Alzheimer's Disease (AD) or senile dementia of Alzheimer's type is a disorder of loss of mental functions resulting from brain tissue changes of cause that are yet to be elucidated (at least two genes predisposing to AD have been identified). The main characteristic of AD is memory loss. Alzheimer's disease is also manifested in behavorial changes, like sudden periods of defiance, abusive behavior, 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. The symptoms of the disease were first identified by Alois Alzheimer in 1906.
These changes include loss of brain tissue cells (with a typical upward progression through memory centers such as the EC and the hippocampus) and collection of specific inclusions such as neurofibrillary 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). Alzheimer's disease is the most frequent reason for dementia in the elderly and constitutes almost half of all patients with dementia. There is no known definitive treatment.
There are ongoing tests of Alzheimer's disease vaccine. First results are promising. In the future it can be of use in families with history of Alzheimer's Disease.
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)