Robert L. Folmer, Ph.D.
Oregon Hearing Research Center
Mail Code NRC04
Oregon Health & Science University
3181 SW Sam Jackson Park Road
Portland, OR 97201-3098
Telephone: (503) 494-8032
Fax: (503) 494-5656
email: folmerr@ohsu.edu
web: www.dangerousdecibels.org
According to the OSHA's Occupational Noise Exposure Standard and Hearing Conservation Amendment (published in the Federal Register on March 8, 1983), if workers are exposed to excessive sound levels, "the employer shall administer a continuing, effective hearing conservation program."
Children are often exposed to excessive levels of sound
At some time in their young lives, 97% of 273 third graders surveyed by Blair et al (1996) had been exposed to hazardous sound levels. Chermak & Peters-McCarthy (1991) reported that 43% of the elementary school students in their study routinely listened to a personal stereo system or television at a loud volume. Thirty percent of the students said they sometimes participated in other noisy activities (such as shooting firearms or attending auto races); however, only 5.5% of the students ever used hearing protection while engaged in these activities. Sources of excessive sound exposure for children include loud music (Lipscomb, 1972; Meyer-Bisch, 1996), real or toy firearms (Woodford, 1973; Lipscomb, 1974), power tools (Roeser, 1980; Plakke, 1985), fireworks (Ward & Glorig, 1961; Gupta & Vishwakarma, 1989), loud toys (Axelsson & Jerson, 1985; Hellstrom et al, 1992); snowmobiles or other loud engines such as jet skis or motorcycles (Bess & Poynor, 1972).
Noise-Induced Hearing Loss (NIHL) in children
When humans of any age are repeatedly exposed to hazardous sound levels without using adequate hearing protection, the common result is noise-induced hearing loss (NIHL). Several studies have demonstrated that the prevalence of NIHL among children is increasing (Woodford & O'Farrell, 1983; Chermak & Peters-McCarthy, 1991; Montgomery & Fujikawa, 1992). Anderson (1967) reported a surprisingly high prevalence of NIHL in school-aged children more than 30 years ago. Blair et al (1996) claimed that 1% of the school age population has some degree of NIHL. Niskar et al (2001) estimated that 12.5% of all children in the United States aged 6 to 19 years have noise-induced hearing threshold shifts (NITS) in one or both ears. Studies by Weber et al (1967), Cozad et al (1974) and Hull et al (1975) all found relatively large numbers of school boys who failed hearing screenings at 4000 Hz -- an indicator of NIHL. Evidence of NIHL was also observed in Swedish (Costa et al, 1988), Chinese (Morioka et al, 1996) and French (Meyer-Bisch, 1996) children.
What are the consequences of NIHL in children?
Even though the degree of high frequency hearing loss detected in these studies was generally mild and usually not even noticed by the children involved, Lass et al (1986) warned: "the significance of the problem lies in the insidious nature of noise-induced hearing loss (NIHL) as well as the cumulative interaction between this type of loss and sociocusis. It follows then that a mild high-frequency hearing loss in a 16-year-old high school student may well deteriorate to a debilitating degree in later life. Additionally, there is another factor that could indicate that damage to the auditory system in this population is more prevalent and/or significant than might be believed from results of hearing tests." Prasher (1998) reiterated the assertion that audiometric thresholds may be normal despite substantial loss of outer and inner hair cells.
Children with high frequency hearing loss in Anderson's (1967) study had more learning difficulties and behavioral problems than their classmates who had normal hearing. Bess et al (1998) reported that, compared to their classmates with normal hearing, children with minimal sensorineural hearing loss (MSHL) scored significantly lower on the Comprehensive Test of Basic Skills; they also exhibited more behavioral problems and lower self-esteem. Thirty-seven percent of children in the study with MSHL failed at least one grade compared to the school district average of eight percent or less.
What should be done?
In response to this trend of increasing NIHL among children, numerous experts have recommended the implementation of hearing conservation education programs in schools:
"Educating students to the possible consequences of future vocational and avocational noise exposure, as well as instructing them in how to protect their hearing when exposed to noxious noise levels, may prevent further hearing loss and perhaps extensive communication problems later in life." (Cozad et al, 1974)
"The findings from this survey certainly suggest the need for some form of hearing conservation program at the high school level." (Roeser, 1980)
"Hearing-conservation programs are needed to provide students with the proper information about hearing and hearing loss, and about the protective measures to prevent hearing loss at home, in school (e.g., in industrial art classes), and at social/recreational events." (Lass et al, 1987a)
"Education on the hazards of noise is needed at all levels, and early education is particularly important." (Florentine, 1990)
"Strategies to prevent damage from sound exposure should include the use of individual hearing protection devices, education programs beginning with school-age children, consumer guidance, increased product noise labeling, and hearing conservation programs for occupational settings." (National Institutes of Health Consensus Development Conference Statement, 1990)
"Due to the rising numbers of children acquiring noise-induced hearing loss (increasingly in the elementary school years), education about the impact of excessive noise on hearing would be a worthwhile addition to the health curriculum of any school district. It is only through early and repeated education that we may reach these young people so that they may responsibly prevent permanent hearing loss." (Anderson, 1991)
"Hearing conservation programming should begin no later than third or fourth grade in order to prevent noise-induced hearing loss." (Chermak & Peters-McCarthy, 1991)
"Education regarding the potential dangers of high decibel levels for students should begin in the elementary grades." (Montgomery & Fujikawa, 1992)
"Comprehensive, age-appropriate educational programs must be developed for elementary and secondary students and their parents to acquaint them with potentially hazardous noise sources in their environment." (Brookhouser et al, 1992)
"Otolaryngologists should support efforts to provide information about NIHL as part of health education in our schools." (Dobie, 1995)
"The percentage of high-frequency hearing losses is greater in the upper grades, suggesting that hearing conservation programs should be introduced in the elementary grades." (Blair et al, 1996)
"Educate the public and especially children to practice lifetime hearing health with regular audiograms and ear protection against toxic noise." (Wheeler, 2000)
Even though children are often exposed to excessive sound levels, there are no policies requiring hearing conservation practices to be taught in our nation's classrooms. In spite of mounting evidence that the prevalence of NIHL is increasing among children -- and contrary to the recommendations of countless audiologists and other experts in the field -- basic hearing conservation information (that could prevent many cases of NIHL) remains conspicuously absent from most school curricula.
Why aren't hearing conservation practices taught in most schools?
The problem is not a lack of hearing conservation education materials and resources. The problem is not a lack of agreement among experts about what should be done. Given the paucity of hearing conservation instruction that is offered in our nation's schools, the problem is a lack of dissemination of this important information to our children.
- Lack of perpetuation of hearing conservation instruction. A relatively small number of teachers, audiologists, nurses, or trained volunteers have presented hearing conservation curricula in selected classrooms across the country. However, if the person who implemented the program retires, moves, or stops making such efforts for other reasons, hearing conservation education in those schools usually diminishes or ceases completely.
Lass et al (1987a) recommended the following: Instruction about 1) normal auditory mechanisms; 2) types of hearing loss and their causes; 3) noise and its effect on hearing; 4) warning signs of noise-induced hearing loss; and 5) specific recommendations for preventing noise-induced hearing loss. Anderson (1991) added the following topics to the list: Instruction about consequences of hearing loss and how it can affect life quality; what kinds of noises or noisy activities are most dangerous to hearing?
It is not necessary to spend exorbitant amounts of class time to cover the basics of hearing, hearing loss and hearing conservation. Teachers should be encouraged to integrate the information into existing lesson plans on hearing, sound, music, science, math, and health.
Chermak et al (1996) reported that students who received the hearing conservation message through an interactive style of instruction exhibited greater improvement on post-instruction tests than students who heard it in a more traditional lecture format. Results from a study by Bennett & English (1999) agree with this conclusion. Therefore, a hearing conservation program for children should be as interactive as possible and utilize a variety of media and activities.
What resources are available to facilitate hearing conservation instruction in classrooms?
Table 1 lists twelve organizations that produce or use a variety of materials in a comprehensive hearing conservation curriculum for school-age children.
To view Table 1 please Click Here. (Requires Adobe Acrobat)
The Crank It Down! curriculum includes construction of a sound thermometer, spaghetti and Play-doh model of stereocilia, and demonstrations of proper usage of hearing protection. The "Know Noise" video and "Unfair Hearing Test" audiocassette -- a list of 10 common words with high frequencies filtered out to simulate hearing loss -- (both available from the Sight and Hearing Association) also are used. Crank It Down! has been presented by trained guest speakers to students in second, third, fourth, and fifth grades. Presentations to students in second and third grades can be shortened and simplified by leaving out the sound thermometer and "Unfair Hearing Test" activities. Crank It Down! materials are available from the National Hearing Conservation Association.
Dangerous DecibelsTM is a hearing health education program being developed by the Oregon Hearing Research Center and the Oregon Museum of Science and Industry. Program goals are to raise public awareness about mechanisms of hearing and hearing loss, and to educate people about sources of, effects of, and how to protect themselves from hazardous levels of sound. When completed, the program will include 11 permanent museum exhibits; classroom curricula and activities for all school-age children; training and materials for teachers; epidemiological and educational research components.
HIP Talk was developed by the House Ear Institute in Los Angeles. The curriculum, originally designed for fifth- and sixth-graders, includes information about ear anatomy (illustrations are provided), environmental noise, hazardous sounds, and ways to protect hearing. Also included are separate quizzes for elementary, middle school, and high school students; the "HIP Talk" video (produced in 1992, 34 minutes); 400 pairs of foam ear plugs to distribute to students; and a form that solicits comments about the curriculum from teachers. The video is a significant component of the curriculum. Because much of the video consists of a panel discussion among musicians and a moderator, it will not hold the attention of most students. However, a brief segment of the video contains an effective simulation of hearing loss: the audio portion of a Flintstones cartoon is filtered to demonstrate mild, moderate, and severe high frequency hearing loss.
Know Noise is distributed by the Sight and Hearing Association of St. Paul, Minn. The Know Noise program includes lesson plans, activities, illustrations, and transparencies for grades three through six. Also included are the "Know Noise" video (produced in 1993, 14 minutes), the "Unfair Hearing Test" audiocassette, supplemental articles, and teacher comment forms. The main weakness of this program is the video. Although it conveys some useful information, the "Know Noise" video, like many hearing conservation videos, is dated. This problem is recognized by producers of educational materials: videos are expensive to make and they tend to go out of date quickly. If the fashions, music, and dialogue seem antiquated or "corny" to an audience of children (especially older children), these distractions tend to dilute any educational message contained in the video. However, carefully selected portions of videos that are less susceptible to this aging process (and still convey pertinent information) may be used indefinitely.
Wise Ears, one of the most complete hearing conservation curricula for children available on the Internet, is provided by the National Institute on Deafness and Other Communicative Disorders (NIDCD). Their web site includes lesson plans and activities for grades three through six, questions and answers about hearing, an interactive sound ruler, and three videos. NIDCD also distributes the video "I Love What I Hear" (produced in 1992, 8 minutes) to be used in the classroom.
Table 2 lists seventeen organizations that produce one or a few types of material (e.g., a video or printed material) designed for children or which could be adapted for use in a classroom.
To view Table 2 please Click Here. (Requires Adobe Acrobat)
Perry Hanavan's "Virtual Tour of the Ear" web site provides a comprehensive list of links to dozens of web sites that contain a variety of illustrations, photographs, micrographs, and animations of the outer, middle, and inner ear as well as auditory structures in the brain.
To encourage people to protect their ears from hazardous noise, most hearing conservation programs include some information about how the ear works and how excessive sound exposure causes permanent damage to inner ear structures. One of the fastest and most entertaining ways to convey this information is to use animations such as those in "The Hearing Video" produced by the Workers' Compensation Board of British Columbia, Canada. Portions of this fast-paced, informative, and entertaining video can be used with students of all ages. One negative aspect of "The Hearing Video" is its relatively high purchase price. A less expensive video that illustrates auditory system function and damage is "Quieting the Skies" (available from N.A.S.A. Central Operation of Resources for Educators). A much more technical, anatomically accurate and expensive video series, "Human Hearing," is being produced in four volumes by Caldwell Publishing Co., in Redmond, Wash.
Most of the other resources listed in Table 2 provide basic information (booklets, pamphlets, posters, or web sites) about hearing and the consequences of excessive sound exposure. For example, Howard Leight Industries produces posters and leaflets with photomicrographs of a normal cochlea with the caption "This is your inner ear," and a cochlea damaged by excessive sound exposure with the caption "This is your inner ear without plugs. Any questions?"
How effective are hearing conservation programs for children?
Numerous studies evaluated the effectiveness of hearing conservation programs administered in elementary schools (Chermak & Peters-McCarthy, 1991; Blair et al, 1996; Chermak et al, 1996; Bennett & English, 1999), middle schools (Lass et al, 1987b; Knobloch & Broste, 1998), and high schools (Lewis, 1989; Lerman et al, 1998; Lukes & Johnson, 1998). All these studies concluded that, compared to preinstruction responses, students' performance on hearing knowledge and noise awareness questionnaires improved significantly after they participated in hearing conservation programs.
It is much more difficult to assess potential changes in behavior that might occur as results of these programs. Knobloch and Broste (1998) reported that 87.5% of students who received hearing conservation instruction used hearing protection devices in noisy environments at least some of the time. Only 45% of students in control groups who did not receive such training reported using hearing protection in similarly noisy conditions. Studies by Lass et al (1987b), Lewis (1989), and Chermak et al (1996) all reported postinstruction increases, compared to preinstruction responses, in student intentions to protect their ears from excessive sounds.
The ultimate goal of hearing conservation education programs is to reduce the prevalence of noise-induced hearing loss among children and adults. Even if hearing conservation instruction began immediately in all of the nation's classrooms, it would take years to determine if such instruction had any effect on the prevalence of NIHL in the United States. However, every person who can be spared the debilitating consequences of NIHL (including communication difficulties, isolation, frustration, depression, or chronic tinnitus) is worth the effort.
Conclusion
Hearing conservation should receive attention and resources similar to those allocated for anti-smoking, anti-drug, teen pregnancy, and sexually transmitted disease education programs that are now presented routinely in public schools. The time is now to wage a public health campaign against NIHL, a potentially debilitating condition that, according to Dobie (1995), "is almost entirely preventable."
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This article was adapted from Folmer RL, Griest SE, Martin WH. Hearing conservation education programs for children: a review. Journal of School Health 2002;72(2):51-57.
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