We are excited to have you join us for an amazing educational line up, check out the agenda below for the 2025 Conference. Please note that this agenda is subject to change.
The Basics Workshop is designed to offer attendees a comprehensive perspective on the substance and conduct of an effective occupational hearing conservation program (HCP). This annual workshop, held on the conference’s first day, is a “short course” that will clarify and illustrate key hearing conservation requirements, practices, and resources that are used in HCPs (and will be cited in subsequent platform presentations in this conference). The speakers will define basic concepts and foundational knowledge used in HCPs, and then describe fundamental applications that are important and essential for hearing loss prevention. The format is designed for a broad audience – from first-time conference attendees (like students or new employees) to experienced hearing conservationists seeking clarification about hot-topic issues from disciplines outside their own specialty.
This one-day workshop will include presentations in the morning and hands-on demonstrations of fit testing equipment in the afternoon. The morning will begin with background on hearing protector fit testing, summary of recent updates to regulations and best practices, implementation, and case studies of fit testing in practice. The morning session will conclude with presentations from fit test system manufacturers. Manufacturer presentations will touch on how their system works, the types of hearing protection they can be used with, and the testing they’ve performed to validate their system.
In the afternoon, attendees will engage in hands-on demonstrations. Manufacturers will set up equipment at stations spaced throughout the room. Attendees will rotate to different stations and have opportunities to try out the equipment. By the end of the workshop, attendees will have gained an understanding of the best practices in hearing protection fit testing, and ideas on how hearing protector fit testing fits within hearing conservation programs.
Music Audiology is a small speciality, however music people (performers, engineers, industry support professionals, avid concert goers) are a large population who seek hearing services from all practitioners. In this session, many of the most active and prolific speakers, clinicians, and researchers in the field will share important updates to best practice and technology/procedure updates pertinent to anyone interested in this population. Specific topics of focus will include recent progress in teleaudiology, best practices for safe use of in-ear monitors, verification and demystification of custom filtered hearing protection for performers, and updates on the many global initiatives for hearing loss prevention.
The Basics Workshop is designed to offer attendees a comprehensive perspective on the substance and conduct of an effective occupational hearing conservation program (HCP). This annual workshop, held on the conference’s first day, is a “short course” that will clarify and illustrate key hearing conservation requirements, practices, and resources that are used in HCPs (and will be cited in subsequent platform presentations in this conference). The speakers will define basic concepts and foundational knowledge used in HCPs, and then describe fundamental applications that are important and essential for hearing loss prevention. The format is designed for a broad audience – from first-time conference attendees (like students or new employees) to experienced hearing conservationists seeking clarification about hot-topic issues from disciplines outside their own specialty.
This one-day workshop will include presentations in the morning and hands-on demonstrations of fit testing equipment in the afternoon. The morning will begin with background on hearing protector fit testing, summary of recent updates to regulations and best practices, implementation, and case studies of fit testing in practice. The morning session will conclude with presentations from fit test system manufacturers. Manufacturer presentations will touch on how their system works, the types of hearing protection they can be used with, and the testing they’ve performed to validate their system.
In the afternoon, attendees will engage in hands-on demonstrations. Manufacturers will set up equipment at stations spaced throughout the room. Attendees will rotate to different stations and have opportunities to try out the equipment. By the end of the workshop, attendees will have gained an understanding of the best practices in hearing protection fit testing, and ideas on how hearing protector fit testing fits within hearing conservation programs.
Music Audiology is a small speciality, however music people (performers, engineers, industry support professionals, avid concert goers) are a large population who seek hearing services from all practitioners. In this session, many of the most active and prolific speakers, clinicians, and researchers in the field will share important updates to best practice and technology/procedure updates pertinent to anyone interested in this population. Specific topics of focus will include recent progress in teleaudiology, best practices for safe use of in-ear monitors, verification and demystification of custom filtered hearing protection for performers, and updates on the many global initiatives for hearing loss prevention.
Exposures to noise – that is, unwanted or harmful sound – have long been linked in workplace and (community!) settings to a host of adverse health effects, including noise-induced hearing loss (surprise, amirite?), cardiovascular disease (including hypertension and ischemic heart disease), and injuries. Yet millions of Americans remain unaware of the dangers of noise and occupational and environmental policies continually under-recognize noise as an important pollutant. On this auspicious 49th NHCA conference, what do we *really* know about noise exposures in American workplaces and communities, and how much harm those exposures are causing? This talk will provide an overview of trends and patterns in workplace and community noise in the US, discuss estimates of health risks associated with noise, and address health disparities and occupational and environmental justice issues. It will also highlight gaps in our understanding, opportunities for research that will help us better understand the impacts of noise, and potential paths forward for reducing noise in America.
The National Health and Nutrition Examination Survey (NHANES) is a program of studies designed to assess the health and nutritional status of adults and children in the United States. The examination component of NHANES typically includes a hearing threshold evaluation. Large datasets such as NHANES provide essential information on hearing in various populations as well as an opportunity to examine methodological aspects of audiometry. However, conventional audiometers provide limited stimulus, calibration, test protocol, and data options for researchers. An audiometric system designed to overcome these limitations built on commercially available hardware will be discussed in this presentation. The current system includes automated, semi-automated, and manual threshold-finding procedures; in-situ and fully automated calibration; full control of stimulus and test protocol parameters; comprehensive time and presentation histories; and continuous comparison of stimulus presentation levels against both ambient noise limits and presentation level for boothless applications. The system was developed in 2011 for NIOSH-sponsored projects and has been used in NHANES since 2017. Technical challenges, methodological issues, and performance metrics of the system will be presented. Examples of scientific findings which the system made possible will be discussed. Tools like this have the potential to help transform hearing testing in the future.
Gaps in the public health prevention of hearing loss likely exist in the US, but these have not been wholistically characterized previously. Using data on personal environmental noise exposure and hearing-related surveys from >100,000 participants consented and enrolled in the Apple Hearing Study from 2019-2022, we used multilevel regression and poststratification models to estimate the population at risk of noise-induced hearing loss (primary prevention), the prevalence of poor/fair hearing ability and diagnosed hearing loss (secondary prevention), and the use of hearing aid/cochlear implants (tertiary prevention). Modeling estimates suggest that 88 million US adults (95% confidence interval: 81-95) are consistently exposed to noise levels high enough to cause hearing loss. Around 67 million (62-72) perceive a poor/fair ability to hear, of which only roughly half have been diagnosed with a hearing loss (36 million [32-40]). Nearly 16.5 million (16-17) of those diagnosed with a hearing loss are estimated to not be using hearing aids or cochlear implants. Regulation of noise (e.g., work- and transportation-related), audiological testing, especially of younger adults, and expanded access to hearing assistive devices are needed to reduce the considerable gaps in hearing-related public health.
Objective: This study aimed to determine the effect of noise exposure history on the rate of pure-tone threshold change per year. Methods: Participants were 1,347 adults (mean age 63.4 [SD 14.3], follow-up time 5.1 [SD 5.7] years, 57.3% female, 17.6% racial Minority) from a longitudinal cohort study. Noise exposure history, determined via self-report and military history, was categorized as no/little, some, or high exposure. Outcome measures were audiometric thresholds (0.25-8.0 kHz) and pure-tone average (PTA [0.5, 1.0, 2.0, 4.0 kHz]), averaged bilaterally. Linear mixed regression models were used to estimate the effect of age (per +1 year) on the rate of threshold and PTA change. Results: Participants with more noise exposure had poorer baseline thresholds at most frequencies 1.0-8.0 kHz and PTA. Those with high noise exposure (vs no/little) showed higher rates of threshold change per year at 1.0 and 2.0 kHz. Those with some and high noise exposure showed lower rates of change per year at 3.0-8.0 kHz and 4.0-8.0 kHz, respectively, where hearing loss had already occurred. Conclusions: Noise exposure was associated with poorer baseline hearing, and higher rates of annual decline at some mid frequencies. Noise exposure can have immediate and potentially long-term negative impacts on hearing.
In 2009, damage to the synapses connecting the inner hair cells to the auditory nerve fibers was identified as one of the earliest noise-induced pathologies in the cochlea. Since then, there has been tremendous interest in the identification of damage-risk relationships in rodent models. In addition, there have been many efforts to translate these findings from rodent models to humans. Whereas studies in rodents and non-human primates have been rigorously controlled using a single exposure to calibrated noise, studies in humans have attempted to estimate the cumulative effects of lifetime exposure and seek associations between exposure estimates and functional measurements, and identify biomarkers for specific damage, such as cochlear synaptopathy. This session will review the current understanding of noise-induced cochlear synaptopathy in rodents, non-human primates, and humans, and provide an overview of key questions in the application of these data to workers with chronic exposure to noise in the workplace. An overview of new studies assessing chronic noise exposure in non-human primates will be provided. In addition, this session will provide practical take home messages you can share with patients who have questions about noise-induced hearing deficits beyond the audiogram.
Background: The purpose of this study was to estimate the prevalence of hearing difficulty and workplace exposures to ototoxic chemicals and noise within U.S. industries and occupations.
Methods: National Health Interview Survey data from 2023 were examined, including 17,726 workers. Weighted prevalence and adjusted prevalence ratios of self-reported hearing difficulty and self-reported workplace exposures to ototoxic chemicals, noise and a combination of these exposures were estimated by industry, occupation and demographic. Workplace exposure to secondhand smoke was examined combined with other ototoxic chemicals, but also separately.
Results: Eleven percent of workers reported hearing difficulty. Within the past year, 13% were exposed to ototoxic chemicals and 5% were exposed to secondhand smoke. Twenty-eight percent of workers had a history of occupational noise exposure, with 16% exposed within the past year. Seven percent were exposed to both noise and ototoxic chemicals.
Conclusions: Hearing hazards in the workplace are common. This study was the first to report the prevalence of ototoxic chemical exposure among U.S. workers. This exposure cannot be overlooked when protecting worker hearing. Both noise and ototoxic chemical exposures can be reduced using the hierarchy of controls. Workers with both exposures should receive special attention in hearing conservation programs.
Hearing Protector Fit Testing (HPFT) is quickly gaining acceptance as a critical element of a successful hearing conservation program. NHCA encourages the continued adoption of this practice and recognizes the need for research in this area. To support these goals, NHCA founded the Task Force on Hearing Protection Fit Testing (HPFTTF).
The first task of HPFTTF was to draft an evidence-based Position Statement on HPFT, representing current recommendations and best practices. The Position Statement recognizes HPFT as a powerful tool for preventing noise-induced hearing loss, with potential to shape the practice of hearing loss prevention. Some of the topics covered in the Position Paper are Measurement Methods and Systems, Resulting Data and Statistics, Benefits and Challenges, and Incorporating HPFT into a Hearing Conservation Program (HCP). The document also discusses practical considerations such as how to choose a system, who to test and when to test them, how to interpret and apply results, and special situations.
NHCA recommends the use of HPFT as part of a comprehensive HCP and encourages continued research to further define best practice policy, explore use cases, and evaluate the long-term impact of HPFT.
In 2024, the National Hearing Conservation Association established a task force to draft a position statement on the use of equivalent rectangular bands (ERBs) in audiometric testing. The Occupational Safety and Health Administration does not require testing at 8000 Hz as part of audiometric monitoring for noise-exposed workers. Although inclusion of 8000 Hz is recommended as a best practice, many workplace hearing conservation programs do not test this frequency. One reason is that pure tone thresholds at 8000 Hz can be unreliable due to the short wavelength of the tone and the potential for standing waves in the ear canal. However, epidemiologic surveys have shown that females are more likely to have a maximum audiometric “notch” at 6000 Hz than males, who typically show a maximum “notch” at 4000 Hz. Without testing 8000 Hz, early noise-induced hearing changes may be missed in women. Recent research has shown that the use of ERBs as audiometric stimuli results in thresholds that have equal or greater reliability than pure tone thresholds, even at 8000 Hz. This presentation will provide an update from the NHCA Task Force on the feasibility and effectiveness of using ERBs in place of pure tones for occupational audiometric monitoring.
The primary sense of many marine mammals is hearing. To some degree, nearly all marine mammals rely on hearing for foraging, predator avoidance, and navigation. Anthropogenic noise in the world’s oceans has steadily increased since the industrial revolution. Anthropogenic ocean noise sources (e.g., sonar, seismic surveys, shipping) range in frequencies from tens of Hz to more than hundreds of kHz, can project at levels exceeding 235 dB re 1 µPa, and can be impulsive or continuous. Impacts to marine mammals resulting from noise exposure are like humans, mainly masking, temporary or permanent threshold shift (TTS and PTS, respectively), and behavioral disturbance or annoyance. In some extreme cases, whales have stranded and died after intense noise exposure. Extensive research over the last three decades has sought to determine the thresholds of received sound associated with the onset of TTS. The use of auditory evoked potential methods has also been used to measure audiograms in stranded or wild-caught species, since most marine mammals are not kept under human care. Collectively, these data for the basis of auditory weighting functions that are used to assess potential impacts to marine mammals as defined by the Marine Mammal Protection Act.
The development of professional-level musicianship requires playing and listening to music many hours per day over many years, but extended exposure to loud music (>85 dB) can lead to hearing loss. Because limiting exposure to music or controlling acoustic environments is not always feasible for student musicians, it is important to understand the likelihood of using personal hearing protection. The purpose of this study was to evaluate the impact of social, attitudinal, and emotional input on retention and acceptance of information on hearing preservation by college music students. Two types of instruction were evaluated: the standard written information on hearing preservation disseminated by NASM, and a multimedia video containing the same information, but presented via video interviews of socially relevant role models. Participants comprised 66 music majors enrolled in a large Midwestern university and were randomly assigned to each group. Data were collected and analyzed to understand if there were differences in knowledge scores, satisfaction scores, and intention to use hearing protection between the two groups. Knowledge scores between the two interventions were not significantly different but the video group had significantly higher scores regarding their intention to use hearing protection, suggesting the importance of including role models in interventions.
This project was funded in part by an NHCA Scholarship Foundation Student Research Award
Sound quality is cited as a major barrier to musicians wearing musicians hearing protection devices (MHPD). Level and flatness of attenuation demonstrated significant yet weak correlations with sound quality. This study builds on previous research by using custom-fit products (to remove differences in comfort), recruiting musicians as well as untrained listeners, and adding music perception tests to the test battery.
Both musicians and untrained listener groups are asked to rate the sound quality of music and complete music perception tests while listening to music through custom-fit passive MHPDs (cMHPDs) and electronic uniform-fit MHPD (eMHPDs). Three attenuation filters are used for the cMHPD (9, 15, and 25 dB attenuations) and three attenuation settings were used for the eMHPD (9 and 15 dB, and an off setting).
Data collection is ongoing. Data will be analyzed to test hypotheses related to changes in perceived sound quality and performance on music perception tests with increasing attenuation.
The results of this study will contribute to the understanding of barriers to the use of MHPD by musicians and music appreciators. Data from the music perception tests will reveal whether increasing attenuation compromises performance. Taken together, these findings will help guide education on MHPD use by musicians.
From homeowners cutting grass on the front lawn to large construction companies building skyscrapers, power tools are essential. Unfortunately, power tools can generate hazardous exposures that can cause hearing damage. For those looking to protect their hearing, buying quieter equipment can reduce total noise exposures and prevent hearing loss; however, noise may not be a major purchasing factor for many people. NIOSH researchers aiming to promote the Buy Quiet initiative wanted to better understand the factors motivating power tool purchases and how noise is viewed in comparison to factors like cost and durability. Three questions were included on a recent Porter Novelli FallStyles Survey. Porter Novelli Styles is an online, nationally-representative market research survey. The questions explored factors which influence consumer power tool purchasing decisions. Over 3500 respondents provided data on whether they consider noise and to what degree. This presentation will explore the process of using Porter Novelli ConsumerStyles surveys and the useful insight they provided regarding attitudes toward noise.
A review of current policy issues and trends in interstate practice by audiologists, including ongoing changes to state telepractice laws and an update on the implementation of the audiology and SLP interstate compact (ASLP-IC).
The megatrend on improving sustainability is touching personal protective equipment through standards and regulations relevant to product design, packaging selection and manufacturer claims about product life cycles and their environmental impact. Recent revisions in a European hearing protection standard, anticipated regulations concerning sustainability claims, and increased consumer interest in general sustainability factors, spurred the effort to create a Product Category Rule for hearing protector devices. This project followed on the heels of the first publication of a PCR for respiratory protective devices. A PCR sets the rules for creating a Life Cycle Assessment (LCA) and provide the requirements and guidelines for developing an EPD (Environmental Product Declaration) for a specific product category. Using a standardized approach globally, establishes a consistent and transparent process for conducting the LCA and ensure that functionally similar products are assessed in the same ways. This presentation explains the work undertaken to create the first PCR for hearing protector devices. It describes how the PCR is used to help calculate legitimate LCA’s, which provide the data and foundation for Environmental Product Declarations (EPDs). Benefits of the PCR include the potential to improve authenticity and transparency for consumers when comparing environmental impact of like products.
This project was funded in part by an NHCA Scholarship Foundation Student Research Award
Hazardous noise exposure is an important health concern in many workplaces and is one of the most common work-related injuries in the United States. Dental professionals are frequently exposed to high levels of occupational noise in their daily work environment. This noise is generated by various dental handpieces such as drills, suctions, and ultrasonic scalers. Prolonged exposure to such noise levels is known to have adverse effects on hearing health. Despite the prevalence of occupational noise in dentistry, there is a paucity of comprehensive research specifically addressing the noise intensity of dental handpieces and examining the prevalence of hearing loss and tinnitus in dental professionals. First, noise levels were measured from different dental handpieces and evacuation systems in a typical clinic setting. To evaluate the prevalence of hearing loss and tinnitus, data were collected from 60 dental professionals including participant demographics and audiometric thresholds. Results showed that 15-25% of males and 13-18% of females had hearing loss that exceeded 95 th percentile limits based on the International Organization for Standardization (ISO) normative age-distributions. Tinnitus was reported in 40% of the participants. This study is the first to offer a comprehensive characterization of auditory thresholds in dental professionals with comparisons to the ISO normative age-distributions for males and females.
Firefighters encounter a multitude of toxic substances in their line of duty, significantly impacting their health. NIOSH has investigated many of the exposures and health effects that are prevalent among firefighters. Ototoxic agents (carbon monoxide, hydrogen cyanide, volatile organic compounds, and metals) are some of the hazards firefighters face. Despite the risk of hearing effects, hearing testing is not consistently offered to firefighters, and when available, it is limited to pure-tone audiometry. Cases of ototoxicity may or may not include poorer hearing thresholds, but often lead to difficulties in discriminating sounds such as speech, particularly in adverse listening conditions. Unfortunately, no standardized methods are in place for monitoring hearing in individuals exposed to hazardous chemicals at work. To address this gap, the International Ototoxicity Management Group is finalizing expert consensus resources designed for occupational health and safety programs. The proposed strategies include early identification through self-report questionnaires, expanded hearing testing and vestibular screening, criteria for referral and management of cases. Continuous efforts are needed to improve protective measures and reduce these hazardous exposures firefighters face. Listen as one firefighter joins us to share his story.
The World Health Organization (WHO) Make listening safe initiative aims to realize a world where people of all ages can enjoy all types of recreational listening without risk to their hearing. Over 3 billion people worldwide regularly engage in video gameplay and esports and may be exposed prolonged and high-intensity audio, demonstrating the need to prioritize safe listening among game players. This presentation will provide an overview of the WHO Make listening safe initiative, with a focus on efforts related to safe listening among video game and/or esports players. In addition to providing an overview on the WHO Make listening safe initiative, this presentation will focus on three primary topics. First, the speaker will present an overview of the current evidence base, including details from a systematic review and global surveys, related to the risk of unsafe listening among video game players. Second, the speaker will discuss the creation of evidence-based standards, developed in collaboration with various stakeholders, aiming to promote safe listening among video game players. Third, the speaker will present ways in which the WHO aims to raise global awareness on safe listening.
A Hybrid Model of Presenting Dangerous Decibels to Multiple Classrooms Simultaneously Valerie Pavlovich Ruff, AuD, Sharon Sandridge, Ph.D. Descriptives of cohort one participants in the Apple Hearing Study Lauren M. Smith, MS, MPH, COHC Evaluating the Necessity of Follow-Up Test Two in DoD Hearing Conservation Protocol John Foster, Lt Col, AuD, MSPH, Jennifer Sweny, AuD Hearing Loss and Physical Activity in Aging Farmers Jan Moore, Ph.D. Investigation of Spatial Memory and Learning Skills in Rats with Unilateral Mild-Moderate Congenital Hearing Loss: A Preliminary Behavioral Study FATMA NUR KOMUR, MSc., OZLEM TUGCE CILINGIR KAYA, Ph.D., AYCA CIPRUT, Ph.D., AYSE NUR YAVUZ, Ph.D., ALI CEMAL YUMUSAKHUYLU, Ph.D. Mapping occupational noise research topics Krystin Carlson, PhD Exploration of Prevalence, Progression, and Prevention of Hearing Loss in Osteogenesis Imperfecta Types III and IV by COL1A1 and COL1A2 mutations. Julie Christensen, M.S. Sound exposure and hearing protection: A survey of electronic dance music attendees Hannah Miller, BA Speech Intelligibility and Phonemic Errors in Veterans with Sensorineural Hearing Loss Madison Aivaz, B.S., Sridhar Krishnamurti, Ph.D, Kathleen McDevitt, Undergraduate Student The Role of Music Educators in Hearing Loss Prevention Blake Voss, B.S. Influence of reference transducer location on hearing protector attenuation metrics for impulse noise William J. Murphy, Ph.D. Using data science tools to elucidate information from a complex occupational exposure database. -- Christopher Wendt, MPH Evaluation and Comparison of Hearing Protector Training Methods William J. Murphy, Ph.D.
A Hybrid Model of Presenting Dangerous Decibels to Multiple Classrooms Simultaneously Valerie Pavlovich Ruff, AuD, Sharon Sandridge, Ph.D. Descriptives of cohort one participants in the Apple Hearing Study Lauren M. Smith, MS, MPH, COHC Evaluating the Necessity of Follow-Up Test Two in DoD Hearing Conservation Protocol John Foster, Lt Col, AuD, MSPH, Jennifer Sweny, AuD Hearing Loss and Physical Activity in Aging Farmers Jan Moore, Ph.D. Investigation of Spatial Memory and Learning Skills in Rats with Unilateral Mild-Moderate Congenital Hearing Loss: A Preliminary Behavioral Study FATMA NUR KOMUR, MSc., OZLEM TUGCE CILINGIR KAYA, Ph.D., AYCA CIPRUT, Ph.D., AYSE NUR YAVUZ, Ph.D., ALI CEMAL YUMUSAKHUYLU, Ph.D. Mapping occupational noise research topics Krystin Carlson, PhD Exploration of Prevalence, Progression, and Prevention of Hearing Loss in Osteogenesis Imperfecta Types III and IV by COL1A1 and COL1A2 mutations. Julie Christensen, M.S. Sound exposure and hearing protection: A survey of electronic dance music attendees Hannah Miller, BA Speech Intelligibility and Phonemic Errors in Veterans with Sensorineural Hearing Loss Madison Aivaz, B.S., Sridhar Krishnamurti, Ph.D, Kathleen McDevitt, Undergraduate Student The Role of Music Educators in Hearing Loss Prevention Blake Voss, B.S. Influence of reference transducer location on hearing protector attenuation metrics for impulse noise William J. Murphy, Ph.D. Using data science tools to elucidate information from a complex occupational exposure database. -- Christopher Wendt, MPH Evaluation and Comparison of Hearing Protector Training Methods William J. Murphy, Ph.D.
The selection of appropriate hearing protection devices (HPDs) is crucial for safeguarding against hazardous noise exposure and preventing noise-induced hearing loss. Traditional selection methods primarily rely on the Noise Reduction Rating (NRR), often neglecting other factors. To improve upon these methods, an interactive software platform, the Hearing Protection Optimization Tool (HPOT), was developed to guide HPD selection. The HPOT down-selects HPDs using performance metrics derived from laboratory-based, electromechanical tests. These electromechanical tests have been validated against human subject performance and quantify the adverse effects of HPDs on sound localization, speech intelligibility, self-noise, and level-dependent attenuation. User input indicates the importance of each aspect of performance for their specific application and the software generates a ranked list of the HPD options that best meet both attenuation requirements and desired performance characteristics. The recommendations can be further refined based on logistical constraints such as power requirements, compatibility with additional protective equipment, form factor preferences, and cost. The HPOT significantly advances hearing conservation efforts by eliminating the guesswork in the HPD selection process, allowing users to make informed choices based on objective measures that best align with their protection goals.
Around 9 million Americans currently face the hazard of noise induced hearing loss (Dobie, 2008). Personal Attenuation Ratings (PAR) reflect the custom attenuation provided by ear plugs and can be helpful in implementing hearing conservation programs in industrial settings. PAR ratings can be confounded by lack of instruction on self insertion of ear plugs. Differences in shape and size of ear canals also play a role. The purpose of the current study was to evaluate PARs obtained from paper mill workers. PARs from paper mill workers were compared to a control group comprised of AuD students enrolled in a hearing conservation course. Audiograms and PARs were obtained from 10 paper mills workers after self insertion of ear plugs. A WAHTs system was used to collect the data. The audiometric data was used to compile information on years lived with disability (YLD). Mill workers exhibited high YLD. Statistical analysis was performed using independent samples T test to compare two groups, paper mill workers vs. controls. T test results showed that the PAR values were significantly reduced in paper mill workers, relatively to controls (T= -7.44; P <.001). These results illustrate the importance of experience required in self insertion of ear plugs.
Impulsive noise and blast are known to cause auditory deficits, but the relationship between exposure and injury is not well quantified. To better understand military-specific auditory injuries, Walter Reed National Military Medical Center (WRNMMC), in partnership with the Defense Center for Public Health Aberdeen (DCPH-A) and other collaborators within the DOD, has been engaged in a multiyear effort to characterize the hearing changes that occur following exposure to high-level impulsive noise.
This work has been enabled by two major advances: the development of wearable dosimeters capable of measuring both impulsive and continuous noise, and the development of boothless audiometer systems capable of measuring pre- and post-exposure hearing performance under field conditions. These technologies have made it possible to measure cumulative noise exposures and the resulting hearing changes in hundreds of service members who have been engaged in training events with heavy weapons and other high-level impulsive noise sources. The results provide insights into the development of improved hearing risk criteria for impulsive noise.
The views expressed in this abstract are those of the authors and do not necessarily reflect the official policy of the Department of Defense or the U.S. Government.
Level-dependent hearing protectors enable to perceive or even amplify soft to medium-level sounds, while protecting the ear against damaging high-level signals. This study investigates the effect of two level-dependent hearing protection devices on localization performance with two different warnings signals in noise. In a listening test with 16 normal-hearing subjects inside a horizontal array of 48 loudspeakers, localization performance dropped using earmuffs. In the most extreme cases, signals where perceived as coming from the opposite direction. In addition, the stimuli used in the experiment were recorded with an artificial head in the same measurement setup to calculate the corresponding interaural cues. The technical measurements support the findings of the hearing study by revealing large changes of interaural level differences with earmuffs compared to open ears that were mostly in line with the subjects’ response. Finally, current localization models were run with the recordings to check their performance and predictions with the tested warning signals. These findings indicate that it is critical to test electronic hearing protectors on changed interaural cues to avoid safety risks due to impaired localization. In addition, measurements of these cues can help predicting the perceived sound direction by human listeners, e.g., by modelling the possible outcomes.
Bose A20 headsets are commonplace in aviation; however, the new A30 headset is set to replace them. Aviation headsets serve as communication devices, while allowing for hearing protection. Real-Ear Attenuation at Threshold is a standard measure for determining the passive attenuation of hearing protectors and has strict room requirements for conducting measurements. Field Attenuation Estimation Systems are gaining interest to assess fit for hearing protectors in the operational community, but are limited by the inability to assess over-the-ear hearing protectors. A proposed method of utilizing the WAHTS audiometer with the headset positioned around the neck to conduct psychoacoustic measurements. This study compares standard REAT measurements to the proposed fit check method to assess the passive attenuation of the Bose A30. We will compare the frequency-specific attenuation and calculate the Personal Attenuation Rating for each method. Total attenuation will be reported as well for the Bose A30.
Data analyses will be complete prior to the conference. We anticipate findings of similar nature for REAT and fit testing methods to identify the passive attenuation level of the Bose A30. Outcomes will be used to validate a correction factor for the neck-based procedure due to the level difference between on-ear versus on-neck configurations.
Hearing protection devices are limited in their ability to attenuate high-level firearm impulse noise. Hazardous sound levels can reach the cochlea via the flanking bone/tissue conduction pathway. Assessing bone/tissue’s role in high-level impulse transduction could allow for more accurate assessment of risk to hearing and other body systems (i.e. brain health). The aim of this study was to estimate firearm sound levels conducted via the bone/tissue pathway using temporal bone acceleration recordings from an anatomic head simulator. Firearm impulses from two different rifles were recorded using an anatomic head simulator instrumented with bilateral triaxial accelerometers in the temporal bone region, high level pressure measurement microphones within each ear canal, and a hydrophone and angular rate sensor located near the center of the head. Field levels of the firearm impulses were determined using recordings from a measurement microphone positioned near the head simulator. Firearm impulse-related acceleration was converted to equivalent sound pressure using previously published Reference Equivalent Threshold Acceleration Levels and then compared with recordings made in the sound field. Results indicated that bone/tissue conducted sound levels estimated using this method corresponded with published bone conduction attenuation limits for .5, 1 and 2 kHz frequency bands.
Noise-Induced Hearing Loss is the most prevalent occupational injury in US industry, affecting more than 10 million workers. Earplugs are a ubiquitous choice to mitigate exposure, but optimal use requires training, motivation, and patience, substantially limiting their real-world performance. A shallow insertion leads to poor attenuation, high variability, and the occlusion effect. Typically rated for about 30 dB of attenuation, actual earplug performance averages less than 15 dB with variability on the order of 10 dB (95% CI). In many settings, a majority of wearers receive grossly inadequate protection. Inconvenience, discomfort, and degraded communication also lead to low worker compliance. As many as 80% of workers wear HPDs inconsistently, dramatically limiting efficacy. Last year we presented a novel dynamic toroidal earplug concept designed to address these issues, offering substantially improved ease-of-use for untrained users while providing high attenuation and low variability. This year we present a mature example of this earplug along with subject-fit attenuation data in both trained and inexperienced subjects using both Microphone In Real Ear (MIRE) and Real Ear Attenuation At Threshold (REAT) techniques. This work is supported by the National Science Foundation.
As OSHA standards continue to shape workplace safety protocols, the ability to deliver compliant, reliable, and innovative hearing conservation solutions is more critical than ever. This presentation will delve into the latest advancements in digital audiometry, with a focus on how these technologies can support organizations in meeting OSHA’s requirements. We will explore the latest updates to hearX’s Hearing Conservation solution, which enables compliance at lower cost with more efficient testing and secure cloud data management without needing a traditional sound booth.
Additionally, the session will address the need for rigorous data protection certifications that not only secure sensitive employee information but also ensure full compliance with HIPAA and other relevant regulations. Finally, our presenter will introduce recent enhancements to our cloud-based data management system, designed to streamline reporting and operational efficiency, providing actionable insights supporting compliance and improved employee health outcomes.
Impulsive noise is generated by the rapid release of compressed gases (impulse) or by the collision of solid objects (impact) and is most common in metalworking, construction, shipyard, and mining industries as well as law enforcement and the military. Research on the effect of complex (mixed steady state and impulsive) noise on hearing health suggests it may be more damaging than an equal amount of energy from steady state noise. There is also concern that repetitive low-level blast exposures might result in chronic brain health problems. Unfortunately, no commercial noise dosimeter currently measures complex noise accurately. We report on the collaborative development of a dual-microphone noise dosimeter with a wide dynamic range of 40 dBA up to 185 dB Peak with a sampling rate of up to 96 kHz. Real-time processing accounts for both steady-state and impulses into the calculation of total noise dose, records individual impulses that exceed a pre-specified threshold, and counts the number of impulses. We present data obtained in the laboratory with comparison to reference equipment, as well as in field settings, including military weapons training. We conclude on the utility of the device and future development needed to integrate it into occupational health programs.
The assessment of sound exposure from communication devices and earphones typically requires specialized measurement methods such as the microphone in the real-ear technique or the use of manikins or artificial ears. In practice, however, such assessments are challenging to deploy in most workplaces and are often not conducted on a regular basis due to lack of proper equipment and/or expertise. A simple calculation method has been devised that only requires widely accessible equipment (e.g. sound level meter or noise dosimeter) together with basic information about the devices worn (e.g., attenuation) and the communication or listening task (e.g., duration of listening within the work shift). The calculation method, specified in Canadian standard Z107.56, is intended to increase accessibility to communication device and earphone sound exposure assessments to the widest range of stakeholders in hearing loss prevention. The method brings together the many factors contributing to communication devices and earphone sound exposure and thus it is also useful when examining possible exposure mitigation measures. This paper will present the calculation method and provide examples of its uses.
Conducting a hearing conservation testing program without a sound booth is possible with boothless audiometers. Dr. Victoria Bugtong, Au.D., a former Department of Defense (DOD) Audiologist, shares successes and challenges with setting up and maintaining a permanent boothless hearing conservation testing program. The presentation will guide you through the steps for taking the testing mission out of the sound isolation booth and successfully bringing it to any temporary testing event. The presentation covers all aspects of implementing boothless audiometry in the DOD from preparation, set up, ambient noise considerations, patient documentation and data entry. Dr. Bugtong will share the patient testing processes, and the lessons learned from her years working with boothless audiometers.
In-ear noise dosimetry offers benefits over traditional free-field or body-worn dosimetry because in-ear dosimeters measure actual noise exposure, including the as-worn attenuation provided by the subject’s hearing protection. Furthermore, impulse sounds may be accurately captured with microphones that have lower dynamic range and bandwidth requirements than those needed for freestream or body-worn dosimeters because the hearing protection moderates the peak levels and frequency characteristics of impulse sound waves. However, there are challenges to the use of in-ear dosimeters. The microphone must be integrated into an eartip that is comfortable and easy to use. The sound level measured by the ear-canal microphone should be related to the level at the eardrum and to the free-field, which is the level on which current permissible exposures are based. If the hearing protection device provides communications or a transparent hear-through mode, then any coupling between the microphone and speaker must be addressed. Consideration should also be given to artifacts induced by knocks or cable noise and to the effect of the wearer’s voice or other body noises. The practical benefits, challenges and constraints of in-ear dosimeters are presented through a discussion of the development and testing of a wireless in-ear dosimeter.
“Why Is Everything So Loud” is a question I have been asking myself for many years. It didn’t used to be this way. Since the evolution of humans, loudness has steadily grown and has become engrained in society. How has loudness affected us, how did we accommodate loudness in our lives, and what we can expect in the future? Also, we’ll discuss “quiet,” define it, why quiet is important, and how to achieve it in our daily life.
HPD Fit Testing: Results from the U.S. National Rapid Surveys System Gong, Wei (Primary Presenter), Themann, Christa (Co-Presenter) "To assess the knowledge of HPD fit testing among the U.S population, questions were included in a national online panel survey (National Center for Health Statistics Rapid Surveys System) conducted between October 12 and November 20, 2023. The survey collected self-reported data on adult’s use of HPDs, awareness of fit testing, and perceptions about the importance of HPD fit testing. The survey results were analyzed both overall and in relation to gender, age, education, race/ethnicity, and experience with using hearing protection. The results of the survey provide valuable insights which can inform the implementation of HPD fit testing in hearing loss prevention programs. Disclaimer The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Mention of any company or product does not constitute endorsement by NIOSH, CDC. "
Hearing protector fit testing (HPFT) provides a substantial opportunity for the Department of Defense (DOD) to improve its hearing conservation program (HCP). HPFT ensures individuals are trained to correctly insert their hearing protectors so that they have a hearing protector that provides an appropriate level of protection. The ability to hear and communicate is vital to mission accomplishment, and when auditory function is impaired, critical safety and performance is degraded. Service members and noise-exposed civilians are at significant risk for noise-induced hearing loss. DOD policy requires the incorporation of HPFT into their HCPs. The development of a HPFT task force (TF), led by the Defense Health Agency, Hearing Center of Excellence, will expedite the adoption of this requirement. The TF will ensure a consistent program with respect to equipment, training, public health studies, and recordkeeping. Coordination and collaboration between the DOD and its component organizations supports effective, cohesive, and comprehensive HPFT implementation. This talk will address successes, challenges, and best practices associated with the development of implementation plans, establishment of equipment, training, and information technology requirements, and development of research plans to address gaps for DOD large-scale HPFT program implementation.
Subjective methods to conduct hearing protector fit testing and booth-less audiometry assess hearing thresholds for unoccluded and occluded conditions. During a 2012 NIOSH field evaluation of hearing protection fit testing with HPD Well-Fit™, workers’ personal attenuation ratings (PAR) were tested in four locations (two conference rooms and two small offices). During testing, the ambient noise levels were captured every ten seconds and the timestamps for each threshold identification were recorded with 1-second resolution. The clocks on the computers and the sound level meters were synchronized prior to commencing the field study. The one-third-octave-band noise levels from 20 to 20,000 Hz were logged and compared with the hearing thresholds measured at 500, 1,000, and 2,000 Hz. Ambient background noise may have masked the 500 Hz thresholds for the unoccluded ears more than the thresholds for 1,000 and 2,000 Hz. This paper will consider the potential effects on the overall three-frequency PAR and propose methods to monitor ambient noise.
Hearing protector fit testing (HPFT) measures the amount of attenuation a hearing protector provides while it is being worn. Recent Department of Defense (DOD) policy changes mandating HPFT for certain noise-exposed personnel assume that a significant portion of hearing damage is directly related to poorly fit hearing protectors. However, there is limited direct evidence supporting the effectiveness of HPFT in reducing service-related auditory injuries in the military. Additionally, current HPFT methods are not appropriate for all hearing protector styles.
This presentation will highlight ongoing efforts to improve hearing health and readiness in the military by implementing HPFT in various contexts within DOD Hearing Conservation Programs. It will discuss current findings investigating the relationship between personal attenuation rating (PAR) and various hearing health outcomes (e.g., hearing threshold shifts, noise exposure history, and hearing difficulties). The overarching goal is to transition knowledge from this project to assess the feasibility of a minimal acceptable PAR standard, identify key hearing protection fitting behaviors for standardized education, and underscore the importance of incorporating HPFT within DOD hearing conservation.
The views expressed in this abstract are those of the authors and do not necessarily reflect the official policy of the Department of Defense or U.S. Government.
The Department of Defense (DOD) has implemented new requirements under Instruction 6055.12 for comprehensive hearing conservation programs (HCPs) to protect military personnel from hearing loss. These regulations mandate the use of hearing protection devices (HPDs) as well as their proper fit, particularly for those individuals exposed to hazardous noise or experiencing significant changes in hearing thresholds. To meet these evolving needs, there is a demand for integrated test systems that combine both hearing- and fit-testing capabilities to enhance efficiency and compliance. This presentation will explore the broader challenges of implementing large-scale, effective fit testing and examine an innovative solution that can streamline these processes. We will introduce a new approach to integrating fit testing instructions into the Wireless Automated Hearing Test System (WAHTS) mobile app, as a potential solution to HCP needs. By allowing for asynchronous, multi-user testing with minimal administrative oversight, and providing personalized, interactive education and re-instruction, WAHTS’ new app enables a model for reducing time, personnel, and costs. The discussion will highlight how these technological advancements align with the DOD's commitment to protecting hearing health while optimizing operational efficiency.
The November 22, 2023 update to Department of Defense (DOD) Instruction 6055.12, "Hearing Conservation Program" promulgates a significant new requirement for hearing protector fit testing to be conducted for all DOD personnel who have noise exposures greater than or equal to 95 dBA 8-hour time weighted average (TWA) and who are enrolled in a service hearing conservation program (HCP). This requires multi-frequency REAT or MIRE testing to identify the need for earplug fit training or alternative earplugs for an individual, which imposes significant time and instrumentation in the field setting. A new acoustical physical methodology has been developed to precede in-field REAT or MIRE, not requiring REAT’s threshold tests or MIRE’s in/under-earplug microphones. The Leak-and-Attenuation Test (LAT) comprises an special instrumented headphone worn over the occluding earplug, and via analysis of resonance and sound path lengths that reflect the quality of an earplug’s seal, leaks are identified in a few seconds without requiring both occluded and unoccluded trials as in REAT or MIRE. Simulated ear canal data were reported at NHCA earlier, demonstrating the frequency shift and magnitude parameters that reflect different earplug leak sizes. This paper reports on actual human testing with the LAT headphone system, with a comparison of LAT data for earplug fits with no leaks and different-sized leaks against REAT data for each of the same fits on the same subject. Strong positive correlation between LAT and low-frequency REAT results resulted, evidencing that the LAT system is predictive of REAT results for both well-fit and leaky earplugs. Given such objective data from a very quick occluded-only test, the hearing conservationist can quickly decide whether to re-fit or assign an alternative earplug, before proceeding to the more lengthy REAT or MIRE testing.
Hearing protection devices (HPDs) play a critical role in mitigating noise-induced hearing loss in occupational settings. However, these devices often alter signals, hindering communication and localization abilities, particularly for workers with pre-existing hearing loss for which HPDs may attenuate key signals below their hearing thresholds. While hearing aids have shown promise in addressing similar issues in everyday noise, limited research exists on their efficacy in noisy industrial settings. This study evaluates the performance of typical hearing aid algorithms implemented on a digital hearing protection device, specifically assessing their impact on speech intelligibility in industrial noise. Algorithms under investigation include wide dynamic range compression, linear amplification, compression limiting, noise reduction, and various combinations thereof. Using an adapted Hearing-in-Noise-Test, speech reception thresholds (SRTs) were measured in both industrial noise and quiet conditions for 10 participants with normal hearing and 24 participants with mild to moderate hearing loss. Participants also rated the comfort and quality of the speech signal for each algorithm configuration. This comparison of SRTs and subjective rating provides valuable insights into the effectiveness of various algorithms configurations. The findings will guide further research into optimizing digital HPDs for occupational environments, ultimately improving communication and safety for workers with hearing loss.
The Noise Mapper Application developed by the National Institute for Occupational Safety and Health (NIOSH) can be used to identify areas in the workplace where workers may be exposed to hazardous noise. The app was created to empower workers to measure sound levels in their workplace, make informed decisions about noise exposure, and prevent occupational hearing loss. To evaluate the maps generated by the app, a single sound source or multiple sources were used to generate steady state sound fields within the NIOSH hemi-anechoic chamber (HAC). A sound level meter (Larson Davis, Model 831C) was used to measure A-weighed equivalent continuous sound levels on a grid with a spacing of 1.5 m (5 ft). The NIOSH Noise Mapper app was then used to generate sound level contour plots with a grid spacing of 3.0 m (10 ft). The accuracy of the map was evaluated by comparing the predicted sound levels with the measured sound levels. The results show the app can estimate the sound levels to within ±1.2 dB(A) of the measured values. The test method used to evaluate the NIOSH Noise Mapper app and the results of the comparison will be discussed in this paper.
While protection against high-level noise remains the primary purpose of hearing protection devices (HPDs), auditory situational awareness is also very important to maintain safety at work and to ensure acceptance to wear HPDs. One important factor is speech intelligibility in face-to-face communication, which may be impaired due to the HPD’s sound attenuation. To facility speech perception in conditions with temporarily lower noise levels, level-dependent HPDs offer acoustic transparency or even amplification of environmental sounds to prevent the users to take off their HPDs when attempting to communicate. To evaluate the benefits of such speech enhancing features, conducting formal listening tests is the gold standard. However, subjective testing is time-consuming and costly, and therefore instrumental metrics which accurately predict the outcome of such listening tests would be desirable. This study reviews recent advances in the development of such instrumental metrics and illustrates how they can be applied the context of HPDs. The focus is on level-dependent HPDs, which cannot be assessed using model approaches assuming linear audio signal processing. The contribution will illustrate application examples of benchmarking different HPDs, and demonstrate the potential of current models for real-time assessment of speech intelligibility in dynamically changing acoustic conditions.
