Jana Vinson

Stephen F. Austin State University

February 2002


Continuous Noise-Induced HearingLoss

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In our everyday lives we hear many different sounds. Many times wehear noises that are harmful to our hearing. When we hear noises thatare too loud for a long amount of time, something calledNoise-Induced Hearing Loss can occur. In Noise-Induced Hearing Lossthe inner structures of the ear, which are very sensitive, aredamaged.

In the normal system, sound waves are transformed into electricalenergy. The sound waves are first caught by the outer ear. From theouter ear they travel to the middle ear, which leads to vibrations inthe ear drum. These vibrations are carried through three small bonesin the middle ear called ossicles. Here the vibrations are magnifiedand then carried to the inner ear. After entering the inner ear theyflow through fluid in the cochlea, the part of the ear that allowsyou to hear. The cochlea contains many hair cells which are moved bythe fluid and then signals are carried to the brain and are perceivedas sound. Different levels and variations of sounds have differentimpacts on the motion of the hair cells. Very loud noises for longamounts of time can cause damage to the hair cells, which can causeNoise-Induced Hearing Loss (NIDCD,2002).

Noise-Induced Hearing Loss can be temporary or permanent. Thesymptoms increase gradually as a person is exposed more and more tocontinuous loud noises. Sounds begin to be less clear and muffled.Sometimes a person may not even realize they have a hearing loss(NIDCD, 2002). Noise-Induced Hearing Loss can also be accompanied bypitch distortion, speech impairment and tinnitus, which causesringing in the ears (Prasher, 1998).

Noise-Induced Hearing Loss should be studied for many differentreasons. It is very important for everyone to know the risks ofhearing really loud noise for an extended amount of time. By doingresearch, we can acknowledge these risks and inform the public ofways to prevent hearing loss. Also, research can allow us to come upwith many different ways to treat Noise-Induced Hearing Loss. It isvery important for everyone who experiences these loud noises to beable to know how to prevent hearing loss, or how to get help if losshas already occurred. If there was more information and researchavailable on Noise-Induced Hearing Loss, a huge population of peoplecould prevent hearing loss, even though there are many who alreadyexperience it.

Many people all over the world experience loud noises on the job,during leisure time, or at home, and do not even realize they are atrisk for a hearing loss. Carpenters, construction workers, loggers,firemen, policemen, factory workers and many more jobs involvecontinuous loud noises. Rock stars who play many shows throughouttheir lives experience hearing loss. Symphony musicians andpercussionists are also at risk. People of all different ages are atrisk for hearing loss. Even younger people who attend concerts, go toclubs or just listen to loud music are at a risk for hearing loss. Athome, vacuum cleaners, lawn mowers, power tools, and many more itemsare used, which can also cause a loss. As you can see, there are manydifferent types of people who experience continuous loud noises andmany items that can cause hearing loss.

Approximately one-third of Americans have been affected by loudnoises (NICDCD, 2002). Many different loud noises can cause hearingloss. Usually, hearing sounds of more than 75 decibels (dB) arelikely to cause temporary hearing loss (NIDCD, 2002). To give someexamples, a jet taking off emits loudness of about 140 dB. Attendinga rock concert or using a chainsaw can give off 110 to120 dB, andstereo headphones can have a loudness of 100 dB. Conversation is notnearly as loud compared to the previous sounds, giving off a loudnessof only 60 dB. A whisper gives off only a mere 30 to 40 dB(Rabinowitz, 2000). Now that you have an idea of exactly how loudcertain sounds are, we can begin talking about when a hearing losscan originate, for example, during childhood.

The childhood years have a great impact on whether or notNoise-Induced Hearing Loss can occur. If a parent does not realizeearly in a childís life that hearing loss can be brought aboutby continuous loud noises, then there is a greater chance of damageonce a person gets older. Some types of toys made for children cangenerate enough sound to cause a hearing loss that could be permanent(Rabinowitz, 2000). Children around the world enjoy blasting theirfavorite music on the stereo. There is a chance that children wholisten to loud music often may need hearing aids later on in life(Current Health 2, 2001). In a recent study, it was found that peoplewho use portable stereos regularly and have a history of childhoodear infections can obtain a higher degree of hearing loss than fromattending rock concerts two times a month or more or working in anenvironment with a lot of noise (Napoli, 1999). A study performed inGermany showed that one out of every ten 18-year-olds may already besuffering from a hearing loss. Because of this, Germany is trying topass a law to limit the maximum stereo volume to 90 dB (Charles,1997). Some say that the problem of hearing loss in children islikely to get worse in years to come. If protection does not occur atan early age, todayís children could have more hearingproblems as they get older (Childs,2001).

Hearing loss may also occur when a person is older. There are manyjobs that involve continuous loud noises, and certain jobs involvemore noise than others. People who work in the manufacturing industryare very exposed. Some of these people are exposed to an average of85 dB or more (Nash, 2000). Often there is a lack of concern forthese workers because only a small amount of hearing impairment isapparent. There is a poor system of recording hearing on the job andhearing loss has often been underreported. Many companies that needhearing programs do not have them (Nash, 2000). There are manycompanies, however, that do follow strict regulations. TheOccupational Safety and Health Administration makes regularinspections and gathers information about employees, machines, theworking environment, employers and hearing loss on the job (OSHA,2002, sect. 3, ch. 5). Hearing Conservation Programs are alsoused to eliminate as much hearing loss on the job as possible.Hearing Conversation Programs for industrial workers must examine theworkplace to look for possible hazards, establish a training programfor employees, and monitor the program to see its effectiveness. Itis very important noise issues be addressed and that hearing programsand protectors be used in the right way or there is more of a chanceof hearing loss (Nash, 2000).

The manufacturing industry is not the only industry whereNoise-Induced Hearing Loss has a chance of occurring. Constructionworkers also experience a lot of loud noise on the job. There is notmuch information available on construction workersí exposureto loud noise, how much they use hearing protection, or how manyemployers provide Hearing Conservation Programs. There is a standardthat requires hearing protection and programs to be available toemployees exposed at or above 85 dB for an eight hour time period. Ina recent study at a construction site, it was recorded that workersexperienced noises above this level during a whole project (Lusk,1998). However, it is hard to study construction workers because theyare frequently changing job sites, which makes noise exposureirregular. The construction industry has more lenient regulationsthan other fields and does not have an organization to collect dataon noise hazards. Lusk (1998) performed a study in order to determinewhether operating engineers or carpenters experienced a greater loss.It was found that operating engineers had the most exposure to noise,use of protective devices and perceived hearing loss, whilecarpenters were the opposite. It is important to realize whenstudying Noise-Induced Hearing Loss on the job that different tradeshave different amounts of exposure to loud noise and implement theuse of hearing protection differently.

There are many different ways to prevent and treat hearing loss ina clinical sense. Wearing ear plugs or using other protective devicesis one very common way to prevent Noise-Induced Hearing Loss. Whenear plugs or other hearing protection devices are worn correctly theycan have a positive effect. If they do not fit correctly or are notworn during the whole exposure, they may not work well. There are avariety of hearing protective devices and ear plugs available on themarket so that it is possible to find the one that fits (Nash, 2000).With medical advancements, new treatments are being studied and mayend up replacing ear plugs and other protective devices. An oralsteroid drug has been used to test for hearing loss prevention butcaused too many side effects and was abandoned (Borlik, 1998). Othertreatments have been studied that have been successful. An Army-Navyresearch team came up with a treatment to prevent hearing loss. Theteam used tiny tubes and implanted them into the inner ear. On theoutside of the ear, the tube is connected to a reservoir and pumpthat releases a steroid into the inner ear. The drug coats the haircells to prevent them from damaging. So far three patients have beentreated and have regained partial hearing from this procedure(Borlik,1998). There are also other types of drugs that have beentested. A noise control pill to prevent hearing damage may be on themarket soon. The pill can control the amount of noise that isstimulated in the ear so that damage can be limited (Abdulla, 1998).It has also been found that certain neurotropins, proteins, orfree-radicals may limit noise damage when administered (Abdulla,1998).

There are many ways to prevent hearing loss without the use ofdrugs. One way to protect hearing is through sound conditioning,which involves giving a low exposure to an audible stimulus beforenoise trauma can occur. There is another process called tougheningthat can be used, which involves periodic pre-exposure to high soundlevels (Prasher, 1998). In the workplace, effective training andHearing Conservation Programs are used to reduce the risks of hearingloss. Noise-Induced Hearing Loss can be treated with hearing aids andalso counseling. By using many different hearing protection devicesand treatments, we are learning how to prevent and how to helphearing loss.

Noise-Induced Hearing Loss is being studied more now than it hasin the past. Many new treatments and therapies are being used to helphearing loss. With medical advances, we are able to study how to helphearing loss more in depth. More research should be done on childrenbecause childhood is when a hearing loss can begin. Also, moreinformation should be publicized on how much damage that everydaydevices can do. The involvement of prevention in the workplace isvery well developed and hopefully will expand to other areas such ashouseholds and everyday life.




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Charles, D. (1997). What did you say: personal stereos and clubsound systems are deafening a generation, German research suggests.New Scientist, 155 (2089), 12.

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(2002) NIDCD health information. Retrieved February 10, 2002, fromhttp://www.nidcd.nih.gov/health/pubs_hb/noise.htm.

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