Alzheimer’s disease (pronounced AHLZ-hi-merz) is one of several disorders that cause the gradual loss of brain cells. The disease was first described in 1906 by German physician Dr. Alois Alzheimer. Although the disease was once considered rare, research has shown that it is the leading cause of dementia.

Dementia
Dementia is an umbrella term for several symptoms related to a decline in thinking skills. Common symptoms include a gradual loss of memory, problems with reasoning or judgment, disorientation, difficulty in learning, loss of language skills, and decline in the ability to perform routine tasks.

People with dementia also experience personality changes and behavioral problems, such as agitation, anxiety, delusions (believing in a reality that does not exist), and hallucinations (seeing things that do not exist).

Disorders that cause dementia
Several disorders that are similar to Alzheimer’s disease can cause dementia. These include fronto-temporal dementia, dementia with Lewy bodies, Parkinson’s disease, Creutzfeldt-Jakob disease, and Huntington’s disease. All of these disorders involve disease processes that destroy brain cells.

Vascular dementia is a disorder caused by the disruption of blood flow to the brain. This may be the result of a massive stroke or several tiny strokes.

Some treatable conditions — such as depression, drug interactions, and thyroid problems — can cause dementia. If treated early enough, this dementia may be effectively treated and even reversed.