Collage of four photos showing the aftermath of a serious car accident, armed soldiers in the field wearing full combat gear and helicopters flying in the background, football players colliding violently, an older women bracing herself nervously at the top of the stairs


A car accident. A football tackle. An unfortunate fall. These things—and more—can cause head injuries. Head injuries can happen to anyone, at any age, and they can damage the brain.

Here’s how damage can happen: A sudden movement of the head and brain can cause the brain to bounce or twist in the skull, stretching and injuring brain cells and creating chemical changes. This damage is called a traumatic brain injury (TBI).

The U.S. Food and Drug Administration continues to research TBI and encourage the development of medical devices to help diagnose and treat it.

Causes and Symptoms of TBI 

TBI is often caused by a bump, blow, jolt, or explosive blast to the head, or a penetrating head injury that disrupts the brain’s normal function. Not all hits to the head result in TBI. But when it happens, TBI can range from mild (like a brief change in mental status or consciousness) to severe (like a longer period of unconsciousness or major problems with thinking and behavior after injury).

A concussion is a form of mild TBI—and represents about 75 percent of TBIs that occur each year.

Symptoms of mild TBI include:

  • headache
  • confusion
  • blurred vision
  • behavioral changes

Moderate and severe TBI can produce more symptoms including:

  • repeated vomiting or nausea
  • slurred speech
  • weakness in the arms or legs
  • problems with thinking abilities

If you have questions about TBI, including concussion, talk to your health care provider. Anyone with signs of mild, moderate or severe TBI should receive medical attention as soon as possible. Call 9-1-1 in emergency situations.

Diagnosis of TBI

While it can be hard to formally diagnose TBI, the Centers for Disease Control and Prevention (CDC), the American College of Rehabilitation Medicine, and some others have published guidelines for diagnosing TBI.

A medical exam is the first step in diagnosing potential head injury. Assessment usually includes a neurological exam. This exam includes an evaluation of thinking, motor function (movement), sensory function, coordination, and reflexes.

Imaging tests, including computerized tomography scans (CT scans) and magnetic resonance imaging (MRI) tests do not diagnose TBI. But tests from these FDA-regulated medical devices can help health care providers rule out a life-threatening injury to the brain (particularly bleeding that resulted from the traumatic injury that can require immediate medical or surgical attention).

Health care providers also may use other FDA-regulated devices when considering a diagnosis. For instance, the FDA has reviewed and evaluated the safety and effectiveness of a limited number of other devices that health care providers can use to help assess, diagnose, or manage their patients’ head injuries. In each case, the device was studied in its own clinical trial to demonstrate its safe and effective use. That said, none of these medical devices is intended to replace a CT scan or the judgment of a healthcare provider. And the FDA has not yet cleared or approved any standalone medical products that are intended to specifically diagnose or treat TBI, including concussion.

You can learn more about the medical devices that FDA has cleared or approved for the professional assessment of head injuries on the FDA’s website.

Important safety note: During recent monitoring of the medical device market, the FDA became aware of some firms marketing medical devices for the assessment, diagnosis, or management of a head injury (including concussion) without proper FDA clearance or approval.

Medical devices that are not FDA-approved or FDA-cleared may not correctly diagnose a concussion. And incorrect diagnosis may lead to:

  • A wrong decision to let a person return to play or other activities with a serious head injury;
  • A missed diagnosis of a more serious head injury; or
  • The lack of proper treatment for a head injury.

The FDA issued a Safety Communication in April 2019 to caution about the serious risks of using unapproved or uncleared medical devices for the diagnosis, treatment or management of a concussion.

The bottom line: if you have a head injury, seek medical attention right away. The FDA has not approved any devices that can assess or diagnose a concussion without an evaluation by a health care provider.

More FDA Actions and Research on TBI

The FDA continues to work with the research and clinical community to develop better-designed clinical studies so new medical products can be developed. And it continues to review and evaluate medical devices for safety and effectiveness.

More sensitive and objective ways to diagnose and detect mild TBI are needed. And timely diagnosis is important to prevent repetitive injury and to help develop new therapies. That’s because repetitive injury carries the risk of “second impact syndrome.” If people who have not recovered from a head injury have a second head injury, this can result in more significant injury to the brain and more neurological deficits. And, in some cases, repetitive injury can be fatal.

The FDA continues to research diagnostic tests for mild TBI. They are studying TBI biomarkers (measurable, biological indicators of a particular state or condition), such as brain imaging, biofluid (specific proteins in blood), and physical indicators such as eye tracking and EEG, which tracks and records brain wave patterns. They’re also investigating using other portable imaging devices to detect mild TBI, including diffuse correlation spectroscopy—a device that can monitor blood flows in the brain from the scalp. 

Plus, the FDA’s scientists are doing research with patients at Walter Reed National Military Medical Center in Bethesda, Maryland. They’re recruiting more adult patients—including those with and without TBI—for continued research.

What to Know About the Impact of TBI

People who have TBI can face short- or long-term complications that affect thinking, sensation (including sight or balance), language, or emotions.

People with their first, mild TBI may just need to rest and reduce vigorous activity for a short period of time. Those with moderate to severe TBI may need physical therapy (to help with body movement), occupational therapy (to help with conducting daily activities), or psychiatric therapy and other support.

Little can be done to reverse any brain damage caused by trauma, reports the National Institute of Neurological Disorders and Stroke. But health care professionals will work to stabilize patients and try to prevent further harm. Long-term effects depend on the seriousness of the injury, location of the injury, and the age and general health of a patient.

Remember, if you have any have questions about a head injury, please talk with your health care provider.