What's So Mild About Mild Traumatic Brain Injury?

Bumps to the head are common; children attain many a goose-egg through falls and collisions while playing.  Adult antics seen on America's Funniest Home Videos likely results in bruises and minor head bumps.  So when does a bump to the head become a problem? Welcome to the world of Mild Traumatic Brain Injury (MTBI): often misunderstood, hotly debated in professional circles, and the subject of new research data.

Defining MTBI depends on the authoritative source.  Most sources (e.g., Center For Disease Control, 2003; American Congress of Rehabilitation Medicine, 1993, American Academy of Neurology, 1997) agree that: a person with MTBI has a acute brain injury resulting from blunt trauma, acceleration or deceleration forces, physiologic disruption of brain function that may (loss of consciousness less than 30 minutes) or may not result in loss of consciousness.  This definition differs (presently) from the Post-Concussion Syndrome which does require loss of consciousness in it's description.

Additional initial symptoms of MTBI can include: confusion or disorientation, amnesia around the time of injury (not to exceed 24 hours), seizures following the head injury, lethargy, irritability,vomiting (typically in infants and young children), headaches, and dizziness.

The incidence rate of MTBI is 500/100,000 individuals in the general population.  Typically, the highest rates of these incidence are attributed to the very young and very old, males, individuals with the hyperactive variety of ADHD, substance abusers and individuals from lower socioeconomic groups.   In children, falls (sometimes when falling backward on a swing) are most common.  In adults, motor vehicle accidents (with or without striking the head depending on physical forces of the vehicle in motion or at rest), work-related injuries, blunt trauma, and falls (particularly in the elderly) are most common.

Often times, MTBI individuals are brought to the emergency room of a local hospital.  Ambulance and medical staff use coding systems to grade the severity of the injury.  In some cases, patients are seen for a neurological examination, have x-rays, and often CT scans of the head are observed.  Most commonly, patients are released with a "Head Injury Precaution" sheet and instructions to follow-up with their primary care physician.

Patients, however, are not always told what to expect from their MTBI.  The most common set of symptoms, usually evident within minutes of the injury are physical and cognitive.  Delayed onset of symptoms is rare.  Immediate symptoms can include: headache, nausea, dizziness, fatigue, light and noise sensitivity, feeling mentally "foggy" or slowed down, and difficulty with concentration and short-term memory.  There is usually a significant improvement in symptoms within hours of the trauma.  Symptom recovery, in 80-90 percent of cases, occur over a 7-10 day period post-trauma.  Children and adults usually show the same rate of recovery.  Headaches may linger the longest, representing what many practitioners term the Post-Traumatic Headache.  If an individual has sustained a more severe form of head trauma, the above symptoms can last longer, and the period of recovery slower.  MTBI symptoms that persist well beyond expected time of recovery (i.e., months) can often be attributable to psychological factors, or even external incentives (e.g., litigation).

Review of recent research (McCrea, 2008) has documented the changes in brain functioning after MTBI called the "neurometabolic cascade".  For many years, it was believed that MTBI caused damage to brain cells.  In fact, brain cells are not damaged but "dysfunctional".  That is, a change in the brain's metabolism and connections with other brain cells and normal communication (neurotransmission) is altered.  The return or reversal to "normal" functioning occurs in days or weeks after the MTBI.

The news of rapid recovery after MTBI has many implications.  First, it could help practitioners educate their patients about what to expect after injury.  It also mandates a paradigm shift within the professional community.  For years it was believed that MTBI can result in long-lasting symptoms and problems as a result of damage to brain cells and their connections.  Though still relevant on a case-by-case basis, the majority of individuals with MTBI will get better within weeks to months.

As a neuropsychologist who conducts Independent Medical Examinations (as part of my practice), I am often faced with the question of MTBI permanent deficits by attorneys (plaintiff and defense), courts, and employers/insurance carriers.  Evidence for rapid recovery following MTBI aids in the analysis of a claimant's subjective symptoms and potential alternative explanations for their complaints.  It also affords practitioners a more detailed procedure when conducting neuropsychological testing.

There is nothing "mild" about Mild Traumatic Brain Injury.  Appropriate medical intervention should always be the first step after sustaining a head injury.  Follow-up care with your treating physician and specialists (neurologist, neuropsychologist) is an important part in the recovery process.  The brain has an amazing (and not yet fully understood) capacity for re-compensation of function.


Peter B. Sorman, PhD, ABN
Board Certified Clinical Neuropsychologist

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