Traumatic Brain Injury (TBI)

Traumatic brain injury (TBI) is a serious health condition that happens when a hit or blow to the head causes damage to the brain.

Emergency Information

A person should seek medical attention right away if any symptoms of traumatic brain injury appear, especially within the first 24 hours after a head injury. 

  • Brain injury
  • Head injury
  • Concussion (also called mild TBI)
  • Closed head injury
  • Blunt TBI (non-penetrating TBI)
  • Open head injury (penetrating TBI)
  • Blast injury

Overview

A traumatic brain injury (TBI) happens when an outside force such as a hard bump, blow, or jolt to the head or body damages the brain. An object entering the brain, such as a bullet, can also cause a TBI.

Not all blows to the head cause a TBI. But when they do, health effects can range from mild and temporary to severe and permanent.

There are two main types of TBI:

  • Penetrating TBI (open head injury): An object pierces the skull and enters the brain. This type usually damages only part of the brain.
  • Non-penetrating TBI (closed head injury): A hit or blow to the head makes the brain move inside the head. Examples include falls, car crashes, sports injuries, and being struck by an object.

Some TBIs cause damage right away. These are called primary injuries. Others cause damage that develops slowly over hours, days, or weeks. These are called secondary injuries.

A concussion is a common TBI. Concussions are often called mild TBIs because they are usually not life-threatening. However, they can still cause serious problems, especially if the affected person had a concussion before.

Signs and Symptoms

TBI symptoms can depend on the type of injury, how severe it is, and what part of the brain is damaged. Some symptoms appear right away, while others may show up days or even weeks later. A person should seek medical attention right away if any of these symptoms appear, especially within the first 24 hours after a head injury.

TBI symptoms may include:

  • Headache
  • Confusion
  • Dizziness or lightheadedness
  • Blurred vision
  • Ringing in the ears (also called tinnitus)
  • Tiredness
  • A bad taste in the mouth
  • Changes in sleep habits
  • Behavior or mood changes
  • Trouble with memory, concentration, or thinking
  • Sensitivity to light or sound
  • Nausea or vomiting
  • Brief loss of consciousness (a few seconds to minutes)
  • A headache that gets worse or will not go away
  • Loss of vision in one or both eyes
  • Repeated vomiting
  • Slurred speech
  • Seizures
  • Inability to wake up from sleep
  • The dark center of one or both eyes becomes larger
  • Numbness or tingling in arms or legs
  • Clumsy or uncoordinated movements
  • Increased confusion and restlessness
  • Loss of consciousness lasting minutes to hours
  • Clear fluids coming from the nose or ears

TBI symptoms in children may be different from adults. Children may not be able to tell adults how they feel. The following symptoms in children require medical attention:

  • Changes in eating or breastfeeding
  • Ongoing crying that cannot be calmed
  • Changes in the ability to pay attention, including in school
  • Mood or behavior changes
  • Loss of interest in a favorite toy or activity
  • Changes in sleep patterns
  • Seizures
  • Sadness
  • Loss of a skill, such as toilet training
  • Unsteady walking or loss of balance
  • Vomiting

Post-concussion syndrome occurs when symptoms of a concussion continue for weeks or months after the injury.

TBI can cause a wide range of health effects depending on the type and severity of the injury. Outcomes also depend on a person’s overall health before the injury, the care they receive afterward, and the support available during recovery.

Immediate complications may occur just after a TBI. These may include seizures, nerve damage, blood clots, narrowing of blood vessels, stroke, coma, and infections in the brain.

Longer-term effects may include problems with:

  • Thinking and memory: Difficulty learning, remembering, making decisions, and reasoning
  • Senses: Double vision, loss of taste, ringing in the ears, and tingling or pain
  • Communication: Trouble talking, reading, writing, and expressing thoughts
  • Behavior: Difficulty in social situations, self-control, and relationships
  • Emotions: Depression, anxiety, mood swings, and irritability

Specific types of brain damage from TBI include:

  • Diffuse axonal injury: Widespread damage to bundles of nerve fibers that carry signals between parts of the brain, called white matter. This type of damage often happens after car accidents, falls, or sports injuries.
  • Hematomas: A collection of blood in or around the brain caused by a broken blood vessel. The pooled blood takes up space and can press on the brain, damage nearby tissue, and reduce normal blood flow and oxygen to the brain.
  • Contusions: Bruising or swelling of the brain when very small blood vessels bleed into brain tissue.
  • Skull fractures: Breaks or cracks in the bones of the skull that can damage nearby tissues, blood vessels, and the brain
  • Functional brain damage: Damage to the brain that cannot be detected by imaging tests.
  • Chronic traumatic encephalopathy (CTE): A delayed brain disorder that research suggests is caused in part by repeated TBIs. It is a type of brain disorder in which an abnormal protein (tau) builds up and damages brain cells over time. Symptoms may include problems with thinking, memory, movement, and impulse control. People can also have depression, confusion, and irritability. Studies have shown that repeated blows to the head can cause memory problems, tremors, lack of coordination, and dementia. Recent studies have also found cases of CTE in athletes who played soccer, wrestling, football, boxing and rugby. It can only be definitively diagnosed after death by examining brain tissue.
  • Post-traumatic dementia: This can happen after a single TBI. Studies show that TBIs in early or mid-life may be associated with increased risk of dementia later in life.
  • Neurodegenerative disease: More than half of people with a TBI may develop worsening brain problems over time, including memory loss and dementia. TBIs have been linked to both Alzheimer’s disease and Parkinson’s disease.
  • Bone Fractures: People with a TBI are more susceptible to bone loss and bone fractures. 
  • Mental Health Conditions: People who had a TBI before age 25 may be more likely to be hospitalized later for a mental health condition than those who did not have a TBI at that age.

Diagnosis

All TBIs should be evaluated right away by a doctor or healthcare provider with experience diagnosing and treating head injuries. Doctors use several tools and tests to diagnose a TBI.

Neurological Exam

A doctor will check motor and sensory skills, hearing and speech, coordination and balance, mental status, and changes in mood or behavior.

Brain Imaging

Brain imaging helps doctors see the extent of the injury:

  • Computed tomography (CT) scan: Takes X-rays from many angles to create a complete picture of the brain. It can quickly show whether the brain is bleeding, bruised, or otherwise damaged.
  • Magnetic resonance imaging (MRI): Uses magnets and radio waves to produce more detailed images than CT scans. MRI is more sensitive and can detect subtle brain changes that a CT scan may miss.

The Glasgow Coma Scale (GCS) measures a person’s functioning in three key areas:

  • Ability to speak
  • Ability to open the eyes
  • Ability to move

For many years, evaluation of head injury patients in the emergency room focused upon a patient’s GCS. A score of 13 or higher indicated mild TBI, 9 through 12 indicated moderate TBI, and 8 or below indicated severe TBI. Patients with evidence of bleeding or skull fractures seen on a CT scan were also classified as most severe.

Ongoing TBI research has changed this approach to classifying a recent TBI. The CBI-M framework is a newer, more detailed system. Instead of relying only on simple labels like mild, moderate, or severe, it helps improve diagnosis and treatment by looking at many factors. These include clinical findings, measurable indicators in the body called biomarkers, imaging results, and other factors. This additional information helps doctors have a more complete picture of a person’s injury.

Blood Tests

Blood tests are a growing area of research. In 2018, the FDA approved a test that looks for two proteins released into the blood after a mild concussion. These proteins are normally inside brain cells and help them function but show up in the blood when those cells are injured. Researchers have also found that another protein, called tau, may help identify people who need more time to recover after a concussion.

Baseline Brain Function Testing

This testing is recommended by many athletic organizations at the start of each season. These tests measure memory, attention, and problem-solving ability. They can be repeated after a suspected concussion to help determine when an athlete is ready to return to normal activities.

Other Tests

  • Speech and language tests
  • Swallowing and breathing tests
  • Tests that measure thinking, memory, attention, and problem-solving

Causes and Risk Factors

Leading causes of TBI include:

  • Falls: Falls are the most common cause of TBIs. They happen most often among children and older adults.
  • Motor vehicle crashes: Accidents involving cars, bicycles, and pedestrians are a major cause of TBI.
  • Being struck by or against an object: Sports-related injuries are a significant cause of TBIs. Such activities can include bicycling, football, playground activities, basketball, and soccer.
  • Assaults and violence: TBIs are also caused by intimate partner violence, assaults, shaken baby syndrome, and gunshot wounds.
  • Explosions and blasts: Military personnel and trainers experience blast exposures from roadside bombs and training exercises. Civilians can also experience blast exposures at work, in disaster areas, or in war zones.

Who is at increased risk:

  • Young children, teenagers, and adults age 65 or older
  • People who have already experienced a brain injury or brain disease

Prevention Guidance

Unlike many neurological disorders, TBIs are preventable.

Steps to help prevent TBI include:

  • Always wear a seatbelt in a motor vehicle.
  • Make sure children wear a seatbelt or are in a properly installed child safety or booster seat.
  • Never drive under the influence of drugs or alcohol.
  • Wear a helmet, and make sure it fits correctly, when riding a bike, skateboarding, or playing sports like hockey and football.
  • Build balance and strength with regular physical activity.

Changes at home can prevent falls:

  • Install window guards and safety gates for young children.
  • Improve lighting and remove rugs, clutter, and other tripping hazards in hallways.
  • Use nonslip mats and install grab bars next to toilets and in tubs or showers, especially for older adults.
  • Install handrails on stairways.

Helmets in the United States must pass a drop test: They must be able to fall from 6.5 feet onto a flat surface without cracking.

Treatment and Management

Many factors, including the size, severity, and location of a head injury, influence how a TBI is treated and how quickly a person recovers. People who get medical attention right away at a hospital where clinicians are specially trained to treat serious injuries usually have the best health outcomes.

A person with a concussion should focus on symptom relief and “brain rest,” limiting mentally demanding activities.

Children and teens with a sports-related concussion should stop playing their sport immediately. They should return to play only after being approved by a concussion specialist.

Alcohol and other drugs can slow recovery and increase the chances of another brain injury, which can delay healing. Alcohol and other drugs can also increase the chances of long-term problems, including permanent brain damage and even death.

Emergency care for TBI focuses on:

  • Stabilizing the heart, lungs, and other vital organs
  • Making sure the brain gets enough oxygen
  • Managing blood flow and pressure in the brain
  • Preventing more injury to the head or neck

Surgery may be needed to:

  • Remove blood clots or pools of blood (hematomas) that put pressure on the brain
  • Repair skull fractures
  • Relieve pressure inside the skull

Medicines that may be used include:

  • Anti-anxiety medicine to reduce feelings of nervousness and fear
  • Anticoagulants to prevent blood clots
  • Anticonvulsants to prevent seizures
  • Antidepressants to treat depression and mood swings
  • Diuretics to reduce fluid buildup and lower pressure in the brain
  • Muscle relaxants to reduce muscle spasms
  • Stimulants to increase alertness and attention
  • Over-the-counter or prescribed pain medicines

Research shows that acupuncture may improve some TBI symptoms such as depression and problems with memory, attention, and thinking. Research has also shown that hyperbaric oxygen therapy (breathing pure oxygen) can be helpful when given very soon after a severe TBI. Mindfulness-based therapies may also help with depression and anxiety after a TBI.

Living With TBI

Rehabilitation therapy helps people recover function and relearn life skills. Therapy may include:

  • Physical therapy to build strength, balance, and flexibility
  • Occupational therapy to relearn daily tasks such as getting dressed, cooking, and bathing
  • Speech therapy to improve communication and treat swallowing problems
  • Psychological counseling to build coping skills and improve emotional well-being
  • Vocational counseling to help a person return to work
  • Cognitive therapy to improve memory, attention, learning, planning, and judgment

Rehabilitation generally involves a team of healthcare specialists, a person’s family, and a care coordinator. They work together to design a treatment program to meet a person’s specific needs.

Depending on the TBI, therapy may be needed right after the injury, occasionally throughout a person’s life, or on an ongoing basis.

People with TBI should:

  • Make a follow-up appointment with their doctor or healthcare provider to confirm recovery progress
  • Talk about new or ongoing symptoms and ask how to treat them
  • Pay attention to any new signs or symptoms, even if they seem unrelated to the injury. Some symptoms, such as mood swings or unusual irritability, may appear several weeks after a head injury.

Find Clinical Trials

Clinical trials uncover better ways to prevent, diagnose, treat, and understand diseases and conditions. To ensure results apply to everyone, volunteers of all ages, sexes, and backgrounds, including both healthy individuals and those with specific medical conditions, are needed. Find clinical trials on TBI.

Find Treatment

The following organizations can help connect people with TBI to professionals and services:

Community Support

The following organizations offer support, education, and resources for people with TBI and their families:

Brain Donation

People with TBI can also support research by designating the donation of brain tissue before they die. The NIH NeuroBioBank coordinates a network of brain banks across the country to advance research through the collection and distribution of post-mortem brain tissue.

Note: This resource list is for informational purposes only. It is not comprehensive, and an organization’s inclusion does not constitute an endorsement by NIH. 

Research Information

The National Institutes of Health (NIH) is the largest public funder of biomedical research in the world. NIH invests most of its budget in medical research seeking to enhance life and to reduce illness and disability. NIH-funded research has led to breakthroughs and new treatments helping people live longer, healthier lives, and building the research foundation that drives discovery.

NIH supports research on prevention, diagnostic and imaging tools, the biological mechanisms of TBI, treatment methods, and therapeutic interventions. Brain donation programs and brain banks also help researchers study brain tissue and better understand the long-term effects of TBI.

Current research areas include:

  • Exploring ways to promote the brain’s natural ability to adapt and repair itself, known as neuroplasticity
  • Improving how CTE and related symptoms are defined and diagnosed
  • Finding TBI biomarkers, biological signs of disease that can be found and measured, for TBI
  • Finding biomarkers for CTE to detect this disorder in living people rather than only through autopsy

NIH co-leads the Strategies to Innovate EmeRgENcy Care Clinical Trials (SIREN) network, which supports TBI trials including BOOST3 (Brain Oxygen Optimization in Severe TBI). Through BOOST3, scientists compare two methods for monitoring brain tissue oxygen to determine the best treatment approach for people with TBI.

The completed NIH-funded Transforming Research and Clinical Knowledge in TBI (TRACK TBI) project studied adults and children with TBI at all levels of injury severity and provided tools to improve diagnosis and assess outcomes after injury.

Find NIH-funded research projects using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies.