A traumatic brain injury (TBI) is a blow or jolt to the head that disrupts the function of the brain. Not all blows or jolts to the head result in a TBI. The severity of such an injury may range from “mild” – a brief change in mental status or consciousness – to “severe” – an extended period of unconsciousness or amnesia after the injury. A TBI can result in short or long-term problems with independent brain function.