TBI, a form of acquired brain injury, occurs when a sudden trauma causes damage to the brain.

The damage can be focal – confined to one area of the brain – or diffuse – involving more than one area of the brain.

TBI can result from a closed head injury or a penetrating head injury.

A closed injury occurs when the head suddenly and violently hits an object but the object does not break through the skull.

A penetrating injury occurs when an object pierces the skull and enters brain tissue.