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Dementia

What is dementia?

Dementia is the umbrella term for over 100 neurological disorders which cause a gradual, progressive impairment in brain function.

It is the largest cause of disability of older adults in Australia, and second leading cause of death [1].  

Over 425,000 Australians have dementia, and over 200 people are diagnosed daily [1].  

Dementia causes impairment of cognition (thinking, remembering, reasoning [2]) and can affect language, behaviour, personality and mobility [7].

Alzheimer’s disease is the most common form of dementia, accounting for 60-80% of cases, and is caused by abnormal protein deposits.

Vascular dementia – makes up 10% of dementia [3] and is caused by obstructed flow of blood and oxygen to the brain.

Dementia causes impairment of cognition (thinking, remembering, reasoning [2]) and can affect language, behaviour, personality and mobility [7]. As the disease progresses, the person loses ability to perform everyday tasks and maintain independence. Features vary according to dementia type and severity. Table 1 describes some common findings. .

TABLE 1

Common features of dementia [2,3,5]

Cognition
  • Short-term memory loss
  • Not recognising familiar people
  • Getting lost
  • Difficulty managing complex tasks
  • Poor judgement, reasoning, problem solving and planning
  • Poor attention, difficulty concentrating
  • Confusion
Behaviour and emotions
  • Impulsivity
  • Wandering
  • Emotional numbness or mood swings
  • Loss of interest in usual activities
Movement
  • Stiff muscles
  • Tremor
  • Coordination, walking or balance problems
  • Loss of facial expression
Sleep
  • Insomnia
  • Daytime sleepiness
Language
  • Repeating questions
  • Word-finding problems
  • Trouble communicating
Perception
  • Hallucinations
  • Delusions

Most cases occur when brain cells (neurons) fail and disconnect from other brain cells, eventually dying off. This occurs more in dementia than in normal ageing [2]. This process occurs in Alzheimer’s disease, Lewy body dementia, and frontotemporal dementia, the most common types of “neurodegenerative” dementia. The cause is unknown in most people. Having a first-degree relative with Alzheimer’s disease may increase the risk of developing it by 10-30% [3]. Rare genetic mutations cause dementia in a minority [2]. People with ethnicities such as African-American have higher rates of dementia [4]. Alzheimer’s disease makes up 60-80% of dementia [3], and is caused by abnormal protein deposits forming amyloid plaques and tau tangles. Some brain changes seen in dementia are summarised below [5,6]:

  • A thorough history from the patient and close friends/family
  • Lewy body dementia – caused by abnormal deposits of protein alpha-synuclein (Lewy bodies)
  • Frontotemporal dementia – caused by abnormal amounts or types of tau and TDP-43 proteins in frontal and temporal lobes
  • Vascular dementia – makes up 10% of dementia [3] and is caused by obstructed flow of blood and oxygen to the brain. Changes related to stroke, or white matter may be seen
  • Mixed dementia is a combination of two or more types of dementia.
  • Other diseases can cause dementia, or dementia-like syndromes, such as Creutzfeldt-Jakob disease, Huntington’s disease, and Chronic Traumatic Encephalopathy (repeated traumatic brain injury).

With no single test for dementia, and with other medical conditions able to mimic dementia such as depression, it can take around three years to receive a confident diagnosis. It is often longer for people whose first language is not English [1]. Some or all the following will be needed to reach a diagnosis:

  • A thorough history from the patient and close friends/family
  • Medical history, such as past stroke
  • Physical examination
  • Cognitive tests
  • Laboratory tests for other causes of cognitive impairment, such as anaemia, vitamin B12, and thyroid function
  • Brain imaging to check for abnormalities such as stroke or cerebral atrophy (signs of loss of brain tissue seen in normal ageing or neurodegenerative dementia).

Although there is no cure, some treatments and support are available. It is important to help the person function and have the best possible quality of life. This might involve allied health input to improve independence and mobility, or support for the person’s carer to manage symptoms such as wandering or agitation. Medications that modify the brain’s chemical messengers are available for Alzheimer’s disease and can improve symptoms. However, it is controversial as to whether they slow disease progression [8,9]. Medications used to improve blood vessel health, such as blood pressure and cholesterol, are often used to treat vascular dementia. Research suggests that some Alzheimer’s medications may help in vascular dementia.

Unfortunately, there is no conclusive evidence for dementia prevention. It is suggested that that cognitive training, blood pressure management for people with hypertension, and increased physical activity may be of benefit [10].

Research at the Bionics Institute into dementia

 

• Our researchers are developing the use of transcranial magnetic stimulation, a non-invasive treatment that shows promise of improving cognition in Alzheimer’s disease and a range of other diseases.

• Transcranial Magnetic Stimulation (TMS) is a safe and painless technique, which uses magnetic pulses to alter brain activity.

With your help, we can accelerate this research and improve diagnosis and treatment of dementia. 

Your support today could change the lives of people with dementia around the world. 

 

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Further support services

For more information about support services for people with this condition, go to the Dementia Australia website.

Medical disclaimer

This article contains general information relating to a medical condition. Such information is provided for informational purposes only and does not replace medical advice given by your healthcare professional.

References

1. NHMRC National Institute for Dementia Research. Boosting Dementia | Report on early outcomes. (CC BY 4.0) [Internet]. 2018. Available from: https://www.nhmrc.gov.au/file/15479/download?token=mh688ClE 

2.What Is Dementia? Symptoms, Types, and Diagnosis [Internet]. Source: National Institute on Aging. 2021 [cited 2022 May 4]. Available from: https://www.nia.nih.gov/health/what-is-dementia

3.What Is Dementia? [Internet]. Source: CDC. 2019 [cited 2022 May 4]. Available from: https://www.cdc.gov/aging/dementia/index.html

4.Can I Prevent Dementia? [Internet]. Source: MedlinePlus, National Library of Medicine. 2022 [cited 2022 May 4]. Available from: https://www.alzheimers.gov/life-with-dementia/can-i-prevent-dementia

5.Understanding Different Types of Dementia [Internet]. Source: MedlinePlus, National Library of Medicine. 2022 [cited 2022 May 4]. Available from: https://www.nia.nih.gov/health/infographics/understanding-different-types-dementia

6. Vascular Dementia: Causes, Symptoms, and Treatments [Internet]. Source: National Institute on Aging. 2021 [cited 2022 May 4]. Available from: https://www.nia.nih.gov/health/vascular-dementia

7.Australian Institute of Health and Welfare. Dementia. (CC BY 4.0) [Internet]. 2020 [cited 2022 May 4]. Available from: https://www.aihw.gov.au/reports/australias-health/dementia

8.Dementia in Australia | Prescriptions for dementia-specific medications. (CC BY 4.0) [Internet]. Australian Institute of Health and Welfare. 2021 [cited 2022 May 4]. Available from: https://www.aihw.gov.au/reports/dementia/dementia-in-aus/contents/health-services-used-by-people-with-dementia/prescriptions-for-dementia-specific-medications

9.Alzheimer’s Disease Fact Sheet [Internet]. Source: National Institute on Aging. 2021 [cited 2022 May 4]. Available from: https://www.nia.nih.gov/health/alzheimers-disease-fact-sheet

10.Hodes R. Dementia prevention: What does the evidence tell us? | National Institute on Aging [Internet]. Source: National Institute of Aging. 2017 [cited 2022 May 4]. Available from: https://www.nia.nih.gov/research/blog/2017/10/dementia-prevention-what-does-evidence-tell-us

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