a positive declaration intended to give confidence: He received assurances of support for the project. 2. promise or pledge; guaranty; surety: He gave his assurance that the job would be done. 3. full confidence; freedom from doubt; certainty: to act in the assurance of success.
Summary. Traumatic brain injury (TBI) happens when a bump, blow, jolt, or other head injury causes damage to the brain. Every year, millions of people in the U.S. suffer brain injuries. More than half are bad enough that people must go to the hospital. The worst injuries can lead to permanent brain damage or death.
It would seem an immensely improbable thing that someone could survive a gunshot wound to the head. But many people do survive, and a lot of what doctors know about how to deal with damage to the brain has come from working on people who have survived this sort of injury. Gabrielle Giffords's injury explained: Illustration of path of bullet Photograph: guardian.co.uk.