Cases Of Noise-induced Hearing Loss Research Articles

Noise-induced hearing loss and hearing protection: Attitudes at a South African coal mine.

Negative attitudes and beliefs are major contributing factors to the rising numbers of noise-induced hearing loss (NIHL) cases in coal mines both locally and internationally. International literature confirms limited knowledge surrounding employees' attitudes and beliefs regarding NIHL and hearing protection devices (HPDs), hence the need for the study. To ascertain the attitudes and beliefs about NIHL and HPD use among employees at a large scale underground coal mine in Mpumalanga. A descriptive and exploratory cross-sectional study was conducted using a self-administered questionnaire, developed by the National Institute for Occupational Safety and Health (NIOSH) on Beliefs about Hearing Protection and Hearing Loss (BHPHL). Participants (n= 241) included employees from a coal mine in Mpumalanga, South Africa. Out of 241 completed surveys, this study found that 84% were aware of when to replace earmuffs; 95% believed wearing HPDs could prevent hearing loss in noisy environments; 83% felt their hearing was impacted by loud noise. Additionally, 86% mentioned discomfort from earmuff pressure; 95% emphasised HPD importance; and 95% used HPDs around loud sounds. Moreover, 98% knew how to properly wear earplugs, while lower education levels were linked to higher susceptibility to NIHL. The study identified positive attitudes towards NIHL and HPD use, but existing NIHL cases must be acknowledged. Organisations can use the findings to develop tailored hearing conservation programmes (HCP), including education, involving employees in protection decisions and promoting diligent HPD usage.Contribution:This study contributes to the limited literature on noise perceptions, NIHL, and HPD use in mining, emphasising the impact attitude has on HPD use and assessing the effect of miners NIHL knowledge on compliance. The findings, unique to coal mining, hold significance for enhancing hearing conservation and reducing NIHL.

Plasma metabolomics analyses highlight the multifaceted effects of noise exposure and the diagnostic power of dysregulated metabolites for noise-induced hearing loss in steel workers.

Noise exposure can lead to various kinds of disorders. Noise-induced hearing loss (NIHL) is one of the leading disorders confusing the noise-exposed workers. It is essential to identify NIHL markers for its early diagnosis and new therapeutic targets for its treatment. In this study, a total of 90 plasma samples from 60 noise-exposed steel factory male workers (the noise group) with (NIHL group, n = 30) and without NIHL (non-NIHL group, n = 30) and 30 male controls without noise exposure (control group) were collected. Untargeted human plasma metabolomic profiles were determined with HPLC-MS/MS. The levels of the metabolites in the samples were normalized to total peak intensity, and the processed data were subjected to multivariate data analysis. The Wilcoxon test and orthogonal partial least square-discriminant analysis (OPLS-DA) were performed. With the threshold of p < 0.05 and the variable importance of projection (VIP) value >1, 469 differential plasma metabolites associated with noise exposure (DMs-NE) were identified, and their associated 58 KEGG pathways were indicated. In total, 33 differential metabolites associated with NIHL (DMs-NIHL) and their associated 12 KEGG pathways were identified. There were six common pathways associated with both noise exposure and NIHL. Through multiple comparisons, seven metabolites were shown to be dysregulated in the NIHL group compared with the other two groups. Through LASSO regression analysis, two risk models were constructed for NIHL status predication which could discriminate NIHL from non-NIHL workers with the area under the curve (AUC) values of 0.840 and 0.872, respectively, indicating their efficiency in NIHL diagnosis. To validate the results of the metabolomics, cochlear gene expression comparisons between susceptible and resistant mice in the GSE8342 dataset from Gene Expression Omnibus (GEO) were performed. The immune response and cell death-related processes were highlighted for their close relations with noise exposure, indicating their critical roles in noise-induced disorders. We concluded that there was a significant difference between the metabolite’s profiles between NIHL cases and non-NIHL individuals. Noise exposure could lead to dysregulations of a variety of biological pathways, especially immune response and cell death-related processes. Our results might provide new clues for noise exposure studies and NIHL diagnosis.

Association between UBAC2 gene polymorphism and the risk of noise-induced hearing loss: a cross-sectional study.

The purpose of this article was to investigate the association between the ubiquitin-associated domain-containing protein 2 (UBAC2) gene polymorphism and noise-induced hearing loss (NIHL) and to further explore the role of single-nucleotide polymorphism (SNP) in UBAC2 in NIHL. A case control study involving 660 NIHL cases and 581 controls was conducted in this research. After genotyping by multiplex polymerase chain reaction (PCR) with next-generation sequencing, the correlation between SNPs and NIHL was analyzed using logistic regression analysis. Haplotype analysis was performed by Haploview 4.1 software. Then luciferase reporter assays and siRNA were used to explore the mechanism of SNPs in UBAC2 affecting NIHL susceptibility. The correlation analysis showed that rs3825427 AA genotype, rs9517701 GG genotype, rs7999348 GG genotype, and rs2296860 AA genotype were all associated with increased risk of NIHL (P < 0.05). The haplotype AGGA (rs3825427-rs9517701-rs7999348-rs2296860) also had a higher risk of NIHL (OR = 1.314; 95% CI, 1.098-1.572; P = 0.003). The results of the luciferase reporter assays showed that the fluorescence intensity of CTCF-OE + UBAC2 WT + TK was significantly higher than that of CTCF-NC + UBAC2 WT + TK and CTCF-OE + UBAC2 MT + TK (all P < 0.01). In CTCF knockdown cells, the expression of UBAC2 was also significantly downregulated (P = 0.0038), indicating that the transcription factor CTCF positively regulated the expression of UBAC2 and the rs3825427 C allele acted as an enhancer, which can promote CTCF to bind to the promoter of UBAC2, thereby promoting transcription. UBAC2 gene polymorphism is related to NIHL susceptibility. The UBAC2 rs3825427 regulates the expression level of UBAC2 by affecting the combination of CTCF and DNA, thus affecting the susceptibility of NIHL.

Noise Pollution and Its Correlations with Occupational Noise-Induced Hearing Loss in Cement Plants in Vietnam.

Noise-Induced Hearing Loss (NIHL) is a global issue that is caused by many factors. The purpose of this study was to survey noise level to identify NIHL and its relationship with other factors in cement plants in Vietnam. Noise level was measured at one cement plant and three cement grinding stations located in the South of Vietnam. The audiometric data of exposed workers were surveyed to determine NIHL. Finally, the relationship between NIHL and noise level in cement plants was determined. The results show that noise level in almost all processes exceeded the permissible exposure limit (PEL). In this study, 42 cases (10% of exposed workers) with occupational NIHL were found with mean age (SD) of 49 (9.0) years. All NIHL cases were found in the departments in which the noise level exceeded the PEL, which included quarry (n = 16), maintenance (n = 12), production (n = 10), co-waste processing (n = 3) and quality assurance (n = 1). There was a positive and significant correlation between the NIHL and the excessive noise exposure in the cement plants (r = 0.89, p = 0.04).

Expression of serum proteins in noise induced hearing loss workers of mining based industry

Noise Induced Hearing Loss (NIHL) is caused by excessive noise exposure due to occupational activities thus affects communication and quality of life. Prolonged occupational and environmental exposure to loud noise damages key molecules present in the micro-machinery of the ear which are required for the mechano-electrical transduction of sound waves in cochlea. Specific proteins are known to be associated with hearing loss and related structural and functional disabilities in the human inner, outer hair cells and cochlea. Rationale of this study was to identify the cochlear proteins associated with the pathophysiology of NIHL using proteomic approaches in mining based industrial workers. Total (n = 210) samples were collected from mining based industrial workers of central India. Subjects were categorized based on audiometric analysis. Proteome changes of the host serum were investigated using one and two-dimensional electrophoresis in combination with LC-MS/MS and MALDI-TOF-MS. Up-regulated 46 cochlear proteins among confirmed NIHL cases were identified by MASCOT. Shrinkage discriminant analysis provided top 25 discriminating feature proteins namely myosin, transthyretin, SERPIN, CCDC50, enkurin, transferin etc. The identified potential proteins may be used as biomarkers for early detection and to understand the pathogenic mechanism of NIHL. Evaluation of these biomarkers in follow-up cases may further aid in improving NIHL diagnosis. SignificanceHuman proteome study in Noise Induced Hearing Loss (NIHL) cases has not been published till date. This study represents most comprehensive proteomic analysis in NIHL cases taken from Indian mine workers. The identified key twenty-five discriminating feature proteins which are upregulated when an individual develops (or is in stage of development of) NIHL, provides insights into the potential roles of these varied proteins in disease progression. The proteins thus identified by proteomic approach may be used as early diagnostic biomarker to predict the occurrence of disease at very early stage.

CARD8 polymorphism rs2043211 protects against noise-induced hearing loss by causing the dysfunction of CARD8 protein.

Inflammation is a complicated process and is considered to be responsible for the development of noise-induced hearing loss (NIHL). CARD8 is an important component of inflammasome that has been implicated in inflammation. To decide the relationship between the polymorphisms of CARD8 gene and NIHL risk and deduce the potential mechanism, three SNPs (rs2043211, rs1062808, and rs12459322) were genotyped in a Chinese population consisting of 610 NIHL cases and 612 normal hearing controls. The possible impacts of SNPs on CARD8 structure and function were assessed using a variety of bioinformatics tools. Plasmids expressing wild-type and/or mutated CARD8 were transfected into HEK293 cells to verify the effect of SNPs on CARD8 protein expression level by western blot. The results revealed that rs2043211 AA genotype and A allele were associated with decreased risk of NIHL. Stratified analysis found that the male, drinking and exposed to noise ≥ 92dB, subjects harboring rs2043211 A allele had a low risk of NIHL. The haplotype AGG (rs2043211-rs1062808-rs12459322) was significantly associated with a decreased risk of NIHL. SNP rs2043211 was predicted to be deleterious and affects CARD8 protein structure and stability. Furthermore, the functional experiment showed the mutant CARD8 could significantly decrease the CARD8 protein expression level. This study confirms that rs2043211 A allele may reduce NIHL risk by causing the loss of PPI combined with the decreased CARD8 expression level leading to CARD8 functional changes, and it may be one valuable genetic biomarker of NIHL susceptibility for Chinese noise-exposed workers.

Echolocating Whales and Bats Express the Motor Protein Prestin in the Inner Ear: A Potential Marker for Hearing Loss

Prestin is an integral membrane motor protein located in outer hair cells of the mammalian cochlea. It is responsible for electromotility and required for cochlear amplification. Although prestin works in a cycle-by-cycle mode up to frequencies of at least 79 kHz, it is not known whether or not prestin is required for the extreme high frequencies used by echolocating species. Cetaceans are known to possess a prestin coding gene. However, the expression and distribution pattern of the protein in the cetacean cochlea has not been determined, and the contribution of prestin to echolocation has not yet been resolved. Here we report the expression of the protein prestin in five species of echolocating whales and two species of echolocating bats. Positive labeling in the basolateral membrane of outer hair cells, using three anti-prestin antibodies, was found all along the cochlear spiral in echolocating species. These findings provide morphological evidence that prestin can have a role in cochlear amplification in the basolateral membrane up to 120–180 kHz. In addition, labeling of the cochlea with a combination of anti-prestin, anti-neurofilament, anti-myosin VI and/or phalloidin and DAPI will be useful for detecting potential recent cases of noise-induced hearing loss in stranded cetaceans. This study improves our understanding of the mechanisms involved in sound transduction in echolocating mammals, as well as describing an optimized methodology for detecting cases of hearing loss in stranded marine mammals.

Genetic variation in KCNQ4 gene is associated with susceptibility to noise-induced hearing loss in a Chinese population

Noise-induced hearing loss (NIHL), one of the most widespread occupational health risks worldwide, is a kind of complex disorder resulting from both genetic and environmental factors. KCNQ4 channels are crucial to the internal ear potassium recycling. To explore whether KCNQ4 polymorphism is associated with individual susceptibility to NIHL, we performed this genetic association study on 571 NIHL cases and 639 normal hearing controls selected from about 2700 Chinese noise-exposed workers. General information and audiometric data were obtained through questionnaires and pure-tone audiometry (PTA). DNA samples were collected and genotyping for three selected SNPs (rs709688, rs2769256 and rs4660468) was performed. Significant differences were observed between cases and controls for the genotype frequency and allele frequency in rs4660468, suggesting that rs4660468 CT/TT genotype and T allele may be risk factors for NIHL. In subjects exposed to noise for more than 16 years (OR = 1.23, 95% CI = 1.09–1.53) and those who exposed to noise >92 dB (OR = 1.29, 95% CI = 1.08–1.69), increased risks of NIHL were found after stratified analysis for rs4660468. Our results suggest that rs4660468 T allele of KCNQ4 involves with a higher risk of NIHL and could be one biomarker of susceptibility for Chinese noise exposed workers.

Occupational health and safety of road haulage company employees.

Background:This paper follows up on a project that was launched in 2008 and contributed to the development of the new Italian Society of Occupational Medicine (SIML) guidelines for the road haulage industry.Objective:To reach a better understanding of occupational illness amongst truck drivers, in order to define appropriate health monitoring protocols and promote a healthy life-style.Methods:We assessed 673 male drivers (mean age 43.85 years, SD 9.56; mean working seniority 27.28 years, SD 10.59), employed by 46 different companies. The drivers, who were gradually recruited in the study over the years, had a maximum of 8 re-assessments each, for a total of 2608 examinations. We applied a survey protocol consisting in a medical examination, questionnaires for the most common risks and instrumental and laboratory tests in compliance with SIML guidelines.Results:We identified a total of 44 work-related diseases: 22 cases of noise-induced hearing loss (NIHL) and 22 cases of lumbar degenerative disc disease. As regards metabolic disorders, we observed 28 cases of diabetes mellitus, in most cases (71.4%) as a first diagnosis or under poor therapeutic control. We observed poorly-controlled hypertension in 103 drivers, the majority of whom (54%) were diagnosed for the first time. Over 30% of the workers in our study were obese and approximately 40% were tobacco smokers. We identified just 9 individuals (1.3%) with a positive toxicological screening for use of recreational drugs. Our data confirm a high prevalence of occupational illness amongst truck drivers. Cardiovascular and metabolic conditions require close monitoring.

Asymmetrical Hearing Loss in Cases of Industrial Noise Exposure: A Systematic Review of the Literature.

Asymmetrical hearing thresholds are common in people claiming compensation for noise-induced hearing loss (NIHL). When present and otherwise unexplained, there is some controversy as to whether such asymmetry can be attributed to occupational noise exposure. In this review, our main objectives were to collate the overall prevalence of this finding in subjects with NIHL, and further, to provide a balanced argument regarding causality. MEDLINE, CINAHL, EMBASE, Cochrane, Google Scholar. No date or language restrictions. A systematic review of the literature was performed and data on noise exposure, pure tone audiometry, and lateralized hearing outcomes were reviewed. Newcastle-Ottawa (N-O) criteria were employed to assess quality of studies where applicable. N/A CONCLUSION:: Six studies met the inclusion criteria giving a total of 4,735 individual cases with NIHL. Asymmetrical hearing loss accounted for between 2.4% and 22.6% of NIHL cases (L-R difference >15 dB for any frequency 0.5-8 kHz). However, the overwhelming majority of subjects in this review have symmetrical hearing loss when adjusted for other significant variables, e.g., age, sex, and binaural hearing deterioration. Subjects considered for noise exposure remuneration were men (94.3% SE ± 2.7), aged 52.9 years (inter-quartile range, 46.1-58.4), and from a broad range of industrial backgrounds. Future research will be needed to establish the influence of other factors such as smoking status, exposure to chemical agents, specific drugs, or genetic predisposition.

Guidelines for quantification of noise-induced hearing loss in a medicolegal context.

Guidelines published in 2000 by the authors are widely used by medical and legal professionals in the UK for diagnosis of noise-induced hearing loss in a medicolegal context. However, they cannot be used for quantification of the noise-induced hearing loss, which is required in most cases. This requirement is addressed. A method is developed here to quantify noise-induced hearing loss, thereby overcoming this shortcoming. Assessment of noise-induced hearing loss in medicolegal cases. A consecutive series of 124 cases of noise-induced hearing loss is used for evaluation. Magnitude of noise-induced hearing loss based on hearing threshold levels averaged over the frequencies 1, 2 and 3 kHz. The rationale of the method, practical application and three worked examples are developed. A simpler short-cut method is developed and shown to be equivalent to the full method in most cases. The method offers a practical approach to quantification of noise-induced hearing loss.

Noise-Induced Hearing Loss: Prevention is Possible

Background: In Denmark, the preventive measures against occupational noise-induced hearing loss (NIHL) were intensified in 1995. Apparently, no extant studies have attempted to document the effect of these measures. Objectives: This study aims to estimate the prevalence and severity of noise-induced hearing loss after 1995 and to explain the factors that influence the official statistics regarding hearing loss. Patients and Methods: Screening audiograms from 272 noise-exposed workers were studied in an attempt to distinguish between noiseinduced hearing loss (NIHL) and hearing loss resulting from other causes. The results were compared with deductions that could be made from official work environment statistics. Results: Calculations based on official work environment statistics show that the proportion of NIHL among the reported cases of hearing loss has decreased, so that the proportion of non-NIHL has increased. Further, the severity of occupational NIHL has decreased. Among the 272 tested persons, 88 (32%) presumably had NIHL. A combination of NIHL and hearing losses of other causes was found in 28 (10%), while 43 (16%) had a hearing loss that could not be NIHL. Normal hearing was found in 113 (42%). Overall, roughly, one third of the tested persons had NIHL, and among the 159 cases with hearing loss, a factor other than noise played a role. The measures against NIHL have had a positive effect. When, nevertheless, the annually reported number of cases continues to rise, it is because minimal NIHL cases and cases that are not NIHL are included in the statistics. The present study suggests that the non-NIHL group may amount to about 40 % of the reported cases. The official statistics should be refined to take this confounding aspect into account. Conclusions: Despite rising figures of reported occupational hearing loss, working NBII statistics show that the NIHL problem in the Danish work environment has, in fact, decreased. In our study, we found that roughly one third (around 100 cases) of the 272 screened persons presumably had NIHL, taking into account 88 probable cases (Column B) and 44 questionable ones (Column C + 16 ski slopes). About 45% of those who did not pass the screening had a hearing loss in which noise could be, at the most, a contributory factor. In 116 cases of probable or possible NIHL, the average hearing loss was only 33 dB, and in only 11 cases (9%) was the hearing loss considered severe enough to qualify for compensation. Our audiometric findings are, in all probability, valid for similar plants in this country and suggest that the noise problem is reasonably under control. This corroborates the deductions that can be made from the official statistics. It is evident, therefore, that NIHL incidence and severity can be reduced in countries that implement and enforce appropriate work environment legislation. However, documentation of the effect requires data storage and retrieval systems that can distinguish between NIHL and non-NIHL cases and are also able to grade the severity of NIHL.

Compensation Process for Noise Induced Hearing Loss

Noise exposure from worksite can cause a lasting effect of noise induced hearing loss (NIHL). The effect may vary according to industries with manufacturing and construction industries among heavily affected. However, the total number of compensation cases is still low compared to the affected population of construction industry workers. This might due to inefficient and slow compensation process. This paper aim to evaluate the current compensation process for NIHL, with in-depth discussion about the procedure adopted to find alternative ways to expedite and improve the compensation process involving noise induced hearing loss (NIHL) cases. Although the compensation methodologies is not relatively new, the current practice today still leaves gaps in processing compensation cases efficiently and promptly. In this study, compensation process for NIHL cases were reviewed. Data were collected through articles, regulation and law acts. It was complemented with research visits to social security and insurance providers. The result demonstrates that while the current process adopted is workable, it still inefficient to cater the population of affected.

109 Work-related noise induced hearing loss cases reported by physicians to the Norwegian Registry of Work-Related Illnesses: Data from 2005–2009

BackgroundThis study provides an epidemiological profile of hearing loss cases reported to the Norwegian Labour Inspectorate (NLI) and also a distribution of cases by the notifying physician type.Materials and MethodsThe...

Noise-Induced Hearing Loss Still a Problem in Shipbuilders: A Cross-Sectional Study in Goa, India

Background:Workplace safety regulations seek to mitigate noise-induced hearing loss (NIHL), conventionally associated with the shipbuilding industry. Despite this, are workers still predisposed to NIHL?Aims:To study the prevalence of NIHL among noise-exposed subjects in the shipbuilding industry in Goa and to compare it with that among the non-exposed population working in the same industry in relation to certain relevant factors.Subjects and Methods:This is a cross-sectional study in the shipbuilding industry, Goa This study examined 552 workers: 276 shipbuilders and 276 office staff, of similar age, duration of employment and socio-economic status working at a shipbuilding enterprise. An interviewer-administered questionnaire was followed by audiometry. Values were presented as percentages, Mean (SD) and odds ratio (OR) and its 95% confidence interval (CI) (Woolfe's method). Fisher's exact test and binary logistic regression were used. P value of < 0.05 was taken as significant. SPSS version 16 was used.Results:NIHL was found in 17 (6%) shipbuilders, while no office staff was detected to have this condition (OR = 37.29, 95% CI 22.42-62.18). The shipbuilders with NIHL were 52.5 years of age and had been employed for 30.4 years, on an average. None of the 17 cases of NIHL were found to be using earplugs consistently; 11 reported using them “sometimes” and six “never” used them.Conclusions:NIHL continues to affect shipbuilders, owing their non-compliance to workplace regulation. Health education is the need of the hour.

Lack of association between DNMT1 gene polymorphisms and noise-induced hearing loss in a Chinese population

DNA methyltransferase 1 (DNMT1) plays a crucial role in maintaining of methylation and chromatin stability. And mutations in DNMT1 can induce one form of neurodegenerative diseases with dementia and sensorineural hearing loss. To assess whether single nucleotide polymorphisms (SNPs) or haplotypes of DNMT1 are related to noise-induced hearing loss (NIHL) in a Chinese population, we genotyped three functional polymorphisms (rs12984523, rs16999593, and rs2228612) in a case-control study involving 615 NIHL cases and 644 controls. However, no significant association was detected between these three SNPs and NIHL susceptibility in the Chinese population. Our data suggested that the DNMT1 polymorphisms may not contribute to risk of NIHL in the Chinese population.

Association between Genetic Variations in GRHL2 and Noise-induced Hearing Loss in Chinese High Intensity Noise Exposed Workers: A Case-control Analysis

The grainyhead like 2 (GRHL2) is a transcription factor, and the role among noise exposed workers is not well established. We tested whether GRHL2 polymorphisms are associated with the risk of noise-induced hearing loss (NIHL) in Chinese high intensity noise exposed workers. We genotyped six polymorphisms of GRHL2 gene (i.e., rs611419, rs3779617, rs3735713, rs3735714, rs3735715, and rs6989650) of 340 NIHL cases and 356 control subjects who exposed to noise higher than 85 dB (A) [Lex, 8 h=time-weighted average of levels of noise exposure (Lex) for a nominal 8 h working day] in a Chinese population. Compared with rs611419 AA genotype, the AT/TT genotypes conferred protection against NIHL [adjusted odds ratio (OR)=0.71, 95% confidence interval (CI)=0.52–0.98]. No altered NIHL risk was associated with the other five polymorphisms. In the combined analyses, we found that the combined genotypes with three to eight variant alleles were associated with an decrease risk of NIHL compared with those with zero to two variant alleles, and the decrease risk was more pronounced among subgroups of exposure time>20 yr (0.31, 0.16–0.62) and drinkers (0.51, 0.29–0.90). Polymorphisms of GRHL2 may positively contribute to the etiology of NIHL.

Estimated burden of disease attributable to selected occupational exposures in the United Arab Emirates

As part of an effort to strengthen occupational safety and health programs, the United Arab Emirates (UAE) commissioned a study to estimate the burden of disease attributable to occupational exposure to carcinogens, particulate matter, and noise. We developed an innovative simulation model to estimate the occupational disease burden and facilitate future assessments as more field-based quantitative data become available. We determined that, in 2008, an estimated 46 deaths (95% CI: 27-71) and 17,000 health-care facility visits (95% CI: 16,000-18,000), along with 4,500 cases of noise-induced hearing loss, were attributable to the occupational risk factors covered in this study. Lung cancer and leukemia were associated with the highest number of deaths (38), whereas asthma and chronic obstructive pulmonary disease contributed most to the health-care facility visits (nearly 16,900). The highest estimated occupational disease burden is in construction. These results will help the UAE to institute new policies for environment, health, and safety management.

Assessment of the noise emission of sheep shearing systems

There is concern in New Zealand over the growing number of new cases of noise-induced hearing loss amongst sheep shearers each year. The sound pressure level in the woolsheds where the sheep shearing takes place can be in excess of 97 dBA, due in part to the noise emission of the shearing systems used to shear the sheep. The purpose of this study was to benchmark the noise emission of sheep shearing systems inclusive of the shearing plant, the down tube and the hand piece. In addition, the sources of the noise emission were identified using narrow band data and sound intensity mapping to focus future efforts at reducing the noise emission of the shearing systems.

Hearing-Loss Prevention Practices Should Be Taught in Schools

Children are often exposed to excessive levels of sound, such as loud music, firearms, power tools, and noisy toys. Such exposure puts children at risk for developing noise-induced hearing loss (NIHL) and tinnitus. For more than 30 years, health policy agencies and numerous experts in hearing science have recommended teaching hearing-loss prevention practices to children in schools as a way to reduce the prevalence of NIHL. Despite these recommendations, basic hearing-loss prevention information that could prevent countless cases of NIHL remains conspicuously absent from most school curricula. At least 10 organizations produce or use a variety of materials in a comprehensive hearing-loss prevention curriculum for school-age children. At least 18 additional organizations produce or disseminate materials (Web-based, video, or printed matter) that could be used to teach hearing-loss prevention in classrooms. Therefore, adequate materials and curricula are available for presenting this information to school-age children. It is time to implement the repeated recommendations of experts by providing hearing-loss prevention instruction in all of our nation's schools on a regular basis. These educational efforts should eventually help to reduce the prevalence of NIHL, which is a fully preventable condition.