Alzheimer’s Disease

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    Alzheimer’s disease was described in 1907 by a German neurologist, Alois Alzheimer. Microscopically, his patient’s brain showed plaques and tangles which are characteristic of Alzheimer’s.

    Plaques are an abnormal cluster of the protein “amyloid” on the outside of brain cells. Tangles are twisted strands of the protein “tau” on the inside of brain cells. The abnormal proteins damage connections, prevent messages from being passed between cells, and eventually cause cell death. As the cells die, the brain shrinks. This brain damage probably starts decades before dementia becomes apparent, but at a certain point, the brain stops compensating for cell loss and cannot function properly.

    Who gets Alzheimer’s Disease?

    Generally, Alzheimer’s is a disease of old age. However, it can begin in people aged less than 65 years.

    People with Down syndrome and their first-degree relatives are more likely to develop Alzheimer’s than the general population.

    People with a history of traumatic brain injury are also more at risk.

    There are rare familial forms of inherited Alzheimer’s that begin in younger people. Anyone carrying two APOE4 genes has a slightly increased risk. You can be tested for APOE4, but this is not necessarily helpful information, since if you live long enough, your chances of getting dementia anyway are quite high. By the age of 95, you have a 50% chance of suffering from dementia of one type or another.


    The following symptoms may occur in all types of dementia, including Alzheimer’s:

    • Memory loss especially for recent events, though later longer-term memory is also affected.
    • Difficulty learning new things.
    • Reduction in the ability to pay attention when there are other things going on.
    • Difficulty with planning and making decisions.
    • Difficulty shifting between tasks.
    • Language problems such as difficulty expressing oneself and understanding others, forgetting words, and making grammatical errors.
    • Changes in perception and motor function. This might mean difficulty judging distance, recognising faces, or performing tasks like doing up buttons.
    • Changes in social behaviour such as not greeting or farewelling others or forgetting to use cutlery. However social skills are often present for a long time in Alzheimer’s.


    Alzheimer’s is a diagnosis of exclusion. This means a doctor has determined that it follows the usual pattern of Alzheimer’s and nothing else has been found that could cause the dementia. The diagnosing doctor will:

    • take a thorough medical history from both the patient and someone who knows them,
    • perform an examination,
    • order blood and urine tests,
    • perform cognitive tests such as the Montreal Cognitive Assessment (MoCA),
    • and if necessary, order a CT brain scan.

    There is no definitive test for Alzheimer’s disease though some sophisticated scans like an amyloid PET scan can be very useful. However, these types of scans are not widely available. Genetic testing helps if there is a family history of Alzheimer’s.

    All DHBs have a “Cognitive Impairment Pathway” that the doctor can follow to make the diagnosis and there are specialists available for consultation.


    Drug Treatment

    There are four drug treatments that may help some people with Alzheimer’s. These treatments may slow the progression of the disorder but rarely restore skills that are lost. The medications available in New Zealand are donepezil, rivastigmine, galantamine and memantine. Only donepezil tablets and rivastigmine patches are funded, so the others must be paid for privately.

    Other treatments

    Doing the things that reduce risk can also slow the rate of decline in Alzheimer’s. A promising new treatment is Cognitive Stimulation Therapy (CST) which has been shown to improve symptoms in most forms of dementia.


    The onset of Alzheimer’s can be hard to pinpoint as it begins so subtly. Usually, memory and learning problems occur early on, though people behave normally in social situations even late in the condition. The progression is gradual and smooth without plateaus.

    About 80% of people with Alzheimer’s develop psychological or behavioural problems such as depression or apathy early on and psychosis, irritability, agitation or wandering in the mid-to-late stages.

    With severe Alzheimer’s incontinence, gait disturbance, difficulty swallowing, and seizures occur.

    Survival time after diagnosis is 10-20 years.

    Risk Reduction

    Research has shown that the following things decrease the risk of getting Alzheimer’s:

    • Physical activity
    • Social activity
    • Mental activity
    • Stopping smoking
    • Managing blood pressure, cholesterol, blood sugar and weight
    • Maintaining a healthy diet
    • Protecting your head
    • Reducing stress

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