In mild brain injury , such as a concussion, there is only a brief or momentary loss of consciousness. Symptoms, including dizziness, fatigue or mental slowness, usually improve over several months . Moderate brain injury results in a loss of consciousness for several minutes or hours that is followed by days or weeks of confusion. There are noticeable physical or cognitive impairments that may persist for many months or a lifetime. Severe brain injury results in prolonged unconsciousness, or coma.
Survivors generally have permanent physical or cognitive impairments.
Brain injuries among infants, children, adolescents, and young adults.