| 翻訳と辞書 |
| Noise-induced hearing loss ： ウィキペディア英語版 |
Noise-induced hearing loss
Noise-induced hearing loss (NIHL) is hearing impairment resulting from exposure to high decibel (loud) sound that may exhibit as loss of a narrow range of frequencies, impaired cognitive perception of sound or other impairment, including hyperacusis or tinnitus. Hearing may deteriorate gradually from chronic and repeated noise exposure, such as loud music or background noise, or suddenly, from an acute, high intensity noise incident including gunshots and airhorns. In both types, lound sound overstimulates delicate hearing cells, leading to the permanent injury or death of the cells. Once lost, hearing cannot be restored in humans. There are a variety of prevention and mitigation strategies available to avoid or reduce hearing loss. If not prevented, hearing loss can be managed through assistive devices and cognitive therapies.
Prevention is the single defense against Noise Induced Hearing Loss. The best, first option for protecting hearing is (lowering the volume of sound at its source ). Secondly, limiting the time of exposure to loud noise can reduce injury. Finally, physical protection from the noise can reduce its impact. Government regulations are designed to limit occupational exposure to dangerously loud noise. The largest burden of NIHL, has been through occupational exposures; however, noise-induced hearing loss can also be due to unsafe recreational, residential, social, and military service-related noise exposures. It is estimated that 15% of young people are exposed to sufficient leisure noises (i.e. concerts, sporting events, daily activities, personal listening devices, etc.) to cause NIHL. There is not a limited list of noise sources that can cause hearing loss. Rather, it is important to understand that excessive decibel levels of any source over time can cause hearing loss.
==Mechanisms==
NIHL occurs when too much sound intensity is transmitted into and through the auditory system. An acoustic signal from a sound source, such as a radio, enters into the external auditory canal, and is funneled through to the tympanic membrane (eardrum). The tympanic membrane acts as an elastic diaphragm driving the ossicular chain of the middle ear system into motion. The middle ear ossicles transfer mechanical energy to the cochlea by way of the stapes footplate hammering against the oval window of the cochlea. This hammering causes the fluid within the cochlea (perilymph and endolymph) to push against the stereocilia of the hair cells, which then transmit a signal to the central auditory system within the brain. Different groups of hair cells are responsive to and conductive of different frequencies. There are two known biological mechanisms of NIHL from excessive sound intensity; damage to the hair cells and damage to the myelination or synaptic regions of auditory nerves.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Noise-induced hearing loss」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|