in men than women across every age group. Boys aged 0–4 years have the highest rates of brain injury related hospital visits, hospitalizations, and deaths combined. Multiple mild traumatic brain injuries sustained over a short period of time (hours to weeks), often seen with sports-related injuries, can result in major neurological or cognitive deficits or fatality. Blast-related traumatic brain injuries are often closed-head injuries and result from rapid changes in atmospheric pressure, objects dislodged by the blast hitting people, or people being thrown into motion by the blast Blast-related injuries have shown a recent increase in occurrence with the return of veterans from Iraq such that traumatic brain injury has been coined the "signature injury" of Operation Iraqi Freedom Closed-head injuries can range from mild injuries to debilitating traumatic brain injuries and can lead to severe brain damage or death. Common closed-head injuries include: concussion – a head injury resulting in temporary dysfunction of normal brain function. Almost half of the total concussions reported each year are sports-related intracranial hematoma – a condition in which a blood vessel ruptures causing a pool of blood to form around the brain (subdural hematoma) or between the brain and the skull (epidural hematoma). Intracranial hematoma causes an increase in pressure on the brain and requires immediate medical attention. cerebral contusion – a bruise to the brain tissue as a result of trauma. Contusions are local in nature, separating them from concussions. diffuse axonal injury – These injuries are frequently seen in car accidents and cause permanent damage to the brain. Severe diffuse axonal injuries often lead to comas or vegetative states. Diagnosis Classification Glasgow Coma Scale The Glasgow Coma Scale is commonly used to assess the severity of traumatic brain injuries, including closed-head injuries. The scale tests a patient's eye, verbal, and motor responses. The scale goes up to fifteen points; with fifteen being the most mild injury, less than eight being a severe brain injury, and three being a vegetative state. ASCOT The ASCOT probability of survival encapsulates several of the variables measured in the Glasgow Coma Scale but also includes systolic blood pressure, respiration rates upon admission, and anatomic injuries. The ASCOT was found to be the most sensitive tool for determining severity of head injuries in children and is effective in predicting the outcome of injury. Mechanism based A mechanism-based TBI classification system divides traumatic brain injuries (TBI) into closed