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Taking the ‘Mild’ Out of Mild Traumatic Brain Injury

Cajigal, Stephanie

doi: 10.1097/01.NT.0000281167.09205.a5

Traumatic brain injury has been called the “signature wound” of the Iraq and Afghanistan wars. Yet many experts also point to a problem occurring far from the battlefield: the multitude of mild traumatic brain injury (MTBI) cases each year in the US that go unrecognized by health-care providers and patients.

According to the Centers for Disease Control and Prevention (CDC) more than 1.5 Americans experience traumatic brain injury each year, about 75 percent of which are mild traumatic brain injuries. In a 2003 report to Congress the CDC stated that the magnitude and impact of the mild traumatic brain injuries are probably underestimated because current surveillance systems do not track people with MTBI who don't receive medical treatment. The CDC refers to traumatic brain injury as a “silent epidemic” because the symptoms associated with it (headache, memory disturbance, depression) are often not visible.

But this doesn't mean the symptoms are trivial, experts claim.

“I would love to change the nomenclature in this field because calling it mild traumatic brain injury suggests the consequences are mild,” said Brain Injury Association President Susan Connors. “Sometimes people do fully recover but a lot of people don't, and a lot of people live with some impact for the rest of their lives.”

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One reason concussion is underreported is because there is a misperception about what a concussion is, according to Barry D. Jordan, MD, chief medical officer for the New York State Athletic Commission. “Most people don't realize they have a concussion, especially if they don't have a loss of consciousness. There continues to be a misbelief that if you have concussion there has to be loss of consciousness.”



Amateur athletes are especially prone to misreading the signs of concussion, he said. “A lot of times kids get hit in the head, get a little dazed, confused, maybe miss their assignments, and they don't realize it could be a concussion.”

If there is uncertainty as to when a bump in the head amounts to something serious it might be because there is no standard definition for concussion and also, because until recently, most sports guidelines defined a concussion by a loss of consciousness.

“Unfortunately I think some doctors still go by that definition. I haven't been using that definition for the last 15 to 20 years,” Dr. Jordan said.

[The American Medical Association defines a concussion as “a trauma-induced alteration in mental status that may or may not be accompanied by a loss of consciousness.”]

Connors said mild TBI is sometimes referred to as “hidden TBI” because it is often underdiagnosed or misdiagnosed. “This is increasingly a problem,” she said, “We find lots of physicians who just don't think this could be a brain injury. They diagnose it, for example, as post-traumatic stress disorder since some of the signs and symptoms can be the same.” An MTBI can present with a co-occurring disorder, such as substance abuse or a psychiatric disorder, that hides the underlying problem, she said. Physicians can also mistake the effects of a brain injury with a learning disability or other cognitive disabilities, she added.

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It's important that neurologists be on the lookout for symptoms of TBI in their patients, said Douglas Katz, associate professor of neurology at Boston University School of Medicine, and medical director of Brain Injury Programs at Braintree Rehabilitation Hospital in Massachusetts.

But he acknowledged that diagnosing MTBI can be a challenge. “I think the problem is that often the usual tests that we do — CT scans, brain MRIs, and EEGs — are normal or negative in people with MTBI,” Dr. Katz said. “And there is no blood test for it. And by the time the neurologist sees the patient the elements of the neurologic exam may be perfectly normal.”

To compensate, neurologists should take careful clinical histories, he said. “There are now a whole slew of symptoms that occur after mild brain injury.” The collection of symptoms, referred to as post-concussive syndrome, can include headache, nausea, fatigue, sleep disruption, difficulty concentrating, memory loss, and pain, he said. [See sidebar, “Symptoms of Mild Traumatic Brain Injury.”]

Recovery time varies according to the patient, Dr. Jordan said. Even after three months, about 80 percent of people will experience symptoms, he said.

“Sometimes people will at first not pay attention to those symptoms because they may have another injury they are paying attention to — such as a broken leg or cracked ribs — and may not notice the effects of mild traumatic brain injury until those other problems abate,” Dr. Katz said. “There are also people in sports who want to minimize injury and get back into the game.”

Dr. Jordan said neurologists should familiarize themselves with MTBI symptoms because athletes will often visit them in hopes of being cleared to return to competition. “Most of them will have a non-focal neurological exam so the cognitive function is going to be the most important function to assess,” he said.

“I think neurologists and other physicians can do a lot better at recognizing the problem, diagnosing the syndrome, and making recommendations to patients as they are recovering,” Dr. Katz said.

Without proper guidance, many patients return to activities sooner than they ought to, he said. “They may have difficulty functioning in their daily activities and may fail at things they routinely did before. That can lead to a variety of problems including secondary depression and emotional problems because they think they ought to be fine … and their doctors and everyone else are telling them their exams and tests are normal, yet they know something is wrong and are failing even though they are trying.”

Depression, he said, can exacerbate symptoms of TBI, including concentration, memory, and pain. “Although for the vast majority of people the prognosis is favorable for recovery of function, there have to be modifications in activities until there is improvement and symptomatic treatment of problems.”



Dr. Jordan said recovery should involve rest time until cognitive functions are back to normal.

Gregory J. O'shanick, MD, president and medical director of the Center for Neurorehabilitation Services in Midlothian, VA, and National Medical Director of the Brain Injury Association of America, said the best way to improve TBI care is to establish a “much more sensitive mechanism for identifying” people with TBI symptoms.

Just as studies done on soldiers after World War II and the Korean and Vietnam Wars spurred major understandings in neuroscience, it's possible that the Iraq and Afghanistan wars will improve knowledge of TBI, he said. “Maybe what this will help precipitate is a better understanding and improvement in providing services for civilians as well.”



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Current symptoms reported consequent to MTBI not present before injury or those made worse in severity or frequency by the MTBI:

  • Problems with memory
  • Problems with concentration
  • Problems with emotional control
  • Headaches
  • Fatigue
  • Irritability
  • Dizziness
  • Blurred vision
  • Seizures

Current limitations in functional status reported consequent to MTBI:

  • Basic activities of daily living (e.g., personal care, ambulation, travel)
  • Major activities (e.g., work, school, homemaking)
  • Leisure and recreation
  • Social integration
  • Financial independence

Source: National Center for Injury Prevention and Control. Report to Congress on Mild Traumatic Brain Injury in the United States: Steps to Prevent a Serious Public Health Problem. Atlanta, GA: Centers for Disease Control and Prevention; 2003.

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Documenting a ‘silent Epidemic’

Some researchers have attempted to track the “silent epidemic.”

According to one study, people who refuse emergency medical services (EMS) following a head injury are more likely to be younger, male, victims of assault, and less likely to have lost consciousness (Brain Injury 2004;18:765–773). Researchers identified 333 people with head injuries cared for by EMS in 2001, and found that 16 percent refused EMS transport. Patients refusing transport often felt they did not need care or could obtain care later, the researchers reported.

A study from the Mount Sinai Medical Center of Rehabilitation in New York City reported that “there may be significant numbers of children with undetected brain injury in schools” (Arch Phys Med Rehab 2004;85:S54-60). Researchers recruited 137 public school students and their parents to complete a Brain Injury Screen Questionnaire (BISQ). Most of the children were reported to have experienced blows to the head; half of the children were reported to have experienced an alteration in mental status; and 10 percent were found to be at risk for sustaining a brain injury because they or their parents reported an alteration in mental status and five or more symptoms associated with traumatic brain injury.

In another study, Mount Sinai researchers identified 143 people with “hidden TBI” who described themselves as “nondisabled” but who had experienced a head injury that at a minimum left them dazed and confused (J Head Trauma Rehabil 1998;16:39–56). When investigators compared this group to a larger group of people with known mild TBI, they concluded that hidden TBI occurs at a rate of 7 percent, “a non-trivial” level, they wrote. They also found that people with hidden TBI are more likely than people with known mild TBI to experience emotional distress but not a vocational handicap following injury.

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• National Center for Injury Prevention and Control. Report to Congress on Mild Traumatic Brain Injury in the United States: Steps to Prevent a Serious Public Health Problem. Atlanta, GA: Centers for Disease Control and Prevention; 2003.
    • Shah M, Bazarian J, Mattingly A, Davis E, Schneider S. Patients with head injuries refusing emergency medical services transport. Brain Injury 2004;18(8):765–773.
      • Cantor JB, Gordon WA, Schwartz ME, Charatz HJ, Ashman TA, Abramowitz S. Child and parent responses to a brain injury screening questionnaire. Arch Phys Med Rehabil 2004;85:S54–60.
        • Gordon WA, Brown M, Sliwinski M, Hibbard MR, Patti N, Weiss MJ, Kalinsky R, Sheerer M. The enigma of “hidden” traumatic brain injury. J Head Trauma Rehabil 1998;13(6):39–56.
          ©2007 American Academy of Neurology