Traumatic Brain Injury (TBI)



Traumatic brain injury (TBI) results from an impact to the head that disrupts normal brain function. TBI may affect a person’s cognitive abilities, including learning and thinking skills.

Most TBIs are caused by falls, being struck by an object or by vehicle crashes. Doctors may classify traumatic brain injury as mild, moderate or severe, depending on whether the injury causes unconsciousness, how long unconsciousness lasts and the severity of the individual’s symptoms. Although most TBIs are classified as mild because they’re not life-threatening, a mild TBI can have serious and long-lasting effects; the extent of these effects is not fully understood and requires more research.

TBI resulting from an impact to the head disrupts normal brain function and is a threat to cognitive health in two ways:

A traumatic brain injury’s direct effects which may be long-lasting or even permanent can include:

  • Unconsciousness
  • Inability to recall the traumatic event
  • Depression
  • Confusion
  • Difficulty learning and remembering new information
  • Trouble speaking coherently
  • Unsteadiness,
  • Lack of coordination and problems with vision or hearing.

Certain types of TBI may increase the risk of developing Alzheimer’s or another type of dementia years after the injury takes place.

TBI can affect your brain even if you don’t lose consciousness and your symptoms clear up quickly. Anyone who experiences an impact to the head and develops any symptoms of TBI should seek medical attention, even if symptoms seem mild. Call emergency services for anyone who:

  • Is unconscious for more than a minute or two
  • Experiences seizures, repeated vomiting or symptoms that seem to worsen as time passes.
  • Was ejected from a vehicle and sustained a head injury.
  • Was struck by a vehicle while on foot.
  • Has fallen from a height of more than three feet.

The leading causes of TBI that result in emergency department visits are falls, being struck by an object and motor vehicle crashes. Indirect forces that shake the brain violently within the skull, such as shock waves from battlefield explosions, can also cause TBI. In addition, TBI can result from bullet wounds or other injuries that penetrate the skull and brain. However, it is important to note that not all blows or jolts to the head result in a TBI.

Falls are the most common cause of TBI, and falling poses an especially serious risk for older adults. When a person over 65 years old sustains a serious TBI in a fall, direct effects of the injury may result in long-term cognitive changes, reduced ability to function and changes in emotional health. Older adults who experience loss of consciousness after a TBI are more likely to report subjective memory impairment than seniors who did not experience a TBI.

The severity of symptoms depends on whether the injury is mild, moderate or severe. In all forms of TBI, cognitive changes (changes in how people think) are among the most common, most disabling and longest-lasting symptoms that can result from the injury. The ability to learn and remember new information is often affected. Other commonly affected cognitive skills include the capacity to pay attention, organize thoughts, plan effective strategies for completing tasks and activities and make good judgments. More severe changes in thinking skills — a hallmark characteristic of dementia — may develop years after the injury took place and the person appears to have recovered from its immediate effects.

Mild TBI, also known as a concussion, does not necessarily cause loss of consciousness or causes unconsciousness that lasts for 30 minutes or less. Mild TBI symptoms may include:

  • Inability to remember the cause of the injury or events that occurred immediately before or up to 24 hours after it happened.
  • Confusion and disorientation.
  • Difficulty remembering new information.
  • Problems with finding words.
  • Headache
  • Dizziness
  • Blurry vision.
  • Sensitivity to light and/or sound.
  • Change in energy or motivation.
  • Nausea and vomiting.
  • Ringing in the ears.
  • Trouble speaking clearly.
  • Changes in emotions or sleep patterns.

These symptoms usually appear at the time of the injury or soon after, but sometimes may not develop for days or weeks. Mild TBI symptoms are usually temporary and clear up within hours, days or weeks; however, on occasion, they can last months or longer.

Moderate TBI causes unconsciousness lasting more than 30 minutes but less than 24 hours, and severe TBI causes unconsciousness for more than 24 hours. Symptoms of moderate and severe TBI are similar to those of mild TBI, but more serious and longer-lasting. The more severe injuries may also lead to hemorrhages or other brain injuries that are associated with focal neurologic symptoms, such as localized weakness or sensory loss.

Evaluations by health care professionals typically include:

  • Questions about how the injury happened.
  • Assessment of the person’s level of consciousness and confusion.
  • An examination to assess memory and thinking, vision, hearing, touch, balance, gait, coordination, strength and sensation, reflexes and other indicators of brain function.

Let your physician know if you are taking medications (prescription, over-the-counter or natural remedies), especially blood thinners such as Coumadin and aspirin, because they can increase the chance of complications. Also inform your health care professional if you drink alcohol or take drugs.

Depending on the cause of the TBI and the severity of symptoms, brain imaging with computed tomography (CT) or magnetic resonance imaging (MRI) may be needed to determine if there’s bleeding or swelling in the brain. If you experience a TBI, it should be noted in your permanent medical record and mentioned whenever giving a new doctor your medical history.