What is Alzheimer's disease?

Alzheimer's disease is a form of dimentia that is rapidly increasing across the world. Dimentia is a "decline in cognitive function or mental ability - thinking, reasoning, and remembering." (1). 
Alzheimer's disease is the most common form of dimentia and although the disease can sometimes be managed, it is irreversible.

"Progressive mental deterioration in old age has been recognized and described throughout history. However, it was not until 1906 that a German physician, Dr. Alois Alzheimer, specifically identified a collection of brain cell abnormalities as a disease. One of Dr. Alzheimer’s patients died after years of severe memory problems, confusion and difficulty understanding questions. Upon her death, while performing a brain autopsy, the doctor noted dense deposits surrounding the nerve cells (neuritic plaques). Inside the nerve cells he observed twisted bands of fibers (neurofibrillary tangles). Today, this degenerative brain disorder bears his name, and when found during an autopsy, these plaques and tangles mean a definite diagnosis of Alzheimer's disease" (2)

Sources:

 1. http://www.ahaf.org/alzheimers/about/understanding/adanddementia.html (Alzheimer's disease research)

2. http://www.ahaf.org/alzheimers/about/understanding/history.html (Alzheimer's disease research)