Dementia


Updated July 2006

A deterioration in mental ability due to disorders affecting the brain.

Dementia is a combination of memory loss, confusion and general intellectual decline. The affected person may not realise that there is anything wrong, but their condition is usually distressing for close friends and family. Poor memory alone is not a sign of dementia as some memory impairment is a natural part of ageing. Dementia is relatively common in older people, it was estimated in 2001 that dementia affects one person in 20 aged over 65 years and one in five over 80 years of age in the UK.[1]

Prevalence rates of dementia in Europe by age and sex[2]
Age group Male (%) Female (%)
30-59
0.16 0.09
60-64
1.58 0.47
65-69
2.17 1.10
70-74
4.61 3.86
75-79
5.04 6.67
80-84
12.12 13.50
85-89
18.45 22.76
90-94
32.1 32.25
95-99 31.58 36.0

The underlying abnormality in dementia is a decline in the number of brain cells, resulting in shrinking of brain tissue. Alzheimer’s disease is the most common cause of dementia.

The symptoms may develop gradually over a few months or years, depending on the cause and may include:
  • impairment of short-term memory
  • gradual loss of intellect, affecting reasoning and understanding
  • difficulty engaging in conversation
  • reduced vocabulary
  • emotional outbursts
  • wandering and restlessness
  • neglect of personal hygiene
  • urinary incontinence
In the early stages of the disorder, a person is prone to becoming anxious or depressed due to awareness of the memory loss. As the dementia gets worse, the person may become more dependent on others.

References:
[1] Alzheimer's Society - Facts about dementia
[2] Hofman A et al (1991) The prevalence of dementia in Europe: A collaborative study of 1980-1990 findings. International Journal of Epidemiology 20(3): 736-748.

Further information

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