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Understanding Dementia

Dementia occurs when brain cells die in an abnormal manner. It is a term used to describe progressive degenerative brain disease and it is not part of normal ageing. Dementia affects a person's ability to think, reason, remember, learn new information and skills, solve problems and make judgement. While there is no cure for dementia, treatments are available to manage the symptoms.


Typically the first warning signs are:

  • Memory loss that affects day-to-day function
    It is normal to forget appointments or phone numbers occasionally. However, a person with dementia may start to forget things on a regular basis and not remember them at all. The disease prevents the person from making new memories. Patient suffering from dementia will often only remember memories from the past and slowly lose their ability to capture new information or memories.
  • Difficulty performing familiar task
    A person with dementia will not be able to function normally like an ordinary person. Patients with dementia will slowly forget how to carry out the simple tasks they once were familiar with such as cooking.
  • Problems with language
    A person with dementia may forget usage of simple words or he/she may use the wrong words, resulting difficulty in understanding what they are trying to communicate.
  • Disorientation of time and place
    Patients with dementia are not aware of their surroundings. They may face difficulty in trying to remember the date, time of the day and may even get lost in a familiar environment.
  • Poor or decreased judgement
    Patients with dementia are easily distracted and tend to make poor judgements. For example, since they are unaware of their environment, they may dress inappropriately such as wearing heavy clothing on a sunny day.
  • Misplacing Things
    Misplacing your belongings on a regular basis and not being able to recall where you've kept them could be a tell-tale sign that the person may potentially suffer from dementia. In certain cases where the illness is at an advanced stage, patients may end up keeping their things at inappropriate places such as placing their iron in a freeze. In some severe cases, patients are capable of accusing others of stealing when they are unable to locate their belongings.
  • Changes in Mood or Behaviour
    Patients suffering from dementia may display rapid and irrational mood swings. They can become abnormally irritable, depressed, or agitated for no apparent reason. Dementia can affect and change their usual sleeping pattern, eating habits and sense of hygiene. Some may even result in erratic behaviours such as rummaging through closets and drawers repeatedly without any purpose.
  • Changes in Personality
    Dementia can cause a person to have a dramatic change in personality. For example, they may act in an exaggerated manner such as becoming overly suspicious or being completely withdrawn.
  • Loss of Initiative
    When a person has dementia, he or she tends to be passive and lose any motivation or interest in any business or social activities. They are slow to respond and require cues or assistance in their daily activities. While the condition may be considered mild, it can get very distressing for the caregiver and family. Getting help and receiving treatment at an early stage of dementia can have a more successful effect on patients.


Dementia is essentially caused by the death of the brain cells which leads to the decline of the patient's mental abilities. Many factors such as diseases, old age, alcohol abuse, family genes or severe concussions could have increase a persons risk of developing dementia. Diseases such as Alzheimer's disease and vascular dementia are two common causes for dementia.

Alzheimer's Disease

Alzheimer's disease is the most common cause of dementia and accounts for 50% - 60% of all cases. It destroys brain cells and nerves and disrupts the neurochemicals, which carry messages in the brain, particularly those which are responsible for storing memories. The average duration of the disease usually progresses over a span of eight years from the onset of symptoms.

Approximately 10 million people worldwide are affected by Alzheimer's disease. It is a leading cause of death after cardiovascular disease and cancer. According to Ministry of Health, about 20,000 Singaporeans - a prevalence rate of 5.7 per cent, suffer from dementia. By 2020, the number of dementia patients is expected to more than double to about 45,000.

Alzheimer's disease affects mostly those who are over 65 years old, although in rare cases, it can also happen to people who are of a younger such as in their 40's or 50's.

Vascular Dementia

Vascular dementia, formally known as multi-infarct dementia, accounts for about 30% of dementia. Vascular dementia occurs when blood vessels in the brain are damaged and the supply of oxygen to the brain is reduced. When there is a lack of oxygen supply in the brain, a series of mini strokes (infarcts) will take place causing the death of brain cells. The mini strokes that cause vascular dementia are often so small to display immediate symptoms but may sometimes cause temporary confusion. However, the damage caused by new mini strokes that are accumulated over time, will result in vascular dementia. Vascular dementia and Alzheimer's disease can also occur together, acting in combination to cause dementia.


Individuals who should be screened and diagnosed for dementia include those with progressive cognitive or behavioral complaints suggestive of dementia, as well as patients who are suspected of cognitive impairment despite absence of complaints. Early diagnosis of dementia can help patients and their families receive proper investigations, treatments and counselling for long-term management of the disease.

Clinical assessment for dementia should include:

  • A patient's detailed medical history which includes psychiatric, social, medication history as well as descriptions of the patient's cognitive and behavioural patterns.
  • A physical examination to detect causes of delirium and neurological signs. An examination to assess the patient's mental abilities.
  • Diagnostic tests to rule out metabolic and structural causes of dementia, which should include full blood count, serum electrolytes (including calcium), glucose, liver function tests, thyroid function tests, Vitamin B12 and folate levels, syphilis serology and neuro-imaging.
  • Evaluation of social and care issues.


Some causes of dementia are potentially reversible, such as Hypothyroidism, Vitamin B12 deficiency and alcohol-related syndromes. However, there is presently no cure for the common causes of dementia such as Alzheimer's Disease and Vascular Dementia.

Nevertheless, there are medications available to alleviate symptoms and enhance quality of life. Apart from medications, there are also behavioural therapies, counseling and education to improve care for patients with dementia and their families.


Many new treatments are being developed for the prevention and treatment of dementia. There are ongoing clinical trials and other research efforts in Singapore.


Find out more information from:

Alzheimer's Disease Association Singapore
Changi General Hospital
Singapore Health Services
Health Promotion Board
Butler Hospital
Ah Kong [阿公] - A short film on dementia by Royston Tan


1. What is the difference between Alzheimer's disease and dementia?

Dementia refers to a category of disorders that involve memory loss while Alzheimer's disease is a specific disease. Alzheimer's disease causes dementia; however, several other diseases or conditions, such as stroke, Parkinson's disease, head injury, and vitamin deficiency can also lead to dementia.

2. How can one recognise Alzheimer's disease from normal memory loss or ordinary forgetfulness?

Everyone experiences memory lapses and are forgetful at times. Decline in the ability to remember is also a normal part of ageing. However, such memory problems do not worsen over short periods of time and interfere much with the person's day-to-day activities. In contrast, the memory loss in Alzheimer's disease is much greater than expected for normal ageing. The memory lapses are more frequent, severe, and interfere with a person's ability to manage his or her daily routines.

3. If an individual has been diagnosed with Alzheimer's disease, should they continue to drive?

A person's ability to drive depends on the current stage of the disease as well as his/her remaining abilities to function. Patients who still drive are encouraged to limit their driving to short distances and in areas that are familiar to them.

4. Should a person inform his/her friends and family that they have been diagnosed with Alzheimer's disease?

Patients with Alzheimer's disease will require every support and assistance from their friends and families, especially at an advanced stage of the disease. While informing your friends and family may cause emotional distress, it is advisable to make them aware of your condition early to establish a strong and caring support system.

5. Do all people with Alzheimer's disease wander around? Why =re they so easily irritated?

As the disease progresses to an advanced stage, patients will tend to display a change in their mood or behaviour. Patients might get easily irritated and depressed or tend to be overly suspicious for no apparent reason. Most of them will show signs of indifference towards things or activities they once used to enjoy or to their surroundings.

Patients can seek solace in support groups or via medications. Your family doctor may also refer you to a geriatric psychiatrist who specialises in managing behavioural problems in dementia.

6. Is Alzheimer's disease hereditary? If I have a parent/family member suffering from the disease, does it increase my chances of getting it? If so, are there any tests to check if I am at risk?

A person is most likely to have about 5% chance of developing Alzheimer's disease by the age of 65, 10% - 15 % risk by the age of 75 and 20% to 40% chance by 85 years old. Individuals who may have family members with Alzheimer's disease face twice the average risk of getting the disease. There is an increased risk for those with more than one affected member with Alzheimer's disease since family members may share similar genes.

There are medical tests available that can determine if a person carries Alzheimer's disease genes. However, it is important to understand that people with Alzheimer's disease genes may not necessarily develop the disease. In addition, an Alzheimer's disease diagnosis is usually 90 % accurate even without undergoing genetic tests. Therefore, genetic testing is usually not essential, but is highly recommended.

This article is reproduced with the permission from Agency for Integrated Care (AIC) and Singapore Sliver Pages.

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