Alzheimer's disease is a neurodegenerative disease that, over the course of seven to ten years, renders its sufferers unable to remember much about their lives, recognize their loved ones, engage in coordinated movement, speak properly, or use the toilet on their own. Alzheimer's disease probably does not kill people directly, but impairs their ability to take care of themselves, making them much more susceptible to other ailments and consequently leading to their death. The disease starts with a mild forgetfulness, which gets progressively worse until most of the mental faculties we associate with personality and intelligence are destroyed.

Alzheimer's disease most frequently strikes between the ages of 65 and 85, and afflicts as many as a third of all people who reach the latter end of this age range. Incidence of Alzheimer's disease among 65 year-olds is only 2-3%, but spikes to 25-50% among 85 year-olds. It is found less frequently in those older than 85, because people predisposed to Alzheimer's disease will usually have already died from it.

Because elderly people suffer from various forms of senility, it wasn’t until 1906 that Alzheimer's was identified as an independent entity with its own symptoms and pathology. Alzheimer's disease is not contagious, but emerges in people later in life based on their genetics and certain risk factors, such as smoking and inadequate exercise. Though the original cause of the disease was thought to be failure in the production of the essential neurotransmitter acetylcholine, modern experts tend to focus on the buildup of an extracellular plaque called beta amyloid.

There is no cure for Alzheimer's disease, and it is very hard to prevent once it begins to set in. Because the disease is so common, thousands of studies center on it, thousands of careers are built on it, and billions of dollars have been spent in attempts to stop it, but all of this furious activity has led to little real success. Some are hopeful that stem cell research will lead to a true cure. Others look to bacteria specialized to dissolve amyloid plaque but not surrounding tissue, which might be found in graveyards, where they have adapted over thousands of generations to digest any nutrients in decaying human brains. If Alzheimer's disease proves stubborn, we may have to wait for medical nanotechnology so that the plaque can be removed directly to target the root cause.