What is Dementia? What Causes Dementia? Symptoms of Dementia

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Main Category: Alzheimer's / Dementia
Also Included In: Neurology / Neuroscience;  Psychology / Psychiatry;  Seniors / Aging
Article Date: 13 Mar 2009 - 6:00 PDT

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The word dementia comes from the Latin de meaning "apart" and mens from the genitive mentis meaning "mind". Dementia is the progressive deterioration in cognitive function - the ability to process thought (intelligence).

Progressive means the symptoms will gradually get worse. The deterioration is more than might be expected from normal aging and is due to damage or disease. Damage could be due to a stroke, while an example of a disease might be Alzheimer's.

Dementia is a set of signs and symptoms

Dementia is a non-specific syndrome in which affected areas of brain function may be affected, such as memory, language, problem solving and attention. Dementia, unlike Alzheimer's, is not a disease in itself. When dementia appears the higher mental functions of the patient are involved initially. Eventually, in the later stages, the person may not know what day of the week, month or year it is, he may not know where he is, and might not be able to identify the people around him.

Dementia is significantly more common among elderly people. However, it can affect adults of any age.

What are the symptoms of dementia?

• Memory loss - the patient may forget his way back home from the shops. He may forget names and places. He may find it hard to remember what happened earlier on during the day.


• Moodiness - the patient may become more and more moody as parts of the brain that control emotion become damaged. Moods may also be affected by fear and anxiety - the patient is frightened about what is happening to him.


• Communicative difficulties - the affected person finds it harder to talk read and/or write.

As the dementia progresses, the patient's ability to carry out everyday tasks diminishes and he may not be able to look after himself.

Diseases that cause dementia

• Alzheimer's disease - This is by far the most common cause of dementia. The chemistry and structure of the brain of a person with Alzheimer's disease changes and his brain cells die prematurely.


• Stroke (Vascular problems) - this means problems with blood vessels (veins and arteries). Our brain needs a good supply of oxygen-rich blood. If this supply is undermined in any way our brain cells could die - causing symptoms of vascular dementia. Symptoms may appear suddenly, or gradually. A major stroke will cause symptoms to appear suddenly while a series of mini strokes will not.


• Dementia with Lewy bodies - spherical structures develop inside nerve cells. Brain cells are nerve cells; they form part of our nervous system. These spherical structures in the brain damage brain tissue. The patient's memory, concentration and ability to speak are affected. Dementia with Lewy bodies is sometimes mistaken for Parkinson's disease because the symptoms are fairly similar.


• Fronto-temporal dementia - this includes Pick's disease. The front part of the brain is damaged. The patient's behavior and personality are affected first, later his memory changes.


• Other diseases - progressive supranuclear palsy, Korsakoff's syndrome, Binswanger's disease, HIV and AIDS, and Creutzfeldt-Jakob disease (CJD). Dementia is also more common among patients who suffer from Parkinson's disease, Huntington's disease, Motor Neurone disease and Multiple Sclerosis. People who suffer from AIDS sometimes go on to develop cognitive impairment.

There are two main categories of dementia

According to most experts, there are two main categories of dementia - cortical and subcortical dementias.

• Cortical Dementia - The cerebral cortex is affected. This is the outer layer of the brain. The cerebral cortex is vital for cognitive processes, such as language and memory. Alzheimer's disease is a form of cortical dementia, as is CJD (Creutzfeldt-Jakob disease).


• Subcortical Dementia - A part of the brain beneath the cortex (deeper inside) becomes affected or damaged. Language and memory are not usually affected. A patient with subcortical dementia will usually experience changes in his personality, his thinking may slow down, and his attention span may be shortened. Dementias which sometimes result from Parkinson's disease are subcortical dementias, as are those caused by AIDS and Huntington's disease.

A patient with multi-infarct dementia will have both the cortical and subcortical parts of the brain affected or damaged.

Diagnosis of dementia

Although there are some brief tests, a more reliable diagnosis needs to be carried out by a specialist, such as a geriatric internist, geriatric psychiatrist, neurologist, neuropsychologist or geropsychologist.

The following tests are commonly used:

• AMTS (Abbreviated Mental Test Score) A score lower than six out of ten suggests a need for further evaluation.
• MMSE (Mini Mental State Examination) A score lower than twenty-four out of thirty suggests a need for further evaluation)
• 3MS (Modified Mini-Mental State Examination)
• CASI (Cognitive Abilities Screening Instrument)

It is important that the patient's score is interpreted in context with his socio-economic, educational and cultural background. The tester must also factor in the patient's present physical and mental state - does the patient suffer from depression, is he in great pain?

What is the treatment for dementia?

In the majority of cases dementia is incurable. Researchers are making inroads into treatments that may slow down dementia's progress. Cholinestaerase inhibitors are frequently administered during the early stages. Cognitive and behavioral therapies may also be useful. Several studies have found that music therapy helps patients with dementia. It is important to remember that the patient's caregiver also needs training and emotional support.

In the USA, Tacrine (Cognex), donepezil (Aricept), galantamine (Razadyne), and rivastigmine (Exelon) have been approved for the treatment of dementia caused by Alzheimer's disease - some physicians prescribe these drugs for vascular dementia as well. Selegiline, which is used for treating Parkinson's disease, has been found to slow down the progress of dementia.

In Canada, a country where two languages are spoken, English and French, researchers found that bilingual people who develop dementia do so four years later than monolingual people who develop dementia. The four year difference prevails even after factoring for such variables as cultural differences, education, employment, gender and immigration.

How common is dementia?

• United Kingdom - According to a report by the Alzheimer's Society (UK), approximately 700,000 people in the United Kingdom have dementia, out of a total population of about 61 million. Your chances of having dementia are 1 in 100 during your late 60s, this rises to 6 in 100 in your late 70s, and 20 in 100 in your late 80s. As people live longer experts predict dementia will rise significantly. According to predictions, there will be 940,000 people with dementia in the United Kingdom by 2021.


• Worldwide - According to a study published in The Lancet, approximately 24.3 million people had dementia worldwide in 2005, with 4.6 new cases every year. The number of people with dementia will double every two decades and reach 81.1 million by 2040. The rate of increase is expected to be faster in developing countries which have rapidly-growing life expectancies. (Lancet. 2005 Dec 17;366(9503):2112-7)

Sources - The Alzheimer's Society (UK), NIH, Wikipedia, The Lancet

Written by Christian Nordqvist

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