A state of agitation, confusion, and memory loss that the patient with traumatic brain injury (TBI) enters soon after the injury or on awakening from coma. Edema, hemorrhage, contusions, shearing of axons, and metabolic disturbances impair the brain’s ability to process information accurately, resulting in unusual behaviors that often are difficult to manage. Trauma patients with normal brain scans may have mild TBI and display some of the symptoms of PTA. Posttraumatic amnesia can last for months but usually resolves within a few weeks. During PTA, the patient moves from a cognitive level of internal confusion to a level of confusion about the environment.