Health care - Learning about dementia - Understanding Alzheimer's disease and other related dementias

Dementia is not a disease in and of itself, but a set of symptoms or a syndrome. The brain cells change and changes usually cause problems with:

• memory
• communication (finding and using words correctly as well as understanding what you are being told)
• thinking
• judgment
• reasoning
• mood
• behaviour (such as irritability and depression)
• coping (blame may be placed on others)
• caring for oneself (less showering, forgetting to brush teeth, comb hair, etc.)
• understanding the world (disorientation to place and time)

There are many forms of dementia - Alzheimer's disease is the most common form to date.

Over 600,000 people are living with dementia in Canada. Alzheimer's disease, the most common form of dementia, accounts for 60 to 80% of all diagnoses. Alzheimer's disease is also more common in females than males.

Source: Navigating the Path Forward for Dementia in Canada: The Landmark Study Report, Alzheimer Society of Canada. (2022). Alzheimer's disease: Causes of Alzheimer's disease. Retrieved November 23, 2011.

Alzheimer's disease is the most common form of dementia and it can eventually affect most areas of the brain. Alzheimer's disease usually begins with short-term memory loss. People affected by Alzheimer's disease need to be reminded about things several times, or they may ask the same question several times, or they may forget important day-to-day things, like taking their medications or paying bills. Having trouble finding your way in familiar places can also happen early on. Eventually, Alzheimer's disease affects your thinking and problem-solving ability, your language, and your ability to perform everyday tasks and activities. Alzheimer's disease can also affect your mood and behavior, and this can occur at any time.

Other types of dementia include:

• Vascular dementia
• Lewy Body dementia and Parkinson's Disease dementia
• Frontotemporal dementia
• Mixed dementia (usually vascular dementia and Alzheimer's disease)
• Huntington's Disease
• Alcohol related dementia
• Head injury; acquired brain injury
• Benign brain tumor or hydrocephalus (fluid buildup on brain)
• AIDS related dementia

Source: The information above comes from Alzheimer Society of Peel. (n.d.). Your guidelines to "a journey through care". Mississauga, Canada: Alzheimer Society of Peel.

This is a broad term for dementia associated with problems of blood circulation (oxygen) to the brain. Pure vascular dementia is rare; it is more common to see a mixed dementia (Alzheimer's disease and vascular dementia). When blood is not circulating to the brain to provide oxygen, the cells in the brain die. Strokes are a common cause of vascular dementia. This dementia usually has a sudden onset. Transient Ichemic Attacks (TIAs) are warning signs of a possible stroke and warrant urgent medical attention to prevent a stroke and thus preserve cognitive function. Vascular dementia is slightly more common in men than women.

Source: The information above comes from Alzheimer Society of Canada. (2003, July). Related dementia – vascular dementia. Toronto, Canada: Alzheimer Society of Canada.

The name comes from abnormal structures called Lewy bodies. These bodies are said to cause death of the nerve cells. Some features of this dementia resemble Parkinson's disease. Muscle stiffness, hallucinations, fluctuations in symptoms, and stooped posture are all signs of Lewy Body dementia. This dementia is more common in men than women.

People with Parkinson's disease can also develop symptoms that can be similar to those of Lewy Body dementia, but less severe.

Source: The information was compiled with permission from Australian Government. (2006). Living with dementia. A booklet for people with dementia. Canberra, Australia: Commonwealth of Australia and Alzheimer Society of Canada. (2003, July). Related dementia – Lewy body dementia. Toronto, Canada: Alzheimer Society of Canada.

This type of dementia primarily affects the frontal and temporal lobes of the brain, which are the areas associated with personality and behaviour. The brain cells in these areas shrink or die. A person with this dementia may have difficulty with personality changes, major behavioural problems, difficulties planning and organizing, or with producing or understanding speech. They usually have an intact memory in the early to mid-stages of the disease. This dementia occurs at an earlier age than Alzheimer's disease and can affect both men and women.

Source: The information above comes from Alzheimer Society of Canada. (2007, August). Related dementia – frontotemporal dementia. Toronto, Canada: Alzheimer Society of Canada.

Although there is no cure for dementia presently, researchers all over the world are working hard to find a cure. For an annual summary of research in this area, you can visit the Alzheimer Society of Canada website. Another option is to visit the Canadian Institutes of Health Research Dementia Research Strategy. It provides information on their dementia research strategy, funding and resources. 

If you are interested in becoming involved in research, you can visit the following sites to learn more about research participation opportunities:

Alzheimer Society Research Portal 

ClinicalTrials.gov

Consortium of Canadian Centres for Clinical Cognitive Research (C5R) website