Evaluation of Digits-in-Noise Test and Hearing Handicap Inventory for Adults Screening in Patients with Occupational Noise-Induced Hearing Loss

Objective:To explore the clinical evaluation role of the Digits-in-Noise(DIN)test and Hearing Handicap Inventory for Adults Screening(HHIA-S)for patients with occupational noise-induced hearing loss and to observe and analyze their application values.Methods:Fifty patients with suspected occupational noise-induced hearing loss were randomly selected from the Department of Otolaryngology at the hospital as the research target.The collection period for the research cases spanned from January 2022 to November 2023,and all patients had a history of noise exposure.The DIN test and HHIA-S were used for hearing examinations,with clinical,comprehensive diagnosis serving as the gold standard to study their diagnostic performance.Results:The compliance rate of the DIN test was 88.00%,the HHIA-S’s compliance rate was 80.00%,and the combined compliance rate was 94.00%.The compliance rate of the DIN test and the combined compliance rates of the patients were statistically significant compared to the clinical gold standard data(P<0.05),while there was no difference between the compliance rate of the HHIA-S and the gold standard(P>0.05).The data shows that the sensitivity of the combined diagnosis is significantly higher than the sensitivity data of the DIN test and HHIA-S examination alone(P<0.05).Its specificity is 100.00%,and the accuracy data of the joint diagnosis in the degree were higher than those of the DIN test alone(P>0.05)and the HHIA-S alone(P<0.05).Conclusion:For patients with occupational noise-induced hearing loss,the joint evaluation of the DIN test and HHIA-S can significantly improve their diagnostic value with high sensitivity and accuracy.

Prevalence of Noise-Induced Hearing Loss Related to the Mills in the Markets of the Municipality of Parakou in 2021

Introduction: Noise is the second leading cause of hearing loss in adults after presbycusis. The objective of this work was to study hearing loss induced by the noise of mills in the markets of Parakou. Methods: This was a descriptive and analytical cross-sectional study, conducted from February 3 to June 3, 2021 in the markets of Parakou. It concerned millers and sellers located within a 5 meter radius around the mills and among whom pure-tone audiometry was performed to detect a hearing loss. Subjects with no particular medical health history, under 55 years of age and having been working in these markets since more than 12 months, were included. Results: In this study, 103 subjects were selected, including 43 millers and 61 sellers. Their average age was 29 ± 13 years. The sex ratio was 0.49. The average length of service in the profession was 8 years with the extremes of 3 months and 47 years. They were exposed to noise on average 10 hours per day and 6 days a week. The average duration of weekly noise exposure was 23 h 28 min ± 13 h 32 min with the extremes of 5 h 00 min and 52 h 30 min. The average level of noise exposure was 90 dB with the extremes of 72 and 110 dB. 24 subjects reported symptoms related to noise such as headache, tinnitus, and hearing loss, with respective proportions of 22.33%, 20.39% and 06.80%. The prevalence of noise-related hearing loss was 26.21% (n = 27/103). Subjects with a notch at 4000 Hz and normal Average Hearing Loss (AHL) (20.39%) had a seven-time greater risk of developing noise-induced hearing loss (OR = 6.58;95% CI [2.54 - 18.8], p Conclusion: Hearing loss related to the noise of mills affected both millers and sellers near the mills in markets, hence the importance of regulating mills.

Early detection of noise-induced hearing loss

BACKGROUND Noise-induced hearing loss(NIHL)is the second most common acquired hearing loss following presbycusis.Exposure to recreational noise and minimal use of hearing protection increase the prevalence of NIHL in young females.NIHL is irreversible.Identifying minor hearing pathologies before they progress to hearing problems that affect daily life is crucial.AIM To compare the advantages and disadvantages of extended high frequency(EHF)and otoacoustic emission and determine an indicator of hearing pathologies at the early sub-clinical stage.METHODS This cross-sectional study was implemented in West China Hospital of Sichuan University from May to September 2019.A total of 86 participants,aged 18-22 years,were recruited to establish normative thresholds for EHF.Another 159 adults,aged 18-25 years with normal hearing(0.25-8 kHz≤25 dBHL),were allocated to low noise and noise exposure groups.Distortion otoacoustic emission(DPOAE),transient evoked otoacoustic emissions(TEOAE),and EHF were assessed in the two groups to determine the superior technique for detecting early-stage noise-induced pathologies.The chi-square test was used to assess the noise and low noise exposure groups with respect to extended high-frequency audiometry(EHFA),DPOAE,and TEOAE.P≤0.05 was considered statistically significant.RESULTS A total of 86 participants(66 females and 20 males)aged between 18 and 22(average:20.58±1.13)years were recruited to establish normative thresholds for EHF.The normative thresholds for 9,10,11.2,12.5,14,16,18,and 20 kHz were 15,10,20,15,15,20,28,and 0 dBHL,respectively.A total of 201 participants were recruited and examined for eligibility.Among them,159 adults aged between 18 and 25 years were eligible in this study.No statistical difference was detected between the noise exposure and the low noise exposure groups using EHFA,DPOAE,and TEOAE(P>0.05)except in the right ear at 4 kHz using TEOAE(abnormal rate 20.4%vs 5.2%,respectively;P=0.05).CONCLUSION These results showed TEOAE as the earliest indicator of minor pathology compared to DPOAE and EHFA.However,a multicenter controlled study or prospective study is essential to verify these results.

Saturated hydrogen saline protects against noise-induced hearing loss

Objective To study effects of saturated hydrogen saline in preventing noise-induced hearing loss. Methods Fifteen guinea pigs were randomly divided into 3 groups （5 each）, group one was for control, group two was treated with normal saline and group three was treated with saturated hydrogen saline, which was given intraperitoneally at 1 hour before noise exposure at 1 ml/100 g. One hundred rounds of impulse noise （ 157 dB SPL peak） were delivered as noise exposure. Immediately after exposure to impulse noise and on Days 1, 2, 4 and 8 following exposure, auditory brainstem response （ABR） thresholds were measured. Outer hair cell morphological changes and sueeinate dehydrogenase （SDH） activity were examined on Day 8 post-exposure. Results Immediately after noise exposure, ABR thresholds in saturated hydrogen saline treated animals were lower than the non-treated animals （P 〈 0.05 ）. Microscopy showed little SDH staining, cell swelling and irregular cell arrangement in the non-treated or normal saline treated animals. Whereas in the saturated hydrogen saline treated animals, there was deep SDH staining with significantly reduced cell loss and more regular cellular arrangement compared to the other two groups. The surviving cells counts was 45.17 ±12.15 for non-treated animals, 44.50 ±10.02 for normal saline treated animals and,116.50±2.38 for animals treated with saturated hydrogen saline. While the count was similar between non-treated and normal saline treated animals, it was significantly higher in saturated sions Intraperitoneal injection of saturated hydrogen saline damage. hydrogen saline treated animals （P 〈 0.05）. Concluappears to protect the cochlea against noise-induced damage.

Noise-induced hearing loss in the 21^(st) century: A research and translational update

Millions of people worldwide are exposed to harmful levels of noise daily in their work and leisure environment. This makes noise-induced hearing loss(NIHL) a major occupational health risk globally. NIHL is the second most common form of acquired hearing loss after agerelated hearing loss and is itself a major contributing factor to presbycusis. Temporary threshold shifts, once thought to be relatively harmless and recoverable, are now known to cause permanent cochlear injury leading to permanent loss of hearing sensitivity. This article reviews the current understanding of the cellular and molecular pathophysiology of NIHL with latest findings from animal models. Therapeutic approaches to protect against or to mitigate NIHL are discussed based on their proposed action against these known mechanisms of cochlear injury. Successes in identifying genes that predispose individuals to NIHL by candidate gene association studies are discussed with matched gene knockout animal models. This links to exciting developments in experimental gene therapy to replace and regenerate lost hair cells and post-noise otoprotective therapies currently being investigated in clinical trials. The aim is to provide new insights into current and projected future strategies to manage NIHL; bench to bedside treatment is foreseeable in the next 5 to 10 years.

NOISE INDUCED HEARING LOSS IN CHINA:A POTENTIALLY COSTLY PUBLIC HEALTH LSSUE

Hearing loss and tinnitus are among the most common consequences of long term noise exposure and re-main an under-addressed heath issue in most developing nations including China. The rapid industrializa-tion and life style changes in China increase the concern over noise exposure and noise induced hearing loss (NIHL). Research on NIHL in China is limited. The current paper reviews studies published in English and Chinese language literatures regarding noise exposure and NIHL in China. Their implication on the Chi-nese population is discussed. The possible utility of a research model such as the Dangerous Decibels? as a means to increase understanding of the scope of NIHL among the Chinese population, to educate the gener-al public in China (especially the young) about NIHL and its prevention, and to study effects of language and cultural factors on international information dissemination and behavioral interventions is proposed.

Noise Induced Hearing Loss in Children:Preventing the Silent Epidemic

Noise-induced hearing loss and related tinnitus are often unrecognized problems, especially in non-occupational settings. Research indicates that increasing numbers of children and adolescents have or are acquiring noise induced hearing losses. Noise induced hearing loss can almost completely be prevented with simple precautionary measures. Educational programs rarely exist outside of those mandated in occupational settings. Health Communication theory can be applied to hearing health for developing effective loss prevention programs. Dangerous Decibels is one example of an effective multi-disciplinary effort to develop and disseminated prevention strategies.

Hidden Hearing Loss: Causes, Current Knowledge, and Future Directions

Introduction: Hidden hearing loss (HHL) is a type of auditory disorder that affects the auditory neural processing and hearing sensitivity in subjects with normal hearing thresholds. Unlike central auditory processing disorders, HHL happens when the cochlea (the peripheral auditory organ) is affected. There are several known risk factors to HHL which includes noise exposure, ototoxic drugs, and peripheral neuropathies, and age. Recent studies have shed light on this type of hearing loss, its etiology, prevalence, and how it can affect the auditory acuity in humans. Methods: This paper covers the current research regarding HHL, its causes, the different mechanisms involved in this disorder, and the diagnosis and potential treatments related to it. We will delve deeply into different researches concerning HHL. 4 articles from 285 were selected focusing on normal hearing individuals with bad speech intelligibility were discussed in this paper. In addition, articles discussing the effects of noise exposure on hearing impaired individuals were not considered as this study solely aims to focus on normal hearing sensitivity individuals with HHL, resulting in 4 articles from 285. Results: Numerous literatures over the decades have suggested that HHL is due to the degeneration of cochlear ribbon synapses, or hair cells synapses without hair cell damage. Their association with HHL was noted several times through this study, whether we were studying the effect of noise exposure, of age, or of ototoxicity. In all cases, no significant hair cell damage was observed, and normal thresholds were recovered. However, a decline in the amplitude of Auditory Brainstem Response (ABR) peak I from auditory nerve (AN) responses in noise exposed subjects and a decline in compound action potential (CAP) was measured when certain drugs were applied to the round window of Guinea pigs. Conclusion: Most studies, have proven that cochlear synaptophysin is the major contributor to noise induced, age, and ototoxic related HHL. There are several audiometric tests that were used to help identify HHL including Puretone audiometry in background noise, ABR, CAP, Distortion Product Otoacoustic Emission (DPOAE).

Effects of cigarette smoking on the evolution of hearing loss caused by industrial noise

The few studies evaluating the changes caused by cigarette smoking on hearing loss induced by occupational exposure to noise have reached discordant conclusions. The aim of this study is to investigate the interactions between cigarette smoking and occupational exposure to noise as risk factors in the onset and development of hearing loss. The study was performed on a sample of 557 shipyard workers exposed to noise at an Equivalent Level (Leq) of 93 dBA. On the basis of their smoking habits, they were divided into three groups: group (A), non-smokers;group (B), smokers (15-30 cigarettes per day);and group (C), heavy smokers (over 30 cigarettes per day). The study focussed on the audiometric responses of the subjects at the frequencies of 500, 1000, 2000, 3000 and 4000 Hz. The results were then compared using statistical techniquees (Internal correlation coefficient, exponential model, ANCOVA, NPC test). Comparison of the audiometric responses showed statistically significant differences between the three groups. Non-parametric analysis, performed using the NPC test, highlighted that the interaction between smoking and exposure to noise has an influence on hearing loss at all frequencies, and particularly at high frequencies (3000-4000 Hz). The data obtained from the examined sample show that smoking and exposure to noise cause an increase in occupational hearing loss and that this is directly related to the number of cigarettes smoked.

Survey on worker' s hearing loss caused by instable noise

Objective To study on impact of instable noise i n worker’ s hearing loss.Method1456fracturing workers of oil field were randomly selected as study group,other 351workers were slected as contr ols.Other conditions were similar b etween study group and control group.Level of hearing loss was measured under various intensity of nois e in workers with different period of noise exposure.Result High fre-quency of audition was damaged in workers exposed to instable noise for a l ong time,positive rate was 35.1%.Po stitive rate for tinnitus and language frequency was 18.9%and 5.5%,respectively,which was markedly higher compared with control group.Conclusion Hearing loss will progress with the longation of working time and increase of noise int ensity.

A preliminary study of the mechanism of compound hearing loss caused by ototoxic drugs combined with impulse noise

Background:Hearing loss(HL)is becoming increasingly common and is more commonly caused by noise,ototoxic substances,or a combination of ototoxic factors.However,so far,few studies have examined the mechanism by which compound factors cause HL.The only relevant study is about occupational ototoxic substances combined with environmental noise at 85-110 dB SPL.In this study,to address the shortcomings of existing research,we innovatively focused on HL induced by loud noise(impulse noise,>160 dB SPL)combined with common ototoxic drugs.The aim of this study was to establish and validate a mature animal model,and then to compare the characteristics of audiology,pathomorphology and molecular features,and to preliminarily predict pathogenesis in compound HL.Materials and Methods:We selected guinea pigs to construct in vivo HL model groups for different extents of exposure,including a blank control group,a single-drug group,a single-impulse noise group,and a compound group.The animal model of the mature compound HL group was established using gentamicin combined with impulse noise.We then performed audio-logical and pathological verification.We analyzed the auditory brainstem response(ABR),pathological morphology of the cochlea,and molecules(including important self-radicals,cytokines,and apoptosis signal trans-duction pathway proteins in the pathogenesis of drug-and noise-induced HL),compared the effect of different extents of exposure on HL,and preliminarily predict the pathogenic mechanism of compound HL.Results:Four groups of animal models were established successfully and verified by audiology and pathology.Regarding audiology,there were no sig-nificant differences in the ABR thresholds before exposure(p>0.05),but differences emerged among the groups after exposure.Notably,after 3,7,and 14 days of exposure,there were significant differences in the ABR thresholds between the compound group and both the drug and noise groups(p<0.01),and after 14 days,the HL of the compound group was much more severe(greater than the linear sum of single-factor HL group).Regarding the patho-morphology,compared with the control group,the cochleae were damaged to different degrees in the factor exposure groups.The drug group had the least severe HL,the noise group had serious HL(p<0.05),and the compound group had the most severe HL(p<0.01).The compound group's damage was greater than the linear sum of the single-factor group in many ways,such as the loss and damage of hair cells and cilia,disturbed morphology and arrangement of hair cells,protein metabolism,cell function,and structural defects on the epidermal plate(p<0.01).From a molecular perspective,the trend was similar to pathology and audiology,and the synergistic effect of ototoxic drugs and impulse noise significantly increased cytokine levels(IL-6,ICAM-1,8-OHDG,IL-1,and TNF-α),free radicals Malondialdehyde([MDA],▪OH,LPO,O•2ˉ),and the apoptosis signal transduction pathway protein.There were significant differences between the compound group and single-factor groups(p<0.05).Conclusion:Gentamicin,impulse noise,and compound factors were used to induce HL in animal models,which were verified by audiology and pathology,laying a foundation for future studies.After constructing the animal models,we found that 50 mg/kg of gentamicin for 10 days was a subinjury dose,and 50�impulse noise caused partial HL,but the two factors combined had a significant synergistic ototoxicity effect,which increased the level of oxidative stress and the waterfall response of inflammatory cytokines in the cochleae and enhanced the expression of apoptosis-related proteins,resulting in syn-ergistic pathomorphological and audiological injury.We preliminarily analyzed the pathogenic mechanism of compound HL,establishing the basis for further study of the mechanism,prevention,and treatment of this increasing global problem.

Using Audiometric Data to Weigh and Prioritize Factors that Affect Workers’ Hearing Loss through Support Vector Machine (SVM) Algorithm

Workers’exposure to excessive noise is a big universal work-related challenges.One of the major consequences of exposure to noise is permanent or transient hearing loss.The current study sought to utilize audiometric data to weigh and prioritize the factors affecting workers’hearing loss based using the Support Vector Machine(SVM)algorithm.This cross sectional-descriptive study was conducted in 2017 in a mining industry in southeast Iran.The participating workers(n=150)were divided into three groups of 50 based on the sound pressure level to which they were exposed(two experimental groups and one control group).Audiometric tests were carried out for all members of each group.The study generally entailed the following steps:(1)selecting predicting variables to weigh and prioritize factors affecting hearing loss;(2)conducting audiometric tests and assessing permanent hearing loss in each ear and then evaluating total hearing loss;(3)categorizing different types of hearing loss;(4)weighing and prioritizing factors that affect hearing loss based on the SVM algorithm;and(5)assessing the error rate and accuracy of the models.The collected data were fed into SPSS 18,followed by conducting linear regression and paired samples t-test.It was revealed that,in the first model(SPL<70 dBA),the frequency of 8 KHz had the greatest impact(with a weight of 33%),while noise had the smallest influence(with a weight of 5%).The accuracy of this model was 100%.In the second model(70<SPL<80 dBA),the frequency of 4 KHz had the most profound effect(with a weight of 21%),whereas the frequency of 250 Hz had the lowest impact(with a weight of 6%).The accuracy of this model was 100%too.In the third model(SPL>85 dBA),the frequency of 4 KHz had the highest impact(with a weight of 22%),while the frequency of 250 Hz had the smallest influence(with a weight of 3%).The accuracy of this model was 100%too.In the fourth model,the frequency of 4 KHz had the greatest effect(with a weight of 24%),while the frequency of 500 Hz had the smallest effect(with a weight of 4%).The accuracy of this model was found to be 94%.According to the modeling conducted using the SVM algorithm,the frequency of 4 KHz has the most profound effect on predicting changes in hearing loss.Given the high accuracy of the obtained model,this algorithm is an appropriate and powerful tool to predict and model hearing loss.

Hearing Loss among Grain Millers in the Informal Sector in Benin

Introduction: Noise-induced hearing loss is a preventable health problem worldwide. However, it continues to affect workers especially in the informal sector, due to the lack of medical and environmental monitoring. In Benin, millers are highly exposed. The objective of the study was to assess the hearing health situation of grain millers in the Dantokpa market in 2020. Methods: This was a cross-sectional study that included by exhaustive recruitment 57 millers. The data were collected using a standardized questionnaire followed by blood pressure measurements, noise levels and the performance of audiometries. Descriptive and univariate analysis was performed. Results: The sample consisted only of men. The median age was 25 years with extremes of 18 and 50 years. Noise levels at the workstation ≥ 85 dB (A) were obtained for 94.74% of the workers. No worker was wearing hearing protection equipment. The prevalence of hearing loss was 87.72% (95% CI = [76.32%;94.92%]) and that of occupational deafness was 29.82% (95% CI = [18.43% - 43.40%]) which was associated with age over 28 and high blood pressure. An awareness campaign with donation of hearing pads was carried out. Conclusion: Hearing loss is important among millers who do not benefit from any supervision because they are in the informal sector. A restructuring of this sector is necessary for the hearing health of workers.

Genetic Effects on Sensorineural Hearing Loss and Evidence-based Treatment for Sensorineural Hearing Loss

In this article,the mechanism of inheritance behind inherited hearing loss and genetic susceptibilityin noise-induced hearing loss are reviewed.Conventional treatments for sensorineural hearing loss(SNHL),i.e.hearing aid and cochlear implant,are effective for some cases,but not without limitations.For example,they provide little benefit for patients of profound SNHL or neural hearing loss,especially when the hearing loss is in poor dynamic range and with low frequency resolution.We emphasize the most recent evidence-based treatment in this field,which includes gene therapy and allotransplantation of stem cells.Their promising results have shown that they might be options of treatment for profound SNHL and neural hearing loss.Although some treatments are still at the experimental stage,it is helpful to be aware of the novel therapies and endeavour to explore the feasibility of their clinical application.

Prophylactic effect of Ca^(2+)-deficient artificial perilymph perfusion on noise-induced hearing loss

Objective To investigate the prophylactic effect of low calcium concentration perilymph on noise-induced hearing loss. Methods Forty guinea pigs with normal hearing weighing 250-350 g were assigned to five groups (8 in each group): (1) Ca2+-deficient perilymph perfusion (CDP) for 2 h; (2) white noise (120 dB SPL) exposure (WNE) only for 1 h, (3) combination of calcium-deficient perilymph perfusion and white noise (120 dB SPL) exposure (WNE+CDP); (4) normal artificial perilymph (NAP) perfusion for 2 h; and (5) white noise exposure + normal artificial perilymph perfusion (WNE+NAP) for 2 h. Compound action potentials (CAP) evoked by click was recorded from round window every 15 min. The cochleae from 5 animals in each group were examined with scanning electron microscope. Results The CAP for group 1 experienced a threshold shift (TS) of 15-26 dB, while group 2 yielded a 46-59 dB TS and group 3 a 37-45 dB TS; no threshold shift occurred in group 4. The CAP TS in group 5 was 33-64 dB. The CAP TS of group 3 was less than that of group 2. After one hour of noise exposure, the CAP TS of group 3 were 45.92±2.90 dB and 59.30±3.95dB in group 2. There were significant differences (P<0.05) between groups 3 and 2. The CAP TS of group 3 was less than that of group 5 at the points of 1, 1.5 and 2 h after noise exposure. There was a significant difference between groups 3 and 5 (P<0.01). Stereocilia of 89 OHC3 were in disarray in five cochleae after noise exposure in group 2. The cuticular plates of 8 OHC2,3 sank and the stereocilia became fused in only one animal cochlea after noise exposure in group 3 combined with low calcium perilymph perfusion. Conclusions Low calcium concentration appears to participate in preventing noise-induced hearing loss and the rising of calcium concentrations in inner hair cells after noise exposure, which may have been due to the opening of calcium channels in inner hair cells during noise exposure. The mechanism of the prophylactic effect might be caused by a lower calcium concentration in inner hair cells in the cochlea attenuating the influence of noise exposure on hearing loss; calcium deficient perilymph perfusion prevented calcium accumulation in inner hair cells of the cochlea. The motility of the OHCs might be partially inhibited by low calcium concentration that reduced noise-induced hearing loss in turn.

Development of Chinese herbal medicine for sensorineural hearing loss

According to the World Health Organization’s world report on hearing,nearly 2.5 billion people worldwide will suffer from hearing loss by 2050,which may contribute to a severe impact on individual life quality and national economies.Sensorineural hearing loss(SNHL)occurs commonly as a result of noise exposure,aging,and ototoxic drugs,and is pathologically characterized by the impairment of mechanosensory hair cells of the inner ear,which is mainly triggered by reactive oxygen species accumulation,inflammation,and mitochondrial dysfunction.Though recent advances have been made in understanding the ability of cochlear repair and regeneration,there are still no effective therapeutic drugs for SNHL.Chinese herbal medicine which is widely distributed and easily accessible in China has demonstrated a unique curative effect against SNHL with higher safety and lower cost compared with Western medicine.Herein we present trends in research for Chinese herbal medicine for the treatment of SNHL,and elucidate their molecular mechanisms of action,to pave the way for further research and development of novel effective drugs in this field.

The impact of hearing impairment and noise-induced hearing injury on quality of life in the active-duty military population:challenges to the study of this issue

The objectives of this review were to 1)summarize the available evidence on the impact of hearing loss on quality of life(QOL)among U.S.active-duty service members,2)describe the QOL instruments that have been used to quantify the impact of hearing loss on quality of life,3)examine national population-level secondary databases and report on their utility for studying the impact of hearing loss on QOL among active-duty service members,and 4)provide recommendations for future studies that seek to quantify the impact of hearing loss in this population.There is a lack of literature that addresses the intersection of hearing impairment,the military population,and quality of life measures.For audiological research,U.S.military personnel offer a unique research population,as they are exposed to noise levels and blast environments that are highly unusual in civilian work settings and can serve as a model population for studying the impact on QOL associated with these conditions.This review recommends conducting a study on the active-duty service member population using a measurement instrument suitable for determining decreases in QOL specifically due to hearing loss.

The Effect of a High-Frequency-Hearing-Threshold Weighted Value on the Diagnosis of Occupational-Noise-Induced Deafness

Objective: In order to provide a theoretical basis for the revision of the current diagnostic criteria for occupational noise-induced deafness (ONID), we evaluated the degree of ONID by analyzing different high-frequency-hearing- threshold-weighted values (HFTWVs). Methods: A retrospective study was conducted to evaluate the diagnosis of patients with ONID from January 2016 to January 2017 in Guangdong province, China. Based on 3 hearing tests (each interval between the tests was greater than 3 days), the minimum threshold value of each frequency was obtained using the 2007 edition’s diagnostic criteria for ONID. The speech frequency and the HFTWVs were analyzed based on age, noise exposure, and diagnostic classi-fication using SPSS21.0. Results: 168 patients in total were involved in this study, 154 males and 14 females, and the average age was 41.18 ± 6.07. The diagnosis rate was increased by the weighted value of the high frequencies and was more than the mean value of the pure speech frequency (MVPSF). The diagnosis rate for the weighted 4 kHz frequency level increased by 13.69% (χ2 = 9.880, P = 0.002), the weighted 6 kHz level increased by 15.47% (χ2 = 9.985, P = 0.002), and the weighted 4 kHz + 6 kHz level increased by 15.47% (χ2 = 9.985, P = 0.002). The differences were all statistically significant. The diagnostic rate of the different thresholds showed no obvious difference between the genders. The age groups were divided into less than or equal to 40 years old (group A) and 40 - 50 years old (group B). There were several groups with a high frequency: high frequency weighted 4 kHz ( group A χ2 = 3.380, P = 0.050;group B χ2 = 4.054, P = 0.032), high frequency weighted 6 kHz (group A χ2 = 6.362, P = 0.012;group B χ2 = 4.054, P = 0.032), weighted 4 kHz + 6 kHz (group A χ2 = 6.362 P = 0.012;B χ2 = 4.054, P = 0.032) than those of MVPSF in the same group on ONID diagnosis rate. The differences between the groups were statistically significant. There was no significant difference between the age groups (χ2 = 2.265, P = 0.944). The better ear’s (the smaller hearing threshold weighted value) MVPSF and the weighted values for the different high frequencies were examined in light of the number of working years;the group that was exposed to noise for more than 10 years had significantly higher values than those of the average thresholds of each frequency band in the groups with 3 - 5 years of exposure (F = 2.271, P = 0.001) and 6 - 10 years of exposure (F = 1.563, P = 0.046). The differences were statistically significant. The different HFTWVs were higher than those of the MVPSF values, and the high frequency weighted 4 kHz + 6 kHz level showed the greatest difference, with an average increase of 2.83 dB. The diagnostic rate that included the weighted high frequency values was higher for the mild, moderate, and severe cases than those patients who were only screened with the pure frequency tests. The results of the comparisons of the diagnosis rates for mild ONID were as follows: the weighted 3 kHz high frequency level (χ2 = 3.117, P = 0.077) had no significant difference, but the weighted 4 kHz level (χ2 = 10.835, P = 0.001), 6 kHz level (χ2 = 9.985, P = 0.002), 3 kHz + 4 kHz level (χ2 = 6.315, P = 0.012), 3 kHz + 6 kHz level (χ2 = 6.315, P = 0.012), 4 kHz + 6 kHz level (χ2 = 9.985, P = 0.002), and 3 kHz + 4 kHz + 6 kHz level (χ2 = 7.667, P = 0.002) were significantly higher than the diagnosis rate of the mean value of the PSF. There was no significant difference between the 2 groups for the moderate and severe grades (P > 0.05). Conclusion: Different HFTWVs increase the diagnostic rate of ONID. The weighted 4 kHz, 6 kHz, and 4 kHz + 6 kHz high frequency values greatly affected the diagnostic results, and the weighted 4 kHz + 6 kHz high frequency hearing threshold value has the maximum the effect on the ONID diagnosis results.

EFFECTS OF MODERATE NOISE EXPOSURE ON HEARING FUNCTION IN C57BL/6J MICE

Objective To study characteristics of hearing loss after exposure to moderate noise exposure in C57BL/6J mice. Methods Male C57BL/6J mice with normal hearing at age of 5-6 weeks were chosen for this study. The mice were randomly sclccted to be studied immediately after exposure （Group P0）, or 1 day （Group P1）, 3 days （Group P3）, 7 day （Group P7） or 14 days （P14） after exposure. Their before exposure condition served as the normal control. All mice were exposed to a broad-band white noise at 100 dB SPL for 2 hours, ABR thresholds were used to estimate hearing status at each time point. Results ABR threshold elevation was seen at every tested frequency at P0 （P〈0.01）. Elevation at high-frequencies （16 kHz and 32 kHz） was greater than at lower frequencies （4 kHz and 8 kHz, P〈0.05）. From P1 to P14, ABR thresholds continuously improved, and there was no significant difference between P14 and before exposure （P〉0.05）. Conclusion There is a frequency specific re- sponse to 100 dB SPL broad-band white noise in C57BL/6J mice, with the high-frequency being more susceptible. Hearing loss induced by moderate noise exposure appears reversible in C57BL/6J mice.

Impact of noise on hearing in the military

Hearing plays a vital role in the performance of a soldier and is important for speech processing. Noise-induced hearing loss is a significant impairment in the military and can affect combat performance. Military personnel are constantly exposed to high levels of noise and it is not surprising that noise induced hearing loss and tinnitus remain the second most prevalent service-connected disabilities. Unfortunately, unlike civilian personnel, military personnel have little option but to remain in noisy environments in order to complete specific tasks and missions. Use of hearing protection devices and follow-up audiological tests have become the mainstay of prevention of noise-induced hearing loss. This review focuses on sources of noise within the military, pathophysiology and management of patients with noise induced hearing loss.