The National Institute on Aging stated in its Mar. 2006 booklet Understanding Alzheimer's Disease:

“Alzheimer’s disease is an illness of the brain. It causes large numbers of nerve cells in the brain to die. This affects your ability to remember things and think clearly. Doctors don’t know what causes the disease. They do know that it usually begins after age 60 and nearly half of people age 85 and older may have Alzheimer’s. However, it is not a normal part of aging…

There are medicines that can treat the symptoms of Alzheimer’s. However, there is no cure. Some medicines keep your memory loss and other symptoms from getting worse for a time. These medicines work best if Alzheimer’s disease is found early. Other medicines work to help you sleep better or feel less worried and depressed. These medicines don’t directly treat the disease. They do help you feel more comfortable.”

Mar. 2006