the conflicts overseas have both of them, so it's hugely important for us to be able to investigate that on a large scale," she added.

The researchers analyzed data from 251 US veterans of the Operation Iraqi Freedom and Operation Enduring Freedom conflicts in Iraq and Afghanistan.

Of these, 116 had no history of deployment-related TBI or PTSD (control participants), 53 had a history of deployment mild TBI, 32 had current PTSD, and 50 had a history of deployment mild TBI and PTSD (combined).

The team administered a series of neuropsychological tasks measuring cognitive function, including cognitive processing speed, IQ, verbal memory, and psychological distress, and took into account a number of potential confounding factors. All tasks were performed during a period of 4 to 6 hours on a single day.

Investigators found that veterans with mild TBI performed worse than control participants on measures of visual scanning and visual attention, as well as of processing speed.

The combined group also performed worse than control individuals on measures assessing visual scanning, visual attention, semantic fluency, immediate/short delay and long delay recall, as well as processing speed.

The combined group also performed worse than veterans with mild TBI on measures of semantic fluency and verbal memory, and they performed worse than PTSD veterans on measures of number sequencing, delayed verbal memory, and visual-motor coordination/mental speed.

The team reported that the mild-TBI group tended to perform worse than PTSD veterans on measures of flexibility of thinking and visual-motor coordination, whereas the PTSD group tended to perform worse on measures of verbal memory.

Finally, the combined group reported greater symptoms of depression and PTSD than the other groups, as well as greater anxiety and insomnia than the control and mild-TBI groups.

Cognitive Decline

Combs commented that, in some respects, these findings of worse outcomes in the combined group were surprising.

"The literature to this point has said that when you have both mild traumatic brain injury and PTSD, it really doesn't look too different than just when you have PTSD alone," she said.

She added, however, that subjective experiences with returning veterans who have both conditions suggest that the current findings are at least partially to be expected.

"The big finding from this that we were not expecting, and we weren't really sure what to make of at first, was the decline seen with the veterans who only sustained a mild traumatic brain injury," Combs noted.

In these cases, the literature suggests that patients with mild TBI should recover within approximately 3 months.

"When we actually explored it a little further, [our finding] kind of made sense," she said, "because one of the big things we wanted to do with this study was control for a lot of extraneous variables that can create a lot of noise within your data."

"Unfortunately, in this type of literature, you have a lot of issues where your groups are not the same age, they have different educations, different IQs, they have a lot of different psychiatric disorders."

Noting that the team also took into account poor effort, Combs added: "We made sure to screen and balance the groups on all those variables to make them as comparable as possible to each other, so we could try to hone in on the disorder itself and not any of the other variables that are hanging around and are connected with them."

Valuable Research

Commenting on the study for Medscape Medical News, Charles Hoge, MD, senior scientist at the Walter Reed Army Institute of Research in Silver Spring, Maryland, welcomed the findings.

"It's a very good study in terms of having a nice longitudinal look at cognitive impairment, so it has a lot of value," said Dr Hoge.

He added that that it "certainly fits in with a lot of other research showing the importance of particularly the experience of a concussion in the deployed environment and what that represents for the individual in terms of their risk not only of PTSD but their risk of more severe, more long-lasting symptoms."

Placing the experience of mild TBI in context, Dr Hoge said that there are a number of generalized factors, alongside concussion, that contribute to significant postdeployment and post-war symptomatology.

He explained that concussion is often associated with blasts, which may have resulted in other casualties.

"These are very horrific, very devastating events for an individual to go through, irrespective of the physical attributes of that event...it is about as close as you can come to losing your life on the battlefield," he said.

Dr Hoge emphasized that as a result, there are a number of difficulties in looking at mild TBI in isolation.

"The mild TBI is not the current health problem. The mild TBI is the injury that happened downrange, which often happened in association with other injuries as well."

"Then when [veterans] come home...they're having postdeployment health concerns, and that may include depression, it may include PTSD, it may include complex grief, it may include residual effects from various injuries that they have had, including concussion, and oftentimes it's difficult to sort out exactly what is the specific etiology for symptoms that individuals have when they come home."

Dr Hoge believes that had the researchers taken into account the severity of PTSD or chronic pain, depression, severity of depression, and other symptoms unrelated to mild TBI, they would have found more associations with cognitive impairment.

Another factor that the study did not take into account was combat intensity and severity. Dr Hoge noted that although there are a number of combat intensity scales, they are often crude measures, asking veterans, for example, about the number of firefights they were in, how many times they discharged their weapons, and how many times they lost a team member.

Nevertheless, he believes that they can help to ensure that groups of veterans are truly comparable and reflect the general level of exposure in the operational environment.

"I think the lens has been so much focused on TBI and PTSD, and I think the medical establishment really has not adequately accepted the fact that a large percentage of individuals are coming home with generalized war-related health concerns that only in part are related to these conditions," Dr Hoge said.

"People have focused a lot of money and attention [on them], which is good, I'm not knocking that. But there are other considerations, and they do have clinical implications, and they do have implications for the strategies that are likely to be most effective."

The authors report no relevant financial relationships.

J Neurotrauma. Published online October 28, 2014. Abstract

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