Temporary and Permanent Hearing Loss

Hearing loss is a decrease in your ability to hear or understand speech and sounds around you. Hearing loss can happen when any part of the ear or the nerves that carry information on sounds to your brain do not work in the usual way. In some cases, hearing loss can be temporary. However, it can become permanent when vital parts of the ear have been damaged beyond repair. Damage to any part of the ear can lead to hearing loss.

Loud noise is particularly harmful to the inner ear (cochlea). A one-time exposure to extremely loud sounds or listening to loud sounds for a long time can cause hearing loss. Loud noise can damage cells and membranes in the cochlea. Listening to loud noise for a long time can overwork hair cells in the ear, which can cause these cells to die. The hearing loss progresses as long as the exposure continues. Harmful effects might continue even after noise exposure has stopped. Damage to the inner ear or auditory neural system is generally permanent.

Temporary and Permanent Hearing Loss

While a single exposure to loud noise can damage your hair cells, it probably won’t destroy them. You may experience ringing in your ears and some sounds may be muffled, but your hair cells will recover and so will your hearing. This is called a temporary threshold shift.

Repeated exposures to loud noise can damage hair cells to the point that they won’t recover. Because the damage is permanent, the result is called a permanent threshold shift. No treatment will restore it. When you destroy hair cells, you destroy hearing.

Exposure to Chemicals

No longer is noise considered to be the only source of hearing loss associated with work. Exposure to chemicals, like aromatic solvents, and metals, such as lead, arsenic, and mercury, can result in hearing loss.

Combined exposures to noise and chemicals can cause more hearing loss than exposure to either agent alone. Vibration and extreme heat are also potentially harmful to hearing when combined with noise.