Text Senility refers to great losses of intellectual capacity that occurs in old age and is【C1】______with the wide- spread loss of nerve cells and the【C2】______of brain tissue. Senility is a great decline from a previous intellectual【C3】______in an aging person. Memory is the mental capacity most 6ften affected. The memory loss may first show itself clearly in simple absentmindedness or a(n)【C4】______to forget or【C5】______things and repeal oneself in conversation.【C6】______the senility progresses, the loss of memory【C7】______in scope until the patient can no longer remember basic social and【C8】______skills or【C9】______independently. There may also be declines in the person's language skills, spatial or temporal orientation.【C10】______or other cognitive【C11】______and personality changes may also be【C12】______to see. Senility usually has a slow, gradual onset and is【C13】______common in persons over age 75. The most common【C14】______of the syndrome is Alzheimer's disease, which【C15】______for about 50 percent of all elderly persons with【C16】______mind and is hard to restore a former state. The second most common cause is vascular senility which arise from hypertension(high blood pressure)or some other vascular condition. In this type, a series of small strokes(中风)progressively destroy small【C17】______of the brain, eventually leading to senility. There is no【C18】______for Alzheimer's disease, but vascular senility can【C19】______be prevented or its【C20】______slowed by treatment of the underlying systemic vascular disorder. Among other significant causes of senility in the elderly are Huntington's chorea, Parkinson's disease, and multiple sclerosis. 【C1】