TBIs are categorized as mild, moderate, or severe. Most TBIs fall into the “mild” category even though the consequences of these brain injuries may be devastating.
The American Congress of Rehabilitation Medicine (ACRM) established the following definition of a mild traumatic brain injury (mTBI):
A traumatically induced physiological disruption of brain function as manifested by at least one of the following:
- Any loss of consciousness
- Any loss of memory for event immediately before or after the accident (retrograde or post-traumatic amnesia)
- Any alteration in mental state at the time of the accident (e.g., feeling dazed, disoriented, or confused) and
- Focal neurological deficits that may or may not be transient (e.g., post-traumatic seizures, intracranial lesions, loss of the sense of smell, visual field deficits, double vision, difficulties with speech, and gait/balance problems).
- Loss of consciousness of approximately 30 minutes or less
- After 30 minutes, an initial Glasgow Coma Scale of 13-15, and
- Post-traumatic amnesia not greater than 24 hours.