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23 November, 2009

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Dementia - different types

Dementia is a broad term used to describe the symptoms of a large group of illnesses that cause a progressive decline in a person’s functioning. Dementia symptoms include loss of memory, intellect, rationality, social skills and normal emotional reactions.

Dementia is not a normal part of ageing
Most people with dementia are older, but it is important to remember that most older people do not get dementia. It is not a normal part of ageing. Dementia can happen to anybody, but it is more common after the age of 65 years. People in their 40s and 50s can also have dementia.

There are many forms of dementia
There are many different forms of dementia and each has its own causes. Dementia may also be a symptom that develops in the later stages of some illnesses. Some of the most common forms or causes of dementia include:

Alzheimer’s disease
Vascular dementia
Parkinson’s disease
Dementia with Lewy bodies
Huntington’s disease
Alcohol related dementia – Korsakoff’s syndrome
AIDS related dementia
Fronto Temporal Lobar Degeneration (FTLD)
Creutzfeldt-Jakob disease.

Alzheimer’s disease
Alzheimer’s disease is the most common form of dementia and accounts for between 50 and 70 per cent of all cases. It is a progressive degenerative illness that attacks the brain. As brain cells shrink or disappear, abnormal material builds up as ‘tangles’ in the centre of the cells and ‘plaques’ form outside the cells. These disrupt messages within the brain, damaging connections between brain cells.

The cells eventually die and this means that information cannot be recalled or assimilated. As Alzheimer’s disease progressively affects different areas of the brain, certain functions or abilities are lost.

Vascular dementia
Vascular dementia is the broad term for dementia associated with problems of circulation of blood to the brain. It is the second most common form of dementia. There are a number of different types of vascular dementia. Two of the most common are:

Multi-infarct dementia – caused by a number of small strokes, called mini-strokes or transient ischaemic attacks (TIA). This is probably the most common form of vascular dementia.
Binswanger’s disease (also known as subcortical vascular dementia) – associated with stroke-related changes to the brain. It is caused by high blood pressure, thickening of the arteries and inadequate blood flow.

Vascular dementia may appear similar to Alzheimer’s disease. A mixture of Alzheimer’s disease and vascular dementia can occur in some people.

Parkinson’s disease
Parkinson’s disease is a progressive disorder of the central nervous system, characterised by tremors, stiffness in limbs and joints, speech impediments and difficulty in initiating physical movements. Late in the course of the disease, some people may develop dementia. Drugs may improve the physical symptoms, but can have side effects including hallucinations, delusions and a temporary worsening of confusion and abnormal movements.

Dementia with Lewy bodies
Dementia with Lewy bodies is caused by the degeneration and death of nerve cells in the brain. The name comes from the presence of abnormal spherical structures called Lewy bodies inside the cells – it is thought these may contribute to the death of brain cells. People who have dementia with Lewy bodies tend to see things (visual hallucinations) or experience stiffness or shakiness (parkinsonism), and their condition tends to fluctuate quite rapidly, often from hour to hour or day to day. These symptoms make it different from Alzheimer’s disease.

Dementia with Lewy bodies sometimes occurs along with Alzheimer’s disease and/or vascular dementia. It may be hard to distinguish dementia with Lewy bodies from Parkinson’s disease and some people who have Parkinson’s disease develop a dementia similar to that seen in dementia with Lewy bodies.

Huntington’s disease
Huntington’s disease is an inherited degenerative brain disease that affects the mind and body. It usually appears between the ages of 30 and 50, and is characterised by intellectual decline and irregular involuntary movement of the limbs or facial muscles. Other symptoms include personality change, memory disturbance, slurred speech, impaired judgement and psychiatric problems.

There is no treatment available to stop the progression of the disease, but medication can control movement disorders and psychiatric symptoms. Dementia occurs in the majority of Huntington’s cases.

Alcohol related dementia – Korsakoff’s syndrome
Too much alcohol, particularly if associated with a diet deficient in thiamine (vitamin B1), can lead to irreversible brain damage. If drinking stops there may be some improvement.

This type of dementia is preventable. The National Health and Medical Research Council of Australia’s recommendations for the safe use of alcohol are that men should drink no more that four standard drinks daily and women should drink no more than two standard drinks daily. Development of alcohol related dementia and Korsakoff’s syndrome has not been reported in people drinking regularly at or below these levels.

The most vulnerable parts of the brain are those used for memory and for planning, organising and judgement, social skills and balance. Taking thiamine appears to help prevent and improve the condition.

AIDS related dementia
AIDS related dementia, or AIDS dementia complex (ADC), is a complication that affects some people with human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS). It is uncommon in people in the early stages of HIV/AIDS, but may increase as the disease advances. Not everyone who has HIV/AIDS will develop ADC. It is thought to affect around seven per cent of people with HIV/AIDS who are not taking anti-HIV drugs.

ADC is a complicated syndrome made up of different nervous system and mental symptoms. There are particular issues that may need to be addressed with this type of dementia, as it often affects young people. Issues to be addressed may include employment, identity and sexuality issues.

Fronto temporal lobar degeneration (FTLD)
This is the name given to a group of dementias that involve degeneration in one or both of the frontal or temporal lobes of the brain. It includes fronto temporal dementia, progressive non-fluent aphasia, semantic dementia and Pick’s disease. About 50 per cent of people with FTLD have a family history of the disease. Those who inherit it often have a mutation in the tau protein gene on chromosome 17, leading to abnormal tau protein being produced. No other risk factors are known.

Creutzfeldt-Jakob disease
Creutzfeldt-Jakob disease is an extremely rare and fatal brain disorder caused by a protein particle called prion. It occurs in one in every million people per year. Early symptoms include failing memory, changes of behaviour and lack of coordination. As the disease progresses – usually very rapidly – mental deterioration becomes pronounced, involuntary movements appear and the person may become blind, develop weakness in the arms or legs and, finally, lapse into a coma.

Deciding if it is dementia
There are a number of conditions that have symptoms similar to those of dementia. By treating these conditions, the symptoms will often disappear.
These include:

Some vitamin deficiencies and hormone disorders
Depression
Medication clashes or overmedication
Infections
Brain tumour.

It is essential that a medical diagnosis is obtained at an early stage, when symptoms first appear, to make sure that a person who has a treatable condition is diagnosed and treated correctly. If the symptoms are caused by dementia, an early diagnosis will mean early access to support, information and medication (should it be available).

How to know if dementia is inherited
This will depend on the cause of the dementia, so it is important to have a firm medical diagnosis. If there are concerns about the risk of inheriting dementia, consult with your doctor or contact Alzheimer’s Australia to speak with a counsellor. Most cases of dementia are not inherited.

The early signs of dementia
The early signs of dementia are subtle and vague, and may not be immediately obvious. However, common symptoms include:

Progressive and frequent memory loss
Confusion
Personality change
Apathy and withdrawal
Loss of ability to do everyday tasks.

Symptoms may be reduced with medication
At present there is no prevention or cure for most forms of dementia. However, some medications have been found to reduce some symptoms.

Support is vital for people with dementia and the help of families, friends and carers can make a positive difference to managing the condition.

Where to get help

Alzheimer’s Australia National Dementia Helpline Tel. 1800 100 500
Your doctor
The Cognitive Dementia and Memory Service (CDAMS) clinic – your doctor can provide details of the CDAMS closest to you
Commonwealth Carers Respite Centre Tel. 1800 059 059
Commonwealth Carers Resource Centre Tel. 1800 242 636
Aged Care Information Line Tel. 1800 500 853

Things to remember

Dementia describes a broad range of symptoms, such as loss of memory, intellect, rationality, social skills and normal emotional reactions.
There are different forms of dementia and each has its own causes.
There is currently no prevention or cure for most forms of dementia; however, symptoms may be reduced with medication.

You might also be interested in:
Alzheimer's disease - latest research.
Alzheimer's disease explained.
Carers - specialist services.
Carers - support available.
Dementia - carers and activities.
Dementia - caring for someone who lives alone.
Dementia - choosing residential care.
Dementia - communication issues.
Dementia - coping with placement.
Dementia - diagnosis and early signs.
Dementia - early planning will help.
Dementia - frontotemporal dementia with Parkinsonism-17.
Dementia - hallucinations and false ideas.
Dementia - how carers can help with dressing.
Dementia - how it affects carers.
Dementia - how to encourage healthy eating.
Dementia - managing incontinence.
Dementia - men and caring.
Dementia - risk reduction.
Dementia - safety issues.
Dementia - sexuality and intimacy.
Dementia - support services are available.
Dementia - taking care of carers.
Dementia - through all its stages.
Dementia - tips for parents and grandparents.
Dementia - tips for young people.
Dementia - when driving is dangerous.
Dementia and depression.
Dementia and memory loss.
Dementia and personal hygiene.
Dementia and sleeping problems.
Dementia and sundowning.
Dementia and travelling.
Dementia and wandering.
Dementia explained.

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