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A Close Look at Noise Induced Hearing Loss In the United States, the most prevalent work related injury is the noise induced hearing loss (NIHL). As the name indicates, NIHL is the result of exposure to loud noise that is too loud or that lasts a long time. Exposure to loud noise causes permanent damages to the hair cells that help in hearing. Hair cells are actually small sensory cells, which converts sound energy to electrical signals that travel to the brain. When no ear hearing protection devices are used it would lead to permanent hearing loss prevention. Types of Noise Induced Hearing Loss People can suffer from NIHL due to one- time exposure to loud noise or repeated exposure to loud noise over a long period of time. The most susceptible are musicians, mine workers, construction workers, factory workers, disc jockeys and so on. Hence, NIHL are of two types NIHL due to Acoustic trauma It refers to permanent ear damage due to single exposure to loud noise such as gunfire, explosions, firecrackers and so on. Gradually developing NIHL It refers to permanent ear damage due to frequent exposure of loud noise for a long time. Occupational Permissible Exposure Limit As per Occupational Safety and Health Administration (OSHA) guidelines, the occupational permissible exposure limit for workers is 85 decibels for 8 hours per day. An exposure, more than 8 hours could result in permanent hearing loss. Gradually developing NIHL depends a lot on the intensity of the sound and duration of exposure. Every increase of 3 decibels doubles the intensity of sound and therefore the duration of exposure should be cut down to half. That means maximum exposure to 88 decibels would be 4 hours a day. Symptoms of NIHL Ear pain and discomfort Exposure to loud noise causes ear discomfort and pain which eases after sometime. Temporary threshold shift Exposure to loud noise results in temporary hearing loss in some people. Normally people regain hearing after 16 to 48 hrs. Ringing ears or buzzing sound in the ear

Exposure to loud noise results in Tinnitus or ringing ears. Those suffering from Tinnitus would feel a constant or intermittent ringing noise in the ears causing great distress. Inability to hear in a noisy environment People find it difficult to differentiate sound from background noise. Hence they are unable to hear soft sounds in a noisy environment. If no preventive measures or proper treatment are taken it would lead to permanent hearing loss. Preventive Measures NIHL is preventable unless and until people take precautionary measures. The following are some of these measures Identify the noises that can cause great damage Avoid hazardous sound environment When working in noisy environment wear hearing protection devices such as noise cancelling ear muffs, ear plugs and so on


Use communication headset in order to have normal conversation in noisy environment When listening to loud noise, take 15 minutes quiet breaks every 2 hrs.

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A Close Look at Noise Induced Hearing Loss