Dementia: an overview

What is dementia?

Dementia is not a specific condition or disease. It is a term that is used to describe a range of symptoms associated with loss of memory, thinking skills and behaviour skills that significantly reduce a person’s ability to perform everyday activities.

Dementia is caused by damage to brain cells. As a result, brain cells have difficulty communicating with each other. The type of dementia that a person has depends on which cells have been damaged.

Dementia is the leading cause of death in Australia, responsible for 1 in 10 deaths in 2023 (Australian Institute of Health and Welfare, 2025). An estimated 446,500 Australians are currently living with dementia, and without a medical breakthrough, this number is expected to exceed 1 million by 2065 (Dementia Australia).

The different Types of dementia

• Alzheimer’s disease
• Vascular dementia
• Early-onset dementia
• Dementia with Lewy bodies
• Parkinson’s disease dementia
• Huntington’s disease
• Korsakoff’s syndrome (alcohol related dementia)
• Creutzfeldt-Jacob disease
• Fronto Temporal Lobar Degeneration (FTLD)
• AIDS Dementia Complex (ADC)

The signs and symptoms of dementia

10 common symptoms of dementia

There are many symptoms of dementia associated with the various types of dementia. Not all of the symptoms for all of the dementia types are listed, and not all of those listed apply to all dementia types. Rather, they are the most common symptoms.

1. Frequent short-term memory loss
2. Lack of clarity in communication and language
3. Lack of focus
4. Confusion
5. Personality change
6. Apathy and withdrawal
7. Decreased or poor judgement
8. Difficulty performing everyday tasks
9. Change in visual perception
10. Adapting to change

For more detail on the symptoms of dementia, click here.

What is early onset dementia?

Early onset dementia (also called younger onset dementia), is dementia that has been diagnosed in anyone below the age of 65. Dementia is much less common in people under the age of 65 and can sometimes go unnoticed, so it’s important to be aware of the signs and symptoms. Approximately 29,000 Australians are living with younger onset dementia (Dementia Australia, 2026).

Symptoms of early-onset dementia

The earlier a diagnosis of early-onset dementia is made, the quicker planning for the future can start. This is critical given the likely financial and family commitments that the person will have. However, it can often take longer to diagnose early-onset dementia than later dementia because the condition is not expected and therefore symptoms can be brushed off as something less serious.

The symptoms of early-onset dementia are very similar to those of later dementia. However, memory loss is usually less prevalent early on; while movement, balance and coordination-related issues are most common.

If you have any concerns at all about your behaviour, or that of a loved one, it would be useful to familiarise yourself with the Symptoms of dementia.

Early onset dementia for people who are still working 

Most people with early-onset dementia are still working when they are diagnosed. This raises several issues that need to be managed.

• It may take a while for symptoms to be recognised (and therefore the condition diagnosed), because their activities are split between work and home, and their symptoms are not being observed long enough by a single person. In addition, abnormal behavior at home can easily be dismissed as work-related stress; while abnormal behavior in the workplace can be put down to stress in one’s personal life.
• Someone diagnosed with early-onset dementia may wish to, or be financially obligated to, continue working as long as possible. This raises issues such as how much one needs to reveal to an employer and what sort of protection one has against discrimination. Full disclosure of one’s condition would normally be required for full protection under the law.
• In the early stages of dementia, work activities may be able to be carried out to the same, or close to the same, capacity as before the condition. However, a person’s ability to perform certain tasks will deteriorate over time. Employers are required to make ‘reasonable adjustments’ in such circumstances but to do so they need to be fully informed of the condition of the employee with early-onset dementia.
• It is hard to predict how work colleagues will react to the diagnosis. Some people find it hard to cope with things they don’t understand. In these cases, communication and education can help.

What is Lewy body dementia?

Dementia with Lewy bodies (or Lewy body disease) is a form of dementia in which a build-up of microscopic deposits known as Lewy bodies impair and destroy nerve cells in the brain. Progress of the condition is usually faster than Alzheimer’s disease. The main symptoms are:

• Difficulty concentrating
• Extreme confusion
• Hallucinations
• Difficulty judging distances
• Extreme changes in reasoning
• Tremors and movement associated with Parkinson’s disease.

What’s the difference between dementia and Alzheimer’s Disease?

Alzheimer’s Disease is a type of dementia and is in fact the most common form of dementia. Dementia is the general term used to describe a range of symptoms associated with the loss of memory, thinking and behavioural skills which significantly reduces a person’s ability to perform everyday activities. These result from damage to brain cells.

Alzheimer’s disease is the most common form of dementia. It is responsible for about 60–70% of all dementia cases (World Health Organization). The vast majority of cases are in people over the age of 65 and are a result of sporadic Alzheimer’s disease. However, a less common form, familial Alzheimer’s disease, caused by genetic mutation, can affect people under the age of 65.

What causes Alzheimer’s disease?

Alzheimer’s disease is caused by the build-up of abnormal deposits of protein in the brain. There are two types of deposits, plaques and tangles. The plaques are a protein fragment called beta-amyloid and they build up in the spaces between nerve cells. The tangles are fibres of a protein called tau and they build up inside brain cells. These build-ups usually begin in the outer brain, where short-term memory is controlled. It then spreads and starts to affect long-term memory and other functions.

Research into Alzheimer’s disease has really only taken off within the last couple of decades. However, the prevalence of Alzheimer’s means there are now a great deal of resources being put into understanding the disease. While there is a general understanding of what is happening within the brain of Alzheimer’s sufferers, researchers are still trying to determine exactly how and why the build-ups of beta-amyloid and tau occur.

54% of permanent residential aged care residents have dementia, yet 2 in 3 people with dementia live in the community (Dementia Australia) — meaning home care is the primary support pathway for most Australians living with dementia. Australia spent $4.7 billion on dementia-related health and aged care in 2022–23 (AIHW, 2025).

Getting Support for Dementia Care

If you or a loved one has been diagnosed with dementia, the first step is to register with My Aged Care and complete an aged care assessment to determine the level of support needed. You may be eligible for home care through the Support at Home program, which provides government-funded services like personal care, nursing, and daily assistance. Respite care is also available to give carers a break while ensuring your loved one continues to receive quality support.