Hearing loss at high frequencies may lead to deafness. The frequency of sound that can be perceived by the human ear is usually 20-20,000Hz, and the usual speech frequency is within 500-2000Hz. In clinical terms, frequencies above 1000Hz are classified as high frequency, and high frequency hearing loss is itself high frequency sensorineural deafness. Some people with high frequency hearing loss, in the early speech is not felt deafness, for example, long-term exposure to noise environment, such as mining, plant, workshop workers, etc., in the routine occupational health examination, will find the typical high frequency hearing threshold decline above 4000Hz. With the developmental changes over time, it will gradually ripple toward speech frequencies and eventually lead to significant deafness, affecting verbal communication.