Date: 6 July 2006
What is Dementia?
Dementia is the loss of mental functions -- such as thinking, memory, and reasoning -- that is severe enough to interfere with a person's daily functioning. Dementia is not a disease itself, but rather a group of symptoms that are caused by various diseases or conditions. Symptoms can also include changes in personality, mood, and behavior. In some cases, the dementia can be treated and cured because the cause is treatable. Examples of this include dementia caused by drugs or alcohol, or hormone or vitamin imbalances. In some cases, although the person may appear to have dementia, a severe depression can be causing the symptoms. This is known as pseudo-dementia (false dementia) and is highly treatable. In most cases, however, dementia cannot be cured.
Dementia develops when the parts of the brain that are involved with learning, memory, decision-making, and language are affected by one or more of a variety of infections or diseases. The most common cause of dementia is Alzheimer's disease, but there are as many as 50 other known causes. Most of these causes are very rare.
Because some causes of dementia can be cured or partially treated, it is very important that your doctor is thorough when making the diagnosis, so as not to miss potentially treatable conditions. The frequency of "treatable" causes of dementia is believed to be about 10%.
Causes of Dementia?
There are several things which could cause dementia:
Diseases that cause degeneration or loss of nerve cellsin the brain such as Alzheimer's, Parkinson's and Huntington's.
Diseases that affect blood vessels, such as stroke, or multi-infarct dementia, which is caused by multiple strokes in the brain.
Toxic reactions, like excessive alcohol or drug use.
Nutritional deficiencies, like vitamin B12 and folate deficiency.
Infections that affect the brain and spinal cord, such as AIDS dementia complex and Creutzfeldt-Jakob disease.
Certain types of hydrocephalus, an accumulation of fluid in the brain that can result from developmental abnormalities, infections, injury, or brain tumors.
Head injury -- either a single severe head injury or longer term smaller injuries, like in boxers.
Illness other than in the brain -- kidney, liver, and lung diseases can all lead to dementia.
Alzheimer's disease causes 50-60% of all dementias. But researchers have found that two nervous diseases, which were originally incorrectly diagnosed as Alzheimer's, are emerging as major causes of dementia: Lewy body disease and Pick's disease.
How Common Is Dementia?
Although dementia has always been somewhat common, it has become even more common among the elderly in recent history. It is not clear if this increased frequency of dementia reflects a greater awareness of the symptoms, or if people simply are living longer and thus are more likely to develop dementia in their older age.
Dementia caused by nervous system disease, especially Alzheimer's disease, is increasing in frequency more than most other types of dementia. Some researchers suspect that as many as half of all people over 80 years old develop Alzheimer's disease. Also, the increased incidence of AIDS dementia complex, which results from HIV infection, helps account for the increased dementia in recent history, although with the invention of newer and better drugs to treat HIV, the occurrence of AIDS-associated dementia is declining.
Who Gets Dementia?
Dementia is considered a late-life disease because it tends to develop mostly in elderly people. About 5-8% of all people over the age of 65 have some form of dementia, and this number doubles every five years above that age. It is estimated that as many as half of people in their 80s suffer from dementia.
Dementia due to long-term drug abuse.
Tumors that can be removed.
Subdural hematoma, accumulation of blood beneath the outer covering of the brain that results from a broken blood vessel, usually as a result of a head injury.
Normal pressure hydrocephalus.
Metabolic disorders, such as a vitamin B12 deficiency.
Hypothyroidism, a condition that results from an under-active thyroid.
Hypoglycemia, a condition that results from low blood sugar.
Non-treatable Causes of Dementia
Multi-infarct dementia (Dementia due to multiple small strokes).
Dementias associated with Parkinson's disease and similar disorders.
AIDS dementia complex.
Creutzfeldt-Jakob disease (CJD), a quickly progressing and fatal disease that consists of dementia and muscle twitching and spasm.
Other types of dementias
1. Vascular dementia
Vascular dementia is caused by diseases of the artery in the brain and can be prevented to a certain extent. Those who have diabetes mellitus, hypertension, hypercholesterolaemia and other risk factors such as smoking, obesity have a high risk of developing vascular dementia. The clinical presentation depends on the areas in the brain that have infracted or areas in the brain that have their blood supply cut off.
2. Dementia of Lewy Body
Visual hallucinations occur in about 85 % of those who have Dementia of Lewy Body. Most of their hallucinations vary from frank amusements to intense terror. They usually have partial insight as described, in that they know they can see these visions. But when the visions are terrifying then they are unable to rationalize it. They would also have features of Parkinsonism, that is tremors, gait disturbances, falls, fluctuating consciousness and also have memory problems similar to Alzheimer's disease dementia.
Most early stages of the dementing illness the patient may be seen by the psychiatrist for symptoms suggestive of depression which maybe the harbinger of a dementing illness. As the dementia progresses the depressive symptoms will disappear.
What are the most important early indications of dementia?
1. Forgetfulness with effects at work:
Most people sometimes forget names or appointments. If this happens more frequently and inexplicable states of confusion also occur, this might be an indication for a decline in memory function.
2. Difficulties with familiar activities:
People who are very busy are sometimes absent-minded and for example forget the pot on the stove. People with dementia possibly not only forget the pot on the stove but also that they have cooked at all.
3. Language problems:
Most people sometimes experience difficulties in finding the right words. Dementia sufferers often cannot remember simple words and instead they use inappropriate fillers which makes it difficult to understand the sentences.
4. Problems with spatial and temporal orientation:
A lot of people sometimes forget e.g. the day of the week or they get lost in unfamiliar surroundings. Dementia sufferers might be in their own street and no longer know where they are, how they got there and how to get home again.
5. Impaired capacity of judgement:
People not always choose clothes suitable for the weather. Dementia sufferers sometimes wear totally inappropriate clothes. For example, they wear a bathrobe while shopping or several blouses on top of each other on a hot summer day.
6. Problems with abstract thinking:
For many people running a bank account is a challenge. Dementia patients can often neither recognise numbers nor carry out simple calculations.
7. Leaving things behind:
From time to time almost everybody leaves their keys or a wallet behind. Dementia sufferers however might put things in completely inappropriate places, such as for example the iron in the fridge or a watch in the sugar bowl. Afterwards they do not remember where they put them.
8. Mood swings and behavioural changes
Everybody has mood swings. People with dementia may have very sudden mood swings, often without discernible cause.
9. Personality changes:
With advancing age the personality of most people changes a little. People affected by dementia may experience a very pronounced personality change suddenly or over a longer period of time. Somebody who is generally friendly, for example, becomes unexpectedly angry, jealous or timid.
10. Loss of initiative:
Nobody continuously works with the same motivation. Dementia patients sometimes loose the zest in their work and the interest in their hobbies completely without enjoying new activities.