Memory loss and confusion have long been recognized as possible consequences
of aging. However it was not until 1910 that the term Alzheimer's disease
(AD) was first used to describe individuals with progressive intellectual deterioration.
The condition was named in honor of Dr. Alois Alzheimer who,
in 1906, described the unique pathological findings within the brain that remain
diagnostic for Alzheimer's disease.
Our understanding of AD has evolved significantly since Dr. Alzheimer's time.
AD is now considered an age-related brain disorder caused by the injury and
death of nerve cells in particular areas of the brain. It is also now recognized
as the most common form of dementia, a term used by doctors to describe a
syndrome of multiple intellectual deficits that has many different causes.
AD is always characterized by progressive intellectual deterioration.
This includes not only memory loss, which is usually the most prominent feature
of AD, but also changes in language and visualspatial skills. For example, even
in the early stages of AD, individuals may have difficulty with word finding
in conversation or get lost in unfamiliar environments. AD is also frequently characterized by the coexistence of a variety
of psychiatric and behavioral signs, such as depression or personality changes, although these are not always present.
The initial intellectual changes of AD are usually subtle, and it may be difficult
to accurately date their precise onset. However all affected individuals eventually
become profoundly impaired and completely dependent upon others for even the
most basic activities, such as toileting. Average survival is approximately
8 to 10 years but some individuals with AD can survive more than 20 years.