Severity of TBI

Mild, Moderate, and Severe TBI

Traumatic Brain Injury severity is commonly described as Mild, Moderate, or Severe. Injury severity is traditionally based on duration of loss of consciousness and/or coma rating scale or score, post-traumatic amnesia (PTA), and brain imaging results. Mild, Moderate, and Severe TBI may be characterized as follows:

  • Mild TBI
    • Brief loss of consciousness, usually a few seconds or minutes
    • PTA for less than 1 hour of the TBI
    • Normal brain imaging results
  • Moderate TBI
    • Loss of consciousness for 1 – 24 hours
    • PTA for 1 – 24 hours of the TBI
    • Abnormal brain imaging results
  • Severe TBI
    • Loss of consciousness or coma for more than 24 hours
    • PTA for more than 24 hours of the TBI
    • Abnormal brain imaging results

Severe TBI may be further sub-categorized as follows:

  1. Coma- a state of unconsciousness from which the individual cannot be awakened
  2. Vegetative State- a state in which an individual is not in a coma (i.e. awakes) but is not aware of the environment
  3. Persistent Vegetative State- a Vegetative State that has lasted for more than a month
  4. Minimally Responsive State- a state in which a person with a severe TBI is no longer in a coma or vegetative state and inconsistently interacts with/responds to the environment.