Научная электронная библиотека
Монографии, изданные в издательстве Российской Академии Естествознания
What Is Alzheimer’s Disease? What Causes Alzheimer’s Disease?
Alzheimer’s disease is a progressive neurologic disease of the brain leading to the irreversible loss of neurons and the loss of intellectual abilities, including memory and reasoning, which become severe enough to impede social or occupational functioning. Alzheimer’s disease is also known as simply Alzheimer’s, and Senile Dementia of the Alzheimer Type (SDAT) .
During the course of the disease plaques and tangles develop within the structure of the brain. This causes brain cells to die. Patients with Alzheimer’s also have a deficiency in the levels of some vital brain chemicals which are involved with the transmission of messages in the brain – neurotransmitters.
Alzheimer’s disease is the most common form of dementia. The disease gets worse as it develops – it is a progressive disease. There is no current cure for Alzheimer’s, although there are ways of slowing down its advance and helping patients with some of the symptoms. Alzheimer’s is also a terminal disease – it is incurable and causes death.
According the National Institute on Aging, there are estimated to be between 2,4 million and 4,5 million Americans who have Alzheimer’s. There are approximately 417,000 people in the UK with Alzheimer’s, according to the Alzheimer’s Society.
Why the name Alzheimer’s disease?
Aloysius Alzheimer was a German neuropathologist and psychiatrist. He is credited with identifying the first published case of “presenile dementia” in 1906, which Kraepelin later identified as Alzheimer’s disease – naming it after his colleague.
In 1901, while he worked at the city mental asylum in Frankfurt am Main, Germany, Dr. Alzheimer had a 51 year old patient called Mrs. Auguste Deter. The patient had distinct behavioral symptoms which did not fit any existing diagnoses – she had rapidly failing memory, disorientation, confusion, had trouble expressing her thoughts, and was suspicious about her family members and the hospital staff. Her symptoms progressed relentlessly. Dr. Alzheimer wrote that she once said to him “I have lost myself”.
Over the coming years Auguste Deter would take up more and more of Dr. Alzheimer’s time, to the point of almost becoming an obsession for him. The lady died in 1906 and Dr. Alzheimer, who was working at Kraepelin’s lab in Munich, had her patient records and brain sent there.
Along with two Italian doctors, Dr. Alzheimer performed an autopsy. The autopsy revealed that her brain had shrunken dramatically, but there was no evidence of atherosclerosis (thickening and hardening of the walls of the arteries). He used a silver staining technique he had learnt from ex-colleague Franz Nissl which identified amyloid plaques and neurofribrillary tangles in the brain – two hallmarks of the disease.
In November, 1906 Dr. Alzheimer gave the first lecture ever that presented the pathology and the clinical symptoms of presenile dementia together. Kraepelin started using the term Alzheimer’s disease, which by 1911 was being used throughout Europe and by European doctors when diagnosing patients in the USA.
Fairly recently, Dr. Alzheimer’s findings were reevaluated when his original microscope preparations on which he based his description of the disease were rediscovered in Munich.
A researcher from Prague, Oskar Fischer, and a contemporary of Dr. Alzheimer’s, may have described the pathology of dementia in greater depth than did Alzheimer himself, say Czech scientists who have been digging through historical archives in Prague.
What are the symptoms of Alzheimer’s disease?
Doctors say Alzheimer’s disease can sometimes be tricky to diagnose because each patient has unique signs and symptoms. Several of the signs and symptoms present in Alzheimer’s disease also exist in other conditions and diseases.
Alzheimer’s disease is classified into several stages. Some doctors use a 7-stage framework, while others may use a 4, 5 or 6-stage one.
A common framework includes
1. Pre-Dementia Stage.
2. Mild Alzheimer’s Stage.
3. Moderate Alzheimer’s Stage.
4. Severe Alzheimer’s Stage.
Most patients take from 8 to 10 years to progress through all stages. However, some may live for 20 years after neuron changes first occur.
Alzheimer’s disease and life expectancy
The main reason Alzheimer’s disease shortens people’s life expectancy is not usually the disease itself, but complications that result from it. As patients become less able to look after themselves, any illnesses they develop, such as an infection, are more likely to rapidly get worse. Caregivers will find it harder and harder to identify complications because the patient becomes progressively less able to tell if he/she is unwell, uncomfortable, or in pain. Pneumonia and pressure ulcers are examples of common complications which may lead to death for people with severe Alzheimer’s disease.
What are the causes or risk factors of Alzheimer’s Disease?
Although a great deal of research has been done and is currently being done on the possible causes of Alzheimer’s, experts are still not sure why the brain cells deteriorate. However, there are several factors which are known to be linked to a higher risk of developing the disease. These include:
- Age
After the age of 65 the risk of developing Alzheimer’s doubles every five years. Although Alzheimer’s is predominantly a disease that develops during old age, some younger people may also develop the condition. According to the Canadian Medical Association Journal the risk of developing Alzheimer’s is as follows:
? Ages 65–74, 1 in 100
? Ages 75–84, 1 in 14
? Age over 85, 1 in 4.
Family history
People who have a close family member who developed Alzheimer’s have a slightly higher risk of developing it themselves – just a slightly higher risk, not a significantly higher risk. Only about 7 % of all cases are associated with genes that cause the early onset inherited familial form of the disease. Among those who do inherit the condition, it may start at an earlier age.
Down’s syndrome
People with Down’s syndrome have an extra copy of chromosome 21, which contains a protein that exists in the brain of people with Alzheimer’s. As people with Down’s syndrome have a larger amount of this protein than others, their risk of developing the disease is greater.
How is Alzheimer’s diagnosed?
A doctor can diagnose most cases of Alzheimer’s. However, nobody can be 100 % sure until after death, when a microscopic examination of the brain detects plaques and tangles. There is no basic testing, such as a blood test, urine test, biopsy, or image scan for diagnosing Alzheimer’s disease. A brain scan may help identify changes in the brain.
What is the treatment for Alzheimer’s disease?
Alzheimer’s is a terminal disease. This means it has no cure and will end in death. However, there are various medications which can help slow down the progression of the disease, and others that can improve the signs and symptoms, such as sleeplessness, wandering, depression, anxiety and agitation.
The doctor may prescribe the following medications to help slow down the disease:
Neurotransmitters – A neurotransmitter is a chemical that transmits neurologic information from one cell to another. Without neurotransmitters our nervous system, which includes the brain, would not work. We would be paralyzed, blind, with no thoughts, no movement – we would be dead.
Match the terms with their definitions
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irreversible |
not able to be reversed; not able to be revoked or repealed; irrevocable |
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Terminal disease |
terminating in death |
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reasoning |
the act or process of drawing conclusions from facts, evidence, etc |
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neurotransmitter |
a chemical by which a nerve cell communicates with another nerve cell or with a muscle |
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tangle |
a confused or complicated mass of hairs, lines, fibres, etc., knotted or coiled together |
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plaque |
any small abnormal patch on or within the body |
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life expectancy |
the statistically determined average number of years of life remaining after a specified age for a given group of individuals |
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complication |
a disease or disorder arising as a consequence of another disease |
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Pressure ulcer |
a chronic ulcer of the skin and underlying tissues caused by prolonged pressure on the body surface of bedridden patients |
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agitation |
a state of excitement, disturbance, or worry |
Say if these statements are true or false
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true |
false |
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1. During the course of the disease plaques and tangles develop within the structure of the brain. |
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2. Alzheimer’s disease has nothing in common with dementia. |
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3. Alzheimer’s is also a terminal disease – it is incurable |
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4. Pneumonia and pressure ulcers are examples of common complications which may lead to death for people with severe Alzheimer’s disease. |
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5. Alzheimer’s disease does not shorten people’s life expectancy |
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6. After the age of 65 the risk of developing Alzheimer’s doubles every two years. |
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7. Several of the signs and symptoms present in Alzheimer’s disease also exist in other conditions and diseases |
Fill in the gaps with the appropriate words
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Deteriorate; progression; brain cells; complications; severe; plaques; inherited; life expectancy; tangles |
1. Although a great deal of research has been done and is currently being done on the possible causes of Alzheimer’s, experts are still not sure why the brain cells …
2. Only about 7 % of all cases are associated with genes that cause the early onset … familial form of the disease.
3. Nobody can be 100 % sure until after death, when a microscopic examination of the brain detects … and …
4. There are various medications which can help slow down the … of the disease, and others that can improve the signs and symptoms, such as sleeplessness, wandering, depression, anxiety and agitation.
5. The main reason Alzheimer’s disease shortens people’s … … is not usually the disease itself, but … that result from it.
6. Pneumonia and pressure ulcers are examples of common complications which may lead to death for people with … Alzheimer’s disease.
7. During the course of the disease plaques and tangles develop within the structure of the brain which causes … … to die.