Traumatic brain injury
Since a major cause of TBI are vehicle accidents, their prevention or the amelioration of their consequences can both reduce the incidence and gravity of TBI. In accidents, damage can be reduced by use of seat belts, child safety seats and motorcycle helmets, and presence of roll bars and airbags. Education programs exist to lower the number of crashes. In addition, changes to public policy and safety laws can be made; these include speed limits, seat belt and helmet laws, and road engineering practices.
Changes to common practices in sports have also been discussed. An increase in use of helmets could reduce the incidence of TBI. Due to the possibility that repeatedly "heading" a ball practicing soccer could cause cumulative brain injury, the idea of introducing protective headgear for players has been proposed. Improved equipment design can enhance safety; softer baseballs reduce head injury risk. Rules against dangerous types of contact, such as "spear tackling" in American football, when one player tackles another head first, may also reduce head injury rates.
Falls can be avoided by installing grab bars in bathrooms and handrails on stairways; removing tripping hazards such as throw rugs; or installing window guards and safety gates at the top and bottom of stairs around young children. Playgrounds with shock-absorbing surfaces such as mulch or sand also prevent head injuries. Child abuse prevention is another tactic; programs exist to prevent shaken baby syndrome by educating about the dangers of shaking children. Gun safety, including keeping guns unloaded and locked, is another preventative measure. Studies on the effect of laws that aim to control access to guns in the United States have been insufficient to determine their effectiveness preventing number of deaths or injuries.
Recent clinical and laboratory research by neurosurgeon Julian Bailes, M.D., and his colleagues from West Virginia University, has resulted in papers showing that dietary supplementation with omega-3 DHA offers protection against the biochemical brain damage that occurs after a traumatic injury. Rats given DHA prior to induced brain injuries suffered smaller increases in two key markers for brain damage (APP and caspase-3), as compared with rats given no DHA. “The potential for DHA to provide prophylactic benefit to the brain against traumatic injury appears promising and requires further investigation. The essential concept of daily dietary supplementation with DHA, so that those at significant risk may be preloaded to provide protection against the acute effects of TBI, has tremendous public health implications.”
Traumatic brain injury
Systems also exist to classify TBI by its pathological features. Lesions can be extra-axial, (occurring within the skull but outside of the brain) or intra-axial (occurring within the brain tissue). Damage from TBI can be focal or diffuse, confined to specific areas or distributed in a more general manner, respectively. However, it is common for both types of injury to exist in a given case.
Diffuse injury manifests with little apparent damage in neuroimaging studies, but lesions can be seen with microscopy techniques post-mortem, and in the early 2000s, researchers discovered that diffusion tensor imaging (DTI), a way of processing MRI images that shows white matter tracts, was an effective tool for displaying the extent of diffuse axonal injury. Types of injuries considered diffuse include edema (swelling) and diffuse axonal injury, which is widespread damage to axons including white matter tracts and projections to the cortex. Types of injuries considered diffuse include concussion and diffuse axonal injury, widespread damage to axons in areas including white matter and the cerebral hemispheres.
Focal injuries often produce symptoms related to the functions of the damaged area. Research shows that the most common areas to have focal lesions in non-penetrating traumatic brain injury are the orbitofrontal cortex (the lower surface of the frontal lobes) and the anterior temporal lobes, areas that are involved in social behavior, emotion regulation, olfaction, and decision-making, hence the common social/emotional and judgment deficits following moderate-severe TBI. Symptoms such as hemiparesis or aphasia can also occur when less commonly affected areas such as motor or language areas are, respectively, damaged.
One type of focal injury, cerebral laceration, occurs when the tissue is cut or torn. Such tearing is common in orbitofrontal cortex in particular, because of bony protrusions on the interior skull ridge above the eyes. In a similar injury, cerebral contusion (bruising of brain tissue), blood is mixed among tissue. In contrast, intracranial hemorrhage involves bleeding that is not mixed with tissue.
Hematomas, also focal lesions, are collections of blood in or around the brain that can result from hemorrhage. Intracerebral hemorrhage, with bleeding in the brain tissue itself, is an intra-axial lesion. Extra-axial lesions include epidural hematoma, subdural hematoma, subarachnoid hemorrhage, and intraventricular hemorrhage. Epidural hematoma involves bleeding into the area between the skull and the dura mater, the outermost of the three membranes surrounding the brain. In subdural hematoma, bleeding occurs between the dura and the arachnoid mater. Subarachnoid hemorrhage involves bleeding into the space between the arachnoid membrane and the pia mater. Intraventricular hemorrhage occurs when there is bleeding in the ventricles.