Medical and scientific issues: musician earplugs.
Regardless of the accuracy of these statements, the authors did not mention that current earplugs are inadequate and that they do not perform as claimed in their marketing material. The authors also failed to mention that serious concerns about these products have been reported and debated during meetings of the National Hearing Conservation Association, American Academy of Audiology, and the Performing Arts Medicine Association.
Believing that all musicians should be fully informed about these issues, this article provides additional information about this topic to the horn community. The 2010 Safe in Sound Award bestowed by the National Institute of Occupational Safety and Health recognized that hearing health is a priority at the University of North Texas. A summary of our efforts at UNT can be found in an article published in the International Journal of Audiology. (2)
All musicians should have their hearing tested on an annual basis. Starting early in one's career, routine audiometric evaluations are crucial and the only way to determine whether hearing loss exists or is being prevented.
In addition to the obvious challenges related to testing musicians attending an international music conference--one subject reported that sounds from the hallway were audible during threshold testing--musicians must understand that hearing sensitively fluctuates in response to numerous factors. A person's audiometric threshold at a given test frequency can change. Measurement variability is associated with recent sound exposures, prior audiometric experience, attention, motivation, upper respiratory problems, medications, and other factors. Therefore, musicians need to work with an audiologist to schedule testing times when life patterns are normal and sound exposures are minimal.
If test results show a threshold shift of 15 dB at any test frequency in either ear, be sure to ask the audiologist to repeat the test immediately. Testing should be conducted again within 30 days of any audiogram that continues to show a significant threshold shift. Ideally, a minimum of 12 hours of quiet should precede the confirmation audiogram to determine whether the shift is a temporary or permanent change in hearing sensitivity.
Such protocols are often mandated for regulated industries and should be used when testing musicians. Unlike the protocol used in the Brisbane report, research seeking to characterize prevalence rates for hearing loss among musicians should follow the protocols listed here.
Audiologists are aware of two types of earplugs marketed directly for musicians. Developed and trademarked by Etymotic Research as "Musicians Earplugs," the first type uses a pre-fabricated filter (ER-9, ER-15, and ER-25) that couples to the end of a custom-made mold, which has a bore. (3) These earplugs are marketed with the claim that sound is reproduced as it is normally heard, preserving the tonal balance of music. (4)
The other type, a non-custom, ready-fit version of the custom product, was jointly developed and patented by Etymotic Research with the Aearo Corporation. (5) In addition to being sold by Etymotic Research as ETY-Plugs and the ER-20 High Fidelity Hearing Protector, the same product is also marketed to musicians as the HEAROS High Fidelity Earplugs, the WestStar Earplugs ER 20, the Fender Touring Earplugs, the 3M Hi-Fi Earplug, and the Vic Firth VICEARPLUG.
Promoters encourage audiologists to sell these products directly to public school music programs through a national marketing campaign titled Adopt-a-Band. (6,7) Like their custom-fit counterparts, the ready-fit earplug is also marketed to musicians with the claim that they replicate the natural response of the ear canal so that, when sound enters the earplug, it is reproduced unchanged, exactly as the ear would hear it, only quieter. (8)
Horn Players' Use Rates
According to the study conducted during the 2010 IHS Symposium, use rates of earplugs among horn players appears to be inadequate, but some horn players may be open to beginning or increasing this use, particularly with respect to the custom-molded varieties. The authors also imply that the attitudes and habits toward hearing protectors are generally poor due to the lack of knowledge.
While this may by partially accurate, additional explanations are valid and essential to consider. For example, results from several large-scale studies suggest that musicians rate the use of these products negatively. (9-13) In addition to problems with pressure, discomfort, and even pain, musicians report that low usage rates are due to interference with their playing ability, distortion of timbre, sonority, and the dynamics of the music they and their colleagues are playing.
Musicians report difficulty monitoring their own playing, that the custom-fit musician earplugs are not better than pre-formed, and that the problems created by wearing these products are worse than the fears of hearing loss. Audiologists should explain that musicians perform differently when using custom musician earplugs as shown through pronounced effects on both the sound level and the spectral characteristics of the musical output of performing musicians. (14)
Similarly, musicians should understand that the special claims for flat attenuation (reduction of all sounds equally) are based on the Real-Ear Attenuation at Threshold (REAT) test procedure (ANSI S12.6-1997)--a subjective method of determining the attenuation of a hearing protector by subtracting the open-ear hearing threshold from the occluded ear threshold.
The REAT was designed to provide estimates obtained by listeners with normal-hearing sensitivity in a laboratory setting and based on subjective non-occluded and occluded hearing thresholds at octave frequencies ranging between 125 and 8000 Hz.
The REAT procedure is not a valid procedure for supporting the special claims used in marketing these products to audiologists, musicians, and music schools. The REAT procedure does not include music stimuli or musicians. Music is differentiated by complex spectral characteristics, most of which are concentrated in the low frequencies (i.e., < 100 Hz).
Research has shown that the REAT procedure has known limitations for accurately assessing occluded perception of frequencies below 500 Hz, due to masking by physiological noise. (15) Furthermore, our objective measurements inside the ear of KEMAR (artificial head test fixture) demonstrate that the spectral characteristics of music are indeed altered by these products, regardless of whether the earplug was the custom or non-custom type.
These findings clearly indicate that the claims used to market these earplugs to musicians and music schools are misleading. The Food and Drug Administration states that "Any manufacturer wishing to make claims regarding the acoustic effectiveness of a device, other than its noise reduction ratings, must demonstrate the validity of such claims, including the presentation of test data and the specific methods used to validate the claims" (Federal Register/Vol. 74, No 149, pg 3986). Our testing of the non-custom variety earplugs demonstrates that they do not provide the level of protection claimed.
Marketing materials disseminated by Etymotic Research report a Noise Reduction Rating (NRR) of 12 dB, but claim that the user can expect 20 dB of attenuation when the plug is used correctly. Our protocols ensured a best-fit scenario, yet found that the ER-20 provided only an attenuation level of 4.5 dB and dramatically influenced the spectral characteristics of the music stimuli.(see chart) These differences are due to accounting for the full frequency range of music and the differences in A-vs C-weighting. (16)
There is a critical need for new Noise Reduction Rating guidelines to incorporate the C-weighted scale for earplugs intended to be used by musicians.
Our findings directly challenge the integrity of the musician earplugs that are sold today. While the overwhelming data reveals flaws in the measurement process and design of these earplugs, the manufacturer continues to promote and sell its products.
As a result, it is imperative that musicians becoming aware and proactive in promoting changes to the earplug industry and to the audiology community regarding their needs--while taking the necessary precautions by limiting their exposure to loud conditions.
(1) W.J. Wilson, I. O'Brian, and A.P. Bradley. "The Audiological Health of Horn Players." Journal of Occupational and Environmental Health. 10:11, 2013, 590-596.
(2) K. Chesky, K. "Schools of music and conservatories and hearing loss prevention," International Journal of Audiology, 2011; 50: S32-S37.
(3) M. Killion, E. DeVibiss, and J. Stewart. "An Earplug with uniform 15 dB attenuation," The Hearing Journal, 41 (5), 1988, 14-17.
(4) P. Niquette. "Uniform Hearing Protection for Musicians," Hearing Loss in Musicians: Prevention and Management. Plural Publishing 2009.
(5) E. Berger, R. Falco, M. Killion, and J. Stewert. Audibility earplug. U.S. Patent 5113967 A, May 19, 1992.
(6) C. Palmer, C. "Hearing Protection of Young Musicians: Focusing on Life-Long Habits," Spectrum (a publication of the National Hearing Conservation Association), 2007, 24(3), 1, 8-9.
(9) M.F. Zander, C. Spahn, and B. Richter. "Employment and acceptance of hearing protectors in classical symphony and opera orchestras," Noise Health 2008;10:14-26.
(10) K.H. Huttunen, V.P. Sivonen, and V.T. Poykko. "Symphony orchestra musicians' use of hearing protection and attenuation of custom-made hearing protectors as measured with two different real-ear attenuation at threshold methods," Noise Health. 2011; 13:176-88.
(11) H. Laitinen. "Factors affecting the use of hearing protectors among classical music players," Noise Health 2005;7:21-9.
(12) Kris Chesky, Maria Pair, Eri Yoshimura, and Scott Landford. "An Evaluation of Musician Earplugs with College Music Students," International Journal of Audiology. 2009;73(6):785-92.
(13) M.H. Mendes, T.C. Morata, and J.M. Marques. "Acceptance of hearing protection aids in members of an instrumental and voice music band, Rev Bras Otorrinolaringol. 2007;73(6):785-92.
(14) Emil Kozlowski, Jan Zera, and Rafal Mhyhski. "Effect of Musician's Earplugs on Sound Level and Spectrum During Musical Performances," International Journal of Occupational Safety and Ergonomics, 2011; 17(3): 249-254.
(15) E.H. Berger. "Methods of measuring the attenuation of hearing protection devices," Acoust. Soc. Am. 1986; 79,1655.
(16) Lee D. Hager. "Hearing Protectors 2009: Rating, Evaluation and the NRR," EHS Today. (2009).
Kris Chesky is an associate professor in the University of North Texas College of Music and director of the Texas Center of Music and Medicine.. He is a graduate of Berklee College in Boston and UNT in trumpet and jazz. In addition to earning a doctorate, he has published numerous studies related to the occupational health of musicians. Amyn M. Amlani, Ph.D., is an Associate Professor on the faculty of the Department of Speech and Hearing Sciences, University of North Texas. Dr. Amlani holds the B.A. degree in Communication Disorders from the University of the Pacific, the M.S. degree in Audiology from Purdue University, and the Ph.D. degree in Audiology from Michigan State University.
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|Author:||Chesky, Kris; Amlani, Amyn|
|Publication:||The Horn Call|
|Date:||Feb 1, 2014|
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