Alzheimer's disease
Dementia is a chronic state of confusion in which the patient finds it hard to remember, learn, and communicate.
There is a gradual impairment of memory and association with previously acquired brain functions.
The most common cause of dementia occurring in patients over 45 yrs of age is Alzheimer's disease.
There are several suspected causes of Alzheimer's including chemical and genetic theories.
Studies have shown an impairment of various neurotransmitters including acetyl choline in Alzheimer's patients.
It is also characterized by the formation of senile plaque involving the accumulation of beta amyloid, and abnormal neurofibrillary tangles.
Beta amyloid is derived from a larger molecule called amyloid precursor protein (APP). APP is normally present on the cell surfaces and the cleavage of APP results in the formation of beta amyloid.
Neurofibrillary tangles consist of insoluble twisted fibers that are found inside of the brain's cells. They primarily consist of a protein called tau, which forms part of a structure called a microtubule. In Alzheimer's the tau protein is abnormal and the microtubule structures collapse.
Recent drugs like inhibitors of cerebral acetylcholine esterase have been shown to be of some benefit to Alzheimer's patients. | 
