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本世纪内30岁的成人开始感到耳聋,以后每十年耳聋加重一倍和两倍.约有150O万的美国人耳聋严重,影响听声音和语言的能力.根据耳聋研究基金会的报告,在1965至1977年12年间美国耳聋病人增加了90%,共主要原因是人口日益老化和环境噪音更大了.耳聋的主要原因如下:(一)噪音:在当今机械化社会,随着年纪增长几乎没有一个人能够避免由于过度噪音引起的永久性听力损伤.约40%的美国工业呈现危险噪音水平,估计约有1千万工人患噪音聋.研究人员们发现非洲Mabaan部落中的70岁男人,由于不接触机械化社会的噪音,他们的听力与20岁的美国人的听力相等.
30-year-olds in this century are beginning to feel deaf, doubling their deafness every ten years thereafter.About 150 million Americans suffer from severe deafness that affects their ability to hear sounds and speech.According to the report of the Deaf Research Foundation, 90% increase in deafness in the United States during the 12 years between 1965 and 1977 was mainly due to an aging population and a greater environmental noise. The main causes of deafness are as follows: (i) Noise: In today’s mechanized society there is almost no About 40% of U.S. industries are exposed to dangerous levels of noise and an estimated 10 million workers are suffering from deafness. Researchers found that a 70-year-old man from the Mabaan tribe in Africa, as a result of an accidental hearing loss Without the noise of a mechanized society, their hearing is equal to that of a 20-year-old American.