Alzheimer's Overview
Alzheimer's Disease is the most common cause of dementia in older people. It's a medical condition that disrupts the way the brain works.
AD affects the parts of the brain that control thought, memory and language. Although the risk of getting the disease increases with age, it is not a normal part of aging. The cause of the disease is unknown and there is no cure.
It is estimated that currently 4 million people in the United States may have Alzheimer's disease. The disease usually begins after age 65; the risk of AD goes up with age.
While younger people may have the disease, it is much less common. About 3 percent of men and women ages 65-74 have AD and nearly half of those over age 85 could have the disease.
AD is named after Dr. Alois Alzheimer, a German psychiatrist. In 1906, Dr. Alzheimer described changes in the brain tissue of a woman who had died of an unusual mental illness.
He found abnormal deposits (now called senile or neuritic plaques) and tangled bundles of nerve fibers (now called neurofibrillary tangles). These plaques and tangles in the brain have come to be characteristic brain changes due to AD.
Symptoms include:
Initial mild forgetfulness
Confusion with names and simple mathematical problems
Forgetfulness to do simple everyday tasks, like brushing their teeth
Problems speaking, understanding, reading and writing
Behavioral and personality changes
Aggressive, anxious or aimless behavior

Information from the National Mental Health Association.