What causes Alzheimer's?

The exact cause of the disease is unknown. Alzheimer's disease is linked to gradual formation of plaques in the brain, particularly in the hippocampus and adjoining cortex.

As the disease develops, it destroys chemical messengers used by the cells of the brain to communicate with each other.

Dame Iris Murdoch died from Alzheimer's disease

It is thought that the disease either disrupts the production of an important neurotransmitter known as acetylcholine, or stimulates the over-production of an enzyme, cholinesterase, which eliminates it once it has performed its proper function.

It seems that the disease can be inherited, with people who have a parent or sibling with Alzheimer's up to five time as likely to develop the disease as those who do not.

Some believe that highly chemically reactive oxygen molecules known as free radicals may cause tissue damage which leads to Alzheimer's. Free radicals have also been linked to cancer and heart disease.

Other theories have linked the disease to physical trauma, such as whiplash injuries. The body's own immune system has also been blamed.

What are the symptoms?

Alzheimer's Disease has a gradual onset.

Well established features of the disease include:

• Poor or decreased judgement
• Difficulty in performing difficult tasks
• Problems with language
• Disorientation to time and place
• Problems with abstract thinking
• Problems with memory
• Change in mood and behaviour
• Change in personality
• Loss of initiative

The disease is often associated depression, anxiety and sleep disturbance.

The rate of decline varies from patient to patient. The disease course runs anywhere from three to twenty years, with eight years being the average life span after diagnosis.

How is the disease diagnosed?

There is no single diagnostic test for Alzheimer's disease.

Patients require a thorough physical, psychiatric and neurological examination by a doctor when symptoms are noticed.

Doctors are able to diagnose the disease with 90% accuracy, even though proof can only be obtained by examining the brain after death.

Many other disease processes can mimic Alzheimer's such as thyroid imbalances, vitamin B12 deficiency, brain injuries, tumours, and depression.

What treatment is available?

Various types of therapy are used to try to stimulate Alzheimer's patients.

These include: art therapy, music therapy, playing with toys.

Some health professionals try to encourage patients to reminisce about past memories as a way to reduce depression without the use of drugs.

A variety of drug treatments have been shown to benefit patients. These include:

• Antioxidants such as selegiline designed to limit the impact of free radicals
• Cholinesterase Inhibitors including tacrine (Cognex) and donepezil (Aricept)
• The female sex hormone oestrogen
• Nonsteroidal Anti-Inflammatory Drugs (NSAIDS)

This page contains basic information. If you are concerned about your health, you should consult a doctor. The Alzheimer's Disease Society runs a helpline on 0845 300 0336