Occupational Hearing Loss

Alternate Names : Noise-Induced Hearing Loss, Acoustic Trauma

What are the signs and symptoms of the condition?

The person with occupational hearing loss may have a feeling of fullness in the ears. Sounds may seem muffled. He or she cannot hear very well, especially at high frequencies. There is usually a high-frequency ringing in the ears.

Most people recover their hearing completely within 24 to 48 hours. However, even when hearing returns, hair cells are permanently damaged. People who are exposed to noise repeatedly over a long time will have those noise injuries build up. The result is a hearing loss at high frequencies that slowly gets worse. These people may not even be aware that anything is wrong with their hearing.

Some sounds are so loud that high-frequency hearing is immediately and permanently lost. Examples include explosions, artillery fire, fireworks, and gunshots. Some people seem to be more prone to injury from noise exposure. The same noise that causes hearing loss in them may present no difficulty for others. Hearing that does not return after an acute noise injury is called a permanent threshold shift.