Traumatic Brain Injury (TBI)
TBI is an injury from some type of trauma, such as a blow, jolt, or penetrating object, that disrupts normal brain functions. Falls, car accidents, impact while playing sports, and objects piercing the skull are common causes of TBI. A TBI can range from mild, sometimes called a concussion, to serious, which can cause long-term problems. NICHD is one of many NIH institutes and other federal agencies working to understand and prevent TBI and to help people recover from TBI and related conditions.
About Traumatic Brain Injury (TBI)
TBI is an injury to the brain from some type of trauma or force, such as a bump or blow to the head or an object such as a bullet entering the skull. TBI can cause problems with brain function. Some TBIs result in mild, temporary problems. A more severe TBI can lead to serious physical, mental, and emotional symptoms; coma; and even death.1 People or children who have already experienced brain injury or brain disease are at higher risk for developing TBI.
A text alternative is available at: http://www.nichd.nih.gov/news/resources/links/Pages/TBI_VTA.aspx.
TBI includes (but is not limited to) several types of injury to the brain:
- Skull fracture occurs when the skull cracks. Pieces of broken bone from the skull may cut into the brain and injure it, or an object such as a bullet may pierce the skull and enter the brain.
- Contusion is a bruise of the brain, where swollen brain tissue combines with blood released from broken blood vessels to increase pressure on the brain. A contusion can occur from the brain shaking back and forth against the skull, such as from a car crash or sports injury or in shaken baby syndrome.
- Intracranial hematoma occurs when a major blood vessel in or around the brain is damaged and begins bleeding. The pooling of blood puts pressure on the brain.1,2
Concussion is among the most common forms of TBI.1 A concussion can happen when the head or body is moved back and forth quickly, such as during a car crash or sports injury, or from a blow to the head. Concussions are often called “mild TBIs,” because they are usually not life-threatening. However, they still can cause serious problems, especially if the person has experienced a concussion before.3,4
People may also experience non-traumatic brain injuries that result from a problem, such as a stroke, infection, or broken blood vessel, inside the brain or skull. A person who has a non-traumatic brain injury may have some of the same symptoms as a person who has a TBI. Both traumatic and non-traumatic brain injuries can have serious, long-term effects on a person’s ability to think and function.5,6
TBI can happen to anyone, but some people are more likely to experience a TBI than others. For example, according to the Centers for Disease Control and Prevention (CDC),1 young children, teenagers, and adults age 65 or older are at higher risk for TBI. CDC statistics1 also show that males are at higher risk than females in most age groups.
In addition, members of the military—both those in combat and those in reserves—are at higher risk for TBI than people who are not in the military.7 For instance, many military personnel in Iraq and Afghanistan have been exposed to TBI hazards, such as improvised explosive devices. TBIs from blasts and explosives have features that are distinct from features of non–blast-related injuries. Blast-related TBIs can include damage from waves of intense pressure, sometimes called blast or shock waves, and from high-temperature winds of an explosion, as well as contact with physical objects and penetrating pieces of shrapnel.8 NICHD works with the U.S. Department of Defense on TBI research. For more information about TBI in the military, visit the Defense and Veterans Brain Injury Center website.
What are common symptoms of traumatic brain injury (TBI)?
TBI symptoms vary depending on:
- The type of injury
- How severe the injury is
- What area of the brain is injured
TBI injuries can be both local (the exact place on the brain where the injury occurred) and include the surrounding tissues, which can also be affected by the damage to the initial site. This means that some symptoms appear right away, while others may appear several days or even weeks later and evolve over time. A person with TBI may or may not lose consciousness. Loss of consciousness, sometimes called a blackout, does not necessarily mean the TBI is severe, especially if the blackout lasts for only a short time. Learn about treatments for TBI.
What causes traumatic brain injury (TBI)?
A TBI is caused by an external force that injures the brain. It can occur when a person’s head is hit, bumped, or jolted. It also can occur when an object, such as a bullet, pierces the skull or when the body is shaken or hit hard enough to cause the brain to slam into the skull.
Among the leading causes of TBI are falls, motor vehicle crashes and traffic-related accidents, being struck by or against an object, and assaults.1
Many TBIs, especially in young people, happen while people are playing sports or doing recreational activities. Some activities that lead to emergency department visits for TBI are bicycling, football, playground activities, basketball, and soccer.2 Learn more by viewing NICHD’s video and infographic on TBI in kids.
In the military, the leading causes of TBI are gunshots, fragments from an explosion, blasts, falls, motor vehicle crashes, and assaults.3
How do healthcare providers diagnose traumatic brain injury (TBI)?
Healthcare providers use different tests and measures to diagnose TBI. Often, multiple measures are used together to diagnose TBI and to map out a path for treatment and recovery. Some of these tests are described in the following sections. In addition to “neuro-checks”—a series of quick questions and tasks that help healthcare providers assess how well a TBI patient’s brain and body are working—some in-depth tests help reveal levels of injury or damage in TBI patients.
Please note: This website does not include all tests that may be used to diagnose TBI.
What are the treatments for traumatic brain injury (TBI)?
A variety of treatments can help a person recover from TBI and can sometimes reduce or eliminate certain physical, emotional, and cognitive problems associated with TBI. The specifics of treatment, including the type, setting, and length, depend on how severe the injury is and the area of the brain that was injured.
What are the possible effects of traumatic brain injury (TBI)?
TBI can have a range of effects that depend on the type of injury, how severe the injury is, and what part of the brain is injured.1 According to the Centers for Disease Control and Prevention, these health effects can sometimes remain for a long time or even be permanent.2
Sometimes, a person will have medical complications just after the injury. People with more severe TBI are more likely to have complications. Some complications of TBI include seizures, nerve damage, blood clots, narrowing of blood vessels, stroke, coma, and infections in the brain.1
The likelihood of many of these problems decreases as more time passes and the person’s condition stabilizes. However, some problems, such as seizures, may continue even after a person’s condition is stable.
TBI may cause problems with various brain functions, and some of these problems do not appear until days or months after the injury. Some problems may be temporary, while others may persist throughout a person’s life after the injury. Possible longer-term effects of TBI include problems with:
- Cognition, such as difficulty learning, remembering, making decisions, and reasoning
- Senses, such as double vision, a bitter taste in the mouth or loss of the sense of taste, ringing in the ears, and tingling or pain
- Communication, such as trouble talking, reading, writing, and explaining feelings or thoughts
- Behavior, including difficulty with social situations, relationships, self-control, and aggression
- Emotions, including depression, anxiety, mood swings, and irritability1,3
Research suggests that having one or more TBIs may increase the likelihood of later having a disease that causes the breakdown of brain cells. Some evidence indicates that TBI is linked to:
- Alzheimer’s disease, which impairs memory, emotions, and thinking skills
- Parkinson’s disease, which causes problems with motor skills and controlling body movement
- Chronic traumatic encephalopathy, which causes problems with memory, thinking, and motor skills. It is more common in those who have repeated TBIs or head impacts, including athletes involved in boxing, football, and hockey.4