Alzheimers Disease
Alzheimer's disease (AD) or senile dementia of Alzheimer's type is a disorder or loss of mental functions resulting from brain tissue changes; the causes are yet to be fully elucidated (mutations in at least four genes predisposing to AD have been identified).
The diagnostic characteristic of AD is development of amyloid plaque in the brain, although this can only be determined post mortem. The typical visible symptom is progressive and chronic memory loss. Alzheimer's disease is also manifested in behavorial changes, which may include confusion, disorientation, sudden periods of defiance, abusive behavior, or violence, etc. in people who have no previous history of such behavior (rarely, an affected person experiences euphoria). Thus, Alzheimer's disease presents a problem in patient management, as well.
Etiology
Associated neuropathologic changes include loss of brain tissue cells (with a typical upward progression through memory centers such as the entorhinal cortex and the hippocampus) and collection of specific inclusions such as neurofibrillary ("tau") tangles and senile plaques. It is not yet certain whether these changes are primary (the cause of the disease) or secondary (the result of the disintegration of brain tissue), although the currently dominant hypothesis assigns cause to plaque.
Some research is pursuing the possibility that it is a dietary deficiency, possibly of B vitamins, which is an underlying cause.
Whatever the mechanism, a strong epidemiological association has been shown between a diet high in fat and cholesterol and development and progress of the disease. In addition, animal feeding trials of high cholesterol and fat have demonstrated increased anatomical symptoms upon autopsied brains. This may confirm the B vitamin approach, since the hgh fat diet may be low in foods containing B vitamins.
Prevalence
Alzheimer's disease is the most frequent reason for dementia in the elderly and affects almost half of all patients with dementia.
Typically only 3% of persons aged 65 show signs of the disease while 50% of persons aged 85 have symptoms of Alzheimer's. However the proportion of persons with Alzheimer's begins to decrease after
age 85 because of the increased mortality due to the disease, and relatively few people over the age of 100 have the disease.
Diagnosis
Unfortunately, a definitive diagnosis of Alzheimer's disease must await an autopsy, at present. However, many increasingly sophisticated diagnostic tests have been proposed (including: brain scans, behavioral tests and testing for genetic predisposition).
Psychological testing generally focuses on memory, attention, abstract thinking, the ability to name objects, and other cognitive functions. However, results of psychological tests do not easily distinguish between Alzheimers Disease and other types of dementia. Psychological testing can be helpful in establishing the presence of and severity of dementia. It can also be useful in distinguishing true dementia from temporary (and more treatable) cognitive impairment due to depression or psychosis, which has sometimes been termed pseudodementia.
Treatment
There is no known definitive treatment, although there are drugs which reduce neurotransmitter degredation and delay memory loss associated with the disease. Non-steroidal anti-inflammatory drugs (including ibuprophen, acetominophen, and aspirin) seem to slow progress of the disease, according to clinical trials, but the mechanism is not understood.
There are ongoing tests of an Alzheimer's disease vaccine. Initial results in animals were
promising. However when the first vaccines were used in humans, brain inflammation resulted and the trials were stopped. It is hoped that research will provide a better formulation and that in the future it can be of use in families with history of Alzheimer's Disease.
Nutrition and Alzheimer's
Some work is being done to investigate the role of raised levels of homocysteine, and possible prevention or treatment through taking of foods high in B vitamins and antioxidants to control the levels of homocysteine.
This view is supported by Teodoro Bottiglieri, a neuropharmacologist at the Baylor Institute of Metabolic Disease in Dallas, Texas, and Andrew Mc Caddon, a researcher at the University of Wales.(See the Times newspaper, January 31 2004 "Could vitamins help delay the onset of Alzheimers?" by Jerome Burne).
A study (Archives of Neurology 2004;61:82-88) has reported that vitamins E and C might reduce the risk of Alzheimer's disease.
See also: Seshadri S, Beiser A, Selhub J, et al. Plasma homocysteine as a risk factor for dementia and Alzheimer's disease. N Engl J Med. 2002 Feb 14;346(7):476-83.
Social issues
Alzheimer's is considered to be a major public health
challenge since the average age of the industrialized world's population is increasing.
History
The symptoms of the disease as a distinct nosologic entity were first identified by Emil Kraepelin, and the characteristic neuropathology was first observed by Alois Alzheimer in 1906. In this sense, the disease was co-discovered by Kraepelin and Alzheimer, who worked in Kraepelin's laboratory. Because of the overwhelming importance Kraepelin attached to finding the neuropathological basis of psychiatric disorders, Kraepelin made the generous decision that the disease would bear Alzheimer's name (J. Psychiat. Res., 1997, Vol 31, No. 6, pp. 635-643).
The disease was thought to be uncommon, until the 1960s when it was realized that much of what had been regarded as the normal process of aging was actually the result of this disease.
See also
Familial Alzheimer disease
Famous Alzheimer's Sufferers
Referenced By
Alois Alzheimer | Disease | Diseases | E.B. White | E. B. White | Illness | Learning disability | Medical condition | Mental Retardation | Mentally retarded | Retarded
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