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.
Not all head trauma results in a TBI. The severity of a brain injury may range from mild, causing brief change in mental status or consciousness, to severe, causing permanent symptoms and irreversible damage. For years, studies have suggested that CT scans were being overused to rule out traumatic brain injuries.