Traumatic brain injury

When a person experiences a sudden injury to the head, they may have a traumatic brain injury that can damage the brain and, among other symptoms, increase the risk of dementia.

Older man doing physiotherapy with a therapist


A traumatic brain injury (commonly referred to as a TBI) may occur when a person experiences a sudden injury to the head caused by an external object. However, not all head traumas will result in a TBI.

A TBI can happen if an object forcefully hits a person’s head or when something pierces through the skull to the brain. Either of these experiences can cause damage to brain cells and blood vessels, and a person’s physical and cognitive functioning can be broadly affected as a result.

The extent of a TBI depends on what part of the person’s brain has been damaged and the severity of the trauma.


A TBI is also commonly referred to as an acquired brain injury or a repeated head trauma.

“Dementia pugilistica” and “punch-drunk syndrome” are two of the terms used to describe a TBI that is caused by the repeated brain damage that can result from contact-heavy sports like boxing or football.

A TBI is often categorized as either being a mild, moderate or severe brain injury.


A TBI can often affect the overall cognitive functioning of a person and may result in significant challenges with thinking and learning.

Depending on where the injury occurred in the brain, a TBI can cause symptoms of dementia, including memory, concentration and attention problems, speech and eating problems, and difficulty with balance and coordination.

Typically, in cases where people develop dementia after a brain injury, the problem is forming new memories or remembering recent events (referred to as “short term memories”). Old memories (or “long term memories”) are typically not affected.

A TBI may cause permanent or temporary changes in how a person thinks, acts, moves, speaks and feels. A TBI may also affect parts of the body’s internal functioning, such as:

  • the ability to regulate body temperature
  • sleep
  • appetite
  • sexual drive,
  • energy level, etc.

Signs and symptoms of a TBI may appear immediately after the head trauma was experienced or may take several days or weeks to appear after the injury occurred.

A TBI is often categorized as either being a mild, moderate or severe brain injury.

Symptoms of a mild TBI

With a mild TBI, a person may not lose consciousness; however, some people may lose consciousness for a few seconds or minutes.

Common symptoms associated with a mild TBI include:

  • feeling sleepy and dizzy,
  • nausea or vomiting,
  • headaches,
  • confusion,
  • blurred vision,
  • mood swings, and
  • difficulty with thinking and memory.

Typically the person will not require more than a day of hospital observation. Mild TBI are also called concussions. A small percentage of people will have symptoms lasting for more than 6 months. Unless the person experiences repeated concussions, the prognosis is good with full recovery of function.

If the person is involved in activities that produce repeated concussions (hockey, football, etc.) the risk of developing serious problems with thinking, memory and behaviour becomes a serious issue.

Symptoms of moderate and severe TBI

In moderate and severe TBI, the person experiences altered level of consciousness or fully loses consciousness for more than 24 hours. Sometimes the person has problems remembering the day—or the days and weeks after—the head injury occurs. This is more commonly seen in serious accidents or acts of violence.

In addition to experiencing similar symptoms to a person with a mild TBI, someone with a severe TBI may also experience:

  • comatose states
  • seizures
  • abnormal speech or language
  • loss of coordination
  • impaired thinking, and
  • agitation.


A physician will typically ask a number of questions related to how the injury occurred. The physician will also assess a person’s level of consciousness and may conduct some neurological exams to evaluate different aspects of a person’s cognitive functioning, such as memory and thinking.

Brain imaging (like a CT scan) may be requested by a physician depending on the nature and severity of the brain injury. This can help to detect any abnormalities in the brain, such as bleeding or swelling.

Risk factors

Falls, car accidents and sports injuries are among the most common causes of a TBI.

Older adults are at an increased risk of long-term physical and cognitive changes if they have a serious fall that causes a TBI.

Some other examples of events which may result in a TBI include:

  • explosive blasts
  • bullet wounds that pierce the skull, and
  • violence.

Children under the age of 4, young adults between the ages of 15 and 24 and adults over the age of 75 are most at risk of experiencing a TBI.


People with a mild TBI usually do not require any treatment other than rest and at-home monitoring for any change in symptoms.

Gradual return to school, work or sports activities is recommended with close monitoring.

Depending on the nature of a person’s injuries, someone with a severe TBI may require a lengthy hospital stay, surgery, medication and inpatient rehabilitation.

Therapeutic approaches

Therapeutic approaches also help support people living with a TBI to manage the associated symptoms:

  • Occupational therapy can help a person to relearn and perform daily activities, while physiotherapy can help improve balance, walking and movement after a brain injury has occurred.
  • Speech therapy may be required to help people improve their ability to communicate and to learn how to use an assistive communication device, if needed.
  • Social workers are excellent at helping patients and their relatives find a way to adapt to their new roles and realities.

Often times a consultation with a neuropsychiatrist is required to help manage some of the cognitive, behavioural and emotional symptoms of a brain injury. Rehabilitation medicine specialists are also an integral part of the treatment team that a person with a brain injury requires.

More useful links and resources

Concussion Awareness Training Tool.  A series of online educational modules and resources addressing concussion recognition, diagnosis, treatment, and management. Created by the BC Injury Research and Prevention Unit.

Dementia Talks! Canada Webinar Recording. Let's discuss concussion, brain injury and dementia.