Dementia is the loss of mental functions such as thinking, memory, and reasoning that is severe enough to interfere with a person’s daily functioning. Rather than a disease itself, dementia is a group of symptoms caused by various diseases or conditions. They damage and kill the brain cells, which results in impairment of cognitive ability.
Dementia develops when the parts of the brain that are involved with learning, memory, decision-making, and language are affected by one or more of a variety of infections or diseases. The most common cause of dementia is Alzheimer’s disease, but there are as many as 50 other known causes. In some cases, the dementia can be treated and cured because the cause is treatable. Examples of this include dementia caused by substance abuse, combinations of prescription medications, and hormone or vitamin imbalances. In other cases, although a person may appear to have dementia, a severe depression can be causing the symptoms. This is known as pseudo dementia and is highly treatable. In most cases, however, true dementia can never be cured.
Considered a late-life illness, dementia tends to develop mostly in elders. About 5% to 8% of all people over the age of 65 have some forms of dementia, and this number doubles every five years above that age. It is estimated that as many as half of people in their 80s suffer from dementia. One of file main symptoms is memory loss, which becomes worse as the illness progresses. Subjects with mild to moderate degree of dementia may fail to find right words to name things and become more repetitive. In later stages of the condition, subjects may lose track of time and be unable to work out directions even in familiar places. Oftentimes, symptoms also include changes in personality, mood, and behavior.
Although dementia seems to be unavoidable and irreversible as one ages, there are still ways that may prevent or delay the development of dementia. For example, several studies have found that people who engage in intellectually stimulating activities, such as social interactions, chess, crossword puzzles, and playing a musical instrument, significantly lower their risk of developing dementia. Those ways may not apply to all forms of dementia, but many people are encouraged by the results of the studies and believe it will eventually become possible to prevent some forms of dementia.
【Group】46. Where is the passage most likely taken from?
(A) A guide to general pathology.
(B) A review of political philosophy.
(C) A journal of sociological studies.
(D) A report on archaeological findings.