The difficulty lies in how the terms are understood in popular culture. They evoke a different level of severity, extent of cognitive impairment, and recovery outcome. To most Marines and soldiers, “concussion” suggests a fleeting sports injury sustained during a high-school football game or a boxing knockout, whereas “mTBI” conveys real brain damage and the emergency room. It connotes the trauma of structural and functional brain damage.
To athletic military members, a diagnosis of concussion likely appears benign, since it is associated with sports. This social construction carries important practical consequences for America’s warfighters, who do not link TBI to neural damage. Faced with high operational tempos and little recovery time, both on deployment and at home, warfighters are accustomed to toughing it out. In a setting where people already use willpower to overcome mental, physical, and tactical setbacks, labeling mTBI as concussion downplays brain injury. This attitude is a problem because willpower cannot overcome brain damage.
Most Veterans’ Administration hospitals cannot distinguish between military mTBI and sports concussion. Yet the Defense and Veterans Brain Injury Center attributes about 60 percent of all military mTBIs to the force of explosive blasts, not hits to the head. Most of these injuries result in brain pathway damage (known as diffuse axonal injury, DAI), the most common underlying anatomical cause of unconsciousness after brain injury.
The Differences Are Visible
Concussions are characterized by immediate impairments such as feeling dazed and confused (alteration of consciousness), along with visual and sensory disturbances. Unconsciousness does not typically occur, even in grade 3 concussions, the most severe. In this way, military mTBIs are fundamentally different because they often result in unconsciousness.
Physical impact causes most concussions, for example localized brain damage from a boxer’s fist at the site of impact. But an mTBI resulting from a blast injury includes the energy and overpressure forces from blast waves with supersonic velocity. These robust overpressure and electromagnetic forces lead to widespread damage as they travel throughout the entire brain.
Usage of the two terms interchangeably comes from a perception that both conditions heal completely with time. Head Injury , a renowned medical textbook in the field, speaks for all neurology primers in asserting that “post-concussive deficits occur with minimal detectable anatomic pathology and often resolve completely over time, suggesting that they are based on temporary neuronal dysfunction rather than cell death.” 3 The word “detectable” deserves further analysis.
Most imaging technologies are insensitive to blast mTBI damage. They lack the combination of spatial and temporal resolution needed to capture wounded brain pathways. But mTBI damage is detectable: Recent evidence published in the New England Journal of Medicine shows that brain tissue does not completely repair after an mTBI. 4 Six to twelve months after blast injury, service members still exhibited injured connectivity tracts. This new finding, though groundbreaking, will take years to permeate medical literature and shape practice.
The imaging method, called Diffusion Tensor Imaging, shows promise as a military mTBI detector capable of distinguishing that condition from concussion. But its scarcity, cost, and the requisite expertise preclude its use at many VA centers in the near future. Until medical centers around the country incorporate these new findings into routine practice, medical technology cannot produce adequate images of the brain regions that are most likely damaged in a mild TBI.
This is why medical professionals are often tempted to state that mild TBI, which “shows up negative” on brain scans, does not result in significant injury. But because most hospitals and VA centers cannot image blast TBI, the assumption that military mTBI damages the brain in the same way as sports concussion seems not only bold but unfounded.
Healing Takes Time
Downplaying mTBI by calling it concussion may boost troop morale in the short term. But the negative consequences outweigh the immediate psychological benefits. It is true that most mTBI symptoms resolve with time, and that most affected service members feel healed after a week or two of recovery. But feeling better does not mean that brain damage has healed. Symptoms may simply not be noticeable, or may appear unrelated. For instance, a brain injury that involves the frontal lobe may cause emotional disinhibition and anger issues. Since most people would associate emotional irregularity with psychological instability and not with concrete tissue injury, brain injury would likely proceed undiagnosed. As one Marine at the National Naval Medical Center explained it to me:
After the IED went off, I went unconscious and came to after a couple minutes. Later on, the doc told me I had a concussion. I felt better about a week later. A month or two later, though, stuff started to happen. . . . I’d forget things, wicked headaches, I’d get angry really easily. It’s gotten better I guess, but I still forget stuff pretty often. I don’t really know. I don’t like to think about it too much.
Slower reaction times, diminished memorization ability, and other aspects of cognition are not always obvious. Equating mTBI with concussion hinges on “symptomatic resolution.” Latent symptoms may emerge, existing symptoms may linger though slightly diminished, or, as noted and perhaps most important, symptoms may be unnoticeable.
Understating an mTBI can contribute to patients denying brain damage. Indeed, denial is a significant obstacle to ensuring that personnel receive appropriate treatment.
Don’t Force Combat Readiness
Downplaying mTBI may appear to keep higher numbers of troops in the fight in the short term, but this attitude actually decreases combat readiness. Because entire chains of command believe concussions “resolve quickly and completely,” cumulative blast exposure rates are increasing among troops. This perception shapes return-to-duty decisions at all levels of command.
Cognitive impairments, especially those that persist without proper recovery, decrease military-occupation-specialty-specific technical dexterity. Reduced work quality becomes chronic, which places the entire mission at risk. A service member who exhibits a delayed reaction time when firing a weapon, repairing a vehicle, or surveying an area is a liability.
Not only does downplaying mTBI lead to decreased combat effectiveness, it also pushes troops back into the field, dramatically raising the likelihood of multiple blast exposures. The transient-concussion assumption allows troops who experience telltale mTBI signs such as headaches, blurred vision, and memory impairments to forgo treatment in favor of continued fighting.
Mission requirements may supersede individual welfare in certain operational environments, but affording blast-exposed service members time to recuperate is generally feasible. Post-injury, the brain is especially vulnerable to damage. Ensuring adequate recovery is paramount. As seen in National Football League cases of Second Impact Syndrome, a blast-exposed brain likely experiences a window of sensitivity to further damage after the initial wound, eliciting a serious, sometimes life-threatening reaction in the brain.
Extrapolated to military cases, repeated exposures can multiply to greater damage. Legitimizing mTBI, instead of understating the condition, is the first step to limiting blast events. The Army and Navy’s recent decision to award the Purple Heart to those who experience mTBI as a result of direct or indirect enemy actions is a positive step toward recognizing this combat wound—but cultural misconceptions about its severity remain pervasive.
Take the Long View
Greater numbers of warfighters are returning with not-readily-visible wounds. Both the military and society bear caretaking responsibility. An understated diagnosis undermines prospects of receiving adequate disability compensation and medical care, which shortchanges troops. If a service member returns from deployment with memory impairments, a benign concussion label delegitimizes those injuries.
Such cognitive deficits diminish chances for success in both the military and the civilian job market. Whether they hamper memory, personality, spatial awareness, or dexterity, these injuries will plague service members for the rest of their lives. For these reasons, disability compensation is paramount. MTBI, which includes the word “trauma,” gives automatic credibility to patients experiencing its latent effects, affording opportunities for treatment and compensation.
Chronic headaches and selective memory loss may be livable, but neurodegenerative disease is devastating. The NFL reported in 2009 that former players are nine times more likely than the national average to experience diseases such as Parkinsons or Alzheimer’s. 5 These findings, when applied to military populations exposed to blast forces, appear grim.
The number of repeated exposures, and details about the nature of each one, become important facets of a service member’s medical record on which “concussions” may appear instead of “mild TBIs.” Medical records inform treatment, especially with Parkinsons or Alzheimer’s. Obviously, downplaying the extent of potential damage and obscuring the reasons is counterproductive in a treatment setting.
The government’s ability to fund TBI research, generate effective treatment, and perhaps even find a cure hinges on mTBI’s recognition as an invisible wound. As detailed here, the chief obstacle is cultural, and recognizing mTBI’s legitimacy as a nonphysical condition starts with divorcing the injury from concussion.
Unfortunately, the U.S. government feels little pressure to pursue more sophisticated anti-blast armor, improve TBI detection technology, and devise innovative treatments for injured brains. The greater TBI’s visibility, the more research funding will become available. The situation is urgent, as no cures for damaged brains currently exist. Given TBI’s limited treatment options, visibility-driven research findings are especially crucial. They can both determine causes and improve treatment.
Cultural change starts with Navy and Army medical structures. At all levels of the medical chain of command, personnel must emphasize routine specificity. In general, an mTBI diagnosis should be used in blast TBI cases. For impact injuries such as motor-vehicle accidents, “concussion” may continue to be used. In addition, medical documentation and TBI paperwork should be revised to emphasize the use of mTBI terminology where appropriate. It should enter the military medical vernacular, eclipsing concussion diagnosis frequency to the same extent that blast TBI cases eclipse impact head injuries on deployment. Treating head trauma with caution is preferable to underestimation.
After medical personnel, documentation, and training modules reflect this syntax change, warfighters will follow suit. Soldiers and Marines will adopt the use of “mTBI” where appropriate, implicitly legitimizing their not-so-visible wounds. On deployment, acknowledging the sensitivity of an injured brain will increase the likelihood of detection and rehabilitation. At home, using this word instead of “concussion” will foster greater understanding as service members reintegrate into family life. And as TBI veterans reenter society, employers, social workers, and civilian healthcare institutions will interact with more empathy. Mild traumatic brain injury’s visibility will ensure that society treats cognitive impairments with greater sensitivity and respect.
1. “TBI Numbers,” Defense and Veterans Brain Injury Center, 22 July 2011, http://dvbic.org/TBI-Numbers.aspx  .
2. Gregg Zoroya, “20,000 Vets’ Brain Injuries Not Listed in Pentagon Tally,” USA Today , 23 July 2007, http://www.usatoday.com/news/military/2007-11-22-braininjuriesN.htm  .
3. P. Reilly and R. Bullock, Head Injury: Pathophysiology and Management , 2d ed. (New York: Oxford University Press, 2005).
4. C. McDonald, “Detection of Blast-Related Traumatic Brain Injury in U.S. Military Personnel,” New England Journal of Medicine 364, no. 22 (2 June 2011).
5. D. Weir, J. Jackson, and A.Sonnega, “National Football League Player Care Foundation, Study of Retired NFL Players,” University of Michigan Institute for Social Research, 10 September 2009.