Dementia: Overview

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About dementia

Dementia is an umbrella term that describes a set of symptoms affecting brain function. It's a chronic condition that gets more severe over time and is often characterized by:

There are many different types of dementia, each with its own cause. We don't yet fully understand these causes, but researchers suspect that some may be:

There's currently no cure for dementia, but some treatments may help to ease symptoms for some people and can help improve quality of life. The condition is not contagious.

About 3% of all people living with dementia in Canada are younger than age 65. This is known as young onset dementia. Since dementia is less common before age 65, it often goes unnoticed or undiagnosed. Living with young onset dementia comes with unique challenges because the person may be more likely to be:

Each person experiences dementia and its impacts on daily life differently. You may still be able to remain active and engaged in your work, home life and other responsibilities after getting a diagnosis.

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Dementia in Canada

In Canada between April 2020 and March 2021:

These numbers only include people who have had a formal diagnosis from a health care provider and are aged 65 and older. As such, the number of people living with dementia in Canada may be higher.

We expect the number of people living with dementia to continue to increase as Canada's population ages. However, data shows that the rate of newly diagnosed cases in people aged 65 and older has been decreasing over the past 10 years. Taking into account the aging of the population over time, between April 2011 and March 2012 there were 1,545 new cases per 100,000 people in this age group. This decreased to 1,300 new cases per 100,000 between April 2020 and March 2021.

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Types of dementia

Many diseases, injuries and conditions can affect different parts of the brain in ways that may result in dementia. Some conditions like Huntington's disease, Creutzfeldt-Jakob disease and multiple sclerosis have been linked to dementia.

Starting with the most common, here are some types of dementia:

Alzheimer's disease

Early signs of Alzheimer's disease include minor memory issues, such as forgetting new information and having difficulty completing familiar tasks.

Vascular dementia

Vascular dementia is associated with problems with blood flow to the brain, which damages brain cells. Causes for vascular dementia may include:

  • stroke
  • brain aneurysm
  • narrowed blood vessels
  • other cerebrovascular conditions
Lewy body disease (dementia with Lewy bodies)

Lewy body disease is a neurodegenerative disease associated with abnormal proteins in the brain called Lewy bodies. These proteins are also observed in Alzheimer's and Parkinson's diseases, so some symptoms overlap. Lewy body disease can impact a person's ability to think and solve problems. It can also cause:

  • tremors
  • lack of balance
  • slow movements
  • sleep disturbances
  • visual hallucinations

Memory loss usually develops later with Lewy body disease than it would with Alzheimer's.

Mixed dementia

Mixed dementia is when someone lives with 2 or more types of dementia. The most common form of mixed dementia consists of Alzheimer's disease and vascular dementia.

After being diagnosed with dementia, you or your health care provider may overlook the possibility of mixed dementia. This is sometimes the case for the types of dementia that are associated with similar symptoms. If you have any questions or concerns about being diagnosed with mixed dementia, talk to your health care provider.

Frontotemporal dementia

This type of dementia affects the frontal and temporal lobes of the brain. Damage to nerve cells in these areas can limit interactions with other parts of the brain. This type of dementia most often affects:

  • behaviour
  • personality
  • movement
  • communication
Korsakoff dementia (also called Korsakoff's syndrome)

Korsakoff dementia usually happens when someone's levels of vitamin B1 are severely low for a long time. This can cause:

  • forgetfulness
  • difficulty learning new information
  • other common signs of dementia

Vitamin B1 deficiencies have many causes, including:

  • problematic alcohol use
  • poor nutrition
  • dietary disorders
  • some chemotherapy treatments

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