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What is dementia?

Dementia is an umbrella term, which describes the symptoms that occur when the brain is affected by certain diseases or conditions. There are many different types of dementia, although some are far more common than others. Dementia is characterised by a gradual loss of memory and cognitive function. 

The most common types of dementia are:

Alzheimer's disease

This is the most common cause of dementia. During the course of the disease, the chemistry and structure of the brain changes, leading to the death of brain cells.

Vascular dementia

If the oxygen supply to the brain fails, brain cells may die. The symptoms of vascular dementia can occur either suddenly, following a stroke, or over time, through a series of small strokes.

Dementia with Lewy bodies

This form of dementia gets its name from tiny spherical structures that develop inside nerve cells. Their presence in the brain leads to the degeneration of brain tissue.

Fronto-temporal dementia

In fronto-temporal dementia, damage is usually focused in the front part of the brain. Personality and behaviour are initially more affected than memory.

Mixed dementia

A type of dementia where the person has a diagnosis of both Alzheimer’s disease and vascular dementia.

It should be remembered that dementia is not a natural part of aging. If you have a major episode of forgetfulness, such as returning to a property you lived in over 20 years ago and insisting that it is your current home, this should be discussed with your GP, and not put down to old age.

Last reviewed: 14 May 2024