Fact sheet N°362April 2012
Dementia is a syndrome – usually of a chronic or progressive
nature – in which there is deterioration in cognitive function (i.e. the
ability to process thought) beyond what might be expected from normal
ageing. It affects memory, thinking, orientation, comprehension,
calculation, learning capacity, language, and judgement. Consciousness
is not affected. The impairment in cognitive function is commonly
accompanied, and occasionally preceded, by deterioration in emotional
control, social behaviour, or motivation.
Dementia is caused by a variety of diseases and injuries that
primarily or secondarily affect the brain, such as Alzheimer's disease
Dementia is one of the major causes of disability and
dependency among older people worldwide. It is overwhelming not only for
the people who have it, but also for their caregivers and families.
There is often a lack of awareness and understanding of dementia,
resulting in stigmatization and barriers to diagnosis and care. The
impact of dementia on caregivers, family and societies can be physical,
psychological, social and economic.
Dementia affects each person in a different way, depending
upon the impact of the disease and the person’s personality before
becoming ill. The signs and symptoms linked to dementia can be
understood in three stages.
Early stage: the early stage of dementia is often overlooked, because the onset is gradual. Common symptoms include:
Middle stage: as dementia progresses to the middle stage, the signs and symptoms become clearer and more restricting. These include:
Late stage: the late stage of dementia is one
of near total dependence and inactivity. Memory disturbances are
serious and the physical signs and symptoms become more obvious.
There are many different forms, or causes, of dementia.
Alzheimer's disease is the most common form of dementia and may
contribute to 60–70% of cases. Other major forms include vascular
dementia, dementia with Lewy bodies (abnormal aggregates of protein that
develop inside nerve cells), and a group of diseases that contribute to
frontotemporal dementia (degeneration of the frontal lobe of the
brain). The boundaries between different forms of dementia are
indistinct and mixed forms often co-exist.