Memory DisordersDementia refers to a progressive decline in memory and other cognitive functions related to several different causes including Alzheimer’s disease. Dementia itself is not a disease; it is a symptom of an underlying brain disorder. There are many possible causes of dementia, some of which can be eliminated with proper diagnosis and treatment, particularly if the cause is found promptly. Other forms of dementia may be managed with specific treatments. There are many different forms of dementia. The two most common causes of dementia are Alzheimer’s disease and vascular dementia.