Types of Dementia

There are many different types of dementia although some are far more common than others. They are often named according to the condition that has caused the dementia. Some of the more common types are outlined below.

Alzheimer's disease

This is the most common type of dementia. During the course of the disease, individual brain cells become damaged. The numbers gradually increase over time so the brain starts to function less well. It starts slowly, and the decline can happen over a number of years. It usually affects short–term memory first.

Vascular dementia
This is the second most common type of dementia. If the oxygen supply to the brain fails, brain cells may die. The symptoms of vascular dementia can occur either suddenly, following a stroke, or over time, through a series of small strokes.

Lewy bodies Dementia
This form of dementia gets its name from tiny spherical structures that develop inside nerve cells. Their presence in the brain leads to the degeneration of brain tissue. This causes the brain to function less well in sending and receiving messages.

Fronto-temporal dementia
In fronto-temporal dementia, damage is usually focused in the front part and side parts of the brain. Personality and behavior are initially more affected than memory.

Other conditions
These are the main types of dementia. However, other illnesses or conditions can cause dementia, including:

Mild cognitive impairment
Mild cognitive impairment (MCI) is a relatively recent term, used to describe people who have some problems with their memory but do not actually have dementia.

Creutzfeldt-Jakob disease
Prions are infectious agents that attack the central nervous system and then invade the brain, causing dementia. The best-known prion disease is Creutzfeldt-Jakob disease, or CJD.

Korsakoff's syndrome
Korsakoff's syndrome is a brain disorder that is usually associated with heavy drinking over a long period. Although it is not strictly speaking a dementia, people with the condition experience loss of short term memory. Alcohol–related dementia is caused by a lack of vitamin B1. Heavy drinkers may not be able to absorb the vitamin well, and may also have a poor diet.

HIV-related cognitive impairment
People with HIV and AIDS sometimes develop cognitive impairment, particularly in the later stages of their illness.

Information on providers of dementia services is available.

Further information on Dementia can be found on Alzheimer Society website.