What is dementia?

In general terms, dementia is a syndrome – which means a group of related symptoms – that is associated with an ongoing decline of mental processes. This deterioration is commonly marked by:

• Memory loss
• Change in personality
• Noticeable reduction in mental agility and thinking speed
• Impaired reasoning
• Impaired judgement

See our dementia symptoms page for more information.

What causes dementia?

The most common causes of dementia are known as neurodegenerative diseases, which include Alzheimer’s disease. These diseases cause the brain cells to degenerate at a faster rate than normal, leading to the deterioration of mental and, sometimes physical, ability.

Visit our causes of dementia page for more information.

Different stages of dementia

As the causes of dementia are degenerative, they progress over a period of time. Five stages of dementia have been outlined and form part of the Clinical Dementia Rating (CDR), which is used by professionals to assess the progression of symptoms in patients with dementia.

These five stages range from CDR-0, which represents no impairment in a person’s abilities, to CDR-3, which represents a significant impairment that means the patient is no longer able to function or engage in any day-to-day tasks without help.

For more information, see our stages of dementia page.

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