外傷性脳損傷
Traumatic brain injury happens when the head suffers from a sharp blow, or suddenly accelerates or decelerates. In these cases, the brain gets churned around, and can be damaged by the bony bumps and knobs inside the skull, or by the twisting and tearing of fibres in the brain. If the traumatic brain injury is severe enough, it can lead to an initial coma, which is then followed by a time of post-traumatic amnesia. Post traumatic amnesia typically resolves itself gradually, however it will leave a mild, but permanent deficit in the patient's memory.