ARTICLE IN BRIEF
Returning vets with mild traumatic brain injury have more headaches, longer-lasting neurocognitive deficits, and unique imaging patterns, according to three new reports.
SEATTLE—-Mild traumatic brain injuries incurred on the battlefield by veterans of the wars in Iraq and Afghanistan tend to have different and often more severe clinical and imaging features from those incurred on the playing field by so-called weekend warriors, according to several studies reported at the AAN meeting here.
The largest of the studies found that nearly all soldiers (97.8 percent) who had had a concussion, which was attributed to blast exposure, had headaches in the following months. Among the 37 percent with headaches beginning within a week of the exposure, 60 percent had migraine-like features, 40 percent had headaches that interfered with normal activities, and 30 percent had headaches 15 or more days per month or chronic daily headache.
A smaller study, among combat veterans referred for secondary evaluation of a mild traumatic brain injury (TBI), found that even months or years after the exposure, 63 percent had abnormalities on neurological examination that were best attributed to the exposure. Their headaches, moreover, were often accompanied by sleep problems, nightmares, and other symptoms of post-traumatic stress disorder (PTSD).
Finally, diffusion tensor imaging of blast-exposed returning veterans with documented mild TBI found a diffuse, pepper-spray pattern of injury, similar to that associated with inflammatory damage as opposed to the more focal patterns seen after motor vehicle accidents or sports injuries.
Together, the findings suggest that neurologists who examine and treat returning veterans with mild TBI need to be on the lookout for complexities beyond those typically seen in domestic injuries, researchers said.
“I know that neurologists outside of the military are very interested in learning more about post-traumatic headaches in veterans so that they can optimize the care of these individuals,” said a co-author of the large survey, Lt. Col. Jay C. Erickson, MD, PhD, director of the neurology residency program at Madigan Army Medical Center in Tacoma, WA. One implication of the new findings, he said, is that “these individuals should be screened very carefully for comorbid conditions such as sleep disorders, post-traumatic stress disorder, and depression.”
INCREASED HEADACHES, SURVEY FINDINGS
Investigators surveyed all of the more than 5,000 soldiers returning from service in Iraq or Afghanistan to Ft. Lewis in Washington State between June and October of 2008. Almost 20 percent, or 1,033, reported having experienced a concussion, head injury, or blast exposure. Of these, 978 completed a 13-item, self-administered questionnaire.
Overall, the mean headache frequency was 8.4 headache days per month, the survey found. The mean severity was 5.4 on a 10-point scale, and the mean duration of each headache was 4.4 hours.
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“Headaches are highly prevalent among returning US soldiers with a history of mild traumatic head injury,” the study concluded. “Post-traumatic headaches tend to be migraine-like and contribute to functional impairment in this population.”
Even so, another co-author of the study emphasized that most of those studied were able to effectively treat their headaches with over-the-counter pain relievers.
“For 90 percent or more of soldiers who took either ibuprofen or acetaminophen they were able to return to duty within two hours,” said Capt. Brett J. Theeler, MD, of the US Army Medical Corps and a colleague of Dr. Erickson's in the neurology service at Madigan. “Despite the fact that these headaches were frequent, they were not a source of significant disability for most soldiers, and they were not a frequent source of sick call visits.”
LASTING NEUROCOGNITIVE DEFICITS
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But a smaller cohort study by Robert L. Ruff, MD, PhD, a neurologist at the Cleveland VA Medical Center and professor of neurology at Case Western Reserve University School of Medicine, found longer lasting effects among 155 consecutive veterans who had sought treatment after a mild TBI caused by exposure to an explosion while deployed in Iraq or Afghanistan. The blast exposures had occurred between eight months and four years earlier.
Eighty of 126 veterans — 19 had been excluded because they did not complete the evaluation process or were deemed not to have had a mild TBI — who completed the evaluation had neurocognitive deficits. Those with deficits were more likely to have headaches (OR = 82.2), features of migraine headaches, more severe pain (p < 0.001) or more frequent headaches (p < 0.001), compared to those without neurocognitive deficits. Those with neurocognitive deficits were also more likely to have PTSD (p < 0.001), impaired sleep (p < 0.001) with nightmares and were exposed to more explosions (p < 0.001).
The findings suggest that “mild head trauma caused by an explosion appears to be associated with more lasting deficits than are those associated with a civilian injury such as a sports injury,” Dr. Ruff said.
The more lasting and severe effects, he said, might be due to the nature of military exposures, in which a nearby blast causes not only a shock wave, but can also throw materials against the soldier's head, and toss the soldier against walls or other surfaces. In contrast, civilian automobile or sports injuries typically involve a single hit to the head, he said.
While the veterans Dr. Ruff saw appeared strikingly more impaired by their exposures than were those in the larger survey from Madigan, the results may better reflect what clinical neurologists might see in their own practices when they evaluate a returning veteran.
“I looked at people who were having problems and being referred for secondary evaluation,” Dr. Ruff said, whereas the Madigan survey involved all returning veterans, whether or not they had sought or were referred for treatment.
The diffusion tensor imaging study was the first of its kind involving combat blast-exposed soldiers, said study co-author Lt. Col. Michael S. Jaffee, MD, of the US Air Force and national director of the Defense and Veterans Brain Injury Center in Washington, DC.
“There's a different pattern we're seeing with a blast compared to the impact or acceleration-deceleration injuries, the type seen in motor vehicle accidents or athletic injuries,” Dr. Jaffee said. The most surprising finding, he said, was the discovery of a of abnormalities on apparent diffusion coefficient images of blast patients that were not seen with impact injuries, implying that the blast exposures are causing additional changes in the brain similar to those seen following stroke or infection.
“It's reminiscent of a sub-acute to chronic inflammatory-type injury,” said another co-author of the study, David F. Moore, MD, PhD, a neurologist who serves as director of research of the Defense and Veterans Brain Injury Center. “Now that we know inflammation may be an important part of the injury, we can evolve our questions from diagnosis to mitigation and treatment.”
On the treatment front, Dr. Erickson reported an observational, longitudinal study of 58 consecutive soldiers fulfilling the International Classification of Headache Disorders-2 criteria for chronic post-traumatic headaches secondary to mild head trauma. Reliable relief of acute headaches was reported by 79 percent of subjects taking a triptan medication compared to only 29 percent of subjects using a non-triptan abortive agent (p < 0.01).
Another treatment paper by Dr. Ruff involved the use of the generic alpha-blocker prazosin among veterans experiencing severe or repetitive nightmares. While prior studies have established its effectiveness in long-term PTSD patients, the new study examined its use in patients experiencing acute, vivid and disturbing dreams.
“What it seems to do is disrupt REM cycling so that people don't have these repetitive nightmares,” Dr. Ruff said. “It doesn't block people from having dreams, but the dreams are not as vivid or as long. It reduces the nightmares and lets these guys sleep.”
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The prazosin treatment, he found, helps to break a destructive cycle in which intense nightmares cause veterans to actually fear sleep, leading to sleep deprivation which in turn increases anxiety and irritability.
“What we've been doing as an initial step in treating these people is to address the sleep problems,” Dr. Ruff said. “If they can get a good night's sleep, a lot of the other problems take care of themselves.”