Diffuse axonal injury

Diffuse axonal injury (often shortened to DAI) is one of the most common forms of traumatic brain injury. In traumatic brain injury, the damage is focused to one area of the brain, in diffuse axonal injury, the damage occurs over a larger area of the brain. DAI mainly damages white matter, which makes it one of the major causes of unconsciousness and persistent vegetative state after head trauma. It occurs in about half of all cases of severe head trauma.
Frequently, people suffering such damage fall into a coma; Over 90 percent of the patients with severe DAI never regain consciousness. Those who do wake up often remain significantly impaired.
Other authors state that DAI can occur in every degree of severity from (very) mild or moderate to (very) severe. Concussion may be a milder type of diffuse axonal injury.