When a person suffers a "mild" traumatic injury to the brain, the brain may not function normally for a few seconds to several months. It is possible that permanent injury occurs. The person may not even loose consciousness. Sometimes rapid acceleration/deceleration such as in a car accident with or without hitting one's head and with or without loosing consciousness may cause a mild traumatic injury to the brain. More often one has been hit in the head and may have had a brief loss of consciousness. Any of these types of mild head injuries may result in a constellation of symptoms called a concussion.
With a concussion people develop headache, nausea, vomiting, visual disturbances, poor concentration and attention span, dizziness, memory difficulties, even difficulties with balance and gait. The injured person may not remember the injury and may not remember a short time before and/or after the trauma. Residual effects may last for several hours to several months. Radiologic studies such as CAT Scans and MRI Scans of the brain are usually normal. When the symptoms persists for more than a few days, the syndrome is called a Post Concussive Syndrome. Should the syndrome persist, neuropsychologists can do testing to better define the specific injury in order that specific cognitive therapies may be directed at the deficits.