What is “Mild” Traumatic Brain Injury?

Historically, words such as “mild”, “moderate”, and “severe” were used to define brain injury. For many years, these terms were utilized based on duration of loss of consciousness.

Today, it is universally accepted that brain injury can occur without loss of consciousness, without direct external trauma to the head, and without positive findings on CT, MRI, or other sophisticated diagnostic testing.

Acknowledging this latter point, in the 1995 Journal of Neurotrauma it is stated:

“Although current computerized tomography (CT) and magnetic resonance imaging (MRI) techniques have shown great utility in diagnosing various aspects of traumatic brain injury, damage resulting from mild diffuse brain injury often goes undetected with these procedures.” (Emphasis added). [Smith, D.H.; Meaney, D.F.; Lenkinski, R.E.; Alsop, D.C.; Grossman, R.; Kimura, H.; McIntosh, T.K.; Gennarelli, T.A.; (1995) New Magnetic Resonance Imaging Techniques for the Evaluation of Traumatic Brain Injury. J. Neurotrauma 12(4): 573-577]

We at the Scarlett Law Group find it repugnant to utilize terms such as “mild” or “moderate” to describe a permanent brain injury. However, until the language of health care practitioners, experts, and others change, we seem destined to face use of these terms to describe brain injury. We must, therefore, assist all people with the true meaning of the words “mild” and “moderate” as they pertain to brain injury. When it describes a brain injury, we believe the word “mild” is synonymous with “serious” or "profound".

The Mild Traumatic Brain Injury Committee of the Head Injury Interdisciplinary Special Interest Group of the American Congress of Rehabilitative Medicine define mild traumatic brain injury as follows:

DEFINITION: “A patient with mild traumatic brain injury is a person who has had a traumatically induced physiological disruption of brain function, as manifest by at least one of the following:

  • Any period of loss of consciousness;
  • Any loss of memory for events immediately before or after the accident;
  • Any alteration in mental state at the time of the accident (i.e., feeling dazed, disoriented, or confused); and
  • Focal neurological deficits that may or may not be transient; but where the severity of the injury does not exceed the following:
  • Post-traumatic amnesia (PTA) not greater than 24 hours;
  • After thirty minutes, an initial Glasgow Coma Scale (GCS) of 13-15;
  • Loss of consciousness of approximately thirty minutes or less;

This definition includes:

  • The head being struck;
  • The head striking an object;
  • The brain undergoing an acceleration/ deceleration movement (i.e., whiplash) without direct external trauma to the head. It excludes stroke, anoxia, tumor, encephalitis, etc. Computed tomography magnetic resonance imaging, electroencephalogram or routine neurological evaluations may be normal. Due to the lack of medical emergency, or the realities of certain medical systems, some patients may not have the above factors medically documented in the acute stage. In such cases, it is appropriate to consider symptomology that, when linked to a traumatic head injury, can suggest the existence of a mild traumatic brain injury.


The above criteria define the event of mild traumatic brain injury. Symptoms of brain injury may or may not persist, for varying lengths of time, after such a neurological event. It should be recognized that patients with mild traumatic brain injury can exhibit persistent emotional, cognitive, behavioral and physical symptoms, alone or in combination, which may produce a functional disability. These symptoms generally fall into one of the following categories, and are additional evidence that a mild traumatic brain injury has occurred.

  • Physical symptoms of brain injury (e.g., nausea, vomiting, dizziness, headache, blurred vision, sleep disturbance, quickness to fatigue, lethargy, or other sensory loss) that cannot be accounted for by peripheral injury or other causes;
  • Cognitive deficits (e.g., involving attention, concentration, perception, memory, speech/language or executive functions) that cannot be completely accounted for by emotional state or other causes; and
  • Behavioral changes and/or alterations and degree of emotional responsivity (e.g., irritability, quickness to anger, disinhibition, or emotional lability) that cannot be accounted for by a psychological reaction to physical or emotional stress or other causes.


Some patients may not become aware of, or admit, the extent of their symptoms until they attempt to return to normal functioning. In such cases, the evidence for mild traumatic brain injury must be reconstructed. Mild traumatic brain injury may also be overlooked in the face of more dramatic physical injury (e.g., orthopedic or spinal cord injury). The constellation of symptoms has previously been referred to as minor head injury, post-concussion syndrome, traumatic head syndrome, traumatic dephalgia, postbrain injury syndrome and post-traumatic syndrome.” J Head Trauma Rehabil 1993:8(3):86-87

If you or someone you know has been injured or suffered Traumatic Brain Injury or TBI, you need the assistance of the Scarlett Law Group. Call (415) 688-2176 today to speak with a California Personal Injury Attorney.

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