MILD TRAUMATIC BRAIN INJURY (mTBI)
The American Congress of Rehabilitation Medicine defines a mild Traumatic Brain Injury (mTBI) as:
A patient with mild traumatic brain injury is a person who has had a traumatically induced physiological disruption of brain function, as manifested 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 (eg, feeling dazed, disoriented, or confused); and
- Focal neurological deficit(s) that may or may not be transient; but where the severity of the injury does not exceed the following:
- Loss of consciousness of approximately 30 minutes or less;
- After 30 minutes, an initial Glasgow Coma Scale (GCS) of 13–15; and
- Post-traumatic amnesia (PTA) not greater than 24 hours.
This definition includes:
- The head being struck,
- The head striking an object, and
- The brain undergoing an acceleration/deceleration movement (ie, 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 symptomatology that, when linked to a traumatic head injury, can suggest the existence of a mild traumatic brain injury.
In short, the American Congress of Rehabilitation Medicine defines a mTBI as a traumatically induced disruption of brain function, consisting of loss of consciousness or altered mental status, that may have resulted from a blow or no-blow to the head. Other organizations that provide definitions of mTBI include the Centers of Disease Control, the World Health Organization, and the Department of Veterans Affairs.
The Demographics and Clinical Assessment Working Group of the International and Interagency Initiative toward Common Data Elements for Research on Traumatic Brain Injury and Psychological Health formed an expert group who proposed the following definition:
TBI is defined as “an alteration in brain function, or other evidence of brain pathology, caused by an external force.”
- a) Alteration in brain function is defined as one of the following clinical signs:
1) Any period of loss of or decreased level of consciousness;
2) Any loss of memory for events immediately before (retrograde amnesia) or after the injury (PTA);
3) Neurologic deficits (weakness, loss of balance, change invision, dyspraxia paresis/plegia (paralysis), sensory loss, aphasia, etc); or
4) Any alteration in mental state at the time of the injury (confusion, disorientation, slowed thinking, etc).
- b) or other evidence of brain pathology:
Such evidence may include visual, neuroradiologic or laboratory confirmation of damage to the brain.
- c) Caused by an external force may include any of the following events:
1) The head being struck by an object;
2) The head striking an object;
3) The brain undergoing an acceleration/deceleration movement without direct external trauma to the head;
4) A foreign body penetrating the brain;
5) Forces generated from events such as a blast or explosion; or
6) Other force yet to be defined.
Moreover, concussions are considered to be mild Traumatic Brain Injuries. Concussions are caused when the brain receives trauma from an impact, sudden momentum or movement change. The blood vessels in the brain may stretch and cranial nerves may be damaged. A person may or may not experience a brief loss of consciousness (not exceeding 20 minutes). They may remain conscious, but feel “dazed.”