Ototoxicity refers to the adverse effects of substances on auditory or vestibular functions. This study examines the evidence of ototoxicity's association with exposure to common environmental pollutants, as documented in toxicological profiles by the Agency for Toxic Substances and Disease Registry. Our aim was to evaluate whether the evidence supports modifying the charting of ototoxic effects in the summary tables of these toxicological profiles and providing a guide for scientists to access these data. Health outcomes of interest included hearing loss, vestibular effects, cochlear lesions, tonal alterations, cellular damage, and ototoxicity-related outcomes (neurological, nephrotoxic, hepatic, and developmental effects). We obtained ototoxicity information for 62 substances. Hearing-related effects were reported, along with neurological effects. Overall, 26 profiles reported strong evidence of ototoxicity, including 13 substances previously designated as ototoxic by other health and safety agencies. Commonly studied outcomes included hearing loss, damage to ear anatomy, and auditory dysfunction. Vestibular dysfunction and tinnitus are rarely studied. Our findings highlight the lack of conclusive evidence of ototoxic properties for many substances, especially for pesticides and herbicides. This review supports charting the evidence of ototoxicity separately in toxicological profiles' summary tables. Improving the communication of ototoxicity-related health effects might impact their recognition and prompt further research. A stronger evidence base could support improved prevention efforts in terms of serious health outcomes.

BACKGROUND: Several health institutions developed strategies to improve health content on Wikimedia platforms given their unparalleled reach. The objective of this study was to compare an online volunteer-based Wikimedia outreach campaign with university course Wikipedia assignments (both focused on improving hearing health content in Wikimedia's public digital knowledge archives), in terms of the reach of the contributions and the extent of the participants' input. A secondary objective was to examine the feasibility and the implementation of the different strategies. METHODS: The research team partnered for the (1) coordination of improvements in hearing and healthcare content through educational programs using Wikimedia platforms, (2) participation in the global campaign Wiki4WorldHearingDay2023 and (3) evaluation of the proposed strategies. Metrics used in the comparison of the two strategies included the number of articles edited, number of views of the edited articles (as reach) and the extent of edits, captured as the number of words. The feasibility evaluation included assessing recruitment success and the implementation of the proposed plan among faculty, students from various university programs, and volunteers representing different constituencies. RESULTS: The effort increased the availability of quality plain language information on hearing conditions and hearing care. Both strategies demonstrated to be feasible by their success in recruiting participants who contributed to the effort and by measurable outputs as edits. The contribution of content to Wikimedia platforms as part of education activities provided a more robust result. Wiki4WorldHearingDay2023 145 participants (78 from educational programs) contributed 167,000 words, 258 + references and 140 images to 322 Wikipedia articles (283 existing and 39 new ones), which were viewed 16.5 million times. Contributions occurred in six languages. Edits in Portuguese, mainly by those involved in educational programs, led the number of articles (226 or 70.2%) that were expanded or created during the 5-month tracking period. CONCLUSIONS: The elements that contributed to the success of the studied strategies include an impact topic, coordination with educational programs, international multidisciplinary collaborations, the dissemination of the initiative in several platforms, connection with a robust local Wikimedia affiliate, and the use of a technical infrastructure that provides metrics and coordination mechanisms.

BACKGROUND: Global Burden of Disease studies identify hearing loss as the third leading cause of years lived with a disability. Their estimates point to large societal and individual costs from unaddressed hearing difficulties. Workplace noise is an important modifiable risk factor; if addressed, it could significantly reduce the global burden of disease. In practice, providing hearing protection devices (HPDs) is the most common intervention to reduce noise exposure at work. However, lack of fit of HPDs, especially earplugs, can greatly limit their effectiveness. This may be the case for 40% of users. Testing the fit and providing instructions to improve noise attenuation might be effective. In the past two decades, hearing protection fit-test systems have been developed and evaluated in the field. They are called field attenuation estimation systems. They measure the noise attenuation obtained by individual workers using HPDs. If there is a lack of fit, instruction for better fit is provided, and may lead to better noise attenuation obtained by HPDs. OBJECTIVES: To assess: (1) the effects of field attenuation estimation systems and associated training on the noise attenuation obtained by HPDs compared to no instruction or to less instruction in workers exposed to noise; and (2) whether these interventions promote adherence to HPD use. SEARCH METHODS: We used CENTRAL, MEDLINE, five other databases, and two trial registers, together with reference checking, citation searching, and contact with study authors to identify studies. We imposed no language or date restrictions. The latest search date was February 2024. SELECTION CRITERIA: We included randomised controlled trials (RCTs), cluster-RCTs, controlled before-after studies (CBAs), and interrupted time-series studies (ITSs) exploring HPD fit testing in workers exposed to noise levels of more than 80 A-weighted decibels (or dBA) who use hearing protection devices. The unit 'dBA' reports on the use of a frequency-weighting filter to adjust sound measurement results to better reflect how human ears process sound. The outcome noise attenuation had to be measured either as a personal attenuation rating (PAR), PAR pass rate, or both. PAR pass rate is the percentage of workers who passed a pre-established level of sufficient attenuation from their HPDs, identified on the basis of their individual noise exposure. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed study eligibility, risk of bias, and extracted data. We categorised interventions as fit testing of HPDs with instructions at different levels (no instructions, simple instructions, and extensive instructions). MAIN RESULTS: We included three RCTs (756 participants). We did not find any studies that examined whether fit testing and training contributed to hearing protector use, nor any studies that examined whether age, gender, or HPD experience influenced attenuation. We would have included any adverse effects if mentioned by the trial authors, but none reported them. None of the included studies blinded participants; two studies blinded those who delivered the intervention. Effects of fit testing of HPDs with instructions (simple or extensive) versus fit testing of HPDs without instructions Testing the fit of foam and premoulded earplugs accompanied by simple instructions probably does not improve their noise attenuation in the short term after the test (1-month follow-up: mean difference (MD) 1.62 decibels (dB), 95% confidence interval (CI) -0.93 to 4.17; 1 study, 209 participants; 4-month follow-up: MD 0.40 dB, 95% CI -2.28 to 3.08; 1 study, 197 participants; both moderate-certainty evidence). The intervention probably does not improve noise attenuation in the long term (MD 0.15 dB, 95% CI -3.44 to 3.74; 1 study, 103 participants; moderate-certainty evidence). Fit testing of premoulded earplugs with extensive instructions on the fit of the earplugs may improve their noise attenuation at the immediate retest when compared to fit testing without instructions (MD 8.34 dB, 95% CI 7.32 to 9.36; 1 study, 100 participants; low-certainty evidence). Effects of fit testing of HPDs with extensive instructions versus fit testing of HPDs with simple instructions Fit testing of foam earplugs with extensive instructions probably improves their attenuation (MD 8.62 dB, 95% CI 6.31 to 10.93; 1 study, 321 participants; moderate-certainty evidence) and also the pass rate of sufficient attenuation (risk ratio (RR) 1.75, 95% CI 1.44 to 2.11; 1 study, 321 participants; moderate-certainty evidence) when compared to fit testing with simple instructions immediately after the test. This is significant because every 3 dB decrease in noise exposure level halves the sound energy entering the ear. No RCTs reported on the long-term effectiveness of the HPD fit testing with extensive instructions. AUTHORS' CONCLUSIONS: HPD fit testing accompanied by simple instructions probably does not improve noise attenuation from foam and premoulded earplugs. Testing the fit of foam and premoulded earplugs with extensive instructions probably improves attenuation and PAR pass rate immediately after the test. The effects of fit testing associated with training to improve attenuation may vary with types of HPDs and training methods. Better-designed trials with larger sample sizes are required to increase the certainty of the evidence.

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:The first objective of this review is to assess the effects of field attenuation estimation systems and associated training on noise exposure at the ear and adherence to hearing protection use. A secondary objective is to assess whether the effects of field attenuation estimation systems differ according to age, gender, earplug type, and HPD use experience. 

This study aimed to scope the literature, identify knowledge gaps, appraise results, and synthesize the evidence on the audiological evaluation of workers exposed to solvents. We searched Medline, PubMed, Embase, CINAHL, and NIOSHTIC-2 up to March 22, 2021. Using Covidence, two authors independently assessed study eligibility, risk of bias, and extracted data. National Institute of Health Quality Assessment Tools was used in the quality evaluation of included studies; the Downs and Black checklist was used to assess the risk of bias. Of 454 located references, 37 were included. Twenty-five tests were studied: two tests to measure hearing thresholds, one test to measure word recognition in quiet, six electroacoustic procedures, four electrophysiological tests, and twelve behavioral tests to assess auditory processing skills. Two studies used the Amsterdam Inventory for Auditory Disability and Handicap. The quality of individual studies was mostly considered moderate, but the overall quality of evidence was considered low. The discrepancies between studies and differences in the methodologies/outcomes prevent recommending a specific test battery to assess the auditory effects of occupational solvents. Decisions on audiological tests for patients with a history of solvent exposures require the integration of the most current research evidence with clinical expertise and stakeholder perspectives. © 2023 Thieme Medical Publishers, Inc.. All rights reserved.

The National Institute for Occupational Safety and Health (NIOSH) evaluated continuous and impact noise exposures and hearing loss among workers at a hammer forge company. Full-shift personal noise exposure measurements were collected on forge workers across 15 different job titles; impact noise characteristics and one-third octave band noise levels were assessed at the forge hammers; and 4,750 historic audiometric test records for 483 workers were evaluated for hearing loss trends. Nearly all workers' noise exposures exceeded regulatory and/or recommended exposure limits. Workers working in jobs at or near the hammers had full-shift time-weighted average noise exposures above 100 decibels, A-weighted. Impact noise at the hammers reached up to 148 decibels. Analysis of audiometric test records showed that 82% of workers had experienced a significant threshold shift, as defined by NIOSH, and 63% had experienced a standard threshold shift, as defined by the Occupational Safety and Health Administration (OSHA). All workers with an OSHA standard threshold shift had a preceding NIOSH significant threshold shift which occurred, on average, about 7 years prior. This evaluation highlights forge workers' exposures to high levels of noise, including impact noise, and how their hearing worsened with age and length of employment. © 2023. Thieme. All rights reserved. Thieme Medical Publishers, Inc.

This case study examined the feasibility, reach, and potential impact of using Wikipedia as a tool for hearing health promotion. Activities involved editing existing Portuguese-language Wikipedia hearing health articles, as well as translating English-language hearing health articles to Portuguese during the Wiki4WorldHearingDay2019 and Wiki4YearOfSound2020 online campaigns. The Wikipedia efforts that took place in Brazil were carried out by 10 volunteer undergraduate students in Speech-Language Pathology and Audiology at the Federal University of Santa Catarina, in Brazil. Among new and existing Wikipedia articles, the group edited 37 articles, which attracted more than 220,000 views during the set tracking period. Students were responsible for 60% of the Portuguese-language edits during the Wiki4WorldHearingDay2019 campaign and more than 90% of the Portuguese-language edits during the first half of the Wiki4YearOfSound2020 campaign. Moreover, the quality indexes for pages either created or edited were improved in all situations by registering an increase rate ranging from 33% to 100%. Wikipedia-centered activities expanded the availability of quality scientific content, written in plain language, to the public. Students worked together in order to select topics, assess existing information, validate it, create new content, and share information-steps that contributed to the mission of health promotion and knowledge dissemination for the benefit of society.

This study aimed to assess temporary and permanent auditory effects associated with occupational coexposure to low levels of noise and solvents. Cross-sectional study with 25 printing industry workers simultaneously exposed to low noise (<80 dBA TWA) and low levels of solvents. The control group consisted of 29 industry workers without the selected exposures. Participants answered a questionnaire and underwent auditory tests. Auditory fatigue was measured by comparing the acoustic reflex threshold before and after the workday. Workers coexposed to solvents and noise showed significantly worse results in auditory tests in comparison with the participants in the control group. Auditory brainstem response results showed differences in III-V interpeak intervals (p = 0.046 in right ear; p = 0.039 in left ear). Mean dichotic digits scores (exposed = 89.5 ± 13.33; controls = 96.40 ± 4.46) were only different in the left ear (p = 0.054). The comparison of pre and postacoustic reflex testing indicated mean differences (p = 0.032) between the exposed (4.58 ± 6.8) and controls (0 ± 4.62) groups. This study provides evidence of a possible temporary effect (hearing fatigue) at the level of the acoustic reflex of the stapedius muscle. The permanent effects were identified mainly at the level of the high brainstem and in the auditory ability of binaural integration.

The National Institute for Occupational Safety and Health (NIOSH) and several university programs have collaborated on a large effort to expand and improve occupational safety and health content in Wikipedia using a platform developed by Wiki Education. This article describes the initiative, student contributions, and evaluations of this effort by instructors from two universities between 2016 and 2020. The Wiki Education platform allowed instructors to set timelines and track students' progress throughout the semester while students accessed training to best expand health content in Wikipedia. Students chose topics in occupational health based on their interests and by a set of topics deemed as a priority by the "WikiProject Occupational Safety and Health." Students' contributions were peer-reviewed by instructors, NIOSH Wikipedians-in-Residence, and traditional Wikipedians. Students presented their projects in class at the end of the semester. Students from both schools expanded 55 articles, created 8 new articles, and translated 2 articles to Spanish, adding 1270 references; these articles were viewed over 8 million times by May 2020. Feedback received from the implementation suggested that students learned about science communication and digital literacy-providing valuable content on occupational health while reducing misinformation in the public domain. The process of identifying and addressing gaps in occupational health in Wikipedia requires participation and engagement toward improving access to information that otherwise would be restricted to the scientific literature, often behind a paywall. The Wikipedia assignment proved to be an engaging approach for instruction and information literacy. It helped students improve their science communication skills and digital literacy, tools that are likely to be critical for successful communication of science in their future careers.

Purpose Several military occupations, particularly those within the U.S. Air Force, require working with or around jet fuels. Jet fuels contain components that are known to affect central nervous function, yet effects of these fuels on auditory function, specifically auditory processing of sound, are not well understood at this time. Animal studies have demonstrated that exposure to jet fuels prior to noise exposure can exacerbate the noise exposure's effects, and service members exposed to jet fuels are at risk of noise exposure within their work environments. The purpose of this article was to give a brief synopsis of the evidence on the ototoxic effects due to jet fuel exposure to aid audiologists in their decision making when providing care for populations who are occupationally exposed to fuels or while during military service. Conclusions Exposure to jet fuels impacts central nervous function and, in combination with noise exposure, may have detrimental auditory effects that research has yet to fully explain. Additional longitudinal research is needed to explain the relationships, which have clinical implications for service members and others exposed to jet fuels. In the meantime, audiologists can gain useful information by screening for chemical exposures when obtaining patient case histories. If jet fuel exposure is suspected, the Lifetime Exposure to Noise and Solvents Questionnaire can be used to estimate a noise exposure ranking and identify other potentiating agents such as jet fuel and industrial chemicals. A history of jet fuel exposure should inform the selection of hearing tests in the audiometric evaluation and when devising the treatment plan.

A survey was administered to 385 noise-exposed workers from an auto parts factory and 1268 non-noise-exposed health department employees in China. Individual 8 h A-weighted equiva-lent sound levels (LAeq,8h), earplug personal attenuation ratings (PARs), and pure-tone audiometric tests were performed. The average LAeq,8h of noise-exposed workers was 87 dB (A) with a mean PAR of 7 dB. The prevalence of high-frequency hearing loss was 65% for noise-exposed workers and 33% for the non-noise-exposed employees. The use of earplugs had no observable effect on the prevalence of high-frequency hearing loss of the study participants (OR 0.964, 95% CI 0.925–1.005, p = 0.085). No significant relationship between the effectiveness offered by earplug use and high-frequency hearing thresholds at 3, 4, and 6 kHz was found (t = −1.54, p = 0.125). The mandatory requirement of earplug use without individualized training on how to wear HPDs correctly had no detectable effect on the prevention of hearing loss at the auto parts factory. The hearing conservation program at the surveyed factory was not effective. Periodic hearing tests, earplug fit testing, expanding the offer of different types of hearing protection, and employee education about the importance of protecting their hearing were recommended to the occupational health and safety program. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PURPOSE: To conduct a systematic review of the effectiveness of interventions to prevent occupational hearing loss, following up on the findings of the most recent version of Cochrane systematic review on the same topic. RESEARCH STRATEGY: Searches were carried out in PubMed, Web of Science and Scopus databases. SELECTION CRITERIA: The following interventions were considered: engineering/administrative controls; hearing protection devices (HPD); and audiological monitoring. DATA ANALYSIS: For bias risk analysis, each study was assessed according to randomization, allocation, blinding, outcomes, other sources of bias. RESULTS: 475 references were obtained. Of these, 17 studies met the inclusion criteria: one randomized, one interrupted time series, and 15 before and after studies. Most studies were conducted in industries; three in military and/or shooting training environments; one in an orchestra, and one in construction. Most studies showed a high risk of bias. Six studies found a reduction in short-term exposure to noise through engineering/administrative controls; one found a positive impact due to changes in legislation; five studies have found positive effects of HPD in reducing exposure to noise and of educational trainings in the use of HPD; lastly, two studies found a reduction in noise levels and an increase in the using of HPD due to the implementation of hearing conservation programs. CONCLUSÃO: Todos os estudos analisados concluíram que as intervenções utilizadas resultaram em efeitos positivos sobre a audição e/ou sobre a exposição ao ruído. Em relação aos efeitos de longo termo, a grande maioria dos estudos limitou-se a avaliar efeitos imediatos ou de curto termo, reforçando que estudos incluindo follow-up de longo termo devem ser desenvolvidos.

OBJECTIVES: To evaluate (1) the accuracy of the International Organization for Standardization (ISO) standard ISO 1999 [(2013), International Organization for Standardization, Geneva, Switzerland] predictions of noise-induced permanent threshold shift (NIPTS) in workers exposed to various types of high-intensity noise levels, and (2) the role of the kurtosis metric in assessing noise-induced hearing loss (NIHL). DESIGN: Audiometric and shift-long noise exposure data were acquired from a population (N = 2,333) of screened workers from 34 industries in China. The entire cohort was exclusively divided into subgroups based on four noise exposure levels (85 ≤ LAeq.8h < 88, 88 ≤ LAeq.8h < 91, 91 ≤ LAeq.8h < 94, and 94 ≤ LAeq.8h ≤ 100 dBA), two exposure durations (D ≤ 10 years and D > 10 years), and four kurtosis categories (Gaussian, low-, medium-, and high-kurtosis). Predicted NIPTS was calculated using the ISO 1999 model for each participant and the actual measured NIPTS was corrected for age and sex also using ISO 1999. The prediction accuracy of the ISO 1999 model was evaluated by comparing the NIPTS predicted by ISO 1999 with the actual NIPTS. The relation between kurtosis and NIPTS was also investigated. RESULTS: Overall, using the average NIPTS value across the four audiometric test frequencies (2, 3, 4, and 6 kHz), the ISO 1999 predictions significantly (p < 0.001) underestimated the NIPTS by 7.5 dB on average in participants exposed to Gaussian noise and by 13.6 dB on average in participants exposed to non-Gaussian noise with high kurtosis. The extent of the underestimation of NIPTS by ISO 1999 increased with an increase in noise kurtosis value. For a fixed range of noise exposure level and duration, the actual measured NIPTS increased as the kurtosis of the noise increased. The noise with kurtosis greater than 75 produced the highest NIPTS. CONCLUSIONS: The applicability of the ISO 1999 prediction model to different types of noise exposures needs to be carefully reexamined. A better understanding of the role of the kurtosis metric in NIHL may lead to its incorporation into a new and more accurate model of hearing loss due to noise exposure.

PURPOSE: Assess the effect of non-pharmaceutical interventions at work on noise exposure or occupational hearing loss compared to no or alternative interventions. RESEARCH STRATEGIES: Pubmed, Embase, Web of Science, OSHupdate, Cochrane Central and Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched. SELECTION CRITERIA: Randomized Controlled Trials (RCT), Controlled Before-After studies (CBA) and Interrupted Time-Series studies (ITS) evaluating engineering controls, administrative controls, personal hearing protection devices, and hearing surveillance were included. Case studies of engineering controls were collected. DATA ANALYSIS: Cochrane methods for systematic reviews, including meta-analysis, were followed. RESULTS: 29 studies were included. Stricter legislation can reduce noise levels by 4.5 dB(A) (very low-quality evidence). Engineering controls can immediately reduce noise (107 cases). Eleven RCTs and CBA studies (3725 participants) were evaluated through Hearing Protection Devices (HPDs). Training of earplug insertion reduces noise exposure at short term follow-up (moderate quality evidence). Earmuffs might perform better than earplugs in high noise levels but worse in low noise levels (very low-quality evidence). HPDs might reduce hearing loss at very long-term follow-up (very low-quality evidence). Seventeen studies (84028 participants) evaluated hearing loss prevention programs. Better use of HPDs might reduce hearing loss but other components not (very low-quality evidence). CONCLUSION: Hearing loss prevention and interventions modestly reduce noise exposure and hearing loss. Better quality studies and better implementation of noise control measures and HPDs is needed.

Ten years ago, we had the privilege to be guest editors of the first International Journal of Audiology (IJA) National Hearing Conservation Association (NHCA) supplemental journal issue, which was released in 2011. We were delighted to again repeat the feat, by being the guest editors of the current supplement, containing a few of the presentations at the 2019 NHCA annual conference. | | The current supplement gives us a chance to revisit and celebrate the tenth consecutive year of these publications. The selection of papers in each of the supplements of this 10-year collection represents well the multidisciplinary nature of NHCA, with its membership that includes a diverse population of individuals (audiologists, industrial hygienists, physicians, scientists, engineers, students and many others) who learn from each other. This rich pool of expertise is unique -and needed- to address the challenge of preventing the harmful effects of noise.

This Cochrane Corner features "Interventions to prevent hearing loss caused by noise at work", published in 2017. The aim of this Cochrane Review was to find out if hearing loss caused by noise at work is being prevented by current interventions. Tikka et al. identified 29 studies that studied the effect of preventive measures. One study evaluated legislation to reduce noise exposure, eleven studies evaluated effects of personal hearing protection devices and 17 studies evaluated effects of hearing loss prevention programmes (HLPPs). There was some very low-quality evidence that implementation of stricter legislation can reduce noise levels in workplaces and moderate-quality evidence that training of proper insertion of earplugs significantly reduces noise exposure at short-term follow-up. This Cochrane review has identified specific strategies that have shown effectiveness in reducing workplace noise, such as the implementation of stricter legislation and the need for training in the proper use of earplugs and earmuffs to reduce noise exposure to safe levels. The overall quality of evidence for the effectiveness of HLPPs in preventing hearing loss was very low, there was limited follow-up of participants receiving training for insertion of earplugs and no controlled studies examining engineering controls to reduce workplace noise.

BACKGROUND: Animal data suggest that jet fuels such as JP-8 are associated with hearing deficits when combined with noise and that the effect is more pronounced than with noise exposure alone. Some studies suggest peripheral dysfunction while others suggest central auditory dysfunction. Human data are limited in this regard. The aim of this study was to investigate the possible chronic adverse effects of JP-8 combined with noise exposure on the peripheral and central auditory systems in humans. METHODS: Fifty-seven participants who were current personnel from the Royal Australian Air Force were selected. Based on their levels of exposure to jet fuels, participants were divided into three exposure groups (low, moderate, high). Groups were also categorised based on their noise exposure levels (low, moderate, high). All participants were evaluated by tympanometry, pure-tone audiometry (1-12 kHz), distortion product otoacoustic emissions (DPOAEs), auditory brainstem response (ABR), words-in-noise, compressed speech, dichotic digit test, pitch pattern sequence test, duration pattern sequence test and adaptive test of temporal resolution. All auditory tests were carried out after the participants were away from the Air Force base for a minimum of two weeks, thus two weeks without jet fuel and noise exposure. RESULTS: Jet fuel exposure was significantly associated with hearing thresholds at 4 and 8 kHz; average hearing thresholds across frequencies in the better ear; DPOAEs at 2.8, 4 and 6 kHz; ABR wave V latency in the right ear; compressed speech and words-in-noise. Further analyses revealed that participants with low exposure level to jet fuels showed significantly better results for the aforementioned procedures than participants with moderate and high exposure levels. All results were controlled for the covariates of age and noise exposure levels. CONCLUSIONS: The results suggest that jet fuel exposure, when combined with noise exposure, has an adverse effect on audibility in humans. Taking all the test results into consideration, jet fuel exposure combined with noise exposure specifically seems to affect the peripheral hearing system in humans.

Over six percent of the world's population has disabling hearing loss.1 Across the globe, it can take years for those with hearing problems to seek care. Even when care is sought, the prescribed interventions are not often adopted.2 This issue has motivated the World Health Organization to coordinate World Hearing Day (WHD), an annual event that aims “to raise awareness on how to prevent deafness and hearing loss and promote ear and hearing care across the world.”3

OBJECTIVE: To examine the auditory system of Brazilian gasoline station workers using an extensive audiological test battery. DESIGN: This was a cross-sectional study. The audiological evaluation included a questionnaire, pure-tone audiometry, acoustic immittance tests, transient-evoked otoacoustic emissions (TEOAEs), distortion product otoacoustic emissions (DPOAEs), auditory brainstem response (ABR) and P300 auditory-evoked potentials. STUDY SAMPLE: A total of 77 Brazilian gasoline station workers were evaluated, and their results were compared with those of 36 participants who were not exposed to chemicals or noise at work. The gasoline station employees worked in 18 different gas stations, and the noise area measurements from all gas stations revealed time-weighted averages below 85 dBA. RESULTS: Of the 77 gasoline station workers evaluated, 67.5% had audiometric results within the normal range, but 59.7% reported difficulties in communication in noisy places. Gasoline station workers showed significantly poorer results than non-exposed control participants in one or more conditions of each of the audiological tests used, except P300. CONCLUSIONS: The results suggest that the gasoline station workers have both peripheral and central auditory dysfunctions that could be partly explained by their exposure to gasoline.

New technologies are reshaping health interventions across disciplines. This technological surge offers a clear opportunity to expand and improve hearing health, particularly in hearing loss prevention. A person's hearing health trajectory is defined by his or her overall hazardous exposures, environmental factors, and genetic determinates.1 Among the many factors that can contribute to hearing health (such as overall health, smoking, diet, and ototoxicant exposure), reducing noise exposure—particularly at work—has the greatest potential to significantly decrease the burden of hearing loss and tinnitus.2 About 24 percent of hearing impairment cases among U.S. workers is attributable to workplace noise exposures. Because noise-induced hearing loss is preventable, approximately one-fourth of hearing impairment cases in this population may be avoided by adopting preventive measures.3 While progress has been made toward the prevention of work-related hearing loss, it remains among the most common occupational illnesses. Overall, nearly one in four U.S. adults has audiometric evidence of noise-induced hearing loss—and most do not realize it.4 People continue to focus on the use of hearing protection to reduce noise exposure, even though only limited evidence is available on the effectiveness of this approach.5 However, new technologies to measure and control noise and test hearing hold the promise of expedited progress.

The National Institute for Occupational Safety and Health (NIOSH), in partnership with the National Hearing Conservation Association (NHCA), has announced the 10th Safe-in-Sound Excellence in Hearing Loss Prevention Award™ winner. The award honors those who have contributed to the prevention of noise-induced hearing loss and tinnitus through effective practices or innovations that will benefit people exposed to noise at work. The initiative was launched to discover and share successful hearing loss prevention programs and public health practices. By disseminating evidence-based strategies, Safe-in-Sound™ aims to enable other groups to effectively advance proven approaches in hearing loss prevention.

The aim of this exploratory study was to examine whether the kurtosis metric can contribute to investigations of the effects of combined exposure to noise and solvents on human hearing thresholds. Twenty factory workers exposed to noise and solvents along with 20 workers of similar age exposed only to noise in eastern China were investigated using pure-tone audiometry (1000-8000 Hz). Exposure histories and shift-long noise recording files were obtained for each participant. The data were used in the calculation of the cumulative noise exposure (CNE) and CNE adjusted by the kurtosis metric for each participant. Passive samplers were used to measure solvent concentrations for each worker exposed to solvents over the full work shift. Results showed an interaction between noise exposure and solvents for the hearing threshold at 6000 Hz. This effect was observed only when the CNE level was adjusted by the kurtosis metric.

Audiologists and other health professionals today share the challenge of dealing with information overload, much of it coming from sources of variable quality. Such exposure to super-abundant information also affects the populations we serve. To complicate things further, we are going through a period of diminished trust in authority and science. So we need to be ready to answer a very basic question: “What is and is not known to work in practice?” (Actually, when we are in the position of being patients ourselves, isn't that what we would want to know about prescribed treatments?)

Introduction The literature has reported the association between lead and auditory effects, based on clinical and experimental studies. However, there is no consensus regarding the effects of lead in the auditory system, or its correlation with the concentration of the metal in the blood. Objective To investigate the maturation state of the auditory system, specifically the auditory nerve and brainstem, in rats exposed to lead acetate and supplemented with ferrous sulfate. Methods 30 weanling male rats (Rattus norvegicus, Wistar) were distributed into six groups of five animals each and exposed to one of two concentrations of lead acetate (100 or 400 mg/L) and supplemented with ferrous sulfate (20 mg/kg). The maturation state of the auditory nerve and brainstem was analyzed using Brainstem Auditory Evoked Potential before and after lead exposure. The concentration of lead in blood and brainstem was analyzed using Inductively Coupled Plasma-Mass Spectrometry. Results We verified that the concentration of Pb in blood and in brainstem presented a high correlation (r = 0.951; p < 0.0001). Both concentrations of lead acetate affected the maturation state of the auditory system, being the maturation slower in the regions corresponding to portion of the auditory nerve (wave I) and cochlear nuclei (wave II). The ferrous sulfate supplementation reduced significantly the concentration of lead in blood and brainstem for the group exposed to the lowest concentration of lead (100 mg/L), but not for the group exposed to the higher concentration (400 mg/L). Conclusion This study indicate that the lead acetate can have deleterious effects on the maturation of the auditory nerve and brainstem (cochlear nucleus region), as detected by the Brainstem Auditory Evoked Potentials, and the ferrous sulphate can partially amend this effect.

All of us are recipients of health care, and most of IJA readers also provide health/audiological services. As patients and providers we expect that the service being rendered stands on a solid scientific base. Nowadays, with the expansion of publications and communication channels, we hear a lot about evidence-based practice (EBP) and systematic reviews. These terms have become commonplace, however, evidence being presented to support effectiveness can range from a “success story” based on a single example, to high quality evidence involving formalized testing in carefully conducted experimental designs. Such inconsistency can become an obstacle for real evidence-based practice. The International Society of Audiology and this journal have a proud history of supporting evidence-based practice. We therefore felt it was time to express our understanding of the matter, to renew the IJA’s commitment to evidence-based audiology, and to update IJA guidelines to authors. In this editorial, we cover new processes being adopted to help IJA contributing authors in the preparation of systematic reviews, which are a cornerstone of EBP. For a broader review of EBP in audiology readers should consider the text book on this topic by Wong and Hickson (2012). | Systematic reviews, are the most important type of review because they are central to Evidence Based Practice (EBP) (Grant and Booth, 2009; CRD, 2012, Manchikanti, 2008); when possible, systematic reviews can include the meta-analysis of studies as well. The purpose of systematic reviews is to identify, evaluate and summarize the findings of all relevant individual studies using well defined strategies, thereby making the most valid information on a given topic available to decision-makers. Their appeal is increasing because they have been shown to facilitate decisions when large amounts of information exist and/or variations in methodology make it hard to determine which results are the most reliable. They are used not only in clinical practice but also to inform health policy decisions. When carried out well, they provide reliable estimates about the effects of interventions so that conclusions are defensible. In addition, systematic reviews can also demonstrate where knowledge is lacking which can then be used to guide future research.

Hearing loss is the third most common chronic physical condition in the United States, and is more prevalent than diabetes or cancer (1). Occupational hearing loss, primarily caused by high noise exposure, is the most common U.S. work-related illness (2). Approximately 22 million U.S. workers are exposed to hazardous occupational noise (3). CDC compared the prevalence of hearing impairment within nine U.S. industry sectors using 1,413,789 noise-exposed worker audiograms from CDC's National Institute for Occupational Safety and Health (NIOSH) Occupational Hearing Loss Surveillance Project (4). CDC estimated the prevalence at six hearing impairment levels, measured in the better ear, and the impact on quality of life expressed as annual disability-adjusted life years (DALYs), as defined by the 2013 Global Burden of Disease (GBD) Study (5). The mining sector had the highest prevalence of workers with any hearing impairment, and with moderate or worse impairment, followed by the construction and manufacturing sectors. Hearing loss prevention, and early detection and intervention to avoid additional hearing loss, are critical to preserve worker quality of life.

Dobie and Clark’s recent article “Exchange rates for intermittent and fluctuating occupational noise: A systematic review of studies of human permanent threshold shift” aimed to compare the suitability of a 3-dB versus 5-dB exchange rate (ER) in predicting hearing loss from non-impulsive intermittent or fluctuating noise exposures by reviewing studies of human noise-induced permanent threshold shift. The authors concluded that 3-dB ER systematically overestimates the risk of noise-induced hearing loss for intermittent or fluctuating noise. We contend that the authors did not arrive at their conclusions through an appropriate investigation. The article used flawed methodologies in the treatment and analysis of the data/studies and drew conclusions that were not substantiated by the cited data. | The authors indicated that their review did not aim to make recommendations for regulation of occupational noise, but suggested that their review provided evidence for a re-examination of recommendations in their concluding remarks. The National Institute for Occupational Safety and Health (NIOSH) maintains its recommendation of the 3-dB ER to provide sufficient protection for the many variations of continuous, intermittent and fluctuating noise exposure scenarios encountered in the workplace. In view of the advances in noise measurement and the studies’ other weaknesses, we question the suitability of revisiting a narrow segment of the human evidence (excluding robust animal studies and temporary threshold shift studies) based on outdated methodologies to address such an important issue.

INTRODUCTION: Earlier studies have demonstrated an auditory effect of lead exposure in children, but information on the effects of low chronic exposures needs to be further elucidated. OBJECTIVE: To investigate the effect of low chronic exposures of the auditory system in children with a history of low blood lead levels, using an auditory electrophysiological test. METHODS: Contemporary cross-sectional cohort. Study participants underwent tympanometry, pure tone and speech audiometry, transient evoked otoacoustic emissions, and brainstem auditory evoked potentials, with blood lead monitoring over a period of 35.5 months. The study included 130 children, with ages ranging from 18 months to 14 years, 5 months (mean age 6 years, 8 months ± 3 years, 2 months). RESULTS: The mean time-integrated cumulative blood lead index was 12 ug/dL (SD ± 5.712 microg/dL (SD ± 5.7 range: 2.433). All participants had hearing thresholds equal to or below 20 dBHL and normal amplitudes of transient evoked otoacoustic emissions. No association was found between the absolute latencies of waves I, III, and V, the interpeak latencies I---III, III---V, and I---V, and the cumulative lead values. CONCLUSION: No evidence of toxic effects from chronic low lead exposures was observed on the auditory function of children living in a lead contaminated area.

Moshammer and colleagues (1) have recommended routine implementation of a temporary threshold shift (TTS) screening test to identify workers particularly at risk of developing noise-induced hearing loss (NIHL) from occupational exposure to hazardous noise. Their work addresses an important occupational health problem. NIHL ranks among the most common work-related injuries in many countries, with an estimated global annual incidence of 1.6 million cases and accounting for approximately 16% of disabling adult hearing losses worldwide (2,3). Individuals vary in their susceptibility to the damaging effects of noise and no suitable method currently exists to predict the susceptibility of a particular worker. | In their study, Moshammer et al. measured TTS in newly-hired employees following exposure to a 20-minute, high intensity, low frequency experimental noise. They then followed the workers over time to see who ultimately developed a permanent threshold shift (PTS). The authors report that a TTS of 14 dB or more measured 2.5 minutes after the experimental exposure identifies workers at greater risk for PTS. They recommend routinely using this procedure to screen for susceptibility to noise in workplace hearing loss prevention programs. | However, this recommendation is premature in view of the study results. The TTS measure had a sensitivity of 82%, meaning that 18% of those who developed PTS were not identified by the TTS screening – a high false negative rate, particularly as we already know how to prevent PTS through reduction of noise exposures and consistent use of properly-fit hearing protection. Specificity was 70% at best, corresponding to a false positive rate 30%. If this procedure were implemented, approximately a third of the workers would be told that they are particularly at risk for NIHL when they aren’t, raising unnecessary alarm and opening the door to potential discrimination in work assignments, promotions, etc.

OBJECTIVE: To assess the effectiveness of interventions for preventing occupational noise exposure or hearing loss compared to no intervention or alternative interventions. DESIGN: We searched biomedical databases up to 25 January 2012 for randomized controlled trials (RCT), controlled before-after studies and interrupted time-series of hearing loss prevention among workers exposed to noise. STUDY SAMPLE: We included 19 studies with 82 794 participants evaluating effects of hearing loss prevention programs (HLPP). The overall quality of studies was low to very low, as rated using the GRADE approach. RESULTS: One study of stricter legislation showed a favorable effect on noise levels. Three studies, of which two RCTs, did not find an effect of a HLPP. Four studies showed that better use of hearing protection devices in HLPPs decreased the risk of hearing loss. In four other studies, workers in a HLPP still had a 0.5 dB greater hearing loss at 4 kHz (95% CI - 0.5 to 1.7) than non-exposed workers. In two similar studies there was a substantial risk of hearing loss in spite of a HLPP. CONCLUSIONS: Stricter enforcement of legislation and better implementation of HLPPs can reduce noise levels in workplaces. Better evaluations of technical interventions and long-term effects are needed.