What is Dementia? Part 1

What is dementia?
The word dementia is used to describe a number of different conditions that affect the brain. Each of these conditions leads to a progressive decline in mental ability, such as memory loss, confusion, and problems with speech, concentration, thinking and perception.

Who is likely to develop dementia?
Most people who develop dementia are over 65, although it does affect some younger people, usually in their forties and fifties (about one in a thousand). One in twenty people over 65 has dementia, and it affects one in five people over the age of 85. While dementia is most common in older people, it is not an inevitable part of ageing – the vast majority of older people remain mentally healthy.

What forms of dementia are there?
The most common types of dementia are Alzheimer’s disease and vascular dementia. Although they have similar symptoms, they develop in different ways. Alzheimer’s disease, which accounts for about 60 per cent of dementia, is characterised by changes in the structure of the brain, which causes brain cells to die. It usually starts gradually and progresses at a slow, steady pace. Vascular dementia occurs when a series of small strokes cut off the blood supply to parts of the brain. Unlike Alzheimer’s disease, it often develops in sudden steps as these strokes happen.

Other, less common, types of dementia include: Lewy body disease (similar to Alzheimer’s, although people with Lewy body disease are more likely to experience hallucinations – seeing, hearing, smelling or feeling things that aren’t there – and physical difficulties, such as tremors and falls); Pick’s disease (also known as frontal lobe dementia, referring to the part of the brain affected); Huntingdon’s disease or Chorea (a rare form of dementia that usually develops at a younger age); and Creutzfeldt-Jakob Disease (the human form of ‘mad cow disease’, which is also very rare and thought to be linked to eating infected beef ).

Dementia can also occur as a result of Parkinson’s disease, AIDS, a brain tumour, head injuries or alcohol misuse. Some of these rarer kinds of dementia can be treated – however, this booklet mainly looks at the most common forms, which are not currently curable (see Can dementia be treated?)

What are the early symptoms of dementia?
The most common early sign is a loss of short-term memory – the person forgets things they have just said or done, even though they may clearly remember things that happened a long time ago. Sometimes people with early dementia say they feel they know something is wrong, but can’t identify exactly what it is.
Other symptoms vary, but tend to be noticed by others as ‘odd’ or ‘uncharacteristic’ behaviour, such as loss of interest in things the person enjoys, confusion, loss of skills and ability to do things they previously took in their stride, irregular sleeping patterns, reduced decision-making ability or mood swings.

Does dementia run in families?
Many people worry that if a relative of theirs has dementia, they will one day develop it too. Research suggests that there may be a genetic component to dementia, but that in most cases there is no clear family link. Instead, experts think that there may be a range of factors (including lifestyle, age, genetics, education and environment) which influence susceptibility to dementia. One exception is in families where several people have developed Alzheimer’s disease before the age of 60, where a clear genetic connection, linked to faulty chromosomes, has been shown.

Can dementia be treated?
Unfortunately, the most common types of dementia cannot be cured. Certain drugs may help reduce symptoms in the short term, although they do not work for everyone. However, dementia is not usually a direct cause of death, and people may live with the condition for many years. There are lots of ways of coping with dementia, and some of these are discussed in this blog.