Dementia

Dementia (from the Latin de mens—from the mind) is not a specific disease itself, but rather a group of psychological and behavioral symptoms associated with a variety of diseases and conditions that affect the brain (Rabins, Lyketsos, and Steele 1999). Generally, dementia is characterized as the loss or impairment of mental abilities. With dementia, these cognitive losses (e.g., in reasoning, memory, and thinking) are severe enough to interfere with a person's daily life. Additionally, such losses are noticeable in a person who is awake and alert—the term dementia does not apply to cognitive problems caused by drowsiness, intoxication or simple inattention (American Psychiatric Association 1994).

Although often associated with later life, the symptoms of dementia can affect people of any age. Before age sixty-five, however, the incidence of dementia is low—affecting one-half to 1 percent of the population (Rabins et al. 1999). As people get older, the risk of dementia rises. While variation in measurement across countries makes it difficult to determine the world-wide prevalence of dementia, it is estimated that dementia affects less than 10 percent of the sixty-five-and-over population globally (Ikels 1998). In the United States, approximately 5 to 8 percent of people over the age of sixty-five suffer from dementia (Tinker 2000). For the oldest old (age seventy-five and over), the risk of dementia is much greater. Approximately 18 to 20 percent of those over the age of seventy-five have dementia and between 35 to 40 percent of people eighty-five years of age or older are affected (Ikels 1998; Rabins et al. 1999; Tinker 2000).