Dementia

Dementia (taken from Latin, originally meaning "madness", from de- "without" + ment, the root of mens "mind") is a serious loss of global cognitive ability in a previously unimpaired person, beyond what might be expected from normal ageing. It may be static, the result of a unique global brain injury, or progressive, resulting in long-term decline due to damage or disease in the body. Although dementia is far more common in the geriatric population, it can occur before the age of 65, in which case it is termed "early onset dementia".

Dementia is not a single disease, but a non-specific syndrome (i.e., set of signs and symptoms). Affected cognitive areas can be memory, attention, language, and problem solving. Normally, symptoms must be present for at least six months to support a diagnosis. Cognitive dysfunction of shorter duration is called delirium.

Especially in later stages of the condition, subjects may be disoriented in time (not knowing the day, week, or even year), in place (not knowing where they are), and in person (not knowing whom they and/or others around them are).

Dementia can be classified as either reversible or irreversible, depending upon the etiology of the disease. Fewer than 10% of cases of dementia are due to causes that may be reversed with treatment.

Some of the most common forms of dementia are: Alzheimer's disease, vascular dementia, frontotemporal dementia, semantic dementia and dementia with Lewy bodies.

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