Prevalence
Alzheimer's disease is the most frequent reason for dementia in the elderly and affects almost half of all patients with dementia.

3-10% of persons aged 65 show signs of the disease, while 50% of persons aged 85 have symptoms of Alzheimer's. 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. Many increasingly sophisticated diagnostic tests have been proposed (including: brain scans, behavioral tests and testing for genetic predisposition) but these are at present used to identify or rule out possible alternative explanations of the symptoms.

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 cure, although there are drugs which reduce neurotransmitter degradation and delay the symptoms of the disease. Non-steroidal anti-inflammatory drugs (including ibuprofen, acetaminophen, and aspirin) also 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. This was based on the idea that if you could reverse deposition of amyloid you would stop the disease. 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.

Anticholinesterase-inhibition treatment is important because there is selective loss of forebrain cholinergic neurons as a result of Alzheimer's. AChE-inhibitors reduce the rate at which ACh is broken down and hence increase the prevelence of ACh in the brain (combatting the loss of ACh caused by the death of the cholinergin neurons). Here are some examples of some drugs:

tetrahydroaminoacridine (THA or Tacrine) - Modest improvement in memory and cognition in 40% of cases. Must be taken four times a day. The treatments causes nausea cramps and is hepatotoxic
donepezil - Single daily dosage, slightly less side effects than tacrine but no efficacy increase.
rivastigmine - Has shown the most effective improvement in cognition, although does also induce nausea and vomiting.
Anticholinesterase inhibitors treat symptoms but do not prevent cell death!

Nutrition and Alzheimer's
Some work is being done to investigate the role of raised levels of homocysteine, and possible nutritional 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 Alzheimer?s?" 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.

Recent studies have shown that non-steroidal anti-inflammatory drugs (NSAIDS) like Aspirin and Ibuprofen can delay the onset of Alzheimer´s disease. Presently there are also studies going on testing cholesterol-lowering drugs, so-called statins, like simvastatin etc. as a means of preventing or delaying Alzheimer´s. There seems to be a connection between the cholesterol level inside the brain cells and the deposition of toxic amyliod plaques which make the brain cells die.

Genetic and population effects
Various gene alleles have been associated with Alzheimer's disease, most notably the apolipoprotein E (ApoE) gene. ApoE normally functions to regulate cholesterol metabolism. In addition, it has recently been discovered that Chinese and North American populations differ significantly in development of full-fledged Alzheimer's from early warning symptoms. Whether the reason for this is genetic, dietary, or social has yet to be investigated.

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).

Famous Alzheimer's sufferers
Enid Blyton
Charles Bronson
Winston Churchill
Perry Como
Alfred Deakin
James Doohan
Ralph Waldo Emerson
Barry Goldwater
Rita Hayworth
Charlton Heston
Beatrice Lillie
Juliana of the Netherlands (Queen 1948 - 1980)
Burgess Meredith
Iris Murdoch
Maurice Ravel
Ronald Reagan
Sugar Ray Robinson
Margaret Rutherford
Cyrus Vance
E.B. White
Harold Wilson