Dementia - Symptoms & Causes

What is dementia?

Dementia is an umbrella term used to describe a set of symptoms caused by one or a combination of neurological disorders. It is not a specific disease and currently has no medical cure.

A person is considered to have dementia when their memory, learning, thinking or decision-making skills are adversely affected by brain diseases.

It can affect adults at any stage of life but the incidence of dementia is more common in people over 65 years of age. In Singapore, dementia affects approximately 6% of people in this age group.

Early onset dementia

When a person younger than 65 years old frequently displays common symptoms of dementia, such as memory loss, this condition is sometimes referred to as early onset dementia.

Dementia vs senility

As dementia is not a normal part of the aging process, it should not be confused with senility, a term sometimes used to describe the state of physical and mental decline associated with old age. Hence, the term senile dementia is no longer used.

What are the symptoms of dementia?

Symptoms may differ depending on the main cause or type of dementia. In general, they include:

  • Decline in brain function
  • Difficulty in completing familiar tasks
  • Loss of interest in work and social activities
  • Memory loss
  • Mood changes
  • Poor judgement
  • Problems in communication
  • Uncertainty about time and place
  • Confusion and disorientation
  • Wandering and getting lost in an acquainted neighbourhood
  • Impulsive behaviour
  • Disregard for the feelings of others

What causes dementia?

There are various brain disorders that can cause symptoms of dementia. These are also sometimes known as types of dementia.

Types of dementia

Alzheimer's disease

This the most common type of dementia. It occurs due to abnormal build-up of proteins, known as tau tangles and amyloid plaques, that damage healthy neurons (brain cells).

Vascular dementia

The second most common form of dementia. It occurs due to damage in the blood vessels, resulting in reduced blood supply to the brain.

Lewy body dementia

This results from abnormal clump-like deposits of the protein alpha-synuclein, called Lewy bodies, in the brain.

Frontotemporal dementia

This uncommon form of dementia usually occurs in people younger than 60 years old. It occurs due to build-up of abnormal amounts of certain proteins in the brain.

Parkinson's disease

The term 'Parkinson's disease dementia' refers to changes in thinking and behaviour in someone who has been diagnosed with Parkinson's disease.

Less common causes of dementia include:

  • Huntington's disease. A rare hereditary disease that leads to progressive motor, cognitive, and behavioural problems.
  • Creutzfeldt-Jakob disease. A rare and degenerative brain disorder that may ultimately lead to death.
  • Leukodystrophy-like diseases. A group of conditions defined by abnormalities or degeneration of white matter in the brain.

What are the risk factors for dementia?

Some factors that increase the risk of dementia include:

  • Age above 65 years
  • Excessive consumption of alcohol and drugs
  • Family history of dementia
  • Depression
  • Down syndrome
  • Diabetes, high blood pressure, or high cholesterol levels
  • Build-up of excess fluid in the brain due to infections or tumours

What are the complications of dementia?

While dementia is mainly associated with a decline in brain function, other complications, depending on the cause of dementia, may include:

  • Depression
  • Dehydration and poor nutrition
  • Delusions and hallucinations
  • Loss of ability for social interactions
  • Loss of ability to live safely and independently
  • Insomnia
  • Decreased lifespan

How do you prevent dementia?

Although there is no proven way to prevent dementia, some healthy lifestyle practices can help to reduce the risk:

  • Be physically active. Regular physical activity may delay the onset of dementia and diminish symptoms.
  • Keep your mind active. Mind-stimulating activities such as memory and word games, puzzles, and reading can help reduce symptoms and delay the start of dementia.
  • Manage lifestyle diseases. High blood pressure or hypertension increases the risk of stroke and vascular dementia. By effectively treating and managing such chronic conditions, the risk of dementia is reduced.
  • Manage depression. Managing depression and anxiety is important to help reduce the risk of dementia.
  • Treat hearing problems. Hearing loss is associated with a greater chance of decline in cognitive (mental) abilities.
  • Have a healthy diet. Have a diet rich in fruits and vegetables, whole grains, and omega-3 fatty acids. Lower the intake of fats and refined sugar.
  • Be socially active. This helps to prevent solitude and social isolation which is linked to a greater risk for cognitive decline and Alzheimer’s disease.
This page has been reviewed by our medical content reviewers.

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