Traumatic Brain Injury Traumatic Brain Injury
Centers for Disease Control and Prevention

A traumatic brain injury (TBI) is caused by a blow or jolt to the head or a penetrating head injury that disrupts the normal function of the brain. Not all blows or jolts to the head result in a TBI. The severity of a TBI may range from “mild,” i.e., a brief change in mental status or consciousness to “severe,” i.e., an extended period of unconsciousness or amnesia after the injury.

How many people have TBI?

TBIs contribute to a substantial number of deaths and cases of permanent disability annually.

Of the 1.4 million who sustain a TBI each year in the United States:

50,000 die; 235,000 are hospitalized; and 1.1 million are treated and released from an emergency department.1

Among children ages 0 to 14 years, TBI results in an estimated:

2,685 deaths; 37,000 hospitalizations; and 435,000 emergency department visits annually.1

The number of people with TBI who are not seen in an emergency department or who receive no care is unknown.

For more information about TBI in the United States, including the groups at highest risk, CDC’s surveillance activities, and the numbers of TBI cases in each state, see Overview.

What causes TBI?
The leading causes of TBI are:

Falls (28%); Motor vehicle-traffic crashes (20%); Struck by/against events (19%); and Assaults (11%).1

For more information on the leading causes of TBI, see Causes.

What are the signs and symptoms of TBI?
The signs and symptoms of a traumatic brain injury (TBI) can be subtle. Symptoms of a TBI may not appear until days or weeks following the injury or may even be missed as people may look fine even though they may act or feel differently.

For a list of common signs and symptoms of TBI, see Signs and Symptoms.

What are the long-term outcomes of TBI?
CDC estimates that at least 5.3 million Americans, approximately 2% of the U.S. population, currently have a long-term or lifelong need for help to perform activities of daily living as a result of a TBI.2

TBI can cause a wide range of functional changes affecting thinking, sensation, language, and/or emotions. It can also cause epilepsy and increase the risk for conditions such as Alzheimer’s disease, Parkinson’s disease, and other brain disorders that become more prevalent with age.3

To learn more about the potential outcomes of TBI, see Outcomes.

What are the costs of TBI?
Direct medical costs and indirect costs such as lost productivity of TBI totaled an estimated $60 billion in the United States in 2000.