|Dementia is a broad term
for the deterioration of brain function resulting in memory loss,
reduction in language skills and behavioural and emotional problems.
Alzheimer's disease is the most common type of dementia, accounting
for more than half of all cases.
Alzheimer's disease is rare before the age of 60 but the risk
of developing it increases with age. Around 25% of people over
80 years old have the disease. As the population ages, the number
of people with Alzheimer's disease, and other dementias, will
|The cause of Alzheimer's
disease remains uncertain. It is likely that no single factor
is responsible but that a variety of factors, which may differ
from person to person. Since people whose parents or siblings
develop the disease appear at greater risk of developing it themselves,
there may be a genetic component. However, no straightforward
pattern of inheritance has been found. It's known that head injury
is a risk factor and that Alzheimer's disease often affects people
with Down's Syndrome.
Some researchers have suggested that people who exercise their
brains (doing crosswords and other mental agility exercises) are
less likely to develop the disease. But there is no firm evidence
to show that environmental factors play a part in the development
of the disease.
Whatever the underlying cause, Alzheimer's disease is the result
of the destruction of nerve cells (neurones) in the brain. These
nerve cells cannot be replaced, so the person with Alzheimer's
disease gets progressively worse as more cells are destroyed.
This process causes the breakdown of the brain's communication
systems. When functioning normally, the brain exchanges signals
from other parts of the body, and other parts of the brain, across
the gaps (synapses) that exist between nerve cells. These signals
are essential for brain activity such as language and problem
solving. They are also involved in controlling motor functions,
such as instructing muscles when and how to work.
These message signals cross over these gaps with the help of chemicals
known as 'neurotransmitters', including acetylcholine. Doctors
believe that nerve cell destruction causes a reduction in acetylcholine,
leading to impaired transmission of nerve signals. Drugs that
boost the amount of acetycholine are used to limit the impact
of the disease.
|Symptoms and disease progression
|The onset of Alzheimer's
disease is often difficult to pinpoint as it starts with forgetfulness
and difficulty in finding the right word, common problems associated
with the ageing process.
In these early stages, those closest to the person with Alzheimer's
disease may notice personality changes. For example, a previously
cheerful person may become irritable and even aggressive and may
no longer be able to cope with the demands of a busy life.
As the disease progresses, loss of memory, difficulty in completing
simple tasks, and more overt personality changes, often combined
with depression, become more evident. Mathematical and verbal
skills decline, which may mean that a person is no longer able
to read instructions or count their change. Conversation can become
empty and meaningless. Sometimes people with Alzheimer's may become
paranoid, believing, for example, that their carers are trying
to poison them or that their partner is being unfaithful. The
sense of time and place can also be lost, with sufferers getting
dressed in the middle of night or wandering off and becoming lost,
even on once-familiar territory. This can cause a great deal of
stress and upset for the person's carers and family who, in effect,
have lost the person they once knew.
During the late stages of the disease, people with Alzheimer's
may become totally dependent upon others for their care. Walking
can become difficult, confining a sufferer to bed. He or she may
become incontinent, experience hallucinations and become increasingly
unaware of their surroundings. It is at this stage that residential
care, with round the clock nursing, is often considered.
The average duration of the disease is about ten years, with a
range of between 3-20 years from diagnosis and death. Often the
cause of death in a person with Alzheimer's is another illness,
such as pneumonia, which becomes more common in people who are
bed-bound and so less resistant to infection.
|There is no single test
for Alzheimer's disease and diagnosis depends in part on excluding
other potential causes of dementia. These include vascular dementia
(often known as multi-infarct dementia or MID), dementia with
Lewy bodies (DLB), fronto-temporal dementia (including Pick's
disease), Parkinson's disease, and alcohol-related dementia (Koraskoff's
In a person with suspected of having Alzheimer's, the GP will
try to establish some of the symptoms such as memory loss and
verbal impairment. Physical examination and blood and urine tests
may be carried out to help exclude other causes of dementia. If
the GP is unable to make a diagnosis, a referral will usually
be made to a specialist (a neurologist, a care of the elderly
physician or a psychiatrist) for more specialist tests.
These tests may include the 'Mini-Mental State Examination' (MMSE).
This is a series of questions and tests looking at memory, language
and mathematical skills. Other investigations may include a brain
scan, typically magnetic resonance imaging (MRI). Some people
may also be referred to a 'memory clinic' specialising in mental
|Treatment for Alzheimer's
|Unfortunately, no cure has
yet been found for Alzheimer's disease. However the disease can
be managed with drug treatment, non-drug treatment and support
from a range of services.
|The introduction of a new
class of drugs called 'cholinesterase inhibitors' is the first
time there has been an effective drug treatment for Alzheimer's.
Cholinesterase breaks down and destroys acetylcholine, the neurotransmitting
chemical. Cholinesterase inhibitors help to prevent this breakdown
and so promote a more plentiful supply of acetylcholine. There
are three drugs available in this class: Aricept (donepezil hydrocholoride),
Exelon (rivastigmine) and Reminyl (galantamine). In people in
the early to middle stages of the disease, they may slow down
the progression of symptoms.
Sometimes anti-depressants are prescribed to help treat the depression
that can be associated with Alzheimer's disease. The inappropriate
prescribing of potent psychiatric drugs (neuroleptics) used to
manage 'challenging behaviour', of people in residential care,
has been recognised and criticised.
|There are other techniques
for helping to cope with Alzheimer's disease. These include techniques
known as 'reality orientation', ' reminiscence therapy' and 'validation
therapy'. Art and music therapies are also used, but their effectiveness
is not proven.
|Help and support in terms
of respite care (giving carers a break), social services and residential
care is an important part of the overall care of someone with
|Alzheimers Disease Society
Helpline: Tel: 0845 300 0336
Alzheimers Research Trust
Alzheimer's Association (USA)
National Institute of Neurological Disorders and Stroke
Alzheimer's Association of NSW
|Healthwise (Health Information Resource
Tel : (852) 2849 2400
Fax : (852) 2849 2900
Email : email@example.com
Homepage : http://www.healthwise.org.hk/
This leaflet is for information only. For a detailed
opinion or personal advice, please consult with your own