Medical Legal Educational Blog


By: Robert L. Shepherd, MS, Certified Medical Illustrator, President & CEO, MediVisuals Inc. and Reid Shepherd, BA

When developing demonstrative aids regarding plaintiffs that may have suffered a traumatic brain injury (TBI), the absence of a reference to a traumatic brain injury or references to “mild” traumatic brain injuries in general medical records should not be considered authoritative.  The development and persistence of neuropsychological symptoms through a neuropsychological evaluation is necessary to make such determinations.  Even with a diagnosis of a “mild” TBI following a neuropsychological evaluation, the adjective “mild” should be avoided in demonstrative aids because, as any victim of a “mild” TBI will likely agree, the only “mild” TBI is one that occurs to someone else.  In addition to being misleading, the term “mild TBI” does not have a consistent definition or agreed upon clinical method of detection.1 As the Department of Veteran Affairs reports, “the particular classification used to designate a patient as having mild, moderate or severe (traumatic brain) injury is somewhat arbitrary.”2 For these reasons, and for those discussed later on in this blog, “mild traumatic brain injuries” should be referred to instead as “traumatic brain injuries”.

 Centers for Disease Control and Prevention

Multiple organizations have attempted to produce their own definitions and classification systems for TBI.  The CDC’s, “Report to Congress on Mild Traumatic Brain Injury in the United States,” recommends separate conceptual and operation definitions for both incident cases and prevalent cases of “mild” TBI, which may serve to confuse rather than clarify attempted classifications of TBI.1 While the CDC uses the term “mild,” it acknowledges the fact that “mild” TBIs can cause, “serious, lasting problems,” and reports that 80,000 to 90,000 Americans per year, “experience the onset of long-term disability,” from such injuries.1

 Glasgow Coma Scale (GCS)

In most cases, the diagnosis and classification of TBI is done by emergency responders or nurses who express varied attitudes and a lack of self-confidence in using the most common TBI classification system, the Glasgow Coma Scale (See the Below Chart).3 The GCS has been used to classify TBI on clinical grounds for many years, but the GCS is an old system that overlooks important signs that indicate the presence and severity of TBI.4 The GCS is an extremely basic observational index that, “assesses the level of consciousness after TBI,” and is a, “poor discriminator of the presence or absence of less severe TBI.”5 The scale also fails to account for duration of loss of consciousness, which is an important indicator in determining TBI severity. When this already inadequate scale is used by a medical professional who lacks familiarity with the rating system, the resulting classification should not be considered accurate by any means.                                                                                                                                                                             Department of Veteran Affairs

The Department of Veteran Affairs’ classification scale uses the GCS as one of 4 indices to classify TBI (along with length of coma duration, length of period of altered consciousness or mental status, and length of posttraumatic amnesia), but the Department also acknowledges the limitations of the GCS and of its classification system in general: “While the GCS is recognized as a reliable measurement tool, it is influenced by factors unrelated to the TBI itself…The GCS is not particularly useful in the assessment of mild TBI.”2 Variables such as age, extracranial injury, intoxication, intubation, analgesia, sedation, and many potential comorbidity conditions interfere with the results of these classification scales and can make an accurate diagnosis of neurologic injury on clinical grounds impossible.4, 5

Department of Defense

The Department of Defense uses yet another definition and classification system for TBI severity. In order to determine whether an incident of TBI is mild, moderate, or severe, the DoD created an exhaustive list of over 500 specific injuries and symptoms, each with its own severity classification. A very short sample of the DoD’s classification system is as follows, which gives an idea of just how many factors must be considered when attempting to classify a traumatic brain injury. The extensive, full list of symptoms (found at the link below the chart) can hardly be summarized by a one-word label of “mild,” “moderate,” or “severe.

Several other scales for diagnosing and classifying TBI also exist, including: Abbreviated Injury Scale, Trauma Score, Abbreviated Trauma Score, Brussells Coma Grades, Grady Coma Grades, Innsbruck Coma Scale, and the FOUR Scale, but none of these scales overcome the inherent problems involved in classifying such a varied and complex condition as TBI. In addition to having no accurate way to judge duration of loss of consciousness unless a witness is present at the time of injury, these scales are designed to be used quickly in a clinical setting and do not account for the onset of symptoms which are often delayed. Combine these difficulties with the aforementioned complications from comorbidity conditions and other variables, and it becomes clear that existing attempts at TBI classification systems are often unreliable.



Centers for Disease Control and Prevention: http://www.cdc.gov/traumaticbraininjury/pdf/”mild” TBIreport-a.pdf

Glasgow Coma Scale: http://www.glasgowcomascale.org/downloads/GCS-Assessment-Aid-English.pdf

Department of Veteran Affairs: http://www.publichealth.va.gov/docs/vhi/traumatic-brain-injury-vhi.pdf

Department of Defense: http://www.health.mil/Reference-Center/Publications/2015/12/01/Traumatic-Brain-Injury.



1. Report to Congress on Mild Traumatic Brain Injury in the United States: Steps to Prevent a Serious Public Health Problem. Centers for Disease Control and Prevention. http://www.cdc.gov/traumaticbraininjury/pdf/mtbireport-a.pdf. September 2003. Accessed June 23, 2016.

2. Traumatic Brain Injury. Department of Veteran Affairs. http://www.publichealth.va.gov/docs/vhi/traumatic-brain-injury-vhi.pdf. April 2010. Accessed June 23, 2016.

3. Mattar I, Liaw S, Chan M. Nurses’ self-confidence and attitudes in using the Glasgow Coma Scale: a primary study. Nursing In Critical Care [serial online]. March 2015;20(2):98-107. Available from: Academic Search Alumni Edition, Ipswich, MA. Accessed May 5, 2016.

4. Chieregato A, Martino C, Simini B, et al. Classification of a traumatic brain injury: the Glasgow Coma scale is not enough. Acta Anaesthesiologica Scandinavica [serial online]. July 2010;54(6):696-702. Available from: Academic Search Alumni Edition, Ipswich, MA. Accessed June 23, 2016.

5. Saatman KE, Duhaime A-C, Bullock R, Maas AIR, Valadka A, Manley GT. Classification of Traumatic Brain Injury for Targeted Therapies. Journal of Neurotrauma. 2008;25(7):719-738. doi:10.1089/neu.2008.0586.

6. Traumatic Brain Injury (TBI): DoD Standard Surveillance Case Definition for TBI Adapted for AFHSB Use. Department of Defense. http://www.health.mil/Reference-Center/Publications/2015/12/01/Traumatic-Brain-Injury. December 2015. Accessed June 23,2016.

Bob Shepherd, MS, CMI, FAMI 

Bob Shepherd is a Certified Medical Illustrator, having graduated from one of only four accredited medical illustration graduate programs in North America.


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