Traumatic brain injury (TBI) is an injury to the head caused by an external physical force. Most traumatic brain injuries are caused by accidents or assaults to the skull that are sufficiently hard to cause the brain to move within the skull or to cause the skull to break and directly injure the brain. TBI may produce a diminished or altered state of consciousness and an impairment of cognitive abilities or physical functioning. It may also result in the disturbance of behavioral or emotional functioning. The damage can be focal, confined to one area of the brain, or diffuse, involving more than one area of the brain.

Causes of TBI include:

Symptoms of a traumatic brain injury are varied, and can be mild, moderate or severe, depending on the extent of the damage to the brain. Some initial symptoms may include:

A person with a suspected traumatic brain injury should contact a physician immediately, go to the emergency room, or call 911.

An acquired brain injury (ABI) refers to any type of brain damage occurring after birth that is not hereditary, congenital, degenerative, or the result of an external impact. Acquired brain injury takes place at the cellular level of the brain and may result in mild, moderate, or severe impairments in one or more areas, including cognition, physical functions, and psycho-social behavior.

Causes of ABI include:

Symptoms of ABI are very similar to those of TBI. However, persons with ABI may experience some difficulties more frequently or to a greater degree.

Symptoms of an acquired brain injury may include:

A person with a suspected acquired brain injury should contact a physician immediately, go to the emergency room, or call 911.