Dementia is the “umbrella term” for a large number of diseases which affect the brain. These diseases can impact thinking processes, memory, language and communication, sensory abilities, daily function, mood and behaviour.
Each type of dementia has different patterns of change in the brain. This means different types of dementia have different symptoms. Dementia in younger people (i.e. before 65 years) can look quite different from dementia in older age. Dementia is complex and sometimes doctors can’t differentiate between types of dementia and can’t tell what type of dementia the person has.
There are some drug treatments suitable for some types of dementia but not others. However, there are also non-drug treatments and strategies that tend to work for all the different types of dementia; you can find these on this website in Section 3, Managing Changes.
Common types of dementia are:
- Alzheimer’s disease
- vascular dementia
- Lewy Body dementia
- fronto-temporal dementia, and
- mixed dementia.
Alzheimer’s disease
Alzheimer’s disease is the most common type of dementia across all age groups. About 50-70% of all people with dementia have Alzheimer’s disease. People with Alzheimer’s disease typically have deterioration in the areas of their brain involved in memory (called the hippocampus and temporal lobes), as well as more general changes throughout the brain. Short-term memory (memory of recent events) is affected more than long-term memory. People with Alzheimer’s disease may find it harder to concentrate, solve complex problems, or they may find themselves thinking more slowly.
We don’t know what causes Alzheimer’s disease, however there are medications which may slow progression of symptoms. A healthy lifestyle, including regular exercise, a good diet and staying mentally active, can also help.
Read more about Alzheimer’s disease at Dementia Australia.
Vascular dementia
Vascular dementia is another common form of dementia. ‘Vascular’ means the dementia is related to problems with blood flow in the brain. Blockages can lead to brain cells dying from lack of blood, or little bleeds that cause small strokes. People with vascular dementia experience problems with thinking or cognitive abilities, depending on where their brain damage has occurred.
People with vascular dementia frequently have heart disease, or risk factors for heart disease such as high cholesterol, diabetes and high blood pressure. Managing these risk factors can help slow the progression of vascular dementia. Talk with the person living with dementia and their doctor about treatments and strategies the person should be taking to manage heart disease risk factors.
Read more about Vascular Dementia at Dementia Australia.
Lewy body dementia
Lewy body dementia is a less common type of dementia. People with Lewy body dementia have trouble with their concentration and attention as well as physical movement. They may have visual hallucinations, which is seeing things that are not there, or have delusions which is believing things that are not true. Hallucinations and delusions are very real to the person with Lewy body dementia. Their concentration and attention can fluctuate so that the person can be really clear in the morning but muddled and confused later that same day. Changes in movement may include developing a slow or stiff way of walking and their faces may be less expressive. People with Lewy body dementia can benefit from physiotherapy and exercise physiology to help improve movement.
Lewy body dementia and Parkinson’s disease are related diseases, however in Lewy body dementia the difficulties with thinking are more prominent first, whereas in Parkinson’s disease the difficulties in movement are more prominent.
Read more about Lewy body dementia at Dementia Australia. and at the Lewy Body Dementia Association website
This video describes Lewy Body from the perspective of two couples experiencing it.
Fronto-temporal dementia
Fronto-temporal dementia is a less common type of dementia. People with fronto-temporal dementia have damage in the frontal and temporal lobes (or regions) of their brains. People with fronto-temporal dementia often have different symptoms to other dementias. For this reason, some clinicians might not believe that they have dementia or don’t understand how to support their type of dementia. People with fronto-temporal dementia and carers often have to educate others (including health professionals) about fronto-temporal dementia.
There are three sub-types of fronto-temporal dementia, each with a different pattern of symptoms.
- Semantic dementia is a subtype where the person starts to lose the meanings of words. People with semantic dementia have trouble expressing themselves with words, understanding language, reading and writing. They may benefit from speech pathology to improve communication (see 3.13 Use therapies to help people maintain independence). Brain changes start in the temporal lobe in semantic dementia.
- Progressive non-fluent aphasia is a subtype where the person has difficulty speaking fluently. People with progressive non-fluent aphasia have trouble expressing themselves and following conversations. They may benefit from speech pathology to improve communication (see 3.13 Use therapies to help people maintain independence). Brain changes start in the temporal lobe in progressive non-fluent aphasia dementia.
- Behavioural-variant frontal dementia is a subtype where the person’s behaviour, mood or personality changes. People with behavioural-variant frontal dementia may become more apathetic, socially disinhibited or socially unaware. They often have trouble with judgement, decision making or problem solving. They might develop new behavioural habits that they do repeatedly, including eating and drinking different foods or drinks.
Read more about fronto-temporal dementia at Dementia Australia.
The Sydney University Frontier Clinic specialises in Fronto-Temporal Dementia.
Mixed dementia
People with mixed dementia have a combination of brain diseases. A common mixed dementia is a combination of Alzheimer’s disease and vascular dementia (caused by poor blood circulation in the brain). People with mixed dementia have a mixture of symptoms depending on the combination of brain diseases.
Read more about Mixed Dementia at the UK Alzheimer’s Society
Understanding more
Sometimes health professionals will refer to parts of the brain that are affected in dementia. The brain is incredibly complex and dementia may affect one part of the brain more than others. You can learn what the different parts of the brain do by going to the interactive website Brainline.
You can click on different parts of a diagram of the brain and learn what that part is responsible for and problems that may occur if that part is damaged.
