Earplug
From Wikipedia, the free encyclopedia
An earplug is a device that is meant to be inserted in the ear canal to protect the wearer's hearing from loud noises or the intrusion of water, foreign bodies, dust or excessive wind.
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[edit] Protection from water
Some earplugs are primarily designed to keep water out of the ear canal, especially during swimming and watersports. These may be made of wax or silicone which is custom-fitted to the ear canal by the wearer.
A 2003 study published in Clinical Otolaryngology, found that a cotton ball saturated with petroleum jelly was more effective at keeping water out of the ear, easier to use, and more comfortable than wax plugs, foam plugs, EarGuard, Aquafit, or EarSeal.[citation needed]
As many have advised, including Jacques-Yves Cousteau[1], ear plugs are actually harmful to divers, especially SCUBA divers. Scuba divers breathe compressed air or other gas mixtures, at a pressure matching the water pressure. This pressure is also inside the ear, but not between the eardrum and the earplug, so the pressure behind the eardrum will often burst the eardrum. Skin divers have less pressure inside the ears, but they also have only atmospheric pressure in the outer ear canal.
[edit] Hearing protection
[edit] History
The first recorded use of wax earplugs is in the Odyssey, wherein Odysseus's crew used wax earplugs to avoid being distracted by the Sirens' songs.
Current earplug material was discovered in 1967, at National Research in the USA, by Ross Gardner and his team. As part of a project on sealing joints, they developed a resin with energy absorption properties. This E-A-R material was later developed into commercial memory foam earplugs.
[edit] 'Basic' type plugs
This kind of earplug protection is often worn by industrial workers who work within hearing distance of loud machinery for long periods, and is used by the British Ministry of Defence (MoD) for soldiers to use when firing weapons. Earplugs are rated with "Noise Reduction Ratings" or NRRs (Single Number Ratings, or SNR, in the European Union), which provide a guide to the noise protection, in decibels, afforded by the device. Ratings usually spread between 26 and 33 decibels.
Most earplugs are made of memory foam, that is typically rolled into a tightly compressed cylinder (without creases) by the wearer's fingers and then inserted in the ear canal. Once released, the earplug expands until it seals the canal, blocking the sound vibrations that reach the eardrum. Other plugs simply push into the ear canal without being rolled first. Sometimes earplugs are connected with a cord to keep them together when not in use. Other common material bases for earplugs are wax or silicone, which is rolled into a ball and carefully molded to fit over the external portion of the ear canal, providing a snug custom fit for the wearer.
Other devices that provide hearing protection include electronic devices worn around and/or in the ear, designed to cancel out the loud noise of a gunshot, while possibly amplifying quieter sounds to normal levels. While rich in features, these electronic devices carry a price over one hundred times their foam counterparts.
Since they reduce the sound volume, earplugs are often used to help prevent hearing loss and tinnitus (ringing of the ears), amongst other ailments.
[edit] Musicians' or 'Hi-Fi' earplugs
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Some earplugs are manufactured to provide a direct decibel drop without affecting the user's perception of bass and treble levels. These are commonly used by musicians and technicians both in the studio and in concert to avoid overexposure to high volume levels whilst providing a good balance over the frequency range.
Musicians who perform music styles noted for their loud nature, especially rock music, often wear earplugs to prevent their own performances from damaging their hearing.
Musicians' earplugs are designed to attenuate sounds evenly across the audio band thus enabling musicians to hear clearly the upper harmonics, vocals, cymbals, and other high frequencies, but at a reduced volume level. They generally achieve this by incorporating a tiny diaphram to reduce low frequencies, together with absorbant or damping material for high frequencies, and so can be quite costly, being intended for constant re-use unlike simple earplugs which are disposable. These earplugs usually give an attenuation of only about 20dB and are not intended for protection from very high noise levels (>105 dB).
Some "Musicians" earplugs are custom made for the individual listener. This involves visiting an audiologist to undergo a hearing test and getting the molds made to send to a company who will then make the customer a custom set of molds into which different capsules can be inserted.
These different capsules will provide different levels of attenuation, usually 9, 15, and 25dB. These types of earplugs will provide the flattest attenuation and the truest isolation from outside noise, as they fit firmly into the individuals ears. They also provide much better protection from very high noise levels. This type of plugs is quite popular amongst audio engineers as they can listen to their loud mixes at an even and safe level for extended periods.
In other activities, hobby motorcyclists and skiiers may also choose to use decibel reduction earplugs, to compensate for the ongoing noise of the wind against their head or helmet.
[edit] Flight ear protection
Earplugs are available which help to protect ears from the pain caused by airplane cabin pressure changes. Some products contain a porous ceramic insert which reportedly aids equalization of air pressure between the inner and outer ear thereby preventing pain during landings and take-offs.
[edit] Health risks
Prolonged use of earplugs may cause earwax to build up and plug the outer ear, since it blocks the normal flow of earwax outwards.[2] Therefore, it is necessary to clean both the ear plugs and ears between use in cases of prolonged use, e.g. when sleeping with earplugs. Otherwise tinnitus, hearing loss, discharge, pain, and infection might arise.[2] Earplugs are washed with water and mild soap, and rinsed thoroughly with clean water and dried by air or by using a clean cloth. Earwax removal, on the other hand, can be performed in several ways. Simple movement of the jaw helps the ears' natural cleaning process, so chewing gum and talking can both help. If this is insufficient, the most common method of cerumen removal by general practitioners is syringing with warm water (used by 95% of GPs[3]). A curette method is more likely to be used by otolaryngologists when the ear canal is partially occluded and the material is not adhering to the skin of the ear canal. Cotton swabs, on the other hand, might just push the earwax further into the ear canal.
[edit] Custom molds
Noise and decibel reduction earplugs can be molded to fit an individual's ear canal. This is associated with a higher cost, but can help to reduce the discomfort typically experienced after longer use, or if the level of protection or performance is inadequate.
Pressure and flight earplug molds are less common, as they are typically not used as long as other earplugs, and are therefore less in demand.
[edit] Non-human
Earplugs are available for horses used in sports such as mounted shooting.[4]
[edit] References
- ^ The Silent World (New York:1953, Harper, pp. 5-6)
- ^ a b Columbia University - Ear plugs
- ^ Sharp, J.F., Wilson, J.A., Ross, L., Barr-Hamilton, R.M. (1990). "Ear wax removal: A survey of current practice". Br.Med.J. 301 (6763): 1251-1253. PMID 2271824.
- ^ horse earplugs on a vendor website, accessed 2008-03-02.
[edit] External links
