Alzheimer’s disease

• What is Alzheimer’s disease?
• Statistics on Alzheimer’s disease
• Risk factors for Alzheimer’s disease
• Progression of Alzheimer’s disease
• Symptoms of Alzheimer’s disease
• Clinical examination of Alzheimer’s disease
• How is Alzheimer’s disease diagnosed?
• Prognosis of Alzheimer’s disease
• How is Alzheimers disease treated?
• Alzheimer’s disease references

What is Alzheimer’s disease?

Alzheimer’s disease (AD) is a progressive disease of the brain characterised by failure of memory and disturbances in other cognitive (mental) functions, such as language or perception of reality. It is currently thought that AD results from an increase in the production or accumulation of a specific protein (beta-amyloid protein) that leads to nerve cell damage.

Statistics on Alzheimer’s disease

Dementia affects approximately 160 000 Australians. Alzheimer’s disease is the most common type of dementia, accounting for 50-75% of cases. Alzheimer’s disease occurs most commonly in the elderly. Dementia affects about 10% of those aged over 65 years with 20% of those over 80 years suffering from severe dementia. Women may be at slightly higher risk of developing Alzheimer’s disease than men. An Access Economics report commissioned by Alzheimer’s Australia and published in March 2005 suggests that the number of people with dementia in Australia will be 25% higher by 2050 than was predicted in 2003.

The report estimates that:

• By 2016, dementia will be the leading cause of disease burden in Australia.
• By 2050, the total number of Australians with dementia will be over 730,000, or 2.8% of the population.
• During 2050, it is projected that there will be over 175,000 new cases diagnosed.

Risk factors for Alzheimer’s disease

The most important risk factor for the development of dementia of Alzheimer’s type (DAT) is advancing age.

Other Alzheimer’s disease predisposing factors include:

• Genetic factors: Alzheimer’s disease occurs more commonly in close relatives of the affected patient. A direct genetic link is found in less than 10% of cases of Alzheimer’s.
• Chromosomal defects: Down syndrome is associated with Alzheimer’s disease.
• Diet and aluminium: Excessive exposure to aluminium, abnormal cell membrane metabolism, diet, cholesterol and fat have been suggested to be associated with the development of Alzheimer’s disease. However, the evidence for many of these factors is unclear.

On the positive side, certain drugs, such as HRT in postmenopausal women, statins (cholesterol-lowering drugs) and non-steroidal antiinflammatory drugs (NSAIDs) may all have protective effects against developing Alzheimer’s disease.

Progression of Alzheimer’s disease

Alzheimer’s disease will typically become evident between the ages of 50-70 years old. This condition is slowly progressive, with progressive deterioration in cognitive function, memory loss and behavioural changes occurring in the early stages. As Alzheimer’s disease progresses, patients may lose the ability to speak, coordinate movements or perform simple tasks. In the later stages of disease, patients may lose the ability to walk, become incontinent, and are bedridden for an extended period.

Symptoms of Alzheimer’s disease

Patients with Alzheimer’s disease may experience the following:

• Impaired ability to learn new information, or to recall previously learned information
• A decline in language function, such as difficulty naming items or understanding what is being said
• Dyspraxia: impaired ability to carry out simple tasks
• Impaired ‘executive functions’: planning, organising and sequencing complex tasks
• Behavioural changes: such as wandering, agitation or aggression
• Depression: some depressive symptoms are common, but severe depression is unusual as patients often lack insight into what is happening.

How is Alzheimer’s disease diagnosed?

As there is no definitive test for Alzheimer’s disease, it is considered a disease of exclusion – only diagnosed when all other potential causes have been excluded. A large number of blood tests and brain imaging may be performed to ensure that the symptoms of dementia are not being caused by some curable condition.

Prognosis of Alzheimer’s disease

The prognosis of Alzheimer’s disease is relatively poor, for there is no known treatment to halt the progression of disease or restore cognitive loss. Patients will typically decline from complete to very limited function over a period of eight years and may require full care in the later stages of illness. Death may result from malnutrition, infections such as pneumonia, or heart disease.

How is Alzheimer’s disease treated?

The management of Alzheimer’s Disease consists of medication-based and non-medication based treatments. So far no treatment has been found to cure or reverse the disease. Medicines that restore the deficit in the chemical messengers of the nerve cells (neurotransmitters), such as the cholinesterase inhibitors, have been shown to improve symptoms. These medications include tacrine, donepezil and galantamine. There are also medications available to treat the psychiatric manifestations of AD. Patients will also need support in making legal and financial decisions for the future. Although there is no proven way to prevent AD, there are some practices that may be worth incorporating into your daily routine, particularly if you have a family history of dementia. Talk to your doctor about any of these approaches, especially those that involve taking a medication or supplement.

• Consume a balanced, low-fat diet;
• Exercise regularly;
• Quit smoking;
• Maintain a normal blood pressure;
• Stay mentally and socially active throughout your life;
• Consider taking non-steroidal anti-inflammatory drugs (NSAIDs) like celecoxib, ibuprofen, or indomethacin. Statin drugs (eg. Vytorin), used to treat high cholesterol, may help lower your risk of AD. Talk to your doctor about the pros and cons of using these medications for prevention;
• In addition, research continues into the possibility of a vaccine against Alzheimer’s disease.

Useful resources

View the brochure Alzheimer’s disease: Looking forward. An in-depth look into understanding and managing Alzheimer’s disease.

Videos

Click here to watch a video Dementia 1: Ten for Ten for Life.

Click here to watch a video Dementia 2: Memory Matters.

Click here to watch a video Dementia 3: Caring for the Carer.

More information

For more information on different types of dementia, memory loss and Alzheimer’s disease, see Dementia.

References

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4. Hebert LE, Scherr PA, Bienias JL, et al. Alzheimer disease in the US population: Prevalence estimates using the 2000 census. Arch Neurol. 2003;60(8):1119-22. Abstract | Full text
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8. The dementia epidemic: Economic impact and positive solutions for Australia. Canberra, ACT: Access Economics; March 2003 [cited June 2007]. Available from: URL link
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12. Dementia estimates and projections: Australian Territories and States. Canberra, ACT: Access Economics; February 2005 [cited June 2007]. Available from: URL link