Noise-Induced Hearing Loss

The Prevalence, Knowledge, Attitude, and Practice of Occupational Hearing Loss Among Industrial Workers in Saudi Arabia

PURPOSE

Occupational noise poses a persistent hazard to hearing, while lack of awareness and inadequate hearing protection device (HPD) training heighten the risk of noise-induced hearing loss (NIHL). Few studies have investigated the effects of NIHL and HPD use in Saudi Arabia, with only one in Jeddah. Therefore, this study aimed to estimate the prevalence of occupational NIHL and assess workers' knowledge, attitudes, and practices (KAP) regarding HPDs in Jeddah, Saudi Arabia.

METHOD

This cross-sectional study included 200 industrial workers aged 18-55 years who were exposed to noise. Data were analyzed using descriptive and inferential statistics, including correlations and chi-squared tests. A 32-item questionnaire assessed the KAP regarding occupational NIHL and HPD usage. Hearing screening was conducted using pure-tone audiometry at 0.5, 1, 2, 3, 4, 6, and 8 kHz. Participants who failed screening underwent a comprehensive audiological evaluation.

RESULTS

The analysis revealed that 39.5% of the participants failed hearing screening. Regarding participants' knowledge, 82% believed that noise could affect hearing, 64.5% believed that NIHL could be prevented, and only 35% knew that it was permanent. In terms of HPD usage, 49% always wore them and 34% wore them sometimes. The main reason for not using HPDs was the difficulty communicating with others while wearing them (40%).

CONCLUSIONS

Findings revealed that the prevalence of occupational NIHL was higher than the global prevalence. Thus, hearing conservation programs and enhanced awareness of the permanent nature of NIHL can encourage HPD utilization, which is crucial for preventing diminished productivity, income, and overall quality of life.

Machine Learning Models Can Predict Tinnitus and Noise-Induced Hearing Loss

OBJECTIVES

Despite the extensive use of machine learning (ML) models in health sciences for outcome prediction and condition classification, their application in differentiating various types of auditory disorders remains limited. This study aimed to address this gap by evaluating the efficacy of five ML models in distinguishing (a) individuals with tinnitus from those without tinnitus and (b) noise-induced hearing loss (NIHL) from age-related hearing loss (ARHL).

DESIGN

We used data from a cross-sectional study of the Canadian population, which included audiologic and demographic information from 928 adults aged 30 to 100 years, diagnosed with either ARHL or NIHL due to long-term occupational noise exposure. The ML models applied in this study were artificial neural networks (ANNs), K-nearest neighbors, logistic regression, random forest (RF), and support vector machines.

RESULTS

The study revealed that tinnitus prevalence was over twice as high in the NIHL group compared with the ARHL group, with a frequency of 27.85% versus 8.85% in constant tinnitus and 18.55% versus 10.86% in intermittent tinnitus. In pattern recognition, significantly greater hearing loss was found at medium- and high-band frequencies in NIHL versus ARHL. In both NIHL and ARHL, individuals with tinnitus showed better pure-tone sensitivity than those without tinnitus. Among the ML models, ANN achieved the highest overall accuracy (70%), precision (60%), and F1-score (87%) for predicting tinnitus, with an area under the curve of 0.71. RF outperformed other models in differentiating NIHL from ARHL, with the highest precision (79% for NIHL, 85% for ARHL), recall (85% for NIHL), F1-score (81% for NIHL), and area under the curve (0.90).

CONCLUSIONS

Our findings highlight the application of ML models, particularly ANN and RF, in advancing diagnostic precision for tinnitus and NIHL, potentially providing a framework for integrating ML techniques into clinical audiology for improved diagnostic precision. Future research is suggested to expand datasets to include diverse populations and integrate longitudinal data.

Comparison between logistic regression and machine learning algorithms on prediction of noise-induced hearing loss and investigation of SNP loci

To compare the comprehensive performance of conventional logistic regression (LR) and seven machine learning (ML) algorithms in Noise-Induced Hearing Loss (NIHL) prediction, and to investigate the single nucleotide polymorphism (SNP) loci significantly associated with the occurrence and progression of NIHL. A total of 1,338 noise-exposed workers from 52 enterprises in Jiangsu Province were included in this study. 88 SNP loci involving multiple genes related to noise exposure and hearing loss were detected. LR and multiple ML algorithms were employed to establish the NIHL prediction model with accuracy, recall, precision, F-score, R2 and AUC as performance indicators. Compared to conventional LR, the evaluated ML models Generalized Regression Neural Network (GRNN), Probabilistic Neural Network (PNN), Genetic Algorithm-Random Forests (GA-RF) demonstrate superior performance and were considered to be the optimal models for processing large-scale SNP loci dataset. The SNP loci screened by these models are pivotal in the process of NIHL prediction, which further improves the prediction accuracy of the model. These findings open new possibilities for accurate prediction of NIHL based on SNP locus screening in the future, and provide a more scientific basis for decision-making in occupational health management.

Tranylcypromine upregulates Sestrin 2 expression to ameliorate NLRP3-related noise-induced hearing loss

JOURNAL/nrgr/04.03/01300535-202505000-00030/figure1/v/2024-07-28T173839Z/r/image-tiff Noise-induced hearing loss is the primary non-genetic factor contributing to auditory dysfunction. However, there are currently no effective pharmacological interventions for patients with noise-induced hearing loss. Here, we present evidence suggesting that the lysine-specific demethylase 1 inhibitor-tranylcypromine is an otoprotective agent that could be used to treat noise-induced hearing loss, and elucidate its underlying regulatory mechanisms. We established a mouse model of permanent threshold shift hearing loss by exposing the mice to white broadband noise at a sound pressure level of 120 dB for 4 hours. We found that tranylcypromine treatment led to the upregulation of Sestrin2 (SESN2) and activation of the autophagy markers light chain 3B and lysosome-associated membrane glycoprotein 1 in the cochleae of mice treated with tranylcypromine. The noise exposure group treated with tranylcypromine showed significantly lower average auditory brainstem response hearing thresholds at click, 4, 8, and 16 kHz frequencies compared with the noise exposure group treated with saline. These findings indicate that tranylcypromine treatment resulted in increased SESN2, light chain 3B, and lysosome-associated membrane glycoprotein 1 expression after noise exposure, leading to a reduction in levels of 4-hydroxynonenal and cleaved caspase-3, thereby reducing noise-induced hair cell loss. Additionally, immunoblot analysis demonstrated that treatment with tranylcypromine upregulated SESN2 expression via the autophagy pathway. Tranylcypromine treatment also reduced the production of NOD-like receptor family pyrin domain-containing 3 (NLRP3) production. In conclusion, our results showed that tranylcypromine treatment ameliorated cochlear inflammation by promoting the expression of SESN2, which induced autophagy, thereby restricting NLRP3-related inflammasome signaling, alleviating cochlear hair cell loss, and protecting hearing function. These findings suggest that inhibiting lysine-specific demethylase 1 is a potential therapeutic strategy for preventing hair cell loss and noise-induced hearing loss.

Industrial noise: impacts on workers' health and performance below permissible limits

BACKGROUND

This study investigates the adverse effects of industrial noise below permissible limits on hearing health, work performance, and work stress among workers in medium-sized enterprises.

METHODS

The study included two medium-sized enterprises and a total of 172 workers. A comprehensive noise assessment was conducted in both enterprises. Workplace noise levels were recorded using a Larson Davis SoundAdvisor™ Model 831C sound level meter, following ISO 1996-2:2017 standards. The enterprises were categorized as low-noise (mean: 60.55 dB(A), range: 55.6-66.7 dB(A)) and high-noise (mean: 78.22 dB(A), range: 76.5-80.1 dB(A)) groups. Participants' air conduction hearing thresholds (0.5-8 kHz) were measured using an Interacoustics AS608 audiometer. Sociodemographic data were collected, and auditory complaints were assessed through face-to-face interviews. Workers completed the Job Stress Scale, while their supervisors evaluated their performance using the Job Performance Scale. Statistical significance was set at P < 0.05.

RESULTS

Our analysis revealed elevated hearing thresholds at 2000 and 4000 Hz in both ears and at 6000 Hz in the left ear among workers in the high-noise group. Additionally, employees exposed to higher noise levels demonstrated lower work performance (P < 0.05). However, no statistically significant difference was found in work stress levels between the low- and high-noise groups (P > 0.05). A significant positive correlation was observed between age and hearing thresholds in both groups, whereas no relationship was found between age and work stress or work performance. Furthermore, no correlation was detected between work stress and work performance.

CONCLUSION

This study highlights the serious health risks associated with industrial noise, even when exposure remains below permissible limits. The findings emphasize the need for effective noise control measures to protect workers' health and performance.

Stakeholder perspectives on hearing conservation programmes in the South African mining sector: A qualitative study

PURPOSE

Stakeholders play a crucial role in the success of complex interventions, such as hearing conservation programmes (HCPs), where their active participation directly impacts outcomes. This study aimed to investigate the views of various stakeholders, involved in occupational noise management, in the mining sector in South Africa.

METHODS

A cross-sectional qualitative study was conducted, recruiting 16 participants through purposive and snowball sampling techniques. Participants represented diverse roles, including Mine Health and Safety officials, audiologists, ventilation and occupational health engineers and an occupational hygiene assistant. In-depth interviews were conducted to gather data, which were later analysed using inductive thematic analysis to identify emerging themes.

RESULTS

The in-depth interviews revealed six prominent themes that shed light on both the facilitators and barriers to achieving desired milestones in the implementation of HCPs. These themes were crisis management; some are more equal than others; we have tried, but then reality intervenes; cost of an individual's hearing; knowledge is power; and show and tell.

CONCLUSION

Achieving milestones requires a comprehensive and systematic approach, fostering collaborative engagement among all stakeholders in the mining industry. By viewing and treating HCPs as complex interventions, occupational healthcare can be improved for individuals exposed to excessive noise in the workplace. The study highlights the need for careful consideration of stakeholder perspectives to ensure the feasibility and effectiveness of interventions aimed at eliminating excessive noise in the mining industry.

Construction of a risk prediction model for occupational noise-induced hearing loss using routine blood and biochemical indicators in Shenzhen, China: a predictive modelling study

OBJECTIVES

Occupational noise-induced hearing loss (ONIHL) represents a prevalent occupational health condition, traditionally necessitating multiple pure-tone audiometry assessments. We have developed and validated a machine learning model leveraging routine haematological and biochemical parameters, thereby offering novel insights into the risk prediction of ONIHL.

DESIGN, SETTING AND PARTICIPANTS

This study analysed data from 3297 noise-exposed workers in Shenzhen, including 160 ONIHL cases, with the data set divided into D1 (2868 samples, 107 ONIHL cases) and D2 (429 samples, 53 ONIHL cases). The inclusion criteria were formulated based on the GBZ49-2014 Diagnosis of Occupational Noise-Induced Hearing Loss. Model training was performed using D1, and model validation was conducted using D2. Routine blood and biochemical indicators were extracted from the case data, and a range of machine learning algorithms including extreme gradient boosting (XGBoost) were employed to construct predictive models. The model underwent refinement to identify the most representative variables, and decision curve analysis was conducted to evaluate the net benefit of the model across various threshold levels.

PRIMARY OUTCOME MEASURES

Model creation data set and validation data sets: ONIHL.

RESULTS

The prediction model, developed using XGBoost, demonstrated exceptional performance, achieving an area under the receiver operating characteristic curve (AUC) of 0.942, a sensitivity of 0.875 and a specificity of 0.936 on the validation data set. On the test data set, the model achieved an AUC of 0.990. After implementing feature selection, the model was refined to include only 16 features, while maintaining strong performance on a newly acquired independent data set, with an AUC of 0.872, a balanced accuracy of 0.798, a sensitivity of 0.755 and a specificity of 0.840. The analysis of feature importance revealed that serum albumin (ALB), platelet distribution width (PDW), coefficient of variation in red cell distribution width (RDW-CV), serum creatinine (Scr) and lymphocyte percentage (LYMPHP) are critical factors for risk stratification in patients with ONIHL.

CONCLUSION

The analysis of feature importance identified ALB, PDW, RDW-CV, Scr and LYMPHP as pivotal factors for risk stratification in patients with ONIHL. The machine learning model, using XGBoost, effectively distinguishes patients with ONIHLamong individuals exposed to noise, thereby facilitating early diagnosis and intervention.

A Cross-Sectional Study of the Time of Onset of Hearing Loss in Bus Drivers Following Exposure to Occupational Noise

BACKGROUND AND OBJECTIVES

Occupational noise exposure is a significant risk factor for hearing loss, affecting approximately 5% of the global population. Although noise-induced hearing loss is commonly associated with reduced sensitivity to pure tones, there is limited information regarding when this hearing loss begins after noise exposure. This study aimed to investigate the time of onset of hearing loss in bus drivers exposed to noise for varying durations.

SUBJECTS AND METHODS

The study involved 102 bus drivers aged 25-40 years who had been exposed to noise for periods ranging from 6 months to over 10 years. A control group comprising 102 age-matched individuals without noise exposure was also included. Pure-tone audiometry was performed to assess hearing loss, and time of onset of hearing loss relative to noise exposure duration was evaluated.

RESULTS

Bus drivers experienced only "slight" hearing loss, even after 10 years of noise exposure. By contrast, reduced sensitivity to pure tones was observed after 25 to 48 months of exposure.

CONCLUSIONS

This study confirms that prolonged noise exposure leads to "slight" hearing loss, which can appear as early as 25-48 months after exposure to noise. Among individuals under 40 years of age, significant hearing loss appeared to occur only after 10 or more years of exposure. These findings suggest that the impact of noise on hearing acuity may have been overestimated in previous studies.

Multiscale Finite Element Modeling of Human Ear for Acoustic Wave Transmission Into Cochlea and Hair Cells Fatigue Failure

Hearing loss is highly related to acoustic injuries and mechanical damage of ear tissues. The mechanical responses and failures of ear tissues are difficult to measure experimentally, especially cochlear hair cells within the organ of Corti (OC) at microscale. Finite element (FE) modeling has become an important tool for simulating acoustic wave transmission and studying cochlear mechanics. This study harnessed a multiscale FE model to investigate the mechanical behaviors of ear tissues in response to acoustic wave and developed a fatigue mechanical model to describe the outer hair cells (OHCs) failure. A three-dimensional (3D) multiscale FE model consisting of a macroscale model of the ear canal, middle ear, and three-chambered cochlea and a microscale OC model on a representative basilar membrane section, including the hair cells, membranes, and supporting cells, was established. Harmonic acoustic mode was used in the FE model for simulating various acoustic pressures and frequencies. The cochlear basilar membrane and the cochlear pressure induced by acoustic pressures were derived from the macroscale model and used as inputs for microscale OC model. The OC model identified the stress and strain concentrations in the reticular lamina (RL) at the root of stereocilia hair bundles and in the Deiter's cells at the connecting ends with OHCs, indicating the potential mechanical damage sites. OHCs were under cyclic loading and the alternating stress was quantified by the FE model. A fatigue mechanism for OHCs was established based on the modeling results and experimental data. This mechanism would be used for predicting fatigue failure and the resulting hearing loss.

Lipidomics profiling identifies β-oxidation as a key process in noise-induced hearing loss

Noise-induced hearing loss (NIHL) is the second leading cause of hearing loss worldwide, and the most common cause in young adults. Despite this burden, the molecular mechanisms by which noise causes damage are poorly understood, and there are no pharmacologic therapies to prevent or reduce noise-induced damage to the inner ear. Here, using targeted and untargeted lipidomics, we show that noise exposure induces changes in fatty acid (FA) and acylcarnitine (CAR) species in the inner ear, a metabolic profile indicative of noise-induced increases in β- oxidation. This conclusion is validated through treatment with Etomoxir, an inhibitor of carnitine palmitoyltransferase 1A, the rate-limiting enzyme of long-chain β-oxidation. Furthermore, we demonstrate that blocking β-oxidation with Etomoxir does not affect hearing in a normal acoustic environment but reduces the extent of hearing loss induced by an intense noise exposure (2 hours, 112 dB SPL, 8-16kHz). Together, our findings provide insights into cochlear energy metabolism and suggest that its modulation could be targeted to reduce NIHL.

Recreational noise induced hearing loss: South African undergraduate students' perspectives

Background

Recreational noise-induced hearing loss (NIHL) is an increasing public health concern among young adults who frequently use personal listening devices (PLDs) at high volumes for extended periods. Despite this, awareness of NIHL risks remains low, particularly among university students in South Africa.

Objective

This study aimed to assess undergraduate students' awareness of recreational NIHL, examining their earphone use habits, volume preferences, preventive behaviors, and associations between demographic variables and NIHL awareness.

Methods

A cross-sectional survey was conducted with 154 undergraduate students at a large urban South African university. Quantitative data on listening habits, NIHL awareness, and preventive behaviors were collected and analysed using descriptive including thematic analysis and inferential statistics such as Chi-square tests to examine associations between variables.

Results

Most participants (67.5%) reported daily earphone use, often at moderate (48.1%) or high (33.8%) volumes. Awareness of NIHL was low, with only 9.7% of students feeling very informed. Inferential analysis revealed significant associations between NIHL awareness and age (χ 2 = 12.67, p < 0.05), as well as year of study (χ 2 = 10.89, p < 0.05), with older students and those in upper academic years (third year or beyond) showing greater awareness. Preventive behaviors were inconsistent; 46.1% of students reported lowering volume, while 13.0% took no preventive measures. Further analysis revealed that students who preferred high volumes were more likely to adopt preventive measures, while those who preferred low volumes often took no action, perceiving their existing habits as safe. Thematic analysis identified concerns about hearing health, barriers to safe listening, influence of social norms, and misconceptions about ear health.

Conclusion

The findings highlight a high prevalence of potentially unsafe listening behaviors and low NIHL awareness among South African university students. Recommendations include university-based hearing health programs, leveraging social media for outreach, integrating education into first-year curricula, and promoting affordable protective options, and social media campaigns targeting safe listening practices. These measures could help foster safer listening habits and reduce NIHL risk within this vulnerable population.

Impact of pesticide exposure on auditory health: Mechanisms, efferent system disruption, and public health implications

Pesticide exposure has been linked to adverse effects on auditory health, impacting both peripheral and central auditory systems. Studies suggest that organophosphate, carbamate, organochlorine, and pyrethroid pesticides disrupt auditory processing through oxidative stress, neuroinflammation, and interference with cholinergic signaling. These disruptions may compromise sensory hair cells, spiral ganglion neurons, and auditory pathways, impairing precise signal transmission. The auditory efferent system, responsible for cochlear protection and auditory signal modulation, appears particularly susceptible to pesticide-induced alterations. This system relies on cholinergic transmission to regulate cochlear amplification and selective attention, functions that may be disrupted by pesticide exposure. Evidence from epidemiological and experimental studies highlights the potential for long-term auditory dysfunction in populations exposed to pesticides, with agricultural workers and their families facing elevated risks due to prolonged contact with agrochemicals. This review integrates findings on pesticide exposure and its implications for auditory health, discussing potential peripheral and central ototoxicity pathways. The cumulative effects of chronic exposure are emphasized, including the gradual degradation of auditory processing capabilities. Additionally, the need for targeted interventions, such as audiological monitoring and enhanced safety protocols, is addressed. Further research is critical to elucidate the mechanisms underlying pesticide-induced auditory damage and identify protective strategies. Such investigations can inform evidence-based policies to mitigate the public health impact of pesticide exposure while maintaining agricultural productivity. A multidisciplinary approach is essential to safeguard auditory health in vulnerable populations exposed to these environmental hazards.

Experts' discussion: implications of the World Health Organization's World report on hearing for the cochlear implant field

OBJECTIVE

This review aims to analyse the implications of the World Health Organization's 2021 world report on hearing, with a particular focus on the cochlear implant field. The objective is to understand the challenges and opportunities highlighted in the report and propose viable solutions for effective implementation within the cochlear implant community.

METHODS

Following the release of the World Health Organization's world report on hearing, cochlear implant professionals explored and discussed the implications of the report with examples from various countries to understand the disparities in access, reimbursement policies, and social stigma associated with hearing loss.

RESULTS

The world hearing report identifies hearing loss as a major global health issue, with an estimate of 1.5 billion people currently affected and a projected increase to 2.5 billion by 2050. Key challenges in the cochlear implantation field include disparities in access to services, particularly in low- and middle-income countries, lack of reimbursement policies in many regions, and the social stigma surrounding hearing loss.

CONCLUSION

A multi-faced approach is needed to address the rising prevalence of hearing loss and policy makers must prioritize ear and hearing care as a public health concern. Organizations like the HEARRING group can promote education, awareness, and training, and act as advocates for changes in healthcare systems to expand access to hearing care services.

Noise-induced hearing loss in Turkish special forces personnel

Noise-induced hearing loss is a significant occupational hazard for police personnel. Intense noise from training and military activities can permanently damage the inner ear, leading to hearing loss. The aim of this study is to compare the hearing of Turkish Special Forces personnel with that of healthy individuals. We included 50 male police from Turkish special police forces team and 51 healthy males in the study. After a detailed medical history and a comprehensive otolaryngologic examination, pure-tone audiometry was conducted. Hearing levels were compared between the special forces and the control group. The study included 50 male police from Turkish special police force (study group, mean age 32 ± 3 years) and a control group of 51 healthy males (mean age 32 ± 6 years). Right ear hearing thresholds of 500, 1000, 2000, 4000, 6000, and 8000 Hz were significantly greater in the special forces group, compared to the control group (P < .001 and P = .002, respectively). In addition, left ear hearing thresholds of 500, 2000, 4000, 6000, and 8000 Hz were significantly greater in the special forces group, compared to the control group (P = .03 and P < .001, respectively). This study revealed significantly higher hearing thresholds in special police forces compared to a healthy control group. This suggests chronic loud noise exposure during training and military operations might be causing hearing loss among these personnel. To safeguard the auditory health of this population, robust hearing conservation programs must be implemented. Early identification of hearing loss is essential for mitigating its impact and providing appropriate support.

Functionalized Nanozyme Microcapsules Targeting Deafness Prevention via Mitochondrial Homeostasis Remodeling

Mitochondrial dysfunction, which is the primary mechanism underlying cisplatin-induced hearing loss, can potentially be mitigated by modulating the redox balance and reprogramming the energy metabolism to remodel mitochondrial homeostasis. Herein, N-acetyl-l-cysteine-derived carbonized polymer dots (NAC CPDs) are embedded into manganese porphyrin-doped metal-organic frameworks and encapsulated using a polydopamine (PDA) coating and gelatin methacryloyl (GelMA) hydrogel to afford functionalized nanozyme microcapsules. Owing to their injectability and adhesion properties, these microcapsules exhibit the advantages of prolonged retention in the middle ear and sustained release in the inner ear. The synergy between the manganese porphyrin and polymer dots results in excellent antioxidant properties. The developed nanozymes activate the PI3K-AKT pathway, reprogramming the energy supply mechanism, and inhibiting the oligomerization of BAX in mitochondria to prevent the leakage of mitochondrial DNA and cytochrome c. Therapeutic efficacy and related mechanisms are validated in vivo. Thus, this study on mitochondrial homeostasis remodeling by nanozyme microcapsules opens a new chapter in the treatment of hearing loss.

Peri-Traumatic Near-Infrared Light Treatment Attenuates the Severity of Noise-Induced Hearing Loss by Rescuing (Type I) Spiral Ganglion Neurons in Mice

BACKGROUND

Previous studies have shown that multiple post-traumatic irradiations of the cochlea with near-infrared light (NIR) can significantly reduce noise-induced hearing loss. However, a single NIR pre-treatment was shown to have the same effect. Extending the pre-treatment time did not result in any further reduction in hearing loss. The present study investigated whether a combined NIR pre- and post-treatment had an increased effect on hearing preservation.

METHODS

Frequency-specific auditory brainstem potential thresholds (ABR) were determined in young adult mice. One group (n = 8) underwent NIR irradiation (808 nm, 120 mW, 15 min) of the cochlea, followed by a 30 min noise exposure (5-20 kHz, 115 dB SPL). A post-NIR treatment was administered for 30 min immediately following the noise trauma. After 14 days, hearing loss was determined by ABR measurements. The results were compared with a trauma-only group (n = 8) and an untreated control group (n = 5). Subsequently, the spiral ganglion neuron density was investigated.

RESULTS

A peri-traumatic NIR treatment resulted in a significantly lower hearing loss compared to the trauma-only group. Hearing protection in these animals significantly exceeded the effect of an exclusive pre- or post-treatment across all frequencies. A loss of spiral ganglion neurons in the trauma-only group was observed, which was significantly rescued by the peri-traumatic NIR treatment.

CONCLUSIONS

A single peri-traumatic NIR treatment seems to be the more effective approach for the preservation of hearing thresholds after noise trauma compared to an isolated pre- or post-treatment. One target of the protective effect seems to be the spiral ganglion.

Impacts of hazardous noise levels on hearing loss and tinnitus in dental professionals

BACKGROUND

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 research specifically examining the prevalence of hearing loss and tinnitus in dental professionals.

METHODS

To evaluate the prevalence of hearing loss and tinnitus, data were collected from 60 dental professionals, including participant demographics and audiometric thresholds. Thresholds were compared to the age- and sex-based reference ranges from the International Standards Organization (ISO 7029:2017).

RESULTS

Results showed that 15-25% of males and 13-18% of females had hearing thresholds that exceeded 95th percentile limits based on the ISO normative age- and sex-distributions. Tinnitus was reported in 40% of the participants.

CONCLUSION

This study is the first to examine the characteristics and prevalence of auditory dysfunctions in dental professionals compared to the ISO normative age and sex distributions of hearing status. Findings from this study highlight the need for increasing the awareness of occupational noise hazards among dental professionals and the importance of routine audiological monitoring.

L-Shaped Associations Between Composite Dietary Antioxidant Index and Hearing Loss: A Cross-Sectional Study From the National Health and Nutrition Examination Survey

BACKGROUND

Oxidative stress has been implicated in the pathogenesis of hearing loss (HL). Dietary intake is a modifiable factor that could influence the oxidant and antioxidant capacity. We hypothesized that a higher composite dietary antioxidant index (CDAI) is associated with a reduced odds for HL.

METHODS

Adult participants from the 2001-2012 & 2015-2018 National Health and Nutrition Examination Study were included in this cross-sectional study. The CDAI was calculated from vitamins A, C, E, selenium, zinc, and caretenoid through 24-h dietary recall. Outcomes were HL, speech frequency HL (SFHL), and high frequency HL (HFHL). The associations between CDAI and HL, SFHL, and HFHL were evaluated by weighted multivariable logistic regression.

RESULTS

CDAI was associated with lower odds of HL (OR = 0.98, 95%CI 0.95-1.00, p = .043) and SFHL (OR = 0.97, 95%CI 0.95-1.00, p = .041), but not HFHL (OR = 0.98, 95%CI 0.96-1.00, p = .118) after adjustment for confounders. The multivariable-adjusted model showed a significant trend toward decreased risk of HL, SFHL, and HFHL with increasing CDAI quartile (all p for trend < 0.05). Restricted cubic spline analysis suggested that the associations between CDAI and HL, SFHL, and HFHL were L-shaped, with inflection points of CDAI at -0.61, 2.33, and 4.32, respectively. Subgroup analysis showed that participants with exposure to loud noise benefited from a higher CDAI for SFHL (p for interaction = 0.039).

CONCLUSION

Higher CDAI is associated with reduced odds of HL and SFHL in the U.S. adult population and serves as a promising intervention target to be further explored in prospective longitudinal studies in the future.

Prevalence of Noise-Induced Hearing Loss among Truck Drivers: a Cross-Sectional Study in Lucknow

BACKGROUND

Noise pollution is a significant occupational hazard for heavy-vehicle drivers. This study aimed to determine the prevalence of hearing loss, specifically noise-induced hearing loss, among truck drivers.

METHODS

A total of 200 long-distance truck drivers based in Lucknow City were selected for this study. Pure tone audiometry was used to measure air conduction thresholds in each ear at frequencies ranging from 250 to 8000 Hz. The association of risk factors, such as sleep duration, work experience, age, alcohol drinking, and diabetes, with the prevalence of hearing loss among truck drivers was examined. Participants completed a structured questionnaire addressing hearing health and noise exposure. Data were analyzed using Python software, employing statistical tests such as the chi-square test, rank-sum test, and Wilcoxon signed-rank test.

RESULTS

Based on the World Health Organization guideline, the overall prevalence of hearing loss among 200 drivers was 50.5% in their better ear, with a higher hearing loss rate in the right ear (73.5%) than in the left ear (59.5%). The average hearing thresholds at 500, 1000, 2000, and 4000 Hz of the drivers' right and left ears were 32.61 ± 9.85 and 28.66 ± 8.88 dB, respectively. The audiometric analysis identified key risk factors for hearing loss, including shorter sleep duration (≤6 h), extended work experience (>10 years), older age (>40 years), and alcohol drinking, which were further confirmed as significant predictors through multivariate logistic analysis.

CONCLUSION

Hearing loss is highly prevalent among truck drivers, with the right ear being more affected. The study underscores the need for regular hearing assessments and protective measures to mitigate hearing impairment risks.

Conductive hearing loss does not affect spatial learning and memory in middle-aged guinea pigs

Hearing loss (HL) in mid-life has been suggested as a risk factor for cognitive decline. It is unclear whether this relationship is due to deprivation of auditory input alone, degenerative processes, or a combination. Animal models are useful to investigate underlying neural mechanisms as human studies can be confounded by various factors. However, most animal studies use young animals and often exclude females. We used middle-aged guinea pigs of both sexes to investigate whether 8 weeks of auditory deprivation due to conductive HL caused spatial learning and memory impairments. Forty guinea pigs (20 M, 20 F, ~ 12 months) were tested in the Morris Water Maze (MWM) to assess baseline spatial learning and memory. In 20 of these animals (10 M, 10 F) the ear canal was plugged and 8 weeks later, animals were again assessed in MWM. No deficits in spatial learning or memory were observed in either sex. HL caused a small decline in body weight suggesting some stress associated with conductive HL, although adrenal weight, corrected for body weight, did not change. Our data suggest that auditory input deprivation alone does not affect spatial cognition in middle-age, in line with recent human data suggesting that additional risk factors need to be present.

Prevalence of High Frequency Noise-Induced Hearing Loss Among Medical Students Using Personalized Listening Devices

The misuse of personalized listening devices (PLDs) resulting in noise-induced hearing loss (NIHL) has become a public health concern, especially among youths, including medical students. The occupational use of PLDs that produce high-intensity sounds amplifies the danger of cochlear deterioration and high-frequency NIHL especially when used in noisy environments. This study aims to evaluate the incidence and trends of NIHL among medical students using PLDs. Background/Objectives: The purpose of this study is to assess the prevalence of high-frequency NIHL among PLD-using medical students. Methods: A semi-structured questionnaire covering details on PLD usage, exposure to noisy environments, and hearing difficulties was used to gather the data required. Conventional pure-tone audiometry with extended high-frequency audiometry was preceded by routine clinical evaluation using tuning fork tests and otoscopic examination for hearing loss assessment and to rule out middle-ear pathology. Hearing impairment was determined and categorized according to the Goodman and Clark classification system (250 Hz to 8000 kHz). SPSS version 21 was used in the analysis of the frequency data collected. Results: Out of 100 participants, using conventional PTA, 33% were found to have hearing loss, with 42.9% of males and 23.5% of females affected. Bilateral hearing loss was seen in 36.4% of the cases. Left-sided hearing loss was found to be more common (28%). The duration of usage of PLD had a significant correlation with hearing loss with a p-value < 0.0001. Hearing thresholds were significantly elevated at 16 kHz and 18 kHz in both the right and left ear. Conclusions: The high prevalence of PLD misuse among medical students is a major risk factor for NIHL. To help combat chronic hearing loss, students need to be educated about safe listening levels that can prevent further damage to the cochlea and auditory system.

Combined effects of benzene, toluene, xylene, ethylbenzene, and styrene exposure on hearing loss mediated by oxidative stress at realistic low levels

The link between benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS) exposure and hearing loss (HL) is not well-established. This study investigated 1694 petrochemical workers in southern China to examine the effects of BTEXS urinary metabolites on auditory function, considering oxidative stress (OS) as a potential cause. Using generalized linear models, elastic net regression, and quantile g-computation, we evaluated the single and combined effects of BTEXS, OS indicators, and HL. Subgroup analysis explored interactions between BTEXS and cumulative noise exposure (CNE), while mediation analysis assessed OS's role in BTEXS-related HL. Positive associations were found between hippuric acid (HA) and HL (OR = 1.20, P < 0.05) and high-frequency hearing loss (HFHL) (OR = 1.22, P < 0.05). The ENET model linked 3&4-methylhippuric acid (3&4-MHA) with increased HFHL risk. The qgcomp model showed a 23% increased HL risk and a 20% increased HFHL risk per quartile increase in BTEXS exposure. Toluene metabolites (SBMA and HA) were significant contributors to HL, HFHL, and speech-frequency hearing loss (SFHL). Higher BTEXS SBMA, MA and HA levels exacerbated HL risk in workers exposed to CNE. Interaction analysis revealed synergistic effects between tt-MA and other metabolites on HFHL risk. Total SOD (TSOD) significantly mediated the BTEXS-HL relationship. These findings highlight a dose-effect association between BTEXS exposure and HL due to oxidative damage, with toluene metabolites being critical pollutants. BTEXS exposure also synergistically increased HL risk with noise.

Ultrasound-Triggered NO Release to Promote Axonal Regeneration for Noise-Induced Hearing Loss Therapy

Intense noise poses a threat to spiral ganglion neurons (SGNs) in the inner ear, often resulting in limited axonal regeneration during noise injury and leading to noise-induced hearing loss (NIHL). Here, we propose an ultrasound-triggered nitric oxide (NO) release to enhance the sprouting and regeneration of injured axons in SGNs. We developed hollow silicon nanoparticles to load nitrosylated N-acetylcysteine, producing HMSN-SNO, which effectively protects NO from external interferences. Utilizing low-intensity ultrasound stimulation with bone penetration, we achieve the controlled release of NO from HMSN-SNO within the cochlea. In mice with NIHL, a rapid and extensive loss of synaptic connections between hair cells and SGNs is observed within 24 h after exposure to excessive noise. However, this loss could be reversed with the combined treatment, resulting in a hearing functional recovery from 83.57 to 65.00 dB SPL. This positive outcome is attributed to the multifunctional effects of HMSN-SNO, wherein they scavenge reactive oxygen species (ROS) to reverse the pathological microenvironment and simultaneously upregulate the CREB/BDNF/EGR1 signaling pathway, thereby enhancing neuroplasticity and promoting the regeneration of neuronal axons. These findings underscore the potential of nanomedicine for neuroplasticity modulation, which holds promise for advancing both basic research and the further treatment of neurological diseases.

Evaluating the Impact of Sample Irregularities on the Dynamic Stiffness of Polyurethane: Insights from Experimental and FEM Analysis

This study investigates the dynamic stiffness and damping characteristics of three polyurethane materials-PM, PS, and PST-using a comprehensive vibroacoustic testing approach. The aim is to examine material parameters such as dynamic stiffness, Young's modulus, critical damping factor, and the influence of sample irregularities on the accuracy of measurements. The study employs both experimental testing, in which cuboidal and cylindrical polyurethane samples were subjected to sinusoidal excitation, and finite element modeling (FEM) to simulate the test conditions in sample without irregularities. Results indicate that sample contact surface irregularities (even as low as ~0.04 mm) significantly impact the measured dynamic stiffness, with the effect intensifying for materials with higher Young's modulus values (above 5 MPa). Furthermore, cylindrical samples demonstrated more stable and repeatable measurements compared to cuboidal samples, where surface irregularities were tested in a more controlled environment. The findings underscore the need to consider sample geometry and irregularities in dynamic stiffness assessments to ensure better material evaluations. This work contributes valuable insights for the accurate modeling and testing of materials used in vibration isolation and sound insulation contexts.

From sound waves to molecular and cellular mechanisms: Understanding noise‑induced hearing loss and pioneering preventive approaches (Review)

Noise-induced hearing loss (NIHL) is a significant and urgent global public health concern, arising from prolonged exposure to elevated levels of noise. This auditory impairment harms delicate inner ear structures, particularly the essential hair cells transmitting auditory signals to the brain. Recognized by the World Health Organization as a major contributor to worldwide hearing loss, NIHL requires a comprehensive examination of its molecular and cellular mechanisms. Animal models emerge as indispensable tools for unraveling these intricacies, allowing researchers to simulate and study the impact of noise exposure on auditory structures, shedding light on the interplay of oxidative stress, inflammation and immune responses-crucial factors in NIHL progression. The present review focuses on elucidating the molecular mechanisms of NIHL, with a specific emphasis on findings derived from animal models, alongside the exploration of thorough preventive strategies, including protective measures and probing potential interventions. Understanding the molecular underpinnings not only provides insight into targeted treatment approaches, but also unlocks pathways for exploring and implementing preventive actions. This approach not only deepens the current comprehension of NIHL, but also has the potential to influence the shaping of public health policies, offering a nuanced perspective on this prevalent auditory disorder.

Occupational epidemiological characteristics of noise-induced hearing loss and the impact of combined exposure to noise and dust on workers' hearing-a retrospective study

Introduction

The aim of the study was to investigate the occupational epidemiological characteristics of hearing loss among noise-exposed workers through a cross-sectional study and to explore the impact of combined noise and dust exposure on workers' hearing loss through a longitudinal study.

Results

This cross-sectional study revealed that the risk of speech-frequency hearing loss increases with age (OR = 1.096, 95%CI = 1.081-1.111). Independent factors influencing high-frequency hearing loss include sex, age, hazardous factors, industry category, and enterprise size. Scientific research and technical services (OR = 1.607, 95%CI = 1.111-2.324), wholesale and retail (OR = 2.144, 95%CI = 1.479-3.107), manufacturing (OR = 1.907, 95%CI = 1.429-2.545), and other industries (OR = 1.583, 95%CI = 1.002-2.502) are risk factors for high-frequency hearing loss, whereas being female (OR = 0.297, 95%CI = 0.236-0.373) is a protective factor against high-frequency hearing loss. Independent factors influencing occupational noise-induced hearing loss include sex, working age, hazardous factors, industry category, smoking, and drinking, with the risk of occupational noise-induced hearing loss increasing with working age (OR = 1.045, 95%CI = 1.031-1.058). Noise and dust work (OR = 1.271, 95%CI = 1.011-1.597), other work (OR = 0.619, 95%CI = 0.479-0.800), manufacturing (OR = 2.085, 95%CI = 1.336-3.254), other industries (OR = 2.063, 95%CI = 1.060-4.012), occasional smokers (OR = 0.863, 95%CI = 0.652-1.142), regular smokers (OR = 1.216, 95% CI = 0.987-1.497), and excessive drinkers (OR = 2.171, 95%CI = 1.476-3.193) are risk factors for occupational noise-induced hearing loss, whereas being female (OR = 0.496, 95%CI = 0.347-0.709) is a protective factor against occupational noise-induced hearing loss. The longitudinal study revealed differences in pure-tone hearing threshold test results at 500 Hz, 1,000 Hz, 3,000 Hz, 4,000 Hz, and 6,000 Hz in both ears before and after enrollment among noise-exposed workers (p < 0.05). Combined noise and dust exposure (OR = 4.660, 95%CI = 1.584-13.711), 1st year (OR = 1.540, 95%CI = 1.128-2.103), 2nd year (OR = 1.994, 95%CI = 1.409-2.821), and 3rd year (OR = 1.628, 95%CI = 1.170-2.264) were risk factors for high-frequency hearing loss.

Discussion

Combined noise and dust exposure is a risk factor for occupational noise-induced hearing loss. Additionally, occupational noise-induced hearing loss is influenced by gender, working age, enterprise industry category, smoking, and drinking. Employers should enhance occupational health management and improve workers' occupational health literacy, with a particular focus on older male workers of long working age, and those with unhealthy habits. Combined exposure to noise and dust may have a synergistic effect on causing high-frequency hearing loss, and comprehensive protective measures should be implemented for workers exposed to both.

Health Risks Due to Co-Exposure to Noise and Respirable Crystalline Silica Among Workers in the Open-Pit Mining Industry-Results of a Preliminary Study

Occupational exposure to carcinogenic respirable crystalline silica and noise requires a deeper understanding and an assessment of the possible health risks caused by their combined action. Data on individual exposure to respirable crystalline silica (RCS) and occupational noise (ON) was collected among 44 open-pit miners. The study group was divided into two groups according to the job tasks performed. The individual exposure, exceeding of maximum admissible concentration/intensity, and predicted hearing thresholds (HTs) (according to ISO 1999:2013) were compared between the groups directly participating in the technological process (group 1; N = 23) and performing auxiliary, supervising, or laboratory activities (group 2; N = 21). All the analysed indices were significantly higher for group 1; therefore, the job category may predict ON and RCS exposure among open-pit miners. A statistically significant relationship (rs = 0.66, p < 0.05) was found between the time-weighted average (TWA) 8 h RCS and individual daily noise exposure levels. Exposure to noise in the course of employment causes the risk of hearing impairment (mean HTs for 2, 3, and 4 kHz > 25 dB) up to 74% and 4.4% (in the case of groups 1 and 2, respectively). Further studies are needed before conclusions concerning the effects of co-exposure to ON and RCS on open-pit miners can be made.

Absence of oncomodulin increases susceptibility to noise-induced outer hair cell death and alters mitochondrial morphology

Cochlear outer hair cells (OHCs) play a fundamental role in the hearing sensitivity and frequency selectivity of mammalian hearing and are especially vulnerable to noise-induced damage. The OHCs depend on Ca2+ homeostasis, which is a balance between Ca2+ influx and extrusion, as well as Ca2+ buffering by proteins and organelles. Alterations in OHC Ca2+ homeostasis is not only an immediate response to noise, but also associated with impaired auditory function. However, there is little known about the contribution of Ca2+ buffering proteins and organelles to the vulnerability of OHCs to noise. In this study, we used a knockout (KO) mouse model where oncomodulin (Ocm), the major Ca2+ binding protein preferentially expressed in OHCs, is deleted. We show that Ocm KO mice were more susceptible to noise induced hearing loss compared to wildtype (WT) mice. Following noise exposure (106 dB SPL, 2 h), Ocm KO mice had higher threshold shifts and increased OHC loss and TUNEL staining, compared to age-matched WT mice. Mitochondrial morphology was significantly altered in Ocm KO OHCs compared to WT OHCs. Before noise exposure, Ocm KO OHCs showed decreased mitochondrial abundance, volume, and branching compared to WT OHCs, as measured by immunocytochemical staining of outer mitochondrial membrane protein, TOM20. Following noise exposure, mitochondrial proteins were barely visible in Ocm KO OHCs. Using a mammalian cell culture model of prolonged cytosolic Ca2+ overload, we show that OCM has protective effects against changes in mitochondrial morphology and apoptosis. These experiments suggest that disruption of Ca2+ buffering leads to an increase in noise vulnerability and mitochondrial-associated changes in OHCs.

Dynamic micro-optical coherence tomography enables structural and metabolic imaging of the mammalian cochlea

Sensorineural hearing loss (SNHL) is caused by damage to the mechanosensory hair cells and auditory neurons of the cochlea. The development of imaging tools that can directly visualize or provide functional information about a patient's cochlear cells is critical to identify the pathobiological defect and determine the cells' receptiveness to emerging SNHL treatments. However, the cochlea's small size, embedded location within dense bone, and sensitivity to perturbation have historically precluded high-resolution clinical imaging. Previously, we developed micro-optical coherence tomography (μOCT) as a platform for otologic imaging in animal models and human cochleae. Here we report on advancing μOCT technology to obtain simultaneously acquired and co-localized images of cell viability/metabolic activity through dynamic μOCT (DμOCT) imaging of intracellular motion. DμOCT obtains cross-sectional images of ATP-dependent movement of intracellular organelles and cytoskeletal polymerization by acquiring sequential μOCT images and computing intensity fluctuation frequency metrics on a pixel-wise basis. Using a customized benchtop DμOCT system, we demonstrate the detailed resolution of anatomical and metabolic features of cells within the organ of Corti, via an apical cochleostomy, in freshly-excised adult mouse cochleae. Further, we show that DμOCT is capable of capturing rapid changes in cochlear cell metabolism following an ototoxic insult to induce cell death and actin stabilization. Notably, as few as 6 frames can be used to reconstruct cochlear DμOCT images with sufficient detail to discern individual cells and their metabolic state. Taken together, these results motivate future development of a DμOCT imaging probe for cellular and metabolic diagnosis of SNHL in humans.

Cohort comparison of vision and hearing in 75- and 80-year-old men and women born 28 years apart

PURPOSE

We compared the vision and hearing of older men and women born 28 years apart. In addition, we explored factors explaining the possible cohort differences.

METHODS

Two independent cohorts of 75- and 80-year-old men and women were assessed as a part of the Evergreen study in 1989-1990 (n = 500) and the Evergreen II study in 2017-2018 (n = 726). Studies were conducted with similar protocols, and differences between cohorts were compared for distance visual acuity and hearing acuity. We also studied whether educational level and health factors (i.e. total cholesterol, blood pressure, BMI, and smoking status) underlie the possible cohort differences. Independent samples t-test, Pearson chi-squared test, and linear regression analyses were used as statistical analyses.

RESULTS

Across age and sex groups, the later-born cohort had better visual acuity and a lower prevalence of visual impairment compared to the earlier-born cohort. In hearing, 75-year-old men in the later-born cohort had better hearing acuity, with average hearing level at 32 dB compared to 36 dB in the earlier-born cohort, and 80-year-old men had a lower prevalence of moderate or worse hearing loss (74 % vs. 54 %) than men in the earlier-born cohort. Similar differences were not observed for women. The cohort differences in distance visual acuity and hearing acuity attenuated when adjusting for education level.

CONCLUSIONS

Today older adults retain better vision longer than before, but cohort differences in hearing are less obvious. Differences between cohorts may be partly due to advances in education.

Evaluation of Noise in Paediatric Dentistry and Change in Perception of Operators with Use of Ear Protection Devices

BACKGROUND

Noise sources in paediatric dental offices include machinery and children's cries and screams. Although the presence of occupational noise-induced hearing loss (ONIHL) among dental operators is established, preventive measures such as ear protection devices (EPDs) are not frequently employed as prophylactic intervention. The primary aim of this study was to quantitatively assess the noise levels in paediatric dental clinics and to qualitatively evaluate the operators' perception of noise with and without the use of EPDs.

METHODS

A crossover study was conducted with 93 operators; half of whom first worked without EPD, and the other half worked with EPD. Sound produced near each operator was recorded in decibels (dBs) for five working days, and the maximum sound in decibel for each day was noted and averaged. The results were then compared with the Occupational Safety and Health Administration (OSHA) and National Institute for Occupational Safety and Health (NIOSH) exposure limits. A questionnaire was handed out before the commencement of the study, and another at the end of the study.

RESULTS

The average noise level was 86.68 dB without EPD and 86.83 dB with EPD. About 65.59% dentists considered the level of noise at their workplace to be medium level, and 98.92% did not wear EPD. Most common findings, such as irritability at the end of the day (77.42%), were relieved after use of EPD in 92.47% dentists.

CONCLUSION

The noise in the paediatric department is above the NOISH-recommended exposure limit, which is harmful to the auditory system. In general, dentists are knowledgeable about the noise in the operatory, although their knowledge about EPDs is not high.

Hearing Loss in the Unoperated Ear After High-Speed Drilling in Otologic and Skull Base Surgery

OBJECTIVE

To evaluate if permanent hearing loss occurred in the unoperated ear of patients undergoing otologic and skull base surgery with high-speed otologic drilling.

STUDY DESIGN

We retrospectively studied 250 patients (mean age 57.8 yr; 120 males, and 130 females) undergoing otologic or skull base surgery with high-speed drilling between 2013 and 2019.

SETTING

The University of Pittsburgh Medical Center.

PATIENTS

We evaluated preoperative and postoperative audiograms for patients undergoing surgery for cochlear implantation (95 patients, 38.0%), cholesteatoma or chronic ear disease (88 patients, 35.2%), repair of lateral skull base encephalocele (26 patients, 10.4%), resection of vestibular schwannoma or meningioma of the cerebellopontine angle (23 patients, 9.2%), lateral temporal bone resection (8 patients, 3.2%), microvascular decompression (7 patients, 2.8%), or other operations involving a high-speed otologic drill (3 patients, 1.2%).

MAIN OUTCOME MEASURES

Hearing threshold shift, measured as the difference between postoperative threshold and preoperative threshold for each frequency. The association of age, gender, tested frequency, and surgery type with hearing threshold shift was investigated with analysis of covariance.

RESULTS

A total of 102 patients (40.8%) had a 10-dB or greater worsening of their hearing in at least one frequency on their postoperative audiogram in the contralateral, unoperated ear. One hundred six subjects (42.4%) had no change in hearing of 10 dB or greater at any frequency. Among patients with longitudinal postoperative audiograms, accelerated age-related hearing loss was observed in low frequencies.

CONCLUSIONS

A significant number of patients demonstrated poorer hearing thresholds in the contralateral, unoperated ear after otologic and skull base surgery.

Role of Nursing in Managing Noise-Related Hearing Loss in Children: A Retrospective Study of Earmuffs as a Protective Intervention

BACKGROUND

Noise-induced hearing loss (NIHL) in children is a growing public health concern due to increased exposure to high noise levels in various environments. Early intervention is crucial to prevent long-term developmental and social impacts. This study evaluates the effectiveness of earmuffs as a protective intervention in managing NIHL in children.

METHODS

A prospective study was conducted involving 120 paediatric patients aged 5-12 years diagnosed with NIHL. Patients were divided into an intervention group (n = 60), who received standard treatment plus earmuffs, and a control group (n = 60), who received standard treatment only. Pure-tone audiometry tests were used to assess hearing thresholds at baseline and post-intervention. Family satisfaction was also assessed using a self-administered questionnaire.

RESULTS

Hearing thresholds substantially improved in the intervention group compared with those in the control group. After the intervention, hearing thresholds in the intervention group reduced by 7.31 decibels (dB) at 500 Hertz (Hz), 6.73 dB at 1000 Hz, 6.66 dB at 2000 Hz and 6.92 dB at 4000 Hz (P < 0.05). In the control group, reductions were 3.74, 3.72, 3.64 and 3.80 dB, respectively (P < 0.05). Family satisfaction was significantly higher in the intervention group, with 91.7% expressing satisfaction, compared with 65.0% in the control group (P = 0.030).

CONCLUSION

This study demonstrates the effectiveness of earmuffs in preventing NIHL in children, showing improvements in hearing thresholds and increased family satisfaction. These findings suggest that earmuffs could be beneficial as part of standard preventive measures for paediatric patients exposed to high noise levels and highlight their potential practical and clinical value.

Noise-induced cochlear synaptopathy in C57BL/6 N mice as a function of trauma strength: ribbons are more vulnerable than postsynapses

Noise-induced cochlear synaptopathy is characterized by irreversible loss of synapses between inner hair cells (IHCs) and spiral ganglion neurons (SGNs) despite normal hearing thresholds. We analyzed hearing performance and cochlear structure in C57BL/6 N mice exposed to 100, 106, or 112 dB SPL broadband noise (8-16 kHz) for 2 h. Auditory brainstem responses (ABRs) were assessed before, directly after, and up to 28 days post-trauma. Finally, the number, size, and pairing of IHC presynaptic (CtBP2-positive) ribbons and postsynaptic AMPA receptor scaffold (Homer1-positive) clusters were analyzed along the cochlea. Four weeks after the 100 dB SPL trauma, a permanent threshold shift (PTS) was observed at 45 kHz, which after the higher traumata extended toward middle to low frequencies. Loss in ABR wave I amplitudes scaled with trauma strength indicating loss of functional IHC synaptic connections. Latencies of wave I mostly increased with trauma strength. No trauma-related OHC loss was found. The number of synaptic pairs was reduced in the midbasal and basal cochlear region in all trauma conditions, with ribbon loss amounting up to 46% of control. Ribbons surviving the trauma were paired, whereas 4-6 unpaired postsynapses/IHC were found in the medial, midbasal, and basal regions irrespective of trauma strength, contrasting findings in CBA/CaJ mice. Our data confirm the susceptibility of ribbon synapses and ABR wave I amplitudes to a noise trauma of 100 dB SPL or larger. Notably, peripheral dendrites bearing IHC postsynapses were less vulnerable than presynaptic ribbons in C57BL/6 N mice.

Individual and combined effects of noise exposure and diabetes mellitus on hearing

Hearing loss (HL) is a prevalent health concern with a significant impact on society and the economy. Several factors contribute to the development of hearing impairment, with noise overexposure being the primary culprit. Diabetes mellitus (DM) is also a factor in hearing impairment, and studies have shown a positive correlation between DM and HL; however, the exact causal relationship and pathogenesis remain contentious. Given the ubiquity of noise exposure and the high incidence of DM, individuals may develop diabetes while being chronically exposed to noise. It is particularly important to explore the independent and combined effects of noise and DM on hearing, which can help healthcare professionals understand the potential risks posed by these factors and inspire prevention strategies and potential interventions for hearing impairment. This review summarizes the current research advancements in noise-induced HL and diabetes-related HL and discusses their characteristics and potential mechanisms. Furthermore, this review focuses on the combined effects of noise exposure and DM on hearing, setting the stage for further research and development of intervention strategies to address HL.

The Effect of Thymoquinone on Acoustic Trauma-Induced Hearing Loss in Rats

Background The aim of this study was to investigate the protective effect of thymoquinone, an antioxidant, on hearing loss induced by acoustic trauma in rats. Material and methods This study included 32 Wistar Albino rats divided into four groups: control, acoustic trauma, thymoquinone + acoustic trauma, and thymoquinone only, with eight rats per group. The control group received 0.5 mL of corn oil intraperitoneally for 10 days. The acoustic trauma group was exposed to 100 dB white noise at 4 kHz for 16 hours. The thymoquinone + acoustic trauma group received thymoquinone (10 mg/kg) intraperitoneally for two days before acoustic trauma and eight days after acoustic trauma. The thymoquinone only group received thymoquinone (10 mg/kg) for 10 days. Distortion product otoacoustic emissions (DPOAEs) were measured before and after treatments on days 1, 4, and 10. Results In the control group, DPOAE measurements showed no significant change over the study period. The acoustic trauma group exhibited a significant decrease in DPOAE on the first day after trauma, followed by some recovery. The thymoquinone + acoustic trauma group showed no significant decrease in DPOAE on the first day post-trauma, suggesting a protective effect. The thymoquinone only group also indicated no significant change in DPOAE measurements, suggesting that thymoquinone alone did not affect hearing function. Conclusion Thymoquinone demonstrated a protective effect against acoustic trauma-induced hearing loss in rats, as evidenced by stable DPOAE measurements post-trauma. These findings suggest that thymoquinone may help preserve hearing function by reducing oxidative stress in the cochlea. Further studies are needed to confirm these results in humans and optimize dosage and treatment protocols.

Ototoxicity-Alleviating and Cytoprotective Allomelanin Nanomedicine for Efficient Sensorineural Hearing Loss Treatment

Sensorineural hearing loss (SNHL) represents a significant clinical challenge, predominantly attributed to oxidative stress-related mechanisms. In this work, we report an innovative antioxidant strategy for mitigating SNHL, utilizing synthetically engineered allomelanin nanoparticles (AMNPs). Empirical evidence elucidates AMNPs' profound capability in free radical neutralization, substantiated by a significant decrement in reactive oxygen species (ROS) levels within HEI-OC1 auditory cells exposure to cisplatin or hydrogen peroxide (H2O2). Comparative analyses reveal that AMNPs afford protection against cisplatin-induced and noise-induced auditory impairments, mirroring the effect of dexamethasone (DEX), a standard pharmacological treatment for acute SNHL. AMNPs exhibit notable cytoprotective properties for auditory hair cells (HCs), effectively preventing ototoxicity from cisplatin or H2O2 exposure, as confirmed by both in vitro assays and cultured organ of Corti studies. Further in vivo research corroborates AMNPs' ability to reverse auditory brainstem response (ABR) threshold shifts resulting from acoustic injury, concurrently reducing HCs loss, ribbon synapse depletion, and spiral ganglion neuron degeneration. The therapeutic benefits of AMNPs are attributed to mitigating oxidative stress and inflammation within the cochlea, with transcriptome analysis indicating downregulated gene expression related to these processes post-AMNPs treatment. The pronounced antioxidative and anti-inflammatory effects of AMNPs position them as a promising alternative to DEX for SNHL treatment.

Polymer-Based Nanoparticles for Inner Ear Targeted Trans Differentiation Gene Therapy

Hearing loss is a significant disability that often goes under recognised, largely due to poor identification, prevention, and treatment. Steps are being made to amend these pitfalls in the investigation of hearing loss, however, the development of a cure to reverse advanced forms remains distant. This review details some current advances in the treatment of hearing loss, with a particular focus on genetic-based nanotechnology and how it may provide a useful avenue for further research. This review presents a broad background on the pathophysiology of hearing loss and some current interventions. We also highlight some potential genes that may be useful in the amelioration of hearing loss. Pathways of cellular differentiation from stem or supporting cell to functional hair cell are covered in detail, as this mechanism represents a key means of regenerating these cell types. Overall, we believe that polymer-based nanotechnology coupled with novel excipients represents a useful area of further research in the treatment of hearing loss, although further studies in this area are required.

A Study of Hearing Acuity and the Health of the External Auditory Canal Among Earphone Users in Central India

Background and objective The pervasive use of earphones has raised concerns about its potential impact on hearing acuity and the health of the external auditory canal (EAC). This study aimed to investigate these effects in a sample of individuals in Central India to better understand the associated risks. Materials and methods This observational cross-sectional study was conducted in the Department of Otorhinolaryngology, Acharya Vinoba Bhave Rural Hospital, Sawangi Wardha. A total of 130 participants aged 15-35 years were divided into two groups: 65 earphone users and 65 non-earphone users. The data collection involved medical histories, clinical examinations, and audiometric testing, including pure-tone audiometry (PTA), impedance audiometry, and otoacoustic emissions (OAE). Participants completed a questionnaire on earphone usage, and EAC health was assessed via physical examinations and photographic documentation. Statistical analyses included descriptive and inferential statistics, with significance set at p<0.05. Results Among earphone users, 45 (69.23%) exhibited hearing loss compared to 11 (16.92%) in non-users (p<0.00001). Noise-canceling earphones were associated with fewer cases of hearing loss (6/45, 13.33%) than non-noise-canceling types (39/45, 86.67%) (p<0.00001). EAC issues were more prevalent in earphone users, with 39 (60%) showing normal conditions versus 52 (80%) in non-users. Impactions of wax, otomycosis, and otitis externa were observed more frequently among earphone users. Conclusions The study highlights a significant association between earphone use and increased risk of hearing loss and EAC issues. Noise-canceling earphones may offer some protective benefits. These findings underscore the need for raising awareness and implementing preventive measures to mitigate potential risks associated with prolonged earphone use.

Biomaterials as a new option for treating sensorineural hearing loss

Sensorineural hearing loss (SNHL) usually involves damage to complex auditory pathways such as inner ear cells and auditory nerves. The highly intricate and nuanced characteristics of these cells render their repair and regeneration extremely challenging, making it difficult to restore hearing to normal levels once it has been compromised. The effectiveness of traditional drugs is so minimal that they provide little help with the treatment. Fortunately, extensive experiments have demonstrated that combining biomaterials with conventional techniques significantly enhances drug effectiveness. This article reviews the research progress of biomaterials in protecting hair cells and the auditory nerve, repairing genes related to hearing, and developing artificial cochlear materials. By organizing the knowledge presented in this article, perhaps new insights can be provided for the clinical management of SNHL.

Noise-Induced Hearing Loss Awareness and Prevention: A Cross-Sectional Study Among the Population of the Southern Region of Saudi Arabia

BACKGROUND

Noise-induced hearing loss (NIHL) is a prevalent and preventable health issue globally. This study aims to evaluate the symptoms, knowledge, beliefs, and preventive practices regarding NIHL among the general population of the southern region of Saudi Arabia.

MATERIALS & METHODS

A cross-sectional study was conducted from May to July 2024, using a self-administered, validated electronic questionnaire distributed in Arabic via social media platforms. The questionnaire assessed socio-demographic data, NIHL awareness, attitudes toward prevention, and personal practices regarding noise exposure. The sample included 400 participants analyzed using SPSS version 23 (IBM Corp., Armonk, NY), with associations measured through the chi-square and Fisher's exact tests.

RESULTS

Most participants were Saudi nationals (97%) and females (81.3%). Symptoms of NIHL, such as tinnitus and the need to increase TV or radio volume, were prevalent among participants. Most participants (88.5%) were aware that high sound levels affect hearing, yet only 9.5% correctly identified the minimum duration of exposure that could harm hearing. Social media was the primary source of information (51.3%). Positive preventive practices were noted, with 66% lowering device volumes and 55.3% recommending sound restrictions on tablets. Significant associations were found between better preventive practices and higher income as well as marital status.

CONCLUSION

The study highlights the high basic awareness of NIHL but identifies critical knowledge gaps regarding the minimum sound level and duration that affect hearing negatively. Enhanced public health education and technological interventions are needed to improve prevention practices. Future research should include longitudinal studies and diverse populations to better understand and address NIHL.

Hearing Loss and Oxidative Stress: A Comprehensive Review

Hearing loss is a prevalent condition affecting millions of people worldwide. Hearing loss has been linked to oxidative stress as a major factor in its onset and progression. The goal of this thorough analysis is to investigate the connection between oxidative stress and hearing loss, with an emphasis on the underlying mechanisms and possible treatments. The review addressed the many forms of hearing loss, the role of reactive oxygen species (ROS) in causing damage to the cochlea, and the auditory system's antioxidant defensive mechanisms. The review also goes over the available data that support the use of antioxidants and other methods to lessen hearing loss brought on by oxidative stress. We found that oxidative stress is implicated in multiple types of hearing loss, including age-related, noise-induced, and ototoxic hearing impairment. The cochlea's unique anatomical and physiological characteristics, such as high metabolic activity and limited blood supply, make it particularly susceptible to oxidative damage. Antioxidant therapies have shown promising results in both animal models and clinical studies for preventing and mitigating hearing loss. Emerging therapeutic approaches, including targeted drug delivery systems and gene therapy, offer new possibilities for addressing oxidative stress in the auditory system. The significance of this review lies in its comprehensive analysis of the intricate relationship between oxidative stress and hearing loss. By synthesizing current knowledge and identifying gaps in understanding, this review provides valuable insights for both researchers and clinicians. It highlights the potential of antioxidant-based interventions and emphasizes the need for further research into personalized treatment strategies. Our findings on oxidative stress mechanisms may also affect clinical practice and future research directions. This review serves as a foundation for developing novel therapeutic approaches and may inform evidence-based strategies for the prevention and treatment of hearing loss, ultimately contributing to improved quality of life for millions affected by this condition worldwide.

Analysis of Therapeutic Options for Noise-Induced Hearing Loss: Retroauricular Injection of Methylprednisolone Sodium Succinate Combined with Hyperbaric Oxygenation

OBJECTIVE

To evaluate the clinical effect of retroaural injection of methylprednisolone sodium succinate combined with hyperbaric oxygen (HBO) on the treatment of noise-induced hearing loss.

METHODS

Case data of 220 patients with hearing loss treated at the Zhongda Hospital Southeast University from January 1, 2019 to August 1, 2023 were obtained. As per the treatment plan, the recruited patients were divided into two cohorts: 158 cases in the combined-treatment group (retroaural injection of methylprednisolone sodium succinate combined with HBO) and 62 cases in the single-hormone group (retroaural injection of methylprednisolone sodium succinate). Comparison of the clinical efficacies and postoperative complication rates of the two groups was performed after treatment. MS-Excel was used to build a database for all data, and SPSS26.0 was utilized in the statistical analysis of recorded data.

RESULTS

For patients with low-frequency, high-frequency, and flat descending type, the combined-treatment group showed significantly higher clinical effective rate than the single-hormone group (P < 0.05). For patients with disease duration ≤7 days, the combined-treatment group attained a significantly higher clinical effective rate was than the single-hormone group (P < 0.05). The safety of patients in both groups was evaluated mainly through their adverse reactions. The total incidence of adverse reactions in the single-hormone group reached 9.68%, and that in the combined-treatment group was 8.23%. The two groups revealed no significant difference in terms of incidence of adverse reactions (P > 0.05).

CONCLUSION

HBO combined with retroaural injection of methylprednisolone sodium succinate has good clinical efficacy and safety in the treatment of hearing loss.

Assessment of Noise Exposure and Risk of Hearing Loss for Young People in Amusement Arcades

BACKGROUND

Amusement arcades are one of the most popular entertainment venues for young people, but excessive noise levels inside them could harm young people's hearing. The aim of this study is to assess the characteristics and risk of noise exposure for young people in amusement arcades and understand their knowledge of and attitudes towards safe listening.

METHODS

In this study, noise measurement was conducted in five large amusement arcades to collect 40 noise samples. At the same time, questionnaires were used in each amusement arcade to investigate young players' social information, subjective perception, and cognition of noise-induced hearing loss (NIHL).

RESULTS

The level of the noise samples ranged from 83.05 to 89.4 dBA. There are significant differences in noise levels between amusement arcades (P < 0.05), but there is no significant difference in noise levels between different games (P > 0.05). The subjective questionnaire survey shows that 61.9% of young people feel that the sound of video games is noisy or very noisy, but it is worth noting that 63.5% of them do not know or think that noise will not cause hearing loss, and 39.7% of people will choose to do nothing to help them endure the noise in such an environment. For safe listening, young people are more inclined to choose measures to stay in quiet areas and reduce the volume of game devices.

CONCLUSIONS

The noise levels in most amusement arcades have exceeded the exposure limits recommended by the Environment Protection Agency (EPA); subjective questionnaires also indicate that internal noise levels may cause hearing loss, and young customers did not know enough about safe listening. For young people's hearing safety, these issues need more attention.

Advancing noise management in aviation: Strategic approaches for preventing noise-induced hearing loss

As urbanization and population growth escalate, the challenge of noise pollution intensifies, particularly within the aviation industry. This review examines current insights into noise-induced hearing loss (NIHL) in aviation, highlighting the risks to pilots, cabin crew, aircraft maintenance engineers, and ground staff from continuous exposure to high-level noise. It evaluates existing noise management and hearing conservation strategies, identifying key obstacles and exploring new technological solutions. While progress in developing protective devices and noise control technologies is evident, gaps in their widespread implementation persist. The study underscores the need for an integrated strategy combining regulatory compliance, technological advances, and targeted educational efforts. It advocates for global collaboration and policy development to safeguard the auditory health of aviation workers and proposes a strategic framework to enhance hearing conservation practices within the unique challenges of the aviation sector.

Higher exposure to 1,3-butadiene is associated with more severe hearing loss

While volatile organic compounds (VOCs) impair various organs, their influence on hearing loss (HL) has not been extensively researched. We aimed to identify the association between VOCs and HL or high-frequency hearing loss (HFHL). We extracted data on age, sex, pure tone audiometry, hypertension, occupational noise exposure, and creatinine-corrected urine VOC metabolite concentrations from the eighth Korea National Health and Nutrition Survey. Among the VOC metabolites, N-acetyl-S-(benzyl)-L-cysteine (BMA, P = 0.004), N-acetyl-S-(phenyl)-L-cysteine (SPMA, P = 0.027), and N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA, P < 0.001) showed associations with HL. Additionally, HFHL exhibited significant associations with BMA (P = 0.005), 3- and 4-methylhippuric acid (3, 4 MHA, P = 0.049), mandelic acid (MA, P = 0.015), SPMA (P < 0.001), N-acetyl-S-(3-hydroxypropyl)-L-cysteine (3-HPMA, P < 0.001), and DHBMA (P < 0.001). After controlling other factors, DHBMA were associated with HL (P = 0.021) and HFHL (P = 0.014) and exhibited a linear association with the mean hearing level (β = 0.054, P = 0.024) and high-frequency hearing level (β = 0.045, P = 0.037). Since 1,3-butadiene may act as an ototoxic material, early screening for workers exposed to 1,3-butadiene and reducing exposure to 1,3-butadiene in everyday life may be helpful to prevent further HL.

Prevalence and associated factors of noise-induced hearing loss among workers in Bishoftu Central Air Base of Ethiopia

Excessive occupational exposure to noise results in a well-recognized occupational hearing loss which is prevalent in many workplaces and now it is taken as a global problem. Therefore, this study aims to assess the prevalence of noise-induced hearing loss and associated factors among workers in the Bishoftu Central Air Base in Ethiopia. An institutional-based cross-sectional study was conducted among 260 central air base workers through face-to-face interviews, an environment noise survey, and an audiometric test for data collection. Data were entered by Epi-data version 3.1 and SPSS was used to analyze the data. Finally, a statistical analysis such as descriptive and binary logistic regression analysis was applied. A P-value < 0.05 at 95% CI was considered statistically significant. The overall prevalence of noise-induced hearing loss and hearing impairments was 24.6 and 30.9%, respectively. The highest prevalence of noise-induced hearing loss was recorded for workers who were exposed to noise levels greater than 90 dBA. Out of 132 workers exposed to the average noise level of 75 dB A, only 5% of workers were affected with noise-induced hearing loss, while 128 workers exposed to an average noise level equal to or greater than 90 dB A, 19.6% of workers were identified with noise-induced hearing loss. Regarding sex, around 21.9% of male workers were identified with noise-induced hearing loss. Workers who were exposed to a high noise level workplace previously or before the Central Air Base workplace were five times (AOR = 5.0, 95% CI 1.74-14.36) more likely affected by noise-induced hearing loss than those workers not previously exposed. Those workers who were exposed to greater or equal to 90dBA noise level were 4.98 times (AOR = 4.98, 95% CI 2.59-9.58) more likely to be exposed to noise-induced levels than those who were exposed to less than 90dBA noise level. Moreover, male air base workers were 3.5 times more likely exposed to hearing impairment than female workers (AOR = 3.5, 95% CI 1.01-12.0). This study identified that the prevalence of noise-induced hearing loss and hearing impairments was significantly high. So implementation of a hearing conservation program, giving noise education, and supplying adequate hearing protective devices (HPDs) are essentials.

C-Phycocyanin Attenuates Noise-Induced Cochlear Synaptopathy via the Inhibition of Oxidative Stress and Intercellular Adhesion Molecule-1 in the Cochlea

The synapses between inner hair cells (IHCs) and spiral ganglion neurons (SGNs) are the most vulnerable structures in the noise-exposed cochlea. Cochlear synaptopathy results from the disruption of these synapses following noise exposure and is considered the main cause of poor speech understanding in noisy environments, even when audiogram results are normal. Cochlear synaptopathy leads to the degeneration of SGNs if damaged IHC-SGN synapses are not promptly recovered. Oxidative stress plays a central role in the pathogenesis of cochlear synaptopathy. C-Phycocyanin (C-PC) has antioxidant and anti-inflammatory activities and is widely utilized in the food and drug industry. However, the effect of the C-PC on noise-induced cochlear damage is unknown. We first investigated the therapeutic effect of C-PC on noise-induced cochlear synaptopathy. In vitro experiments revealed that C-PC reduced the H2O2-induced generation of reactive oxygen species in HEI-OC1 auditory cells. H2O2-induced cytotoxicity in HEI-OC1 cells was reduced with C-PC treatment. After white noise exposure for 3 h at a sound pressure of 118 dB, the guinea pigs intratympanically administered 5 μg/mL C-PC exhibited greater wave I amplitudes in the auditory brainstem response, more IHC synaptic ribbons and more IHC-SGN synapses according to microscopic analysis than the saline-treated guinea pigs. Furthermore, the group treated with C-PC had less intense 4-hydroxynonenal and intercellular adhesion molecule-1 staining in the cochlea compared with the saline group. Our results suggest that C-PC improves cochlear synaptopathy by inhibiting noise-induced oxidative stress and the inflammatory response in the cochlea.