Different types of dementia

Alzheimer's disease is the most common type of dementia, responsible for a large part of dementia cases. It leads to memory loss and changes in abilities as it progresses.

People diagnosed with Alzheimer’s disease have a life expectancy of eight to 10 years, contingent on other factors. Someone diagnosed later in life may have a shorter life expectancy whereas someone diagnosed early could live 15 to 20 years with dementia.

Vascular dementia is the second most common type of dementia. It is caused by problems with blood flow to the brain, leading to strokes or the deterioration of brain cells. This can result in cognitive difficulties which affect memory and thinking.

People with vascular dementia have a lower life expectancy, around five years after diagnosis. This is because vascular dementia carries a higher risk of having a stroke or heart attack.

Lewy body dementia (sometimes called LBD) is a subtype of dementia. It leads to brain decline, hallucinations and motor symptoms similar to Parkinson's disease.

People with Lewy body dementia have a general life expectancy of six years. The physical symptoms might create a higher risk of falls and infection.

Frontotemporal dementia (sometimes called FTD) is the most common type of dementia in people under 65. It represents disorders caused by damage to the frontal and temporal lobes of the brain. There are several subtypes of FTD including behavioural variant FTD, progressive non-fluent aphasia and semantic dementia. It will often lead to noticeable changes in personality.

Life expectancy for people with frontotemporal dementia is six to eight years unless they were also diagnosed with motor neurone disease. Motor neurone disease is a movement condition that causes weakness and when mixed with FTD, reduces life expectancy to two to three years.

Dementia connected to a history of drinking alcohol is often called alcohol-related dementia. Korsakoff’s syndrome or Wernicke-Korsakoff syndrome are also alcohol-related brain conditions that can cause dementia. Research suggests it is caused by a vitamin deficiency and if caught early, can be reduced or reversed with proper diet, vitamin supplements and abstaining from alcohol.

Creutzfeldt-Jakob disease is a rare and severe brain condition. It is caused by abnormal proteins that build up in the brain causing damage. It has a rapid progression of symptoms and is often fatal within a year. There are a few types but most people living with the condition have either sporadic or familial types.

There is a chance that someone may develop more than one type of dementia. When this happens, it is known as mixed dementia. Often it will be Alzheimer’s disease and vascular dementia, since they are the most common types.

Young-onset dementia refers to people experiencing dementia symptoms under the age of 65. It can be caused by many different brain conditions or injuries.

• Government of Canada - Dementia: Overview
• Other types of dementia