Traumatic Brain Injury causes more than just a headache

Every day it seems we hear about someone having a concussion––whether a service member in Afghanistan, a professional athlete or a child from our neighborhood. A concussion is a mild traumatic brain injury (TBI), which is any damage to the brain, temporary or permanent, caused by an external force.  Health care professionals used to reserve the term “concussion” for those TBI’s that were expected to have only temporary effects, while “TBI” was used when effects were expected to be long lasting.  This informal convention was based on concussion being a mild TBI, and not a moderate or severe one.  However, the accumulating research indicates that the lifelong impact of TBI’s, including concussions, is not just a factor of the initial severity of the injury.  Long-term effects are also a function of how old you are when the injury occurs, how many you have had before and how soon after your last TBI you experience another.  Thus, persisting effects can occur not only when a TBI is more serious, or when we have had too many of them, but also if we have had them too young, too old, or too close together.

The effects of TBI are more than just a headache.  Though most TBI’s are initially marked by headache, the important long-term consequences are the loss of the ability to regulate our thoughts, emotions and behavior.  You may ask, “how can that be, doesn’t it depend on what part of your head gets hit?” No, it does not––regardless where contact is made with the head, when the force is sufficient to cause movement of the brain within the skull, the frontal areas of the brain are always the most vulnerable to injury.  As a result, the “fingerprint” of TBI is bruising to the frontal lobes, as well as shearing and tearing of neuron bundles connecting to the frontal lobes.  The frontal lobes of the human brain are critical to our learning to control our emotions and plan goal-directed behavior.  These abilities allow us to manage our actions and reactions, and determine whether we will succeed in a complex and ever-changing society.  So, for many, when the headache has stopped, the negative effects have only just begun.

There is another insidious aspect of TBI.  The problems that may arise are not just those experienced in the days, weeks or months immediately following the event.  As is well-documented in the recent Institute of Medicine report, Gulf War and Health Volume 7: Long-Term Consequences of Traumatic Brain Injury, some consequences do not manifest until years after the original injury, in many cases probably triggered by changes that occur normally with aging. Conditions found to emerge or re-emerge in later life included cognitive deficits, depression, suicide, premature death, progressive dementia and Parkinson’s disease.  This list is certainly incomplete, as many consequences have only been studied soon after TBI, but not in later life.  For instance, some hormonal problems were found to develop one to two years after injury but these disorders have not been examined further out.

The potential debilitating consequences of TBI, and the resultant costs to society, demand a longer view.  We are encouraging our children to participate in sports, exposing our military men and women to blasts and touting an active lifestyle among older adults. These and other behaviors are merited, but also put us at greater risk of TBI. We would be well advised to significantly increase the attention we are giving to prevention, treatment and research dedicated to TBI.  We need to understand much more about the short and long-term consequences of concussions, as well as more severe TBI’s. We need to make activities that increase our chances of TBI safer and, when we cannot, know the most effective treatments possible to mitigate the consequences of TBI.

John D. Corrigan is a professor in the department of Physical Medicine and Rehabilitation at The Ohio State University in Columbus, Ohio.