Alzheimer's disease
Alzheimer's disease is one of the diseases which present a picture called ‘dementia’, which includes confusion, memory loss and possible personality change. It is a progressive, irreversible disease which attacks brain cells and kills them. It accounts for between 50 per cent and 70 per cent of all dementia cases.
As brain cells die, the substance of the brain shrinks or ‘atrophies’. Abnormal material called ‘tangles’ builds up in the centre of the brain cells and plaques (lesions of brain tissue) outside the brain cells, disrupting messages within the brain and preventing the memory, for example, from recalling information. Memory of recent events is the first to be affected, but as the disease spreads, long-term memory is also lost.
The disease also affects many of the brain's other functions and consequently, many other aspects of behaviour are disturbed. In its early phases, the symptoms can be subtle, like vagueness, taking longer to do routine tasks, losing the point of a conversation or repeating oneself. As the disease progresses, the changes become more dramatic until, in the last stages, the person may need constant nursing care.
What are the symptoms?
Symptoms vary and the disease progresses at a different pace according to the individual and the areas of the brain affected. A person's abilities may fluctuate in severity from day to day or even within the one day, becoming worse in times of stress, fatigue, ill-health etc. However, there is always a deterioration over time.
The early stages are not immediately obvious and may be dismissed as 'just a passing phase'. You may notice the following.
- Persistent and frequent memory difficulties (especially of recent events), often associated with personality change (such as aggression or obsessiveness), vagueness in everyday conversation and apparent loss of enthusiasm for activities (or giving up activities).
- It may take longer to do routine tasks, losing the point of the conversation, repeating oneself, forgetting well-known people or places, inability to process questions and instructions, loss of manual skills, deterioration of social skills, emotional unpredictability, loss of language skills.
The person may not be aware of the severity of the problem: this is called ‘lack of insight’ and is part of the disease.
Other symptoms
- Loss of memory of well-learned information and skills: how to dress, eat and walk, and when to sleep.
- In more advanced stages, physical symptoms such as weight loss and incontinence may occur.
- New behaviours may occur such as hallucinations or misinterpretations.
Is Alzheimer's the same as being forgetful?
No. Forgetting, in itself, is not necessarily cause for alarm: most people experience normal lapses of memory and concentration. With age, memory recall becomes slower and learning new things takes longer — there can be many causes of this other than Alzheimer's, particularly stress, anxiety and depression. Loss of memory with Alzheimer's is persistent, progressive and disruptive, and is usually accompanied by other symptoms.
Who gets Alzheimer's disease?
- Australians over the age of 65 have a one in 8 chance of developing the disease.
- It does not discriminate on the basis of ethnic origin.
- Women have a slightly greater chance of developing Alzheimer's disease than men, even when allowance is made for their longer lifespan. Scientists are investigating whether hormone replacement therapy reduces this risk.
- The risk increases with age. It is estimated that the prevalence of moderate to severe dementia is 5 per cent for people 65 and over, 16 per cent for people 80 and over and 24 per cent for people 85 and over.
- Although Alzheimer's occurs mostly in people in their 70s and 80s, it can appear in people in their 40s or younger.
- An estimated 135,000 Australians are affected by moderate to severe dementia. In addition there are a large number of people with early symptoms of dementia.
What are the known risk factors?
- Increasing age.
- Being a first degree relative (defined as child, brother, sister or parent) of someone who has been diagnosed with Alzheimer's.
- Being a person with Down Syndrome or a family history of Down Syndrome.
- Head injury.
What are the causes?
At present there is no proven cause, except in a few cases where the disease is inherited. A variety of other suspected causes are being investigated, including lifestyle/environmental factors, biochemical disturbances and immune processes.
Is there a cure?
- At present there is no proven medical treatment which will cure or slow down the disease.
- Drug therapies to ease the symptoms or slow progression are under active study.
- Although there is no cure, there have been many advances in support services for those with Alzheimer's disease and their carers.
What is the prognosis?
From the onset of symptoms, the person with Alzheimer's may have a lifespan of from 3 to 20 years, with the average 7-10 years.
Is there a test for Alzheimer's disease?
There is no single test to identify Alzheimer's at this stage. Rather, the diagnosis is made after a careful clinical consultation. A visit by a community aged care assessment team or service can provide additional information and support by assessing, in addition to a person's medical state, their functional skills and deficits, and their social supports and stresses.
- A careful clinical consultation can be obtained from an appropriately trained person such as a GP interested in aged care, a specialised geriatrician, psychogeriatrician or neurologist.
- This clinical diagnosis might include a detailed medical history, and thorough physical and neurological examination, a test of intellectual function, a psychiatric assessment, a neuropsychological test and perhaps a range of laboratory tests.
- Diagnosis of Alzheimer's disease is called ‘diagnosis by exclusion’ because tests eliminate other conditions with similar symptoms such as reaction to drugs, nutritional deficiencies or depression, and many others.
- After eliminating other causes, a clinical diagnosis of Alzheimer's can be made (with about 80-90 per cent accuracy) if the symptoms and signs are appropriate.
- The combined clinical consultation and community assessment will tell you what the illness may be, whether it can be treated, the extent of the disability, the areas in which the person can still function successfully, and the changes you can expect in the future. It can also tell you what supports are available, both now and in the future.
Last Reviewed: 02 August 2002
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