PRESERVATION // STANDARDS FOR “SAFE LISTENING” Help your patients enjoy Standards for “Safe Listening”: Past, Present, the phone again with CapTel® and Future A global perspective on the challenges of prevention and regulation

By MASAHITO KAWAMORI, LIDIA BEST, and MARK LAUREYNS

The “Make Listening Safe Workgroup” he first known regulation on safe lis- manent deafness...The maximum safe inten- is an initiative of the World Health tening dates back as far as the 6th sity at which no deafening effect will occur is Tcentury BC, when the Greek colony probably in the neighborhood of 85 dB above Organization (WHO) in the framework of Sybaris (now southern Italy) decreed that 0.0002 dyne/cm² for critical bands of noise.” of the World Hearing Forum, and is tinsmiths and potters had to live outside the city because of the noise they made.4 The first 1957: In Noise Control, a “Guide for committed to create a world where record on hearing loss caused by industry Conservation of Hearing in Noise” is pub- nobody’s hearing is put in danger due to noise dates back to 1830 when Fostbroke lished.8 This document was developed by discussed the hearing loss of blacksmiths. the Subcommittee on Noise in Industry, the unsafe listening. This article focuses on Aram Glorig5 stated that, as late as 1935 (ie, Committee on Conservation of Hearing, and standards for safe listening in the industry prior to the Walsh-Healy Public Contracts the American Academy of Ophthalmology for personal players and for personal Act of 1936), audiometric studies on hearing and Otolaryngology. In this document, the loss due to noise were practically nonexistent. “Duration and Distribution of Exposure amplifiers. For each of these three focus During Workday and Work-Life” is promul- areas, WHO estimates the worldwide Select Landmarks in Global Hearing gated as a key aspect for evaluating the impact Loss Prevention of noise on hearing. population at risk to be: For historical perspective, here is a brief “I really enjoy my look back at some of the key landmark pub- 1971: Just after lications and regulations pertaining to “safe the passage of the US CapTel! I can read n 466 million persons with disabling listening” and hearing preservation. Authors’ Occupational Safety and hearing loss (6.1% of the world’s note: The origins of noise standards have a Health Act of 1970— the words and get population).1 long and complicated history, and due to space which created the restrictions are greatly simplified here (eg, see Occupational Safety and all the info I need n 16% of disabling hearing loss in Franks6 and Goldsmith4). Health Administration adults is attributable to occupational (OSHA) and the the first time.” 1950: Karl Kryter National Institute for noise exposure.2 Figure 2. ISO 1999-2013. publishes a monograph Occupational Safety and n 1.1 billion teenagers and young “The Effects of Noise Health (NIOSH)—the first International Henry CapTel user in Wisconsin adults are at risk of hearing loss due to on Man” in the Journal Standards Organization (ISO) publication of Hearing and Speech on occupational noise is published (ISO 1999 the unsafe use of personal audio devices Disorders7 (republished “–Assessment of occupational noise and exposure to damaging levels of in book form in 1970), exposure for hearing conservation purpos- with a specific chapter es”). This standard has been reviewed many at noisy entertainment venues.3 Figure 1. The Effects of Noise on Man. on “Deafening Effects of times, with the latest version issued in 2018 Noise” in which he con- and maintained as ISO 1999-2013 “Acoustics– cludes that “continued repeated exposures Estimation of noise-induced hearing loss” of extended periods (years) to intense noise (Figure 2).9 Noise exposure level over time is from machinery may result in partial but per- the main criterium used in this standard, and

Masahito Kawamori is affiliated with Keio University, Tokyo, Japan, is Rapporteur for Study Group 16–Question 28, International Telecommunications Union (ITU-T) and a member of the World Health Organization’s (WHO) World Hearing Forum “Make Listening Safe Workgroup”; Lidia Best, is Vice-chair of the Joint Coordination Activity on Accessibility and Human Factors (JCA-AHF) at ITU and member of the Workgroup; and Mark Laureyns is affiliated with Thomas More University College in Antwerp, CapTel 840i 1-800-233-9130 l www.captel.com Belgium, the European Association of Hearing Aid Professionals (AEA), and serves as

Chair for the Workgroup. FEDERAL LAW PROHIBITS ANYONE BUT REGISTERED USERS WITH HEARING LOSS FROM USING INTERNET PROTOCOL (IP) CAPTIONED TELEPHONES WITH THE CAPTIONS TURNED ON. IP Captioned Telephone Service may use a live operator. The operator generates captions of what the other party to the call says. These captions are then sent to your phone. There is a cost for each minute of captions generated, paid from a federally administered fund. No cost is passed on to the CapTel user for using the service. CapTel captioning service is intended exclusively for individuals with hearing loss. CapTel® is a registered trademark of Ultratec, Inc. The Bluetooth® word mark and logos are registered trademarks owned by Bluetooth SIG, Inc. and any use of such marks by Ultratec, Inc. is under license. (v2.6 10-19)

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shall be used. The exposure, which was based on the EN 50332- individual hear- 3 standard “Sound system equipment: head- ing protectors shall phones and earphones associated with personal be so selected as to music players–maximum eliminate the risk level to hearing or to measurement methodol- reduce the risk to a ogy, Part 3: measurement minimum; method for sound dose n  Exposure limit Figure 5. The EU Noise at management.” values (at 87 dBA Work regulations. These standards rec- LEX,8h): Under no ommend weekly sound circumstances shall the exposure of the dose being limited to the Figure 7. ITU-T/WHO H.870 worker exceed the exposure limit values. equivalent of 80 dBA for safe-listening guidelines 40 hours/week. For the for A/V and multimedia systems. Safe Listening for Personal Audio Systems higher safety level (ie, for In 2010, the International Technical children and/or sensitive users), the weekly Commission (ITC) published the first stan- sound dose should be limited to the equivalent dard, IEC 62368-1, for personal audio sys- of 75 dBA for 40 hours/week (Table 1b). tems: “Audio/Video, Information and Additionally, ITU and WHO recommend Figure 3. Present-day NIOSH noise intensity and exposure Communication Technology Equipment Part that Personal Audio Systems be equipped with limit summary. Source: CDC website. 1: Safety Requirements” (Figure 6). This focuses a monitoring function that sets the above expo- the studies referenced in the standard looked on personal music play- sure as a 1-week “sound allowance,” and the at the effects of noise on participants’ pure- ers, with an output of 85 display method should be designed in an easy- tone audiograms. The standard takes a dBA dBA or lower considered to-understand manner. The device should also 8-hour time-weighted average (TWA8) as its safe. The LAeq,T (ie, the be able to provide the user with a suitable meth- reference. It is clear from the standard that the A-weighted equivalent od for limiting volume. This refers to a feature risk of noise-induced hearing loss significantly continuous sound level) where a message will be given before or when increases from an exposure of 85 dBA (ie, output is to be lower or users reach 100% of their weekly sound allow- LEX,8h/day) and higher (Figure 3). equal to the relevant RS2 ance. The user will have the option to “continue sound output value of 100 listening” if they do not wish the device volume Figure 6. ITC standard for 1972: The first NIOSH guidelines are pub- audio/video, information, dBA. reduced. If the message is not acknowledged, a lished (Figure 4). In these guidelines,10,11 the and communication tech- Unfortunately, the use default setting will reduce the volume output nology equipment. concept of daily dose is used, and a table for of a max output level has to below the predetermined level based on the “Combinations of noise exposure levels and had the unintended effect that more and more mode selected (eg, 80 dBA or 75 dBA). durations that no worker exposure shall equal compression was used for recorded music files. Since October 2019, you can find the weekly or exceed” is displayed, with exposure levels of: Although the max output value of 100 dBA dose of sound exposure in the Health app on n 85 dBA – 8 hours (LAeq,T) was not exceeded when the personal . We hope other smartphone and head- n 88 dBA – 4 hours music player was tested, the exposure level phone manufacturers will follow Apple’s lead. n 91 dBA – 2 hours could easily exceed 85 dBA or more, which In 2018, IEC 62368-1 was reviewed and This concept is based could result in unsafe listening. the concept was introduced that weekly sound on the energy equiva- In the subsequent ITU and WHO standard dose should be limited to the equivalent of 80 Figure 4. NIOSH’s 1972 publication lence principle; when you H.870 “Guidelines for safe listening devices/ dBA for 40 hours/week as a standard safety double the energy, you systems” (Figure 7) published in August 2018, level added to the Audio/video (Part 1) safety need to reduce the expo- the focus was on evaluating weekly sound-dose requirements. sure time by half.

2003: The European Commission pub- lishes the EU Noise at Work Regulations (Directive 2003/10/EC, Figure 5),12 which sets three action levels: n Lower exposure action values (at 80 dBA LEX,8h): The employer shall make indi- vidual hearing protectors available to workers; n  Upper exposure action values (at 85 dBA Table 1a-b. Left: ITU-WHO standard weekly safe listening time, based on energy equivalence principle. Right: UTU-WHO standard for higher LEX,8h): Individual hearing protectors safety level (eg, for children or sensitive users).

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HR2009_22-25-Kawamori_SafeListening.indd 24 9/11/20 7:43 PM Safe Listening with Personal Amplifiers is needed to ensure that 12 to 17 dB. Further, PSA’s need to provide In December 2015, the European Federation these devices, which are adequate warnings in advertisements, user of Hard of Hearing People (EFHOH) and freely available in the guides, and packaging detailing the risks of the European Association of Hearing Aid market to anyone, are further damaging the user’s hearing as a result Professionals (AEA) published their “Paper safe for users and do not of using the device and provide information to on the potential risk of using ‘Personal Sound further damage users’ users showing how to avoid these risks. Amplification Products’ PSAPs”15 in which 27 hearing. personal sound amplifiers (PSA) commercially For PSAs with the Conclusions available in Europe during 2014 were analyzed capacity to measure In the current standards, the availability of Figure 10. ITU-T/WHO (Figure 8). All 27 devices had a maximum weekly dose, it is required H.871 safe-listening guide- hearing protection at work, for personal music output level of more than 120 dBSPL; 23 had that weekly maximum lines. players, and personal amplifiers, the exposure an output level exceeding sound dose needs to be should be less than 80 dBA for 40 hours. 125 dBSPL, and 8 exceed- less than 80 dBA for 40 hours. For example, Although only setting a maximum output ed 130 dBSPL. None of at 89 dBA, the exposure time is limited to 5 level is not advisable (because this can result the products had a limiter hours/week. For other exposure levels, a lin- in higher compression in the source music file of the maximum power. ear intrapolation and extrapolation applies. or in the amplification), those PSAs that don’t Furthermore, it is very According to ITU-T H.870 and H.871, mea- have the capacity to measure weekly dose need difficult for the end user surements taken of the dynamic range of to be permanently limited to 95 dBA. to understand the differ- sound should be accounted for and the rea- ence between a “hearing sonably foreseeable use of the products. When CORRESPONDENCE can be Figure 8. EFHOH and AEA paper on potential risk of aid” (designed for the PSAs do not have the capacity to measure addressed to Mark Laureyns at: using PSAPs. medical purpose of com- weekly sound dose, the maximum output of [email protected] pensating for a hearing the device needs to be permanently limited REFERENCES are available in loss) and PSAP (a sound amplifier), with the to 95 dBA; a user then is unlikely to use the the online version of this latter shown to provide very high and dan- device at a level higher than 80 dBA since the article at hearingreview.com. gerous sound levels. Both EFHOH and AEA dynamic range of speech has a crest factor of called on all relevant stakeholders to ensure that PSAPs are not used when they exceed unsafe sound levels. This alarming report initiated the ITU standard on personal amplifiers. In 2017, the Consumer Technology Association (CTA) published the ANSI/CTA standard 2051 on “Personal Sound Amplification Performance Criteria”16 (Figure 9). The safety aspects in this standard Figure 9. ANSI/CTA stan- state that “The maximum dard 250 for personal sound OSPL90 output level shall amplification. not exceed 120 dBSPL measured in a 2cc coupler.” This standard exceeds the safety level set by IEC 62368-1 (ie, the LAeq,T to be lower or equal to the sound output value of 100 dBA) by more than 15 dB if we correct 5 dB for the conversion dBSPL to dBA. In 2019, ITU published ITU-T H.871 (Figure 10),17 which can be considered a companion standard to H.870 and describes safety requirements for PSAs, including both PSAPs and personal sound amplification apps (PSAA). Currently there is no other interna- tional standard for PSAs. Thus, this standard

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