Health A-Z


Alzheimer's disease

Alzheimer's disease is a form of dementia that causes a gradual decline in a person's ability to remember, understand, communicate and reason.

Alzheimer's disease is the most common form of dementia and accounts for between 50% and 60% of all dementias. Other terms used for Alzheimer's are pre-senile dementia and primary degenerative dementia (however pre-senile dementia is incorrectly used as a term for Alzheimer's disease).

Alzheimer's disease was first described in a woman by the German neurologist Alois Alzheimer as a physical disease affecting the brain. The disease itself was named Alzheimer’s by Dr Emil Kraeplin in 1910. During the course of the disease, abnormal proteins form plaques and tangles in the structure of the brain. Tangles lead to the death of brain cells. These changes are associated with a shortage of some important chemicals needed for the transmission of messages within the brain.

Alzheimer's is a progressive disease, which means that gradually, over time, more parts of the brain are damaged. As this happens, the symptoms become more severe.

There can be some positives as this woman explains in the video below. 

Key points

  1. Alzheimer's is a form of dementia that causes problems with memory, thinking and behaviour.
  2. It's likely to be caused by a combination of factors, including age, genetic inheritance and environmental factors.
  3. Growing older is the most significant risk factor.
  4. With more people living longer, it is becoming more common.
  5. Alzheimer's affects 1 in 20 people over the age of 65 and 1 in 5 over the age of 80.
  6. Symptoms usually develop slowly and get worse over time.
  7. While there is no cure for Alzheimer's disease, a combination of drug therapy, lifestyle changes and behavioural treatment may help with symptoms but will not stop the process of decline.


So far, no one single factor has been identified as a cause for Alzheimer's disease. It's likely that a combination of factors, including age, genetic inheritance and environmental factors are responsible.

Age: is the greatest risk factor for dementia. Dementia affects approximately 1 in 20 people over the age of 65 and 1 in 5 over the age of 80. The majority of these will have Alzheimer's disease. However, Alzheimer's is not restricted to elderly people. No accurate New Zealand figures are available, but it is reasonable to guess there may be more than 1000 people under 65 with dementia in New Zealand, perhaps half of whom will have Alzheimer's disease.

Genetic inheritance: Some relatives worry that they may inherit Alzheimer's disease. We do know that the chance of a person developing Alzheimer's disease is somewhat greater if they have a parent or sibling with the condition than if there were no cases of Alzheimer's in the immediate family. Similar genetic makeup among relatives is likely to be part of the reason for this.

However, there are very few families where there is a direct inheritance of the disease from one generation to the next, due to mutation of a single gene. In such families, the disease usually appears relatively early in life.

In the general population a number of susceptibility genes that increase the risk of developing the disease but do not cause it have been identified. Because of the difference in their chromosomal makeup, people with Down syndrome who live into their 40s and 50s are highly likely to develop Alzheimer's disease.

Environmental factors: People with an increased risk of developing Alzheimer's disease include those who:


People in the early stages of Alzheimer's disease experience lapses of short-term memory. As the disease progresses they may:

  • Have increasing difficulty managing complex or new tasks and frequently forget the names of people, places, appointments and recent events.
  • Show lack of initiative or withdrawal from usual activities.
  • Experience emotional and personality changes. Frustration in the face of their increasing disability is common. Some feel anxious or sad and may lose confidence. Some become more irritable or suspicious. Others seem to become emotionally bland.
  • Have problems finding the right words or understanding what is said to them.

As the disease progresses, people with Alzheimer's will need more support from those who care for them. Eventually, they will need help with all their daily activities.

While there are some common symptoms of Alzheimer's disease, it is important to remember that everyone is unique. No two cases of Alzheimer's are likely to be the same. People always experience illness in their own individual way.


If you are concerned you or someone close to you may have symptoms of Alzheimer's disease or dementia, it is important to go see your doctor. An early diagnosis will:

  • help you plan for the future
  • enable the person with Alzheimer's to benefit from the treatments that are now available
  • help you identify and access early sources of advice and support.

There is no straightforward test for dementia. A diagnosis is usually made by excluding other conditions such as, depression, delirium or the side effects of drugs. Once dementia has been established, to reach a diagnosis of Alzheimer's disease the GP or specialist will need to rule out:

  • arterial disease of the brain (cerebrovascular disease) and other, less common, causes of dementia
  • potentially treatable factors such as thyroid problems, vitamin deficiencies, anaemia, poor blood oxygenation, metabolic upset or a brain tumour.

Specialist's opinion

Your GP may ask a specialist for help in establishing a diagnosis. The specialist may be:

  • a psychiatrist who deals with older age groups
  • a physician in geriatric medicine
  • a neurologist 
  • a general physician or psychiatrist.

Who you see depends on your age, how physically able you are, and the services available in your area.

Tests for Alzheimer's often include:

  • blood test and a full physical examination to rule out or identify any other medical problems
  • cognitive assessment of a range of brain functions including memory, thinking and language skills
  • head scan may be carried out to give some clues about the changes taking place in the person's brain. There are a number of different types of scan, including CT (computerised tomography), MRI (magnetic resonance imaging) and SPECT (single photon emission computed tomography).


There is currently no cure for Alzheimer's disease. However, a number of drug treatments are available that can help with some of the symptoms or hold back progression of the disease (on average, by 6 to12 months) in some people.

Acetylcholinesterase inhibitors are one such group and include:

  • Donepezil (Aricept), rivastigmine (Exelon) and galantamine (Reminyl)
  • These drugs work by boosting existing supplies of acetylcholine.
  • People with Alzheimer's have been shown to have a shortage of the chemical acetylcholine in their brains.
  • These drugs are mainly helpful for people with mild or moderate Alzheimer's disease.
  • The evidence is growing that they may be useful in other dementing illnesses as well.
  • Side effects may include reduced appetite, nausea, indigestion, diarrhoea, fatigue, sleep disturbances, incontinence of urine and slowing of the heart rate.
  • Only some are currently subsidised in New Zealand.
  • Rivastigmine is available in a once-a-day patch as well as the tablet form, and the patch may have benefits for some patients with mild to moderate Alzheimer's disease.

Another drug, memantine (Ebixa) is also available in New Zealand.

  • This drug works in a different way to the other three – it prevents the excess entry of calcium ions into brain cells.
  • Excess calcium in the brain cells damages them and prevents them from receiving messages from other brain cells.
  • Memantine is promoted as having benefit in more advanced cases of Alzheimer's disease.
  • Side effects may include hallucinations, confusion, dizziness, headaches and tiredness.

Self care

Factors that protect against the development of Alzheimer's disease include:

  • Eating more fruit and vegetables, which are high in antioxidants, can help your general health, as well as possibly playing a protective role against Alzheimer's. A Mediterranean diet is recommended.
  • Modest alcohol consumption may protect against the development of dementia but heavier drinking over a lengthy period will increase the risk.

There is limited evidence for the usefulness of ginkgo biloba extract and other herbal treatments, and for high dose vitamin E. Dietary and other lifestyle changes may also improve the course of Alzheimer's disease. Check out these interesting links:

Learn more

Alzheimers New Zealand Information and support
World Alzheimers Month – quarterly newsletter Alzheimers New Zealand 
Booklets and factsheets Alzheimer's NZ
Short films about Alzheimer's disease Public Broadcasting Service, USA, 2010
FREE 1/2 hour consultation with an Alzheimer's NZ senior trustee Open to existing and newly diagnosed dementia patients, their families and supporters. Freephone 0800 156 015 to book.
World Alzheimer  full Report 2015 (PDF 92 pages) Summary Sheet (PDF 2 pages) Alzheimer's Disease International

World Alzheimer report 2014

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Source: Health Navigator