Brain Injury Support Group

Parts of the brain that can be damaged include the cerebral hemispheres, cerebellum, and brain stem (see brain damage). Symptoms of a TBI can be mild, moderate, or severe, depending on the extent of the damage to the brain. Outcome can be anything from complete recovery to permanent disability or death. A coma can also affect a child's brain.

The damage from TBI can be focal, confined to one area of the brain, or diffuse, involving more than one area of the brain. Diffuse trauma to the brain is frequently associated with concussion (a shaking of the brain in response to sudden motion of the head), diffuse axonal injury, or coma. Localized injuries may be associated with neurobehavioral manifestations, hemiparesis or other focal neurologic deficits.

Types of focal brain injury include bruising of brain tissue called a contusion and intracranial hemorrhage or hematoma, heavy bleeding in the skull. Hemorrhage, due to rupture of a blood vessel in the head, can be extra-axial, meaning it occurs within the skull but outside of the brain, or intra-axial, occurring within the brain. Extra-axial hemorrhages can be further divided into subdural hematoma, epidural hematoma, and subarachnoid hemorrhage. An epidural hematoma involves bleeding into the area between the skull and the dura. With a subdural hematoma, bleeding is confined to the area between the dura and the arachnoid membrane. A subarachnoid hemorrhage involves bleeding into the space between the surface of the brain and the arachnoid membrane that lies just above the surface of the brain, usually resulting from a tear in a blood vessel on the surface of the brain. Bleeding within the brain itself is called an intracerebral hematoma. Intra-axial bleeds are further divided into intraparenchymal hemorrhage which occurs within the brain tissue itself and intraventricular hemorrhage which occurs into the ventricular system.

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.