ABSTRACT
Dementia is a multifaceted cognitive impairment that involves memory, language, and reasoning. In many dementia patients, behavioral disturbances are also present. About one half to two thirds of all cases of dementia are due to Alzheimer’s disease (AD). The prevalence of dementia increases drastically with advancing age; 3.5% of all persons over age 65 may be demented, whereas among those over age 85, the prevalence is 20 to 30% or even higher — up to 50% of those 85 years or older.
