Dementia - Alzheimer's disease

Alzheimer's disease is the most common form of dementia. At least 60 per cent of dementia cases are Alzheimer's disease.

Alzheimer's disease is a brain disease. Proteins in your brain form plaques and tangles that damage neurons – the cells in your brain that carry messages. These neurons can't communicate with each other as well as they used to. The neurons eventually die and your brain's volume shrinks. This damage leads to the symptoms of dementia.

If you have Alzheimer's disease, you might experience memory loss, slower thinking and changed behaviour. These changes can happen in different ways and progress at different speeds for each person.

Alzheimer's disease is progressive. This means that over time, as the disease develops, your memory, thinking and behaviour will become more affected.

There is no known cure for Alzheimer's disease. But there are treatments that can slow the progress of Alzheimer's disease and support to help you live the best life you can.

When I received my diagnosis I was advised to move on with my life and do everything on my wish list […] but I wanted to understand the how, what and why of dementia.

- Robyn, living with Alzheimer's disease

Alzheimer's disease and dementia

Alzheimer's disease is one form of dementia, the most common form. But many other conditions can also lead to dementia.

Dementia is a term that describes a collection of symptoms caused by disorders affecting the brain.

For more on dementia, visit Dementia Australia's introduction to dementia page.

Causes of Alzheimer's disease

The causes of Alzheimer's disease are complex and not fully understood. But there are two changes in the brain that are believed to cause damage that leads to the symptoms of Alzheimer's disease. They are called plaques and tangles.

Beta amyloid plaques and Alzheimer's disease

There is a protein in your brain called beta amyloid (Aβ). Proteins are long molecules that are folded into specific shapes. When beta amyloid proteins fold the wrong way, they clump together and form plaques.

Just like plaque sticks to your teeth, plaques of beta amyloid proteins stick to the outside of cells in your brain, damaging them. This damage leads to the symptoms of Alzheimer's disease.

Tau protein tangles and Alzheimer's disease

Another protein in your brain is called tau. When some forms of tau protein fold the wrong way, they tangle up together. These bundles of tangled protein are also called neurofibrillary tangles.

Tangles of tau proteins inside brain cells cause damage. This damage leads to the symptoms of Alzheimer's disease.

There's a lot of evidence that plaques and tangles are causes of Alzheimer's disease, but they don't explain all cases. Researchers are investigating what other causes of Alzheimer's disease might exist.

Genetics and Alzheimer's disease

The most important known gene affecting your risk of developing Alzheimer's disease is called Apolipoprotein E. It has three types: type 2, type 3 and type 4.

Every person has two Apolipoprotein genes. You can have two of the same type or two different types. If you have at least one type 4, known as ApoE ε4, and especially if you have two type 4s, you are at higher risk of developing Alzheimer's disease than people with other types.

But the risk isn't that much higher. Half of all people aged 85 who have two copies of ApoE ε4 don't have symptoms of Alzheimer's disease.

ApoE ε4 has also been associated with increased risk for cardiovascular disease and vascular dementia.

For more on the way genes affect dementia risk, visit Dementia Australia's genetics and dementia page.

Types of Alzheimer's disease

Sporadic Alzheimer's disease

Sporadic Alzheimer's disease is by far the most common form of Alzheimer's disease. Around 95% of people who living with Alzheimer's disease have sporadic Alzheimer's disease.

People living with sporadic Alzheimer's disease generally don't have a family history of Alzheimer's disease and tend to develop it when they're older.

Familial Alzheimer's disease

A very small number of people inherit Alzheimer's disease from their biological parents. People with familial Alzheimer's disease often start getting symptoms in their 50s, sometimes younger.

Younger onset Alzheimer's disease

If you're diagnosed with any form of Alzheimer's disease when you're younger than 65, it's called younger onset Alzheimer's disease. For more information, advice and support on younger onset Alzheimer's disease, visit Dementia Australia's younger onset dementia page.

Down syndrome and Alzheimer's disease

People with Down syndrome have a much higher chance of developing Alzheimer's disease, and at a much earlier age, than other people. Around half of people living with Down syndrome will develop Alzheimer's disease by age 60. Many people with Down syndrome start experiencing symptoms in their early to mid-50s.

For more information, visit [insert BH Down Syndrome page link].

Risk factors for developing Alzheimer's disease

There are risk factors for developing all forms of dementia. Some, like your age and genetics, aren't in your control. But there are 14 known risk factors for dementia that you can do something about.

Globally, 45% of all dementia diagnoses could be prevented with action on these modifiable risk factors.

To learn more about how you can reduce your risk of developing Alzheimer's disease and other forms of dementia, visit Dementia Australia's brain health and prevention page.

Signs and symptoms of Alzheimer's disease

Everyone's experience of Alzheimer's is unique. Symptoms can be different from one person to another. But it's common for someone living with Alzheimer's disease may experience:

• trouble remembering, especially recent events
• repeatedly saying the same thing
• being vague in everyday conversation
• trouble planning, solving problems, organising and thinking logically
• taking longer to do everyday tasks
• language difficulties, such as problems finding the right word
• trouble remembering the time, where you are and who people are
• trouble becoming motivated and starting tasks
• unusual changes in behaviour, personality and mood.

Someone with these symptoms might not be able to recognise their own changes. Often a family member or friend will notice them instead.

If you have any of these symptoms, or if you know someone else who does, talk to your doctor. They might find another cause for the changes that they can treat, or begin treating and helping you manage Alzheimer's disease in its early stages. The sooner you know, the more you can do.

For more on signs of dementia, visit Dementia Australia's early warning signs page.

Diagnosing Alzheimer's disease

At least we knew what we were dealing with – this is what it is and we can deal with it.

- Angela, on her mum Maria's dementia diagnosis.

Testing for Alzheimer's disease starts with visiting your GP.

Your doctor might:

• talk to you about what changes you've noticed and how they're affecting your life
• talk to people close to you to see what they've noticed
• ask about your lifestyle and medical history. This is so they can understand your dementia risk and what other conditions might be involved
• give you a general physical exam and some thinking and memory tests.

Your doctor might refer you to a specialist, like a neuropsychologist. They can do more tests of your thinking, memory, language and problem-solving.

Your doctor and your specialist might:

• recommend lab tests. Blood, urine and other tests can help spot another condition that could explain your symptoms
• refer you for brain scans. These can't diagnose Alzheimer's disease, but they can help rule out other causes and get a better sense of any degeneration that's happened
• recommend a cerebrospinal fluid (CSF) test. This test measures your levels of beta amyloid and tau proteins, but it isn't required for a diagnosis of Alzheimer's disease and can be invasive.
• recommend new blood tests for beta amyloid and tau proteins that are less invasive that cerebrospinal fluid tests.

Talk to your health professional about your options.

Each of these tests is designed to:

1. look for direct evidence of Alzheimer's disease
2. build up other evidence to suggest a diagnosis
3. rule out other causes of your symptoms.

If the evidence is strong enough and other causes can be ruled out, your health professional may diagnose you with Alzheimer's disease.

Some people feel shock when they're diagnosed with Alzheimer's disease. Other people feel relief. Whatever your reaction, there is support for you.

• National Dementia Helpline
• What next? After your diagnosis
• Hold the Moment Podcast: Where to from here?
• What I wish I had known when I was diagnosed with dementia

Stages of Alzheimer's disease

Alzheimer's disease is progressive. This means that symptoms start mild and become more serious over time.

Alzheimer's disease affects different areas of the brain, damaging different abilities. Short-term memory is often affected first, but later, long-term memory is also affected.

Some people living with Alzheimer's disease keep their senses of touch and hearing, and also respond to emotion, even in the advanced stages of the condition.

In the final stages of Alzheimer's disease, many people become immobile and dependent, requiring extensive care.

Alzheimer's disease has three stages: early, middle and advanced. These stages can overlap. They're not exactly the same for everyone, and they may happen more slowly or quickly for different people.

Early-stage Alzheimer's disease

Early Alzheimer's disease is when symptoms are at their mildest. It's sometimes called ‘mild Alzheimer's disease'.

Because these changes usually happen gradually, it's often hard to notice when this stage begins. The processes that lead to Alzheimer's disease can start up to 20 years before you notice symptoms.

Many people get their diagnosis of Alzheimer's disease after they have already passed through this stage.

If you have early-stage Alzheimer's disease, you might:

• appear more apathetic
• lose interest in hobbies and activities
• be less willing to try new things
• be less able to adapt to change
• be slower to grasp complex ideas
• take longer with routine jobs
• have disturbed sleep
• become more forgetful of recent events
• become confused about time and place
• become lost if you're away from familiar surroundings
• be more likely to repeat yourself or get lost in conversation
• be more upset if a mistake is made
• have trouble managing money
• have trouble shopping or preparing meals.

Middle-stage Alzheimer's disease

Mid-stage Alzheimer's disease is the next stage of the disease. It's sometimes called ‘moderate Alzheimer's disease'. Your symptoms will become stronger. You may find it harder to stay independent. You might require daily support.

If you have moderate Alzheimer's disease, you might:

• become angry, upset or distressed through frustration
• become lost more easily
• become repetitive
• forget recent events
• remember the distant past better, sometimes with confused details
• be less able to perform simple maths
• be unable to choose the right clothing
• forget saucepans or kettles on the stove
• forget the names of your family or friends, or mix-up family members
• neglect your personal hygiene
• have increasingly disturbed sleep
• forget to eat
• get confused about time and place
• see or hear things that are not there
• become suspicious of other people
• make poor decisions.

Late-stage Alzheimer's disease

Late-stage Alzheimer's disease is the final stage. It's sometimes called ‘severe Alzheimer's disease'. Your symptoms will become severe, and you will need care for all your daily activities.

If you have advanced Alzheimer's disease, you might:

• become incontinent
• get confused trying to recognise friends and family
• be restless or fidgety
• forget important events from your early life
• forget current events and information, like where you live
• call out frequently or behave out of character
• have increasingly disturbed sleep
• stop recognising everyday objects and what they're for
• have difficulty walking
• lose your ability to understand or speak
• need help eating, washing, bathing, brushing your teeth, going to the toilet and dressing.

In the final stages of Alzheimer's disease, you are likely to become immobile and require constant care. How fast this happens is different for everyone.

Though there are treatments that can slow the progress of Alzheimer's disease, there is currently no cure. Alzheimer's disease is a terminal condition. The average time from diagnosis to end of life is 7-10 years, but this varies for everyone.

Treatment and management of Alzheimer's disease

Right now, there's no known cure for Alzheimer's disease. However, there are new and promising treatments that have been shown to slow the progression of Alzheimer's disease symptoms at different stages.

Lecanemab (Leqembi): treatment for early-stage Alzheimer's disease

Lecanemab (also known by the brand name Leqembi) is a prescription medicine that binds to beta amyloid protein. This prevents the protein from forming the plaques that damage the brain, and reduces existing plaques.

Lecanemab does not cure Alzheimer's disease, but it can help slow its progression and help you maintain independence for longer.

For more information, including how you can find out if lecanemab is right for you, visit the lecanemab section of Dementia Australia's page on treating dementia.

Donanemab (Kisunla) for early-stage Alzheimer's disease

Donanemab (also known by the brand name Kisunla) is a prescription medicine that targets and breaks down amyloid plaques in the brain, aiming to slow the progression of Alzheimer's disease by reducing cognitive decline and memory loss.

Donanemab does not cure Alzheimer's disease, but it can help slow its progression and help you maintain independence for longer.

For more information, including how you can find out if donanemab is right for you, visit the donanemab section of Dementia Australia's page on treating dementia.

Cholinesterase inhibitors for Alzheimer's disease

Cholinesterase inhibitors are medications that stop important chemicals in your brain breaking down. Those chemicals, which are called acetylcholine and butyrylcholine, help your brain cells communicate with each other.

Cholinesterase inhibitors can help improve your memory and your ability to carry out day-to-day activities if you have Alzheimer's disease.

For more information, visit the cholinesterase inhibitors section of Dementia Australia's page on treating dementia.

Cholinergic medications for Alzheimer's disease

Cholinergic medications work differently to cholinesterase inhibitors. Instead of stopping those important communication chemicals in your brain from breaking down, they either produce more of those chemicals, or they act just like those chemicals, doing the same thing in your brain.

For more information, visit the cholinergic medications section of Dementia Australia's page on treating dementia.

Memantine for Alzheimer's disease

Memantine targets a different brain chemical, called glutamate, that is present in high levels if you have Alzheimer's disease. Memantine blocks glutamate and prevents too much calcium moving into the brain cells causing damage.

For more information, visit the memantine section of Dementia Australia's page on treating dementia.

Dementia Australia support

When I was diagnosed with Alzheimer's (disease) I had never been so scared in my life […] I am happy to say that I have received amazing support from my family, medical team and Dementia Australia.

- Linda, living with younger onset Alzheimer's disease

Whatever your experience of Alzheimer's disease, we're here for you. You can contact the National Dementia Helpline any time of the day or night for information, advice and support.

Where to get help:

• Your GP
• The National Dementia Helpline, 1800 100 500
• NDIS: the National Disability Insurance Scheme: available if you're diagnosed with dementia when you're under 65.
• My aged care: support in navigating decisions around aged care.
• Carer Gateway: emotional and practical services for carers.
• Dementia Behaviour Management Advisory Service (DBMAS): 24/7 advice for people caring for someone with dementia.