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Musicians Can Protect Their Hearing
Michael Santucci, MS, CCC-A
[Abstract: Susceptibility to hearing loss from exposure to loud music can vary widely among musicians. This article describes a hearing conservation program that includes a detailed personal and family history, periodic assessment of hearing, measurement of sound levels in the work place, use of preventive measures and protective devices, and education. Med Probl Perform Art 5:136-138, 1990]
Hearing loss as an occupational hazard in the music industry is of increasing concern to musicians. Research has demonstrated that music, from orchestral to rock, has the capacity to cause permanent hearing loss.1-4 There are a number of possible causes for hearing loss other than exposure to loud sound. However, hearing loss that has resulted from working in a high sound pressure level (SPL) environment is different in one way--it can be reduced or prevented altogether with a comprehensive hearing conservation program.
Hearing conservation involves more than simply wearing ear plugs. A comprehensive hearing conservation program includes a detailed personal and family history, periodic assessment of hearing, measurement of work place sound levels, use of preventive measures, and education. An effective program should allow the professional musician to assess the risks and take preventive action in a way that is unobtrusive and takes into account the need to continue working in a high SPL environment. In addition, flexibility in accordance with the needs of the individual musician is necessary.
Case History
A comprehensive case history can assist the audiologist in isolating the specific problem areas for each musician. Questions are asked about family history of hearing loss, exposure to ototoxic drugs, and diseases of the hearing mechanism. Non-occupational exposures to sound pressure levels, such as military service and noisy recreational activities, are investigated. The number of years an instrument has been played and the direction of the sound source within the musical setting is determined. Inquiries are made about experiences with temporary threshold changes (defined as temporary decreases in hearing), tinnitus (ringing in the ears), and recruitment (intolerance for loud sounds, i.e., abnormal loudness growth) during or following exposures to loud performances.
Audiologic Assessment
Of primary importance in a successful hearing conservation program is the hearing test itself. Testing begins with a pure-tone audiogram--that is, a hearing profile displaying the softest level (threshold) at which a series of pitches (frequencies) can be heard. Thresholds can be measured through headphones (air conduction) and through an oscillator placed behind the ear on the mastoid bone (bone conduction).
Following the completion of the pure-tone audiometric profile, the ability to understand words is evaluated so that the audiologist can assess the effects of hearing loss upon communication. Impedance testing measures are employed to evaluate the function of the middle ear, including the ossicles, eardrum, and eustachian tube. Musicians whose hearing profiles warrant medical attention are referred to an otolaryngologist or otologist for a diagnosis and treatment.
The Occupational Safety and Health Administration (OSHA) mandates that a hearing test be administered after 14 hours of "quite time" away from excessive sound levels. This ensures that temporary hearing loss will not contaminate the test results. This may also be achieved by the use of an effective personal hearing protection device for the required time period before the test is administered.
The testing is repeated periodically to detect any change in hearing status. Most repeat testing is done annually. Semiannual evaluation may be recommended when the musician is exposed to very high sound levels on a regular basis. Repeated evaluation of hearing without any deterioration is the conclusive measure of success of a hearing conservation program.
Measurement of Sound Levels
In order to understand the implications of exposure to high levels of sound, it is advisable to measure the loudness levels of each musician's environment. Sound level measurement is best accomplished during rehearsals and/or performances. Whether the measurements are for an orchestral musician or member of a jazz or rock group, they can be made unobtrusively and accurately through the use of a dosimeter. A dosimeter is a small device used to measure the existing loudness (SPL) near the performer's ear. It is usually worn behind the musician's body on a belt and is equipped with a microphone that is positioned on the musician's collar. The size of both the dosimeter and the microphone is relatively small and can be used without interfering with the musician's performance.
The dosimeter accumulates information about sound levels close to the musician's ear during an actual performance. At the end of the performance, the dosimeter gives the hearing conservationist a time-weighted average of loudness level exposure measured in decibels. It also provides an integrated 60-second exposure time level, an average level during run time, the peak sound pressure level during a performance, and a percentage of dose for each musician. The most appropriate hearing protection devices can be recommended by determining the sound levels at the ear. This measurement plays an important role in the amount of attenuation required to protect each musician's hearing.
Preventative Measures
The correct and consistent use of personal hearing protective devices as well as modifications of the acoustical environment have proved to be effective in the preservation of hearing.5 Acoustical alterations include distancing musicians from the potentially dangerous sound sources and implementing the use of Plexiglass shields and personal baffles to deflect sound waves.
The proper use of hearing protective devices seems to be the most acceptable method of reducing sound levels for individual musicians. This option allows musicians to reduce the potential risk from loud sound without intruding on members of the audience or other musicians.
Commonly used over-the-counter devices are functional in the ability to protect an individual's hearing from high sound doses. The major drawback of over-the-counter ear plugs is that they reduce high frequencies more than low frequencies, which causes a muffled sound reduction that compromises the "brightness" of the music. Recent advances in hearing protective devices allow balanced attenuation with disruption of the frequency response. These devices attenuate sounds in a uniform manner. Figure 1 compares a variety of commonly used hearing protections, as well as two recent developments from Etymotic Research. The graph depicts the even attenuation of both the ER-15 and ER-20 personal hearing protective devices comparing them to the uneven attenuation of a solid custom-molded plug and a foam-type ear plug. Cotton balls are included because they are commonly seen being stuffed into the ears of misguided musicians. The protective ability of cotton is minimal at best. The quality of the ear mold impression needed to design custom devices is crucial.6 Figure 2 shows an acoustically tuned ear mold with an improper seal and undersized channel, compared with an appropriately fitted ear mold. A proper fitting ear mold impression ensures sufficient attenuation values and preferred fidelity of the attenuator.
The ear mold impression is taken following an otoscopic examination for debris or wax. Any blockage in the ear canal must be removed by an otolaryngologist or otologist before the impression is taken. Following a thorough otoscopic examination, a small cotton or foam block is placed deep into the ear canal. An impression is taken by filling the ear canal with silicone putty from a syringe. The impression must have a deep seal within the ear canal in order to reduce a phenomenon termed the "occlusion effect." To demonstrate the occlusion effect, place a finger in the ear while speaking or singing. The result is increased loudness of the voice as heard within the subject's head, especially at low frequencies. The deeper the seal of the custom ear mold, the greater reduction of the occlusion effect. This reduction seems to be more important for vocalists, and for musicians whose instruments come in contact with the face, such as the violin or saxophone.
A hearing protective device requires a certain diameter in the bore of the sound channel to maintain the balanced frequency response. Problems may arise if the ear canal is very narrow. Both a deep seal to reduce the occlusion effect and an adequate sound channel diameter for balanced attenuation may be unobtainable. In such cases, the musician needs to choose between less of an occlusion effect or more of an even frequency distribution. The advantages and disadvantages of each should be discussed. The custom hearing protections are made of soft material that conforms to and seals the ear canal. Depending on body chemistry, these materials may shrink and become less pliant with time. It is recommended that the devices be checked annually to be sure they retain the proper seal.
Reports indicate that, for the most part, hearing protective devices are both comfortable and cosmetic. The ER-15 and other custom-molded plugs have a slight cosmetic advantage over the ER-20 custom-molded plug. The ER-20 is also available in a standard size plug. These standard size devices, although convenient, rely very much on the musician's skill in inserting them properly. They are designed to be inserted deeply into the ear canal. If they become uncomfortable, they may be adjusted for comfort at the expense of improper attenuation. Custom devices can be inserted only in one way, which reduces the risks of improper use or inadequate hearing protection. It is the author's opinion that a custom-molded plug is preferable to the standard size type.
The efficiency of the devise is best determined on the results of sound level measurement. (Note that a ER-15 mold worn in high level sound environments may not be sufficient to protect one's hearing.) Studio musicians and other musicians whose settings and loudness exposure levels constantly change may not be able to benefit from sound level measures. This emphasizes the importance of serial hearing tests to determine the success of a hearing conservation program or protective device.
Education
Education should include a basic understanding of the anatomy of the ear and of the temporary and permanent effects of exposure to loud music. Musicians should be informed about factors that increase the risk of hearing loss. Proximity to the sound source, the loudness and duration (continuous or intermittent) of the music, and the reverberation time of the setting should be discussed.
Individual susceptibility to hearing loss from loud music can vary widely. One musician might be more adversely affected than another in a similar setting for reasons not fully understood at this time.
Discussion
Hearing loss is a problem that musicians may face at some point in their careers. The maintenance of a musician's hearing should be more important than the maintenance of his or her instrument. An instrument can be upgraded or replaced, but we are given only one set of ears! No man-made device can restore hearing to its full potential. The quality of what is heard is only as good as the ears that hear it.
Hearing loss caused by exposure to loud sound over prolonged periods is both subtle in onset and permanent. All musicians should be encouraged to obtain an assessment of their own personal risks based on a complete hearing evaluation and work place sound level measurements. A well administered and comprehensive hearing conservation program can maintain a high quality of hearing for those at risk.
The view that hearing loss is an inevitable physical disability associated with being a musician is incorrect. Advances in technology and the demand for more sophisticated devices now afford musicians viable choices to effectively protect their hearing with the least amount of compromise. In the author's experience, hearing protective devices have been successfully fitted for a large number of musicians from all disciplines of music. They are comfortable and provide proper attenuation with minimal disruption of the performance.
A properly developed hearing conservation program administered by an informed conservationist can dramatically reduce the hearing risks associated with exposure to high sound levels. Consequently the quality of musicians' personal and professional lives can be maintained. It is never too soon or too late to begin to conserve your hearing.
References
1. Axelsson A, Lingren f: Hearing in the classical musician. Acta Otolaryngol (Stoch) Suppl 3773, 1981.
2. Hart C, Geltman C, Santucci M, Schupbach J: The musician and occupational sound hazards. Med Probl Perform Art Vol 2:22-25, 1987.
3. Jansson E, Karlsson K: Sound levels recorded within the symphony orchestra and risk criteria for hearing loss. Scand Audiol 12:215-221, 1983.
4. Westmore G, Eversden I: Noise-induced hearing loss in orchestral musicians. Arch Otolaryngol 107:December 1981.
5. Alberti PW, Abel SM, Riko K: Practical Aspects of Hearing protection Use: New Perspective on Noise-induced Hearing Loss. New York Raven Press, 1982.
6. Killion M, DeVilviss E, Stewart J: An ear plug with uniform 15-dB attenuation. The Hear Journal, May 1988.
Reprinted from Medical Problems Of Performing Artists, Published by Hanley & Belfus, Inc., Philadelphia, PA © 1990
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