Dementia is an acquired clinical condition characterized by persistent and often progressive impairment in multiple intellectual domains, such as memory and the ability to think, reason, and use language. Dementia is most common in the elderly. The prevalence of dementia increases with age, from about 1 percent of individuals aged 65 years to approximately 30–50 percent of individuals 85 years suffering from some form of dementia. Because in the United States the number of people over the age of 65 years is expected to double by the year 2030 to approximately 70 million, the diagnosis and treatment of dementia represents a public health concern of vital and increasing importance. There are multiple causes (etiologies) of dementia, but Alzheimer’s disease (AD), vascular disease (VaD), and diffuse Lewy body dementia (DLBD) are responsible for the majority of dementia cases.