Acquired Brain Injury (ABI) — The Basics


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Acquired Brain Injury(ABI) refers to any damage to the brain that occurs after birth and is not related to a congenital or a degenerative disease. Causes include traumatic injury, seizures, tumors, events where the brain has been deprived of oxygen, infectious diseases, and toxic exposure such as substance abuse.


Millions of Canadians live with the effects of Acquired Brain Injury.

Acquired brain injuries currently impact about 1.5 million Canadians, and every year another 160,000 people experience an acquired brain injury. These rates continue to rise as more Canadians are experiencing and reporting incidents of ABI.

There are more people impacted by acquired brain injuries than the combined numbers of people suffering from breast cancer, spinal cord injury, multiple sclerosis and HIV/AIDS. The effects also extend to those living with and caring for people with ABIs.

It is the mission of Brain Injury Canada to enhance the quality of life for these 1.5 million+ Canadians, their families, and caregivers through education, research, awareness, and advocacy.

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There are 2 types of Acquired Brain Injuries: Non-Traumatic and Traumatic

Non-Traumatic Acquired Brain Injury (ABI)

Non-Traumatic Acquired Brain Injuries are caused by something that happens inside the body or a substance introduced into the body that damages brain tissues. They include:

  • Ischemic stroke (stroke from a blocked blood vessel in the brain)
  • Hemorrhagic stroke (stroke from a burst blood vessel in the brain)
  • Aneurysm (a bulge in a blood vessel in the brain that may leak/rupture)
  • Seizure disorders
  • Brain tumour
  • Poisoning
  • Substance abuse
  • Opioid overdose (heroin, fentanyl, codeine, morphine…)
  • Meningitis
  • Encephalitis
  • Hydrocephalus (fluid accumulates in the brain)
  • Vasculitis (inflammation of the blood vessel walls in the brain)
  • Hematoma (blood collecting on the surface of the brain)

Traumatic Acquired Brain Injury (ABI)

Traumatic Acquired Brain Injuries are caused by something that comes from outside the body, such as a blow, bump, or jolt. It can result in temporary injury, or more serious, long-term damage to brain cells. They include:

  • Motor vehicle accidents
  • Falls
  • Assault
  • Gunshot wounds
  • Domestic violence (assault, strangulation, suffocation)
  • Shaken baby syndrome
  • Sports injuries
  • Explosive blasts, combat injuries

Children may respond to a traumatic Acquired Brain Injury differently than adults. Always take your child to the doctor if they’ve received any trauma to the head or body that you feel concerned about, or that causes changes in your child’s behavior, habits, or responses.

Impact of Acquired Brain Injuries

The effects of a an acquired brain injury can begin to show immediately or increase/decrease over time. Each individual will experience a unique combination of challenges and changes.

Physical Changes

  • Fatigue, difficulties with sleeping, insomnia
  • Challenges with walking, sitting, moving from one location to another, bathing, and household tasks
  • Slurred speech
  • Chronic pain, headaches
  • Changes in vision
  • Seizures, fluid increase in the brain, infections, damaged blood vessels in the brain, vertigo (sensation of dizziness/spinning/loss of balance)
  • Sensory changes: ringing in the ears, trouble with hand-eye coordination, unpleasant tastes or smells, sensations on the skin like tingling, pain, or itching, difficulty with balance, dizziness

Cognitive Changes (Changes in thinking, learning, decision making)

  • Needing more time to understand information
  • Difficulty with making plans, organizing, or beginning tasks
  • Vision problems
  • Challenges with communicating: understanding conversations, finding the right word, speaking in proper sentences, understanding cues, making conversation
  • Difficulty writing
  • Difficulty with concentrations, distracted easily
  • Difficulty remembering things, learning, reasoning and judgment
  • Difficulty making decisions
  • Getting stuck on a single topic, idea, or activity either in conversation or actions (called perseveration)
  • Confusion about the current date, location, time of day
  • Loss/changes to senses and perceptions: sensation, sense of smell or taste, vision, double vision, hearing

Emotional Changes

  • Feeling irritable, having a ‘short fuse’
  • Depression, anxiety, anger
  • Prone to sudden, extreme emotions for no clear reason
  • Showing a limited emotional response to situations
  • Feeling like they have lost their identity, experiencing anxiety about further injuries to the brain

Behavioral Changes

  • Engaging in risky behavior, impulsive
  • Lack of a ‘filter’, saying things that are inappropriate
  • Isolating oneself
  • Difficulty with social and work relationships
  • Changing/inconsistent sleep patterns
  • Change in role – often from being independent to relying on others for care and support
  • Family breakdowns

Concussion is also an acquired brain injury.  Click here to learn more about concussion/mild traumatic brain injury (mTBI).