| Unprotected exposure to explosions, gunshots, and | | | | triples the risk of hearing loss. Conditions that cause |
| rock concerts, listening to music through headphones | | | | nausea or loss of appetite can increase risk of |
| turned too loud, and the din of noisy machinery can | | | | hearing loss by as much as 64 times! |
| temporarily or permanently damage hearing. Acoustic | | | | Eating fresh vegetables cuts risk of injury after |
| trauma is especially destructive of the ability to hear | | | | exposure to loud sound approximately in half, |
| high pitches, and the damage is worst when the loud | | | | light-colored vegetables offering slightly better |
| sound itself is high-pitched. | | | | protection than dark green or yellow vegetables. |
| The way loud sound damages hearing is through | | | | People who have high blood pressure or who get |
| injury to microscopic hairs called stereocilia. These | | | | colds easily are especially at risk to sudden deafness. |
| hairs lie on the surface of the organ of Corti, the | | | | High levels of thyroid hormone, low levels of |
| membrane inside the ear that vibrates so that sound | | | | antioxidants, and fever all increase acoustic damage. |
| is perceived. Every sound causes a surge of fluid | | | | There is also evidence that a high-fat "meat and |
| through the spiral channel in the inner ear known as | | | | potatoes" diet also increases risk of hearing loss |
| the cochlea. The swooshing fluids flow past the | | | | when the ear is exposed to loud noise. |
| stereocilia, and these tiny hairs in turn transmit the | | | | Pharmaceutical treatment of acoustic trauma typically |
| sensation of sound to nerves going to the brain. | | | | involves glucocorticoid (steroid) drugs. People given a |
| Low pitches can be heard even if the surge of fluid | | | | short course of steroid treatment are more likely to |
| passes through just a small part of the cochlea. The | | | | retain their ability to hear low frequencies, but they |
| highest pitches can only be heard if the surge of fluid | | | | are not more likely to be able to hear higher |
| passes all the way to the end of the cochlea. The | | | | frequencies. To protect hearing of higher pitches, a |
| stereocilia must be firmly attached to the organ of | | | | multi-pronged approach combining medicine and |
| Corti and rigid enough to be moved by the fluid for | | | | nutrition is best. |
| sound to be perceived. Since higher pitches need | | | | When is medical treatment necessary? Sometimes |
| more of the ear canal to be heard, the ability to hear | | | | acoustic trauma requires medical care, and in a few |
| higher pitches is lost first. | | | | instances acoustic trauma requires emergency care. |
| A very loud noise causes a very strong rush of fluid | | | | See your doctor when: |
| strong enough to damage the stereocilia. These tiny | | | | A child does not respond to any sound, such as a |
| hairs can be literally torn out by their roots. Even if | | | | whistle or a clap. This is a medical emergency. Go to |
| they are not, the stereocilia can experience metabolic | | | | an emergency room. |
| exhaustion trying to repair themselves. In the latter | | | | A child does not respond to sound after an earache, |
| case, the hairs swell with fluids, become limp, and | | | | headache, upper respiratory infection, or recent air |
| stop moving with the flow of fluid through the | | | | travel. This is also a medical emergency. Go to an |
| cochlea. They may adhere to each other in sticky | | | | emergency room. |
| clumps. | | | | Hearing loss is accompanied by a discharge from the |
| Damage to the stereocilia causes a threshold shift, | | | | ear, earache, dizziness, or sense that things are |
| that is, sounds have to be louder and lower to be | | | | spinning around you. You do not need emergency |
| heard at all. If the hairs have a chance to recover, | | | | care, but arrange to see your doctor as soon as |
| the threshold shift is temporary. Nevertheless, if | | | | possible. |
| there is constant exposure to noise, the stereocilia | | | | You can't hear a (regular, not digital) watch ticking |
| never get a chance to recover, and the threshold | | | | when it is held next to your ear. Arrange to see your |
| shift and related hearing loss become permanent. | | | | doctor as soon as possible. |
| Japanese researchers following over 20,000 patients | | | | You hear a ringing in both ears all the time that began |
| have found that hearing loss is more likely when | | | | after a recent exposure to a loud noise. Arrange to |
| there is fatigue or poor nutrition. Not having had | | | | see your doctor as soon as possible. |
| enough sleep before exposure to loud sound more | | | | |