An Overview of the Dementias
What is Dementia?
This sheet explains what dementia is, who gets it and some of its most common forms. It describes some early signs of dementia, and points out the importance of an early medical diagnosis Dementia is the term used to describe the symptoms of a large group of illnesses which cause a progressive decline in a person’s mental functioning.
It is a broad term which describes a loss of memory, intellect, rationality,social skills and normal emotional reactions.
Who gets dementia?
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 aging. Dementia can happen to anybody, but it is more common after the age of 65 years. People in their 40’s and 50’s can also have dementia.
What causes dementia?
There are different forms of dementia and each has its own causes. Some of the most common forms of dementia are:
Alzheimer’s Disease
Alzheimer’s disease is the most common form of dementia and accounts for between 50% and 70% of all cases. It is a progressive, degenerative disease that attacks the brain. In its early phases, the symptoms can be subtle such as memory loss and vagueness, taking longer to do routine tasks, or losing the point of a conversation. As the disease progresses, the changes will become more dramatic until, in the last stages, the person cannot care for themselves.
Vascular Dementia
Vascular dementia (previously known as multi-infarct dementia) is the second most common cause of dementia. This is a term associated with problems in the circulation of blood to the brain causing a deterioration of mental abilities as a result of multiple strokes, or infarcts, in the brain. A stroke refers to the death of a piece of brain tissue supplied by a blood vessel or blood vessels where it’s blood supply is blocked or interrupted. These strokes may cause damage to specific areas of the brain responsible for speech or language as well as producing generalised symptoms of dementia. As a result, Vascular dementia may appear similar to Alzheimer’s disease.
A mixture of Alzheimer’s disease and Vascular dementia is a common cause of dementia, and it can sometimes be difficult to separate the two.
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 which may include hallucinations, delusions and temporary worsening of confusion and abnormal movements.
Dementia With Lewy Bodies
A significant number of people diagnosed with dementia are found to have tiny spherical structures called Lewy bodies in the nerve cells of the brains. It is thought these may contribute to the death of brain cells. Dementia is often mild at the outset and can be extremely variable from day to day. The symptoms are the fluctuation in the condition, visual hallucinations and extreme sensitivity to classical and psychotic medications leading to marked symptoms of stiffness, tremor and restriction of movement. Dementia with Lewy bodies sometimes co-occurs with Alzheimer’s disease and Vascular dementia.
Pick’s Disease
Pick’s disease, like Alzheimer’s disease, causes progressive and irreversible decline in a person’s abilities over a number of years. It is a rare disorder of the frontal part of the brain which can be very difficult to diagnose. The disorder usually begins between 40 and 65 years of age. Disturbances of personality, behaviour and language may come before, and initially be more severe than, memory defects.
Huntington’s Disease
Huntington’s disease is an inherited, degenerative brain disease which affects the mind and body. It affects 7 in every 100,000 people in Australia. 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 changes, 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 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. This dementia is preventable. If people don’t drink, or they drink at a safe level, they don’t get it.
The most vulnerable parts of the brain are those used for memory, and for planning, organising and judgement, social skills and balance. If drinking stops here may be some improvement. Taking thiamine appears to help prevent and improve the condition.
Creutzfeldt-Jacob Disease
Creutzfeldt-Jacob disease (also known as Mad Cow Disease) is an extremely rare, fatal brain disorder caused by a prion, which is a protein particle. 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.
Is it dementia?
There are a number of conditions which give symptoms similar to those of dementia. By treating these conditions the symptoms will often disappear.
These include:
* Some vitamin and hormone deficiencies
* 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 ensure that a person who has a treatable condition is diagnosed and treated correctly.
Can dementia be 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, discuss it with a doctor, or contact the Alzheimer’s Association and speak to a counsellor.
What are the early signs of dementia?
The early signs of dementia are very 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
What can be done to help?
At present there is no prevention or cure for most forms of dementia. However, some medications and alternative treatments have been found to reduce some symptoms.
Community support is available for the person with dementia, their families and carers and can make a positive difference to managing dementia.
This publication provides a general summary only of the subject matter covered. Any person with dementia or a carer for a person with dementia should seek professional advice about the specific case. The Alzheimer’s Associations in Australia are not liable for any error or omission in this publication, even if negligent.
* Source : Alzheimer’s Australia SA Inc
