REVIEW URRENT C OPINION

Noise-induced hearing loss: a recreational noise perspective Robert Ivory, Rebecca Kane, and Rodney C. Diaz

Purpose of review This review will discuss the real-world risk factors involved in noise-induced hearing loss as a result of common and popular recreational activities prone to mid and high levels of noise exposure. Although there are currently no interventional measures available to reverse or mitigate preexisting hearing loss from noise, we discuss the vital importance of hearing loss prevention from noise exposure avoidance and reduction. Recent findings Despite a seeming understanding of the effects of noise exposure from various recreational activities and devices, a large percentage of the general public who is at risk of such noise-induced hearing loss still chooses to refrain from using hearing protection instruments. Summary While occupational exposures pose the greatest traditional risk to hearing conservation in selected workers, recreational risk factors for noise-induced hearing loss may be more insidious in overall effect given the indifferent attitude of much of the general public and particularly our youths toward hearing protection during recreational activities. Active counseling regarding the consequences of excessive noise exposure and the potential benefits to hearing from usage of hearing protection instruments is critical to providing best possible care in the hearing health professions. Keywords decibel, firearms, hearing protection, impulse noise, noise-induced hearing loss, permanent threshold shift, personal listening device, recreational noise exposure, temporary threshold shift

INTRODUCTION It is well established that high levels of sound can result in a damaged auditory system and hearing loss in animals and humans [1–3]. It has also been established that there is a relationship between damage and the intensity of the sound as well as the duration of exposure [4–6]. This has led to the formulation of damage risk criteria designed to help provide guidance for limits of exposure. Both the National Institute for Occupational Safety and Health and the Occupational Health and Safety Administration (OSHA) have damage risk criteria that differ by start and trade off [7]. Noise exposure is often thought in terms of occupational hazard; however, there are many recreational activities that can expose individuals to hazardous levels of noise. Sources of recreational noise exposure include target shooting, hunting, loud entertainment venues such as sporting events, loud music, and motorized sporting such as road racing, drag racing, and snowmobiling, with www.co-otolaryngology.com

firearms exposure being the recreational activity, type of highest risk to induce permanent hearing loss [1]. The potential harm from recreational noise exposure does not seem to garnish the same degree of concern by the general population as workrelated noise exposure. This is best evidenced by recent literature and even more alarmingly public competitions at national sporting events to break world noise records [8]. Would such a cavalier approach be welcomed by factory owners competing to ratchet up machine noise in factories? This Department of Otolaryngology – Head and Neck Surgery, University of California Davis Medical Center, Sacramento, California, USA Correspondence to Rodney C. Diaz, MD, Department of Otolaryngology – Head and Neck Surgery, University of California Davis Medical Center, 2521 Stockton Boulevard #7200, Sacramento, CA 95817, USA. Tel: +1 916 734 1051; e-mail: [email protected] Curr Opin Otolaryngol Head Neck Surg 2014, 22:394–398 DOI:10.1097/MOO.0000000000000085 Volume 22  Number 5  October 2014

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Recreational noise-induced hearing loss Ivory et al.

KEY POINTS  Recreational sources of noise and excessive sound exposure can place patients at equal risk of noiseinduced hearing loss as can occupational sources of noise, given equivalent loudness and time exposures.  Despite a general awareness of the potential for noiseinduced hearing loss, many people exposed to significant recreational noise exposure choose to refrain from appropriate usage of HPDs.  Active patient counseling regarding the benefits of HPDs and reduction in exposure to excessive sound volume and duration from PLDs can have a beneficial impact on patients’ long-term hearing health.

review will focus on recent literature exploring the hazards posed by different aspects of recreational noise exposures, including identifying recreational noise sources both expected and unexpected, firearms, personal listening devices (PLDs) as well as education and prevention studies.

SPORTS AND SPORTING VENUES Cranston et al. [9] provided a study that bridged occupational and recreational noise exposure. The study evaluated sound noise exposure levels for workers and vendors, as well as fans in small nonprofessional indoor sports arenas. The authors identified three sources of possible hazardous noise sources as follows: first, enhanced reverberant conditions from enclosed environment, second, public address (PA) system needing to be louder than environment, and third, design and building materials could exacerbate the noise. The study used personal dosimeters worn by both workers and fans and area noise monitors to evaluate exposure levels in both venues. Noise monitor measurements for both venues recorded peak levels of 105–124 dBA with equivalent continuous sound pressure levels 81–96 dBA, and 110–117 dBA with equivalent continuous sound pressure levels 85–97 dBA. In neither venue did the workers or fans exceed OSHA noise limits. However, between 40 and 57% of workers and 33 and 91% of fans did exceed American Conference of Governmental Industrial Hygienists (ACGIH) limits. The difference between the two criteria is that OSHA uses permissible exposure limits of 90 dBA for a time-weighted average with a 5-dB exchange rate, whereas the ACGIH uses an 85 dBA for a time-weighted average with a 5-dB exchange rate. Although conventional wisdom tells us that guns expose the user to hazardous noise and require

hearing protection, there has been a sentiment that starter pistols do not pose a similar risk to people’s hearing. Starter pistols are used to signal the start of a race. Researchers have looked into the question of whether starter pistols place athletic participants at risk of noise exposure [10]. Different starter pistols in outdoor settings were tested and compared with standard firearms, and researchers found that starter pistols produce more sound at the shooter’s ear than normal open-barrel guns firing either live ammunition or blanks. Analysis showed that athletes are not at increased risk in this setting owing to the distance from the sound impulse event. However, another study identified other nonathlete participants, such as sporting officials, as being at risk for noise-related hearing loss simply from chronic whistle use [11]. Again, the proximity of the ears at risk of noise exposure to the sound generator in question, along with the chronicity and total time exposure to such noise, rather than the specific type or quality of sound generator, is the overriding factors in hearing loss risk assessment. An interesting study investigating sound impulse exposure from golf driver and ball impacts was undertaken in which rear-ear acoustical measurements were performed to estimate a real-world risk of noise-induced hearing loss [12]. The study demonstrated that the real-ear acoustical characteristics of sound impulses generated from golf ball strikes from a wide range of golf drivers were unlikely to contribute significantly to noise-induced hearing loss.

FIREARMS Hunting has become a popular activity for adults and children. Of the various forms of recreational firearms sports, waterfowl hunting – given its admixture of high-intensity large caliber firearms discharge, high rate of semi-automatic weapons use, high target event rate in comparison to other hunting disciplines, and the necessity to communicate with other members of the hunting blind, thereby making usage of hearing protection devices (HPDs) cumbersome – is the recreational firearms discipline of highest risk for noise-induced hearing loss. A recent study confirms this notion, demonstrating that among adult waterfowl hunters, 88% were aware that use of firearms could cause hearing loss but that large number of them still choose not to use hearing protection while shooting [13 ]. A similar survey study was undertaken to investigate the shooting habits of youth hunters [14 ]. Similar to their adult counterparts, 81% of these youth respondents acknowledged awareness that shooting can result in hearing loss as well as also believing that hearing protection should be used

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whenever shooting. However, only 56% reported that they actually consistently used any form of hearing protection while target practice shooting, and only 16% used such protection while hunting. Twenty-six percent of the respondents reported that they were aware of the more user-friendly form of active electronic hearing protection, yet only 3% reported using such protection while shooting. Also of interest and concern was that 45% of respondents noted temporary tinnitus, and 10% reported constant tinnitus or worsening of preexisting tinnitus after shooting. Given the huge deficiency in usage of HPDs by both adult and youth hunters and firearms shooters, the authors believe that at minimum, young shooters should have their hearing and cochlear status evaluated with baseline audiometry and monitored with annual audiometry and otoacoustic emissions testing. Furthermore, audiologists should actively educate parents and young shooters regarding options for both passive and active HPDs. Audiologists can play a pivotal role by fitting and evaluating the effectiveness of HPDs and train users regarding proper use prior to noise exposure. Audiologists should counsel patients regarding avoidance of noise-induced hearing loss by use of appropriate hearing protective devices and can remind their patients as well of other consequences of damage to the auditory system, including tinnitus and hyperacusis, from usage of firearms. OSHA and National Institute for Occupational Safety and Health recommend that adults limit exposure to impulse sounds to 140 dB sound pressure level (SPL) [7]. The WHO recommends that children should not exceed exposure levels of 120 dB SPL. Furthermore, WHO and the Environmental Protection Agency recommend that children’s noise exposure levels should not exceed 70 dB Leq averaged over a 24-h period (or 75 dB Leq8 for an 8-h period). With sports such as target shooting attracting younger and younger participants, there is legitimate and strong concern that these youth participants may be at increased risk of auditory damage. Youth-specific risk factors of firearms-related noise-induced hearing loss were recently investigated [15]. Because they are shorter, children are more likely to have their ear and muzzle of the firearm closer to the ground as compared with an adult, thereby reinforcing reflected sound impulses off of an acoustically reflective flooring surface such as concrete. Also, a child is more likely to alternatively be seated at a table when target shooting, with the table also acting as an acoustically reflective surface. The proximity of any hard surface reflects more potentially dangerous sound to the child’s 396

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ears. Lastly, because they have shorter arms, children will hold the muzzle of the firearm closer to their ear as compared with an adult. The researchers recommended that smaller caliber firearms be used by children when possible to minimize auditory risk. Furthermore, they stressed that young shooters should shoot from a standing position to extend the distance from any reflective surfacing to their ears. Children and adults should choose firearms that have a greater distance between the muzzle and the shooter’s ear. As with sporting events described above, even nonparticipant spectators can be at risk for noiseinduced hearing loss if in close enough proximity to discharging firearms [16]. In recreational firearms sports, many shooters may argue that the need for hearing safety is often trumped by the need for firearms safety, in the form of the necessity to hear and communicate with fellow hunters in the blind or near vicinity, or with firearms instructors, coaches, or fellow marksmen on the target shooting range for practical instruction, safety warnings, and general communications. In such instances, the usage of active electronic HPDs can play an extremely valuable role. Such devices can offer both audibility when necessary and impulse noise protection when warranted.

PERSONAL LISTENING DEVICES A National Health And Nutrition Examination Survey (NHANES)-based study has demonstrated a striking increase in the prevalence of hearing loss in United States teenagers, from 15% in the 1988–1994 time period of the NHANES III survey to 20% in the NHANES 2005–2006 survey [17 ]. NHANES data from 2005–2008 demonstrate a 7.5% overall prevalence of tinnitus in youths of ages 12–19 and a 4.7% prevalence of chronic tinnitus in this same population, corresponding to 2.5 million and 1.6 million adolescents in the United States [18]. Concern is mounting as the use of PLDs has become de rigueur for today’s teenagers. There is still debate and uncertainty as to the exact extent and contribution of PLD usage to hearing loss. However, there is an increasing body of recent literature supporting the connection between extended and/or elevated usage of PLDs and documented hearing loss, with a clear correlation between such usage patterns and hearing loss in the extended high frequency range of hearing (8–16 kHz) [19,20 ,21 ]. Are today’s youth aware that their use of PLDs may cause hearing loss, or perhaps even other forms of injury? Do they know about hearing health and safe PLD use? Are they interested in learning about ways to use their PLDs safely? While ubiquitous &&

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Recreational noise-induced hearing loss Ivory et al.

among today’s youth, PLD use certainly poses the same risks to hearing health for adults young and old as well. The term ‘iPod oblivion’ has been coined to describe the contemporary phenomenon of a use of a PLD who is so engrossed in listening to one’s PLD that they have become unaware of what is happening in the environment around them. Many listen to their PLD while jogging, biking, or engaging in other physical activities [22]. Few seemed concerned that listening to their PLD while exercising may put them at risk for injury, or death, because of lack of awareness of their immediate surroundings. Several contemporary surveys demonstrate that a majority of today’s youth do not believe that use of PLDs puts them at risk for auditory damage. Adolescents typically lack knowledge regarding estimations of noise exposure likely to cause hearing loss, signs and symptoms of auditory damage, and appropriate measures for prevention of such damage [22,23 ,24,25]. In one study, 45% of surveyed adolescents were unaware that output limiting software could be downloaded to certain brands of PLD, and 75% were unaware that some PLD manufacturers had web sites dedicated to educating users regarding safe listening methods and general hearing health. Even when made aware of such resources, 56% of adolescents surveyed indicated that they would not utilize such resources [22]. With noise-induced hearing loss being the only acquired hearing loss that we have control over, efforts to educate people regarding hazardous noise exposure and hearing protection are an important part of prevention. Although studies above have suggested a lack of interest in hearing preservation among youth listeners of PLDs, other studies are more positive. A 2012 survey of students at one California high school found that a majority of surveyed students were actually concerned regarding acquiring hearing loss [23 ]. In such conditions, adolescents could benefit from disseminated information regarding signs and symptoms of both temporary and permanent hearing loss as well as options available to protect their hearing. Information regarding avoiding iPod oblivion should also be discussed. Today’s youth may be more interested in educational programs when presented in a more engaging, interactive fashion [26 ]. Students who may be more at risk for auditory damage because of occupational noise and other potentially harmful noise, such as those enrolled in vocational-technical programs, would also benefit from additional vocational-specific education and training to prevent auditory damage due to occupational noise exposures. &

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A recent study investigated the direct effects of a hearing loss prevention campaign on the usage of HPDs in the setting of recreational noise exposure [27 ]. A cohort of high school-aged youth were surveyed before and after institution of a government sponsored campaign designed to influence behavioral and control beliefs regarding usage of hearing protection in the setting of noise exposure. The campaign focused on the harmful effects of noise and the direct benefit of hearing protection device usage to preservation of hearing. Youths surveyed demonstrated a more negative attitude toward noise exposure and a more positive attitude toward hearing protection following the campaign. Most significantly, not only was the intention to use hearing protection increased following the campaign but also the actual usage rate increased, demonstrating the real benefit and impact that a simple hearing health campaign can have toward behavioral modification in this age group [27 ]. Education and monitoring are key elements to preventing noise-induced hearing loss in populations who use PLDs. Manufacturers should include warnings regarding the dangers of listening to loud music on the packing of their PLDs. Some recommend that users be alerted with either visual or auditory warnings once the PLD has reached a potentially dangerous output level. Awareness of potential dangers of misusing PLDs should be raised. The media, along with parents, teachers, and healthcare professions should work together to facilitate such a campaign. Dispelling the myth that if others cannot hear the sound from one’s PLD, it must be safe, should also be a priority. Education regarding safe listening limits and hearing protections to students, especially those who may enter prevocational schools, is beneficial. Signs and symptoms of noiseinduced hearing loss, including tinnitus, should be included in an educational plan. Distortion product otoacoustic emissions (DPOAEs) and high frequency audiometry may be used to monitor changes in cochlear function and hearing sensitivity. &&

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CONCLUSION Recreational sources of excessive sound exposure continue to play a large role in noise-induced hearing loss. Epidemiological data suggest a trend of increasing incidence of high frequency neurosensory hearing loss in the adolescent population. As this population has not had any recent significant increase in global exposure to occupational sound levels, nor has this population had any recent degeneration in other healthcare metrics, and with this population’s increasing rise in usage of PLDs, the increasing incidence of high frequency hearing

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loss seems to be correlated with such increased recreational usage of PLDs. Although the general public, as a whole, tends to refrain from usage of HPDs in elevated noise exposure settings, some studies have demonstrated that the same populations do, in fact, harbor concerns about future hearing loss from excessive sound and noise exposure. Active counseling regarding the consequences of excessive noise exposure and the potential benefits to hearing from usage of hearing protection instruments is critical to providing best possible care in the hearing health professions. Acknowledgements None. Conflicts of interest The authors declare no conflicts of interests.

REFERENCES AND RECOMMENDED READING Papers of particular interest, published within the annual period of review, have been highlighted as: & of special interest && of outstanding interest 1. Clark WW. Noise exposure from leisure activities: a review. J Acoust Soc Am 1991; 90:175–181. 2. Peng JH, Wang JB, Chen JH. Recreational noise exposure decreases olivocochlear efferent reflex strength in young adults. J Otolaryngol Head Neck Surg 2010; 39:426–432. 3. Tung CY, Chao KP. Effect of recreational noise exposure on hearing impairment among teenage students. Res Dev Disabil 2013; 34:126–132. 4. Corn M. Noise is a prime target at OSHA. Occup Health Saf 1976; 45:12– 17. 5. Harris DA. OSHA noise regulations: pathways to compliance. Occup Health Saf 1979; 48:52–54. 6. Driscoll DP, Morrill JC. A position paper on a recommended criterion for recording occupational hearing loss on the OSHA Form 200. Noise Committee of the American Industrial Hygiene Association. Am Ind Hyg Assoc J 1987; 48:A714–A716. 7. Sriwattanatamma P, Breysse P. Comparison of NIOSH noise criteria and OSHA hearing conservation criteria. Am J Ind Med 2000; 37:334–338. 8. Engard DJ, Sandfort DR, Gotshall RW, Brazile WJ. Noise exposure, characterization, and comparison of three football stadiums. J Occup Environ Hyg 2010; 7:616–621. 9. Cranston CJ, Brazile WJ, Sandfort DR, Gotshall RW. Occupational and recreational noise exposure from indoor arena hockey games. J Occup Environ Hyg 2013; 10:11–16. 10. Meinke DK, Finan DS, Soendergaard J, et al. Impulse noise generated by starter pistols. Int J Audiol 2013; 52 (Suppl 1):S9–S19. 11. Flamme GA, Williams N. Sports officials’ hearing status: whistle use as a factor contributing to hearing trouble. J Occup Environ Hyg 2013; 10:1–10.

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12. Zhao F, Bardsley B. Real-ear acoustical characteristics of impulse sound generated by golf drivers and the estimated risk to hearing: a cross-sectional study. BMJ open 2014; 4:e003517. 13. Stewart M, Borer SE, Lehman M. Shooting habits of U.S. waterfowl hunters. & Noise Health 2009; 11:8–13. This study describes the unique risk factors associated with a specific discipline of firearms sporting whose participants are at greatest risk of recreational noiseinduced hearing loss. 14. Stewart M, Meinke DK, Snyders JK, Howerton K. Shooting habits of youth && recreational firearm users. Int J Audiol 2014; 53 (Suppl 2):S26–S34. This study describes the significant risks to hearing posed by recreational firearms use in the youth and adolescent population. 15. Meinke DK, Murphy WJ, Finan DS, et al. Auditory risk estimates for youth target shooting. Int J Audiol 2014; 53 (Suppl 2):S16–S25. 16. Flamme GA, Stewart M, Meinke D, et al. Auditory risk to unprotected bystanders exposed to firearm noise. J Am Acad Audiol 2011; 22:93–103. 17. Shargorodsky J, Curhan SG, Curhan GC, Eavey R. Change in prevalence of && hearing loss in US adolescents. JAMA 2010; 304:772–778. This study documents a significant increase in prevalence of hearing loss in United States adolescents between 1994 and 2006. 18. Mahboubi H, Oliaei S, Kiumehr S, et al. The prevalence and characteristics of tinnitus in the youth population of the United States. Laryngoscope 2013; 123:2001–2008. 19. Le Prell CG, Dell S, Hensley B, et al. Digital music exposure reliably induces temporary threshold shift in normal-hearing human subjects. Ear Hear 2012; 33:e44–e58. 20. Le Prell CG, Spankovich C, Lobarinas E, Griffiths SK. Extended high-fre&& quency thresholds in college students: effects of music player use and other recreational noise. J Am Acad Audiol 2013; 24:725–739. This is one of the two recent studies demonstrating a link between excessive usage of PLDs and documented hearing loss, in this study in the extended high frequency spectrum. 21. Sulaiman AH, Husain R, Seluakumaran K. Evaluation of early hearing damage && in personal listening device users using extended high-frequency audiometry and otoacoustic emissions. Eur Arch Otorhinolaryngol 2014; 271:1463– 1470. This is one of the two recent studies demonstrating a link between excessive usage of PLDs and documented hearing loss, in this study in the extended high frequency spectrum and in otoacoustic emissions. 22. Pellegrino E, Lorini C, Allodi G, et al. Music-listening habits with MP3 player in a group of adolescents: a descriptive survey. Ann Ig 2013; 25:367–376. 23. Danhauer JL, Johnson CE, Dunne AF, et al. Survey of high school students’ & perceptions about their iPod use, knowledge of hearing health, and need for education. Lang Speech Hear Serv Sch 2012; 43:14–35. This article describes a high incidence of concern for potential for hearing loss from amplitude and duration excessive usage of PLDs among an adolescent cohort. This study demonstrates the potential for positive intervention in counseling and education of usage of hearing protection strategies in youth at high risk for hearing loss from PLDs. 24. Beach E, Williams W, Gilliver M. Estimating young Australian adults’ risk of hearing damage from selected leisure activities. Ear Hear 2013; 34:75–82. 25. Portnuff CD, Fligor BJ, Arehart KH. Self-report and long-term field measures of MP3 player use: how accurate is self-report? Int J Audiol 2013; 52 (Suppl 1):S33–40. 26. Punch JL, Elfenbein JL, James RR. Targeting hearing health messages for & users of personal listening devices. Am J Audiol 2011; 20:69–82. This article summarizes the unique risks to hearing associated with PLDs and reinforces the importance of targeted messages and campaigns for hearing protection and conservation measures to youths and users of PLDs. 27. Gilles A, Paul Vde H. Effectiveness of a preventive campaign for noise&& induced hearing damage in adolescents. Int J Pediatr Otorhinolaryngol 2014; 78:604–609. This article presents results from a recent and successful campaign to adolescents for prevention of hearing damage from noise exposure, with the program exhibiting improvements in an intent to use and actual usage of HPDs.

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Noise-induced hearing loss: a recreational noise perspective.

This review will discuss the real-world risk factors involved in noise-induced hearing loss as a result of common and popular recreational activities ...
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