Types of Dementia include:
This is the most common cause of dementia and accounts for 50% – 80% of all cases of dementia. It destroys brain cells and nerves disrupting the transmitters which carry messages in the brain, particularly those responsible for storing memories. It is a progressive condition. This means that the structure and chemistry of the brain become increasingly damaged over time. The person’s ability to remember, understand, communicate and reason gradually declines. How quickly dementia progresses depends on the individual but the progression can take many years. Each person is unique and experiences dementia in their own way.
The brain relies on a network of vessels to bring it oxygen-bearing blood. If the oxygen supply to the brain fails, brain cells are likely to die and this can cause the symptoms of vascular dementia. These symptoms can occur either suddenly, following a stroke, or over time through a series of small strokes. Some people with vascular dementia find that symptoms remain steady for a time and then suddenly decline as the result of another stroke. This contrasts with the gradual decline many people with Alzheimer’s disease experience. It is sometimes difficult to determine whether people have Alzheimer’s or vascular dementia. It is also possible to be affected by both.
Dementia With Lewy Bodies
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. Memory, concentration and language skills are affected. Half or more of those affected also develop signs and symptoms of Parkinson’s disease such as slowness or movement, stiffness and tremor. They may also have difficulty in judging distances and are more prone to falls. People with this dementia also commonly experience visual hallucinations. One feature of this dementia which often puzzles care partners is that the abilities of the affected person often fluctuate.
In frontotemporal dementia (FTD), damage is usually focused in the front part of the brain. Personality and behaviour are initially more affected than memory. During the early stages the memory may be unaffected. However, there may be other changes. For example, the person may seem more selfish and unfeeling. They may behave rudely, or may seem more easily distracted. Other symptoms may include loss of inhibition, ritualised behaviour and a liking for sweet foods. In later stages the symptoms are more similar to those experienced in Alzheimer’s disease.
Rarer causes of dementia
There are many other rarer causes of dementia, including progressive supranuclear palsy, Korsakoff’s syndrome, Binswanger’s disease, HIV and Creutzfeldt-Jakob disease (CJD). People with multiple sclerosis, motor neurone disease, Parkinson’s disease and Huntington’s disease can also be at an increased risk of developing dementia.
Sources: Alzheimer's Disease International