Comparison of the risk of noise-induced hearing loss between male police officers and male non-police officers: a nationwide cohort study using propensity score matching in South Korea.

BACKGROUND: Police officers are at a high risk of noise-induced hearing loss (NIHL) owing to the nature of their work. Therefore, this study aimed to compare the risk of NIHL in police officers and controls. METHODS: This study used the National Health Insurance claims data of workers aged 25-65 years obtained from 2005 to 2015. The case group comprised police officers, while the control group comprised general workers and public officers. The study followed a three-phase cohort design. The standardized incidence ratio (SIR) was calculated using an indirect standardization method based on age. Propensity score matching was performed using the greedy matching method, with a police officer-to-control group ratio of 1:3. Cox regression analysis was performed for each matched control group. Statistical significance was determined by a lower limit of greater than 1, based on the 95% confidence interval (CI). RESULTS: The SIR values for police officers were 1.62 (95% CI: 1.44-1.82) compared with general workers and 1.78 (95% CI: 1.66-1.73) compared with public officers. Police officers exhibited an increased risk of NIHL compared with general workers (hazard ratio (HR): 1.71, 95% CI: 1.49-1.98) and public officers (HR: 2.19, 95% CI: 1.88-2.56). CONCLUSIONS: It is necessary to prevent NIHL by reducing occupational noise exposure through measures such as wearing earplugs, improving shooting training methods, and improving the shift work system.

The roles of different gene expression regulators in acoustic variation in the intermediate horseshoe bat revealed by long-read and short-read RNA sequencing data.

Gene expression changes contribute greatly to phenotypic variations in nature. Studying patterns of regulators of gene expression is important to fully understand the molecular mechanism underlying phenotypic variations. In horseshoe bats, the cochleae are finely tuned to echoes of call frequency. Here, using 2 recently diverged subspecies of the intermediate horseshoe bat (Rhinolophus affinis hainanus and R. a. himalayanus) with great acoustic variations as the system, we aim to explore relative roles of different regulators of gene expression (differential gene expression, alternative splicing (AS) and long non-coding RNAs (lncRNAs)) in phenotypic variation with a combination of Illumina short-read and Nanopore long-read RNA-seq data from the cochlea. Compared to R. a. hainanus, R. a. himalayanus exhibited much more upregulated differentially expressed genes (DEGs) and multiple of them may play important roles in the maintenance and damage repair of auditory hair cells. We identified 411 differentially expressed lncRNAs and their target DEGs upregulated in R. a. himalayanus were also mainly involved in a protective mechanism for auditory hair cells. Using 3 different methods of AS analysis, we identified several candidate alternatively spliced genes (ASGs) that expressed different isoforms which may be associated with acoustic divergence of the 2 subspecies. We observed significantly less overlap than expected between DEGs and ASGs, supporting complementary roles of differential gene expression and AS in generating phenotypic variations. Overall, our study highlights the importance of a combination of short-read and long-read RNA-seq data in examining the regulation of gene expression changes responsible for phenotypic variations.

Early identification of potential occupational noise-induced hearing loss: a systematic review.

OBJECTIVE: This systematic review addressed two questions: 1) For which audiometric test frequencies or pure tone averages are hearing threshold levels (HTLs) most susceptible to early occupational noise induced hearing loss (NIHL) before significant damage? 2) Which early flag metric best detects early hearing shifts due to noise for occupational NIHL surveillance? DESIGN: Systematic searches were conducted in Ovid MEDLINE(R) and Embase from July 2021 to May 2024. Eligibility was screened by two independent reviewers using Covidence. HTL results were analysed for susceptibility to noise-induced changes, and sensitivity and specificity of early flag metrics were assessed. STUDY SAMPLE: Of 175 studies retrieved, 18 met the inclusion criteria. RESULTS: Ten studies emphasised the importance of testing at frequencies above 8 kHz, with HTLs at 12, 14, and 16 kHz frequently identified as the most noise susceptible. Conventional frequencies of 3-6 kHz were also noted as susceptible. NIOSH and OSHA metrics had low sensitivity and specificity, but modifications improved their performance to 100% sensitivity and 98% specificity. CONCLUSION: The review highlights the need to refine current metrics and explore extended high frequencies for NIHL monitoring. Research is required to determine frequencies for warning metrics and sensitive metrics for early occupational NIHL detection.

Connexin30-deficient mice increase susceptibility to noise via redox and lactate imbalances.

Noise significantly contributes to one-third of the global burden of hearing loss. The intricate interplay of genetic and environmental factors impacts various molecular and cellular processes that lead to noise-induced hearing loss (NIHL). Defective connexin 26 (Cx26) and connexin 30 (Cx30), encoded by Gjb2/Cx26 and Gjb6/Cx30, respectively, are prevalent causes of hereditary deafness. However, the role of Cx30 in the pathogenesis of NIHL remains unclear. Herein, we observed that homozygous Cx30 knockout (Cx30 KO) mice exhibited poorer hearing recovery after noise exposure (97 dB mean sound pressure level for 2 h) and increased susceptibility to noise. In addition to the exacerbation of noise-induced damage to hair cells and synapses, Cx30 KO mice exposed to noise exhibited increased oxidative stress. The 2-(N-(7-nitrobenz-2-oxa-1,3-dia-zol-4-yl) amino)-2-deoxyglucose assay showed a reduction in glucose levels associated with a decrease in gap junctions as well as a reduction in adenosine triphosphate release. Glucose metabolomics analysis further revealed that Cx30 KO mice had elevated lactate and NAD + levels after noise exposure, thus worsening anaerobic oxidation from glycolysis. Our study emphasizes that Cx30-deficient mice increase susceptibility to noise via redox and lactate imbalances in the cochlea.

[Analysis of disease burden and trends of noise-induced hearing loss in China from 1990 to 2019].

Objective: To analyze the disease burden of Noise-Induced Hearing Loss (NIHL) in China from 1990 to 2019, forecast the disease burden of NIHL from 2020 to 2030, and provide data support for the prevention and control of NIHL. Methods: In July 2022, the disease burden data of NIHL in different age groups and genders in China during 1990-2019 were selected from the GBD database. The Jointpoint regression model was established to analyze the trend of the disease burden of NIHL in China. An age-period-cohort model was constructed to analyze the changing trend of NIHL in terms of age, period, and cohort, and a Bayesian age-period-cohort model was developed to predict the disease burden of NIHL in China from 2020 to 2030. Results: From 1990 to 2019, the disability adjusted life year (DALY) of China's NIHL increased from 1361600 to 2327700 years. The coarse rate of DALY increased from 115.03/100000 to 163.65/100000 (AAPC=1.23, P<0.001), and the normalization rate of DALY decreased from 127.67/100000 to 119.83/100000 (AAPC=-0.21, P<0.001). It is predicted that from 2020 to 2030, the DALYs of China's NIHL will increase from 2412900 in 2020 to 2655000 in 2030, and the DALY normalization rate will decrease from 241.29/100000 in 2020 to 125.71/100000 in 2030. Conclusion: The burden of noise-induced hearing loss (NIHL) in China is significant and should not be overlooked. To reduce this burden, we need to focus on strengthening source management, process control, personal protection, and comprehensive prevention and treatment through various methods.

Rodent models in sensorineural hearing loss research: A comprehensive review.

Sensorineural hearing loss (SNHL) constitutes a major global health challenge, affecting millions of individuals and substantially impairing social integration and quality of life. The complexity of the auditory system and the multifaceted nature of SNHL necessitate advanced methodologies to understand its etiology, progression, and potential therapeutic interventions. This review provides a comprehensive overview of the current animal models used in SNHL research, focusing on their selection based on specific characteristics and their contributions to elucidating pathophysiological mechanisms and evaluating novel treatment strategies. It discusses the most commonly used rodent models in hearing research, including mice, rats, guinea pigs, Mongolian gerbils, and chinchillas. Through a comparative analysis, this review underscores the importance of selecting models that align with specific research objectives in SNHL studies, discussing the advantages and limitations of each model. By advocating for a multidisciplinary approach that leverages the strengths of various animal models with technological advancements, this review aims to facilitate significant advancements in the prevention, diagnosis, and treatment of sensorineural hearing loss.

Prevalence and Factors Associated With Occupational Noise-Induced Hearing Loss Among Palm Oil Mill Workers in Selangor, Malaysia.

Introduction Occupational noise-induced hearing loss (NIHL) continues to be a significant public health issue globally, with Malaysia being no exception. In Malaysia, the majority of NIHL cases are reported from the manufacturing sector, with Selangor among the states with the highest number of confirmed cases. This study aimed to assess the prevalence of and factors associated with occupational NIHL among palm oil mill workers in Selangor, Malaysia. Methods A cross-sectional study was conducted to analyze the data from the data collection form, noise risk assessment reports, and audiometric test results done between 2021 and 2022 with a comparable baseline audiometric test. Results A total of 143 participants from three palm oil mills joined this study. The prevalence of NIHL was 42.7% (n = 61). Following the logistic regression model, NIHL was significantly associated with a duration of employment of 10 years and above, a history of occupational noise exposure at the previous workplace, and the use of personal hearing protectors at the current workplace with an adjusted OR of 2.41 (95% CI (1.14, 5.07)), 5.89 (95% CI (2.38, 14.53)), and 0.36 (95% CI (0.16, 0.83)), respectively. Conclusion The prevalence of NIHL among the study participants was high, and the associated factors are modifiable factors that can be prevented with a comprehensive hearing conservation program in the palm oil mills.

Pathogenesis and New Pharmacological Approaches to Noise-Induced Hearing Loss: A Systematic Review.

Noise-induced hearing loss (NIHL) is responsible for significant adverse effects on cognition, quality of life and work, social relationships, motor skills, and other psychological aspects. The severity of NIHL depends on individual patient characteristics, sound intensity, and mainly the duration of sound exposure. NIHL leads to the production of a reactive oxygen (ROS) inflammatory response and the activation of apoptotic pathways, DNA fragmentation, and cell death. In this situation, antioxidants can interact with free radicals as well as anti-apoptotics or anti-inflammatory substances and stop the reaction before vital molecules are damaged. Therefore, the aim of this study was to analyze the effects of different pharmacological treatments, focusing on exogenous antioxidants, anti-inflammatories, and anti-apoptotics to reduce the cellular damage caused by acoustic trauma in the inner ear. Experimental animal studies using these molecules have shown that they protect hair cells and reduce hearing loss due to acoustic trauma. However, there is a need for more conclusive evidence demonstrating the protective effects of antioxidant/anti-inflammatory or anti-apoptotic drugs' administration, the timeline in which they exert their pharmacological action, and the dose in which they should be used in order to consider them as therapeutic drugs. Further studies are needed to fully understand the potential of these drugs as they may be a promising option to prevent and treat noise-induced hearing loss.

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.

Auditory changes in awake guinea pigs exposed to overcompressed music.

Exposure to loud sound during leisure time is identified as a significant risk factor for hearing by health authorities worldwide. The current standard that defines unsafe exposure rests on the equal-energy hypothesis, according to which the maximum recommended exposure is a tradeoff between level and daily exposure duration, a satisfactory recipe except for strongly non-Gaussian intense sounds such as gunshots. Nowadays, sound broadcast by music and videoconference streaming services makes extensive use of numerical dynamic range compression. By filling in millisecond-long valleys in the signal to prevent competing noise from masking, it pulls sound-level statistics away from a Gaussian distribution, the framework where the equal-energy hypothesis emerged. Auditory effects of a single 4 hour exposure to the same music were compared in two samples of guinea pigs exposed either to its original or overcompressed version played at the same average level of 102 dBA allowed by French regulations. Apart from a temporary shift of otoacoustic emissions at the lowest two frequencies 2 and 3 kHz, music exposure had no detectable cochlear effect, as monitored at 1, 2 and 7 days post-exposure. Conversely, middle-ear muscle strength behaved differentially as the group exposed to original music had fully recovered one day after exposure whereas the group exposed to overcompressed music remained stuck to about 50% of baseline even after 7 days. Subsamples were then re-exposed to the same music as the first time and sacrificed for density measurements of inner-hair-cell synapses. No difference in synaptic density was found compared to unexposed controls with either type of music. The present results show that the same music piece, harmless when played in its original version, induces a protracted deficit of one auditory neural pathway when overcompressed at the same level. The induced disorder does not seem to involve inner-hair cell synapses.

Awareness About Noise Induced Hearing Loss and the Use of Unsafe Listening Practices Among Medical Students.

To assess the Knowledge, Attitude, and Practice on Noise Induced Hearing Loss(NIHL) caused by using Personal Listening Devices (PLD). To assess the usage pattern of PLD among undergraduate medical students studying at a tertiary health center in South India. A descriptive study was conducted by the Department of ENT over a three-month duration on undergraduate medical students who volunteered to fill in an electronic questionnaire form that they received via WhatsApp. A convenient sampling technique was used. NIHL questionnaire consisted of three sets of electronic questionnaires: Q1, Q2, and Q3. In Q1 total score of more than 75% was taken as good knowledge, 50-75% as fair knowledge, and less than 50% as poor knowledge. Q2 score of more than 50% was taken as a good attitude and less than 50% as a need to improve upon attitude. A total of 224(94.5%) participants had consented, out of the 224 students, 132(58.9%) were males and 92(41.1%) were females. 195(87.1%) of the 224 participants are regular users of PLD and the most common PLD used was earbuds (76.8%). The mean total knowledge on NIHL is less than 75%. Medical students have fair knowledge (54.5%). The weaker areas of knowledge were about the nature of the disease believing that NIHL is a reversible condition. Their overall attitude score is good (61.8%). Students more than 18 years of age had a positive attitude score (3.42 +/- 0.856) as compared with students less than 18 years of age (2.69 +/- 0.800). Most participants preferred a volume level of 6.26 +/- 1.517 on a scale of 1 to 10 for PLD, indicating that students prefer to set the volume at higher level. The participants showed fair knowledge and a good attitude concerning NIHL. The present study highlights a concerning lack of practice about NIHL and the prevalence of unsafe PLD among medical students. This underscores the importance of educational interventions to increase awareness among this population.

Application of Machine Learning Algorithms to Analyze the Clinical Characteristics of NIHL Caused by Impulse Noise and Steady Noise.

Background: Occupational hearing loss of workers exposed to impulse noise and workers exposed to steady noise for a long time may have different clinical characteristics. Methods: As of May 2019, all 92 servicemen working in a weapon experimental field exposed to impulse noise for over 1 year were collected as the impulse noise group. As of Dec 2019, all 78 servicemen working in an engine working experimental field exposed to steady noise for over 1 year were collected as the steady noise group. The propensity score matching (PSM) model was used to eliminate the imbalance of age and working time between the two groups of subjects. After propensity score matching, 51 subjects in each group were finally included in the study. The machine learning model is constructed according to pure tone auditory threshold, and the performance of the machine learning model is evaluated by accuracy, sensitivity, specificity, and AUC. Results: Subjects in the impulse noise group and the steady noise group had significant hearing loss at high frequencies. The hearing of the steady noise group was worse than that of the impulse noise group at speech frequency especially at the frequency of 1 kHz. Among machine learning models, XGBoost has the best prediction and classification performance. Conclusion: The pure tone auditory threshold of subjects in both groups decreased and at high frequency. The hearing of the steady noise group at 1 kHz was significantly worse than that of the impulse noise group. XGBoost is the best model to predict the classification of our two groups. Our research can guide the prevention of damage caused by different types of noises.

Quality and Readability of Noise-Induced Hearing Loss Prevention-Related Websites.

OBJECTIVE: This cross-sectional website analysis aimed to determine the readability and quality of English and Spanish websites pertaining to the prevention of noise-induced hearing loss. STUDY DESIGN: Cross-sectional website analysis. SETTING: Various online search engines. METHODS: We queried four popular search engines using the term "noise-induced hearing loss prevention" to reveal the top 50 English and top 50 Spanish websites for data collection. Websites meeting inclusion criteria were stratified based on the presence of a Health on the Net Code certificate (independent assessment of honesty, reliability, and quality). Websites were then independently reviewed by experts using the DISCERN criteria in order to assess information quality. Readability was calculated using the Flesch reading ease score for English and the Fernandez-Huerta formula for Spanish websites. RESULTS: Thirty-six English websites and 32 Spanish websites met the inclusion criteria. English websites had significantly lower readability (average = 56.34, SD = 11.17) compared to Spanish websites (average = 61.88, SD = 5.33) (P < .05). Spanish websites (average = 37, SD = 8.47) were also of significantly higher quality than English websites (average = 25.13, SD = 10.11). CONCLUSION: This study emphasizes the importance of providing quality and readable materials to patients seeking information about noise-induced hearing loss prevention. All of the English and Spanish websites reviewed were written at a level higher than the American Medical Association-recommended sixth-grade reading level. The study also highlights the need for evidence-based information online provided by experts in our field.

Calcitriol alleviates noise-induced hearing loss by regulating the ATF3/DUSP1 signalling pathway.

BACKGROUND: Calcitriol (Cal) is the most active metabolite of vitamin D and has antioxidant and anti-inflammatory properties. The aim of this study was to investigate the role of Cal in noise-induced hearing loss (NIHL) to further elucidate the mechanism of noise-induced oxidative stress in the mouse cochlea. METHODS: C57BL/6 J mice were given six intraperitoneal injections of Cal (500 ng/kg/d). After 14 days of noise exposure, auditory brainstem response (ABR) thresholds, and the cochlear outer hair cell loss rate were analysed to evaluate auditory function. Real-time fluorescence quantitative PCR, immunofluorescence and western blotting were performed in vitro after the treatment of cochlear explants with 100 µM tert-butyl hydroperoxide (TBHP) for 2.5 h and HEI-OC1 cells with 250 µM TBHP for 1.5 h. RESULTS: In vivo experiments confirmed that Cal pretreatment mitigated NIHL and outer hair cell death. The in vitro results demonstrated that Cal significantly reduced TBHP-induced cochlear auditory nerve fibre degradation and spiral ganglion neuron damage. Moreover, treatment with Cal inhibited the expression of oxidative stress-related factors (3-NT and 4-HNE) and DNA damage-related factors (γ-H2A.X) and attenuated TBHP-induced apoptosis in cochlear explants and HEI-OC1 cells. A total of 1479 upregulated genes and 1443 downregulated genes were screened in cochlear tissue 1 h after noise exposure. The level of transcription factor 3 (ATF3) was significantly elevated in HEI-OC1 cells after TBHP stimulation. Gene Transcription Regulation Database （GTRD）and Cistrome database analyses revealed that the downstream target gene of ATF3 is dual specificity phosphatase 1 (DUSP1). Cistrome DB Toolkit database results showed that the transcription factor of DUSP1 was ATF3. In addition, the ChIP-PCR results indicated that ATF3 might be a direct transcription factor of DUSP1. CONCLUSION: The results of our study suggest that Cal attenuates NIHL and inhibits noise-induced apoptosis by regulating the ATF3/DUSP1 signalling pathway.

From sound waves to molecular and cellular mechanisms: Understanding noise­induced 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.

Effects of Castanopsis echinocarpa on Sensorineural Hearing Loss via Neuronal Gene Regulation.

Sensorineural hearing loss (SNHL), characterized by damage to the inner ear or auditory nerve, is a prevalent auditory disorder. This study explores the potential of Castanopsis echinocarpa (CAE) as a therapeutic agent for SNHL. In vivo experiments were conducted using zebrafish and mouse models. Zebrafish with neomycin-induced ototoxicity were treated with CAE, resulting in otic hair cell protection with an EC50 of 0.49 µg/mL and a therapeutic index of 1020. CAE treatment improved auditory function and protected cochlear sensory cells in a mouse model after noise-induced hearing loss (NIHL). RNA sequencing of NIHL mouse cochleae revealed that CAE up-regulates genes involved in neurotransmitter synthesis, secretion, transport, and neuronal survival. Real-time qPCR validation showed that NIHL decreased the mRNA expression of genes related to neuronal function, such as Gabra1, Gad1, Slc32a1, CaMK2b, CaMKIV, and Slc17a7, while the CAE treatment significantly elevated these levels. In conclusion, our findings provide strong evidence that CAE protects against hearing loss by promoting sensory cell protection and enhancing the expression of genes critical for neuronal function and survival.

Roles of Sirtuins in Hearing Protection.

Hearing loss is a health crisis that affects more than 60 million Americans. Currently, sodium thiosulfate is the only drug approved by the Food and Drug Administration (FDA) to counter hearing loss. Sirtuins were proposed as therapeutic targets in the search for new compounds or drugs to prevent or cure age-, noise-, or drug-induced hearing loss. Sirtuins are proteins involved in metabolic regulation with the potential to ameliorate sensorineural hearing loss. The mammalian sirtuin family includes seven members, SIRT1-7. This paper is a literature review on the sirtuins and their protective roles in sensorineural hearing loss. Literature search on the NCBI PubMed database and NUsearch included the keywords 'sirtuin' and 'hearing'. Studies on sirtuins without relevance to hearing and studies on hearing without relevance to sirtuins were excluded. Only primary research articles with data on sirtuin expression and physiologic auditory tests were considered. The literature review identified 183 records on sirtuins and hearing. After removing duplicates, eighty-one records remained. After screening for eligibility criteria, there were forty-eight primary research articles with statistically significant data relevant to sirtuins and hearing. Overall, SIRT1 (n = 29) was the most studied sirtuin paralog. Over the last two decades, research on sirtuins and hearing has largely focused on age-, noise-, and drug-induced hearing loss. Past and current studies highlight the role of sirtuins as a mediator of redox homeostasis. However, more studies need to be conducted on the involvement of SIRT2 and SIRT4-7 in hearing protection.

[Occupational diseases related to otorhinolaryngology]. / Berufskrankheiten mit Bezug zur HNO-Heilkunde.

In the German Ordinance on Occupational Diseases (BKV), there are currently 82 occupational diseases listed, of which 18 partially or completely fall within the field of ENT medicine due to the associated health disorders. Noise-induced hearing loss is usually the focus of attention for the ENT specialist, but it has long since ceased to be the only occupational disease. In order to help uncover possible causalities between occupational noxious substances and diseases, it is important that physicians report their own observations and new scientific findings regarding suspected cases to the German Social Accident Insurance, especially in situations where cancer may be linked to occupational influences.

Serum Levels of Stereocilin as a Hearing Biomarker.

Noise-induced hearing loss (NIHL) often presents with an insidious onset, resulting from the cumulative effect of chronic, high-level noise exposure regardless of etiology. Stereocilin (STRC) is a protein that supports stereocilia attachment and cochlear hair cell function, 2 common targets of noise trauma. In this study, we explored the relationship between STRC and daily noise exposure in young, healthy adults. We found that higher noise exposure levels were associated with lower serum levels of STRC, as was the case for another inner-ear protein, prestin. There was a statistically significant positive correlation between serum STRC and prestin levels. These results support a biomarker approach for the diagnosis and monitoring of NIHL. The ability to detect and measure STRC in the blood also has implications for targeted gene therapy. STRC mutations are known to be associated with autosomal recessive deafness, a condition that is now amenable to targeted gene therapy.

Clinical practice guidelines for the diagnosis and management of acute sensorineural hearing loss.

OBJECTIVE: Acute sensorineural hearing loss represents a spectrum of conditions characterized by sudden onset hearing loss. The "Clinical Practice Guidelines for the Diagnosis and Management of Acute Sensorineural Hearing Loss" were issued as the first clinical practice guidelines in Japan outlining the standard diagnosis and treatment. The purpose of this article is to strengthen the guidelines by adding the scientific evidence including a systematic review of the latest publications, and to widely introduce the current treatment options based on the scientific evidence. METHODS: The clinical practice guidelines were completed by 1) retrospective data analysis (using nationwide survey data), 2) systematic literature review, and 3) selected clinical questions (CQs). Additional systematic review of each disease was performed to strengthen the scientific evidence of the diagnosis and treatment in the guidelines. RESULTS: Based on the nationwide survey results and the systematic literature review summary, the standard diagnosis flowchart and treatment options, including the CQs and recommendations, were determined. CONCLUSION: The guidelines present a summary of the standard approaches for the diagnosis and treatment of acute sensorineural hearing loss. We hope that these guidelines will be used in medical practice and that they will initiate further research.