Concussion

Concussion, from the Latin concutera ("to shake violently"), is the most common type of traumatic brain injury. The terms mild brain injury, mild traumatic brain injury (MTBI), mild head injury (MHI), and minor head trauma and concussion may be used interchangeably. Concussion may be caused by a blow to the head, or by acceleration forces without a direct impact. Common causes include sports injuries, bicycle accidents, car accidents, and falls.

Concussion can cause a variety of physical, cognitive, and emotional symptoms. How long a person remains unconscious may indicate the severity of the concussion. A mild concussion may involve no loss of consciousness or a very brief loss of consciousness. A severe concussion may involve prolonged loss of consciousness with a delayed return to normal.