There are four main types of dementia:
Alzheimer's disease
This form of dementia is characterised by memory loss and declines in other everyday skills. The onset of symptoms is typically gradual, increasing in severity over time. At first, symptoms might be mild forgetfulness about recent events, activities, or the names of familiar people or objects. However as the disease progresses, symptoms escalate to forgetting how to perform simple tasks, such as bathing or making a cup of tea. Thinking might become muddled and problems arise with speaking, reading or writing. Later, symptoms include anxiety and at times aggression, failure to recognise loved ones or wandering away from home.
Vascular dementia
Vascular dementia is triggered by small vessel disease or by minor strokes where blood clots block small blood vessels in the brain, ultimately destroying surrounding brain tissue. Symptoms of vascular dementia include confusion, impaired judgement and planning, frequent falls, loss of bladder control and emotional problems such as laughing or crying inappropriately.
Dementia with Lewy bodies
Dementia with Lewy bodies is caused by brain cell death in certain areas of the brain. It is characterised by steady declines in an individual’s cognitive abilities (e.g., confusion, extreme variation in mood) as well as two or more of the following symptoms:
- changes in thinking and reasoning
- confusion and alertness that varies significantly across a day or from one day to the next
- frequent and detailed visual hallucinations
- spontaneous loss of motor control, similar to Parkinson disease.
Frontotemporal dementia
Early symptoms of fronto-temporal dementia are changes in behaviour, mood or personality but as the disease progresses, changes in cognitive skills, particularly attention, problem-solving, judgement and organising skills also occur. The main symptoms of frontotemporal dementia include:
- declines in social and interpersonal skills
- increasingly impulsive or reckless behaviour
- lack of emotion or concern for others.
Some forms of frontotemporal dementia can also cause problems with language (e.g., loss of speech) and mobility (e.g., shakiness, lack of coordination).