Classification of TBI


Lt Col Reynolds
Traumatic brain injury can be broadly categorized as penetrating or non-penetrating, and as focal or diffuse. Penetrating injuries occur when an object pierces the skull and enters the brain tissue. Non-penetrating injuries, sometimes called blunt or closed head injuries, cause the brain to move within the skull and collide with the bone. Sometimes the brain hits at the site of the injury, but more often it hits the skull at a point directly opposite of the injury site. In some cases, the force is so great that it causes the brain to go back and forth and hit on both sides.

Maj Hemstad
Focal injuries are located in a small, specific area, whereas diffuse injuries occur over a large area of the brain. These categories have to do with what’s called the mechanism of injury, but they generally don’t affect how TBI is diagnosed or treated.

Lt Col Reynolds
The severity of TBI, however, is paramount in diagnosing and treating the injury. TBI can be classified as mild, moderate, or severe. The criteria for classification include:

  • Loss of consciousness
  • Alteration of consciousness or mental state
  • Temporary loss of memory, also known as post-traumatic amnesia, or PTA, and
  • In some cases, structural imaging as seen on a CT scan or MRI

Maj Hemstad
Alteration of consciousness or mental status refers to looking and feeling dazed, experiencing confusion, difficulty thinking clearly, or being unable to describe what happened before or after the event that caused the trauma.