Dementia, which results from certain diseases or injuries, of which Alzheimer's disease is the most common, may leave you bewildered at the changes in your brain.
But there are things you can do to delay the onset of the condition as well as its progression, doctors said.
The two most important risk factors for dementia are age and a positive family history of dementia, that is a genetic predisposition, said Associate Professor Philip Yap, a senior consultant and the director of the geriatric centre at Khoo Teck Puat Hospital.
The risk increases with age, with it doubling every five years after 65 years.
Those who have a parent or sibling suffering from dementia are also at an increased risk of getting it, said Prof Yap.
"It is hard to prevent dementia because while the ageing process can be delayed, it is not preventable."
If you have the genes that predispose you to dementia, the genes cannot be altered. But there is ongoing research in the field of gene therapy, he said.
Healthy lifestyle habits such as exercise and eating a nutritious and balanced diet should start as early as possible, as with the need to build sufficient brain reserves by having more years of formal education.
ASSOCIATE PROFESSOR PHILIP YAP, a senior consultant and the director of the geriatric centre at Khoo Teck Puat Hospital.
For these reasons, dementia is hard to prevent altogether.
However, there are several modifiable risk factors that, if addressed, may delay the onset and progression of the disease. They include:
• Biomedical factors, which include diabetes, mid-life hypertension, mid-life obesity, hyperlipidemia, hearing loss;
• Lifestyle factors, such as smoking, excessive alcohol consumption, decreased physical or cognitive engagement and chronic poor sleep; and
• Psychological and social factors, which include depression, loneliness and social isolation, as well as a limited formal education.
For instance, being married and very satisfied with life reduces the risk of dementia, said Associate Professor Ng Tze Pin, the principal investigator of the long-term Singapore Longitudinal Ageing Study.
Among these factors are two relatively "new" ones - sleep deprivation and hearing loss, Prof Yap pointed out.
"Sufficient sleep, especially slow-wave, deep sleep, is needed for effective consolidation of information. So if sleep is poor, the information is poorly stored in the brain," he said.
"In addition, poor sleep has been shown to be associated with increased accumulation of the primary pathological drivers of Alzheimer's disease in the plaques and tangles in the brain."
Recently, a local study conducted by the National University of Singapore, together with Ng Teng Fong General Hospital, found that hearing loss can increase the risk of dementia by about two times, which highlighted the need for early diagnosis and intervention for hearing loss in order to delay dementia.
"People think that people think that hearing loss is a part of ageing and do not do anything about it," said Associate Professor Reshma Merchant, the head and senior consultant at the division of geriatric medicine at the National University Hospital.
But those with hearing loss may need more effort to hear a degraded sound, so fewer brain resources are available for thinking and memory, for instance. They may also be more socially isolated, which puts them at risk of cognitive decline.
"If you continue smoking, are depressed and physically inactive, your risk of dementia will rise," said Prof Reshma.
Importantly, in order to prevent dementia, one must consider modifying risk factors throughout one's life, said Prof Yap.
"Healthy lifestyle habits such as exercise and eating a nutritious and balanced diet should start as early as possible, as with the need to build sufficient brain reserves by having more years of formal education," he said.