Alzheimer`s disease

Alzheimer`s diseaseDementia is a progressive decrease in cognitive capacity which usually appears in the elderly people. The most common form of dementia is Alzheimer's disease which affects one fifth of people at the age of 80. It starts with the inability to recall recent events. Later, upon disease progression, other cognitive problems appear: solving abstract problems, disturbances in speech, skills and recognition. It can be detected only in an advanced stage by a series of simple mental tests.

Why should you have your DNA analysed for predisposition to Alzheimer`s disease?

The appearance of disease is linked to interrelated influence of various genes; it is a well-known fact that carriers of the apoE4 gene have an increased risk of developing Alzheimer's disease. Many loci, analysed during the genome analysis, can contribute to susceptibility to this disease with a strong genetic component.

How is dementia prevented or treated?

Traditional medicine can currently treat only the symptoms; for the near future, however, effective medicines are on the horizon which will halt the disease progression or prevent it altogether. Thus, it is useful to be aware of the possibility of your increased susceptibility to this disease. This information can aid in early detection of the disease and a successful treatment in the near future.

More detailed description about Alzheimer´s disease

The first signs of the disease are difficulties remembering recent events, while remembering events from the more distant past, e.g. from their youth, pose no difficulties to the patients. On disease progression, difficulties with speech, people recognition, fine motor tasks, spatial orientation and solving abstract problems can develop as well. Additionally and in late phase, confabulations, hallucinations and personality changes may appear.

Diagnosis

An important diagnostic criterion is the inability of an Alzheimer's patient to lead an independent life. In addition, memory loss must be present and other cognitive abilities affected. To date, there is no reliable laboratory test for diagnostic purposes available. Diagnosis can be suspected on the basis of results of simple cognitive tests, but psychological testing enables a more detailed appraisal of cognitive abilities. Imagining studies also aid in making the diagnosis. Serial magnetic resonance imaging shows progressive brain atrophy (brain shrinkage) which is most pronounced in the temporal regions of the brain.

Reasons for Alzheimer`s disease development

The cause of disease in most cases remains unknown. There are, however, some rare families where gene mutations directly responsible for the appearance of this disease have been discovered (gene encoding presenilin1, presenilin2 and APP). In the rest of the population, the appearance of this disease is linked to the influences of many genes. It has also been established that the apoE4 gene carriers have a higher risk for Alzheimer's disease, but the role of apoE4 in its development remains to be elucidated. If the patient's brain tissue is examined under a microscope, protein threads (neurofibrillary tangles) can be detected in the neurons. Protein accumulations (neuritic plaques) are dispersed throughout the brain. The changes are most pronounced in the temporal brain regions which is the area responsible for memory formation. It is not clear which entity is responsible for the reduction in cognitive abilities--the tangles, plaques or both. In addition, there are deficiencies of various chemical transmitters in the brain which are important for inter-neuronal communication. They are called neurotransmitters. Neurons communicate with each other by exchanging these substances and thereby passing information. In Alzheimer's disease, neurons that use the neurotransmitter acetylcholine are very much affected.

Prevention

The brain is like a muscle; if not actively used, it becomes stunted. Thus, intellectual activities such as playing chess, learning new languages, crossword puzzle solving and, above all, regular social interaction with family and friends are all very beneficial for they can somewhat slow down the progression of Alzheimer's disease and ameliorate its course. Moderate physical activity and pursuing sports is also recommended. Dancing is very beneficial as it requires one to acquire new movement skills and memorize dance steps, in addition to offering a chance to exercise and relax.

Effective prevention of Alzheimer's disease with medications is still not possible. In the past, a vaccine was researched that would remove neuritic plaques that form in the brain of Alzheimer's patients. Unfortunately, however, the trial had to be prematurely terminated as some of the patients got encephalitis and succumbed to it. Research is currently under way into the development of newer and cleaner vaccines.

Typically, signs of minor infarction are evident in the brain of Alzheimer's patients. Thus, it is important to treat hypertension, the increased cholesterol level and cardiac arrhythmia in old age. In addition, smoking cessation is much encouraged. All these are risk factors for a stroke that may further worsen the cognitive difficulties.

Therapy

Currently, the treatment for Alzheimer's disease is merely symptomatic; medications that prevent acetylcholine breakdown are employed to this effect. Acetylcholine is a signalling substance used by the nerve cells for communication and is in severe shortage in the brains of Alzheimer's patients. The medications act to inhibit the action of the enzyme acetylcholinesterase that normally breaks down acetylcholine; thus, the concentration of acetylcholine in the brain increases. Unfortunately, however, these medications are not very effective. They improve the patient's memory to some extent and facilitate the contact with the caretakers. Generally, they restore the patient’s mental state to about the same state that was in place 6 months prior to starting the medication.

A different mode of action is exhibited by the drug memantine which blocks glutamate receptors in the brain. Glutamate is a neurotransmitter that excites neurons. When memantine acts to block glutamate receptors, glutamate cannot bind to its receptors and thus cannot excite neurons. Memantine is approved for the treatment of moderate to severe forms of Alzheimer's dementia. A special group is comprised of medications that could prevent the development and progression of Alzheimer's disease. They act to block the enzymes beta-secretase and gamma-secretase, i.e. the enzymes that are responsible for the formation of plaques in the brain. Unfortunately, the recent clinical trials involving these drugs have been unsuccessful.

The search process for a successful drug for Alzheimer's disease is very intense. Worldwide there are currently over 200 medications for Alzheimer's disease in phase III of clinical trials. It is to be expected that a discovery of more successful medications that will significantly slow down the progression of Alzheimer's disease or even altogether prevent its appearance will come about shortly. Thus, testing for Alzheimer's disease is included in our service offerings.