World Hearing Day 2024

The Acoustical Society of America (ASA) takes pride in its mission to generate, disseminate, and promote the knowledge and practical applications of acoustics. This also aligns with one of the objectives of World Hearing Day 2024; to reshape public perceptions surrounding ear and hearing based on accurate, evidence-based information. In support of World Hearing Day[i], we would like to draw attention to a couple Special Issues of the Journal of the Acoustical Society of America (JASA) that delve into the clinical and investigational facets of noise-induced hearing disorders.

Noise-Induced Hearing Disorders: Clinical and Investigational Tools
Guest Editors: Colleen G. Le Prell (Liaison Guest Editor), Odile H. Clavier, and Jianxin Bao

This special issue provides valuable insights into cutting-edge clinical and investigational tools designed to sensitively detect noise injury in the cochlea. Emphasizing the importance of sound exposure monitoring and protection, the collection explores tools available for characterizing individual noise hazards and attenuation. Throughout, there is a concentrated focus on the suitability of diverse functional measures for hearing and balance-related clinical trials, including considerations for boothless auditory test technology in decentralized clinical trials. Furthermore, the issue offers guidance on designing clinical trials to prevent noise-induced hearing deficits such as hearing loss and tinnitus.

World Hearing Day JASA special issue

Issue Highlights

Noise-Induced Hearing Loss: Translating Risk from Animal Models to Real-World Environments
Guest Editors: Colleen G. Le Prell, CAPT William J. Murphy, Tanisha L. Hammill, and J. R. Stefanson

Noise-induced hearing loss (NIHL) stands as a common injury for service members and civilian workers exposed to noise. This special issue focuses on translating knowledge from animal models to real-world environments. Contributors delve into the cellular and molecular events in the inner ear post-noise exposure, exploring potential pharmaceutical prevention of NIHL. The collection includes insights into methods and models used during preclinical assessments of investigational new drug agents, as well as information about human populations at risk for NIHL.

World Hearing Day JASA Special Issue

Issue Highlights

Together, these special issues provide an exploration of noise-induced hearing disorders, offering valuable insights and potential solutions for both clinical and real-world settings. Be sure the share this post to make ear and hearing care a reality for all! For more information about World Hearing Day 2024, visit https://www.who.int/campaigns/world-hearing-day/2024.

[i] Due to an unexpected site wide issue, the posting of this content was unfortunately delayed to after March 3, 2024.

Hard-of-Hearing Music Fans Prefer a Different Sound

Hard-of-Hearing Music Fans Prefer a Different Sound

Modern music can be inaccessible to those with hearing loss; sound mixing tweaks could make a difference.

Listeners with hearing loss can struggle to make out vocals and certain frequencies in modern music. Credit: Aravindan Joseph Benjamin

WASHINGTON, August 22, 2023 – Millions of people around the world experience some form of hearing loss, resulting in negative impacts to their health and quality of life. Treatments exist in the form of hearing aids and cochlear implants, but these assistive devices cannot replace the full functionality of human hearing and remain inaccessible for most people. Auditory experiences, such as speech and music…click to read more

From: The Journal of the Acoustical Society of America
Article: Exploring level- and spectrum-based music mixing transforms for hearing-impaired listeners
DOI: 10.1121/10.0020269

A virtual reality system to ‘test drive’ hearing aids in real-world settings

Matthew Neal – mathew.neal.2@louisville.edu
Instagram: @matthewneal32

Department of Otolaryngology and other Communicative Disorders
University of Louisville
Louisville, Kentucky 40208
United States

Popular version of 3pID2 – A hearing aid “test drive”: Using virtual acoustics to accurately demonstrate hearing aid performance in realistic environments
Presented at the 184 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0018736

Many of the struggles experienced by patients and audiologists during the hearing aid fitting process stem from a simple difficulty: it is really hard to describe in words how something will sound, especially if you have never heard it before. Currently, audiologists use brochures and their own words to counsel a patient during the hearing aid purchase process, but a device often must be purchased first before patients can try them in their everyday life. This research project has developed virtual reality (VR) hearing aid demonstration software which allows patients to listen to what hearing aids will sound like in real-world settings, such as noisy restaurants, churches, and the places where they need devices the most. Using the system, patient can make more informed purchasing decisions and audiologists can program hearing aids to an individual’s needs and preferences more quickly.

This technology can also be thought of as a VR ‘test drive’ of wearing hearing aids, letting audiologists act as tour guides as patients try out features on a hearing aid. After turning a new hearing aid feature on, a patient will hear the devices update in a split second, and the audiologist can ask, “Was it better before or after the adjustment?” On top of getting device settings correct, hearing aid purchasers must also decide which ‘technology level’ they would like to purchase. Patients are given an option between three to four technology levels, ranging from basic to premium, with an added cost of around $1,000 per increase in level. Higher technology levels incorporate the latest processing algorithms, but patients must decide if they are worth the price, often without the ability to hear the difference. The VR hearing aid demonstration lets patients try out these different levels of technology, hear the benefits of premium devices, and decide if the increase in speech intelligibility or listening comfort is worth the added cost.

A patient using the demo first puts on a custom pair of wired hearing aids. These hearing aids are the same devices sold that are sold in audiology clinics, but their microphones have been removed and replaced with wires for inputs. The wires are connected back to the VR program running on a computer which simulates the audio in a given scene. For example, in the VR restaurant scene shown in Video 1, the software maps audio in a complex, noisy restaurant to the hearing aid microphones while worn by a patient. The wires send the audio that would have been picked up in the simulated restaurant to the custom hearing aids, and they process and amplify the sound just as they would in that setting. All of the audio is updated in real-time so that a listener can rotate their head, just as they might do in the real world. Currently, the system is being further developed, and it is planned to be implemented in audiology clinics as an advanced hearing aid fitting and patient counseling tool.

Video 1: The VR software being used to demonstrate the Speech in Loud Noise program on a Phonak Audeo Paradise hearing aid. The audio in this video is the directly recorded output of the hearing aid, overlaid with a video of the VR system in operation. When the hearing aid is switched to the Speech in Loud noise program on the phone app, it becomes much easier and more comfortable to listen to the frontal talker, highlighting the benefits of this feature in a premium hearing aid.

The safe noise level to prevent hearing loss is probably lower than you think

Daniel Fink – djfink01@aol.com
Twitter: @QuietCoalition

Board Chair, The Quiet Coalition, 60 Thoreau Street Suite 261, Concord, MA, 01742, United States

The Quiet Coalition is a program of Quiet Communities, Inc.

Popular version of 3pNS1-What is the safe noise level to prevent noise-induced hearing loss?, presented at the 183rd ASA Meeting.

Ear structures including outer, middle, and inner ear. Image courtesy of CDC

If something sounds loud, it’s too loud, and your auditory health is at risk. Why? The safe noise exposure level to protect your hearing- to prevent noise-induced hearing loss (NIHL) and other auditory disorders like tinnitus, also known as ringing in the ears, might be lower than you think. Noise damages delicate structures in the inner ear (cochlea). These include minuscule hair cells that actually perceive sound waves, transmitted from the air to the ear drum, then from bones to the fluid in the cochlea.

Figure 1. Normal hair cells (left) and hair cells damaged by noise (right). Image courtesy of CDC

[A little detail about sound and its measurement. Sound is defined as vibrations that travel through the air and can be heard when they reach the ear. The terms sound and noise are used interchangeably, although noise usually has a connation of being unpleasant or unwanted. Sound is measured in decibels. The decibel scale is logarithmic, meaning that an increase in sound or noise levels from 50 to 60 decibels (dB) indicates a 10-times increase in sound energy, not just a 20% increase as might be thought. A-weighting (dBA) is often used to adjust unweighted sound measurement to reflect the frequencies heard in human speech. This is used in occupational safety because the inability to understand speech after workplace noise exposure is the compensable industrial injury.]

Many audiologists still use the industrial-strength 85 dB noise level as the level at which auditory damage begins. This is incorrect. The 85 dBA noise level is the National Institute for Occupational Safety and Health (NIOSH) recommended occupational noise exposure level (REL). This does not protect all exposed workers from hearing loss. It is certainly not a safe noise level for the public. Because of the logarithmic decibel scale, 85 decibel sound has approximately 30 times more sound energy than the Environmental Protection Agency’s 70 decibel safe sound level, not about 20% as might be thought.

The EPA adjusted the NIOSH REL for additional exposure time- 24 hours a day instead of only 8 hours at work, 365 days a year instead of 240 days- to calculate that 70 dB average noise exposure for a day would prevent noise-induced hearing loss. This is the only evidence-based safe noise level I have been able to find.

But the real safe noise level to prevent NIHL must be lower than 70 dB. Why? EPA used the 40-year occupational exposure in its calculations. It didn’t adjust for lifetime exposure (approaching 80 years in the United States before the COVID pandemic). NIHL comes from cumulative noise exposure. This probably explains why so many older people have trouble hearing, the same way additional years of sun exposure explains the pigmentation changes and wrinkles in older people.

My paper explains that the NIOSH REL, from which EPA calculated the safe noise level, was based on studies of workers using limited frequency audiometry (hearing tests), only up to 4000 or 6000 Hertz (cycles per second). More sensitive tests of hearing, such as extended-range audiometry up to 20,000 Hertz, shows auditory damage in people with normal hearing on standard audiometry. Tests of speech in noise- how well someone can hear when background noise is added to the hearing test- also show problems understanding speech, even if standard audiometry is normal.

The actual noise level to prevent hearing loss may be as low as 55 dBA. This is the noise level needed for the human ear to recover from noise-induced temporary threshold shift, the muffling of sound one has after exposure to loud noise. If you’ve ever attended a rock concert or NASCAR race and found your hearing muffled the next morning, that’s what I’m talking about. (By the way, there is no such thing as temporary hearing loss. The muffling of sound, or temporary ringing in the ears after loud noise exposure, indicates that permanent auditory damage has occurred.)

55 dB is pretty quiet and would be difficult to achieve in everyday life in a modern industrialized society, where average daily noise exposures are near 75 dB. But I hope that if people know the real safe noise level to prevent hearing loss, they will avoid loud noise or use hearing protection if they can’t.

4pNSa4 – Inciting our children to turn their music down: the “Age of Your Ear” concept

Jeremie Voix
Romain Dumoulin
École de technologie supérieure, Université du Québec, Montréal, Quebec, Canada

Popular version of paper 4pNSa4, “Inciting our children to turn their music down: the AYE concept.”
Presented Thu, Nov 08   1:45pm – 2:00pm in SALON C (VCC)
176th Meeting Acoustical Society of America and 2018 Acoustics Week in Canada (Canadian Acoustical Association) at the Victoria Conference Centre, Victoria, BC, Canada

Problem
According to the World Health Organization (WHO), more than 1.1 billion people are currently at risk of losing their hearing due to excessive exposure to noise. Of this, a significant proportion consists of children, youth and young adults who are exposing themselves to excessive levels of sound through various leisure activities (music players, concerts, movies at the theatre, dance clubs, etc.).

Existing solutions
To address this issue, many approaches have been developed, ranging from general awareness messages to volume limiters on personal music players. For instance, the recent “Make listening safe” [1] initiative from WHO aims at gathering all stakeholders, public health authorities, and manufacturers to define and develop a consolidated approach to limit these non-occupational sound exposures, based on dosimetry. Indeed, significant efforts have been put into the idea of assessing directly on a PMP (personal music player) the individual noise dose, i.e. the product of the sound pressure level  and the duration, induced during music listening.

Need to find a better way to sensitize the users
While many technical issues are still actively discussed in some related standards, a major concern arose with regards to the message communicated to the end-users. End-users need to be educated on the risk of noise induced hearing loss (NIHL) and its irreversibility, but at the same time they also need to be made aware that NIHL is 100% preventable pending safe listening practices are followed.

More importantly, end users have to be left with an appealing noise dose measurement. In that regard, expressing equivalent sound pressure level in decibels (dB) or the noise dose in percentage (%) is of little value given the complexity of one and the abstraction of the other. But communicating about the dangers of music playback is definitely something very new for most of the hearing conservation specialists and communicating with this particular group of youth is only adding to the difficulty.

Our approach
In the quest for a meaningful message to pass to these young end users, this article introduces a new metric, the “Age of Your Ears” (AYE), that is an indication of the predicted extra aging caused by the excessive noise dose each user is exposed to. To perform such prediction, a multi-regression statistical model was developed based on normative data found in ISO 1999 [2] standard. This way, an AYE value can be computed for each subject, using only his age, sex and sound exposure, to represent the possible acceleration of aging caused by excessive music listening, as illustrated in Fig. 1.

Age of Your Ear

Fig. 1: While hearing will normally worsen because of the natural aging process (dotted black line), this ageing can be dramatically accelerated because of over-exposure to noise (solid color lines).

Conclusions
In a world where personal musical players are ubiquitous, and have also been putting hearing at risk, it is interesting to see them as potential tool, not only to address the issues they created, but also for raising awareness on the dangers of Noise-Induced Hearing Loss at large.

The proposed AYE metric will be first implemented in a measurement manikin setup that is currently under development at the Centre for Interdisciplinary Research in Music Media and Technology, housed at the Schulich School of Music at McGill University (CIRMMT). This setup, further described in [3], is inspired by the “Jolene” manikin developed though the “Dangerous Decibels” program [4]. The resulting measurement kiosk will be complemented by a smartphone-based measurement app that will enable musicians to assess their entire noise exposure. It is hoped that the proposed AYE metric will be relevant and simple enough to have a beneficial impact on everyone’s safe hearing practices.

[1] WHO – Make Listening Safe- http://www.who.int/deafness/activities/mls/en/.

[2] ISO 1999:2013 – Acoustics – Estimation of noise-induced hearing loss, 2013.

[3] Jérémie Voix, Romain Dumoulin, Julia Levesque, and Guilhem Viallet. Inciting our children to turn their music down : the AYE proposal and implementation. In Proceedings of Meetings on Acoustics , volume Paper 3007868, Victoria, BC, Canada, 2018. Acoustical Society of America.

[4] Dangerous Decibels – JOLENE – http://dangerousdecibels.org/jolene