In the United States traumatic brain injury (TBI) is a leading cause of death for persons under age 45. TBI occurs every 15 seconds. Approximately 5 million Americans currently suffer some form of TBI disability. The leading causes of TBI are motor vehicle accidents, falls, and sports injuries. While the brain is by far the most complex object on earth, it is soft and vulnerable with a consistency of firm pudding. A concussion is a sudden trauma-induced alteration of the alert state. The person may be unable to concentrate or be confused for a few seconds, or completely lose consciousness and fall down. The brain is capable of recovering from a concussion. How much force is necessary to cause permanent brain damage is under study, and hence still unclear. The brain is vulnerable to traumatic damage in two ways. The cerebral cortex can become bruised - contused - when the head strikes a hard object (or a hard objects strikes the head).