Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Traumatic Brain Injury ?
    ### Response:
    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.
    