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.
Brain disorders can affect anyone, but your risk factors are different for different types of brain disorders. Traumatic brain injury is most common in children, young adults who are under 25 years old, and adults who are 65 and older. Brain tumors can affect people at any age.