How is dementia diagnosed?

A support worker measuring the blood pressure of an older woman sitting in a wheelchair.

The term ‘dementia’ describes a collection of symptoms that are caused by disorders affecting the brain. Dementia affects a person’s memory, behaviour, and ability to clearly think and perform tasks, making everyday life difficult.

While the condition is most prevalent in people aged 65 years and over, people in their 30s, 40s and 50s can develop younger onset dementia.

Typically, one of the first symptoms of dementia is a problem with memory and recalling certain events. This might sometimes be disregarded as a ‘normal’ part of ageing, but there is a difference between normal forgetfulness and dementia. For example, forgetting why you went into the kitchen or misplacing your car keys is normal forgetfulness. Losing the car keys and then not remembering what they are used for, is more likely to be a symptom of dementia.

There are more than 100 diseases which may cause different types of dementia and symptom severity and progression of the condition varies from person to person.

Symptoms of dementia, especially early on, can be subtle and may not be immediately obvious. They can include progressive memory loss, confusion, difficulty handling everyday tasks, among other things. If you see these early warning signs of dementia, raise your concerns with your doctor as soon as possible. Getting a correct diagnosis of dementia at an early stage is important for treatment, support and planning for the future.

Significant support and resources from Dementia Australia are also available to help carers, family members and friends of people who are diagnosed with dementia. Don’t hesitate to reach out if you need help; you are not alone.

Visit the Dementia Australia and Better Health websites for more information.

How is dementia diagnosed?

Dementia can only be diagnosed by a qualified medical practitioner (such as a GP) or by a specialist. A GP will conduct a series of medical and psychological tests to identify the condition which may be causing the symptoms.

There are six main types of assessment that can help to confirm or exclude a diagnosis of dementia.

Medical history

The doctor will ask about past and current medical problems, family medical history, any medications being taken, and the problems with memory, thinking or behaviour that are causing concern.

Physical examination

To help rule out other conditions, a physical examination may include tests of the senses, movement, and heart and lung function.

Laboratory tests

A variety of blood and urine tests may be conducted to identify any possible illness that could be responsible for the symptoms. In some cases, a small sample of spinal fluid may be collected for testing.

Cognitive testing

A variety of tests are used to assess thinking abilities, including memory, language, attention and problem-solving. This can help identify specific problem areas which, in turn, helps identify the underlying cause or the type of dementia.

Brain imaging

There are certain scans that look at the structure of the brain and are used to rule out brain tumours or blood clots as the reason for symptoms. Some scans can also detect patterns of brain tissue loss that can differentiate between different types of dementia. Other types of scans look at how active certain parts of the brain are and can also help determine the type of dementia.

Psychiatric assessment

Psychiatric assessments help to identify treatable disorders, such as depression, and to manage any psychiatric symptoms that may occur along with dementia.

A GP may also refer the person to a neurologist, geriatrician or psychiatrist for further diagnosis.

Find out more about using your Home Care Package to find dementia support.


An MRI can provide an image of the structure of your brain which changes with dementia. An MRI can be used to aid a dementia diagnosis and track its progression but is not the only or primary way to detect the condition.

Other health conditions can present similar symptoms to dementia so it is important to receive a proper diagnosis if you are concerned. Strokes, depression, alcoholism, infections, hormone disorders, nutritional deficiencies and brain tumours can all cause dementia-like symptoms and many of these can be treated.

Dementia can progress very quickly and worsen over a few months or develop slowly over a number of years.

The length of time that a person with dementia lives can vary depending on when they are diagnosed, the type of dementia they have, and how fast the disease is progressing. This varies from person to person.

You can’t control some risk factors of dementia (such as age, sex, gender, and family history), but you can reduce your risk of developing dementia.

Risk factors you can control include obesity, smoking, diabetes, high blood pressure and high cholesterol, so eating a balanced diet, staying mentally and physically active, not smoking, not drinking excessively, managing a healthy weight and making other healthy lifestyle choices, can help reduce your risk of developing dementia.