Factors Related to Dizziness in Workers With Noise-Induced Hearing Loss in Brazil.

Introduction. Noise-induced hearing loss is a rather prevalent condition and can be distressing for a substantial proportion of patients, although researches describing psychological characteristics in noise-induced occupational hearing loss patients are not numerous.The study aims to find the effects of occupational noise on the psychological status among noise-induced hearing loss (NIHL) patients.Methods. Two groups, cross-sectional design. Study sample: 44 occupational noiseinduced male forming NIHL patients group (n = 21) and a control group (n = 23). Both groups were tested using the Russian versions of psychological questionnaires.Results. Almost one third of NIHL patients are the highly anxiety individuals as compared with the healthy participants (p < 0.01). Mixed type of response to the surrounding reality combined a high need for self-actualization with high self-control, tendency to inhibit and restrain behavioral reactions, in this case it is possible to “overlap” both neurotic and behavioral responses, which can affect the general overstrain and manifest by the somatization of the internal conflict. In general, NIHL patients use constructive cognitive, emotional and behavioral coping strategies. Patients use both constructive and tense defense mechanisms. Conclusion. It has been established that in patients with NIHL, in comparison with practically healthy persons, tension accumulates, and a tendency to psychotraumatization appears. However, it is currently difficult to determine whether NIHL is a predisposing factor for these psychological characteristics, so further research is needed to determine how significant this relationship is. Key words: noise-induced hearing loss, occupational noise, psychological profile>˂ 0.01). Mixed type of response to the surrounding reality combined a high need for self-actualization with high self-control, tendency to inhibit and restrain behavioral reactions, in this case it is possible to “overlap” both neurotic and behavioral responses, which can affect the general overstrain and manifest by the somatization of the internal conflict. In general, NIHL patients use constructive cognitive, emotional and behavioral coping strategies. Patients use both constructive and tense defense mechanisms.Conclusion. It has been established that in patients with NIHL, in comparison with practically healthy persons, tension accumulates, and a tendency to psychotraumatization appears. However, it is currently difficult to determine whether NIHL is a predisposing factor for these psychological characteristics, so further research is needed to determine how significant this relationship is.

OBJECTIVESTo investigate the relation between different types of exposure to noise and a classic sign of noise induced hearing loss (NIHL), the audiometric notch.METHODSThe study sample had exposure to both...

Effect of earplug use and factors associated with noise induced hearing loss among occupational workers in Guangzhou, China

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

Purpose To describe the notifications of NIHL in Brazil, according to sociodemographic and labor aspects, in the period from 2006 to 2019. Methods Cross-sectional and descriptive study carried out with data from notification forms for noise-induced hearing loss in Brazil, from SINAN. The data were accessed through the page of the Collaborating Center for Surveillance of Workers’ Health Disorders (ISC-UFBA). Absolute and relative frequencies of sociodemographic variables and work characteristics were analyzed. Results During the period, 7,819 cases of NIHL were reported in Brazil. The year 2016 and the state of São Paulo registered the highest number of notifications, with 1,106 and 2,488 cases, respectively. Throughout the period, there was a higher proportion of cases in: individuals with a formal contract (55.0%), male (88.2%), white (59.1%) and aged between 50 and 59 years (33.7%). Continuous noise was predominant in the work environment (41.1%) and 51.1% of the individuals used individual protection measures, while 12.6% were protected collectively. Conclusion A total of 7,819 cases of NIHL were reported in Brazil in the period analyzed, a number that can be considered disproportionate in relation to the prevalence of this condition. The observed underreporting impacts on the understanding of the magnitude of the problem, and, consequently, on the development and implementation of public health actions and programs, aimed at worker health and safety.

Dear Editor, We read with great interest the article written by Balaji et al., entitled “Hearing Impairment and High Blood Pressure among Bus Drivers in Puducherry” [1]. Noise Induced Hearing Loss (NIHL) is common among vehicle drivers and research in this area is much relevant. In this interesting study, the authors had utilized Hearing Deterioration Index (HDI) as an indirect method for assessing NIHL. In the literature, not many NIHL studies have adopted this method (particularly for determining hearing impairment among noise exposed workers) and the authors should be commended for their effort. Nevertheless, we wish to highlight some issue that might be worthy of consideration. Since HDI is an indirect method for assessing NIHL, perhaps the sentence “at risk of developing NIHL” is preferable to be used. Even though HDI was formulated using large retrospective samples and logical assumptions [2], hearing impairment among noise exposed workers can only be confirmed by a known clinical hearing test, i.e., Pure Tone Audiometry (PTA). The direct measurement of hearing status is always beneficial as some individuals are more susceptible to acquire NIHL than others when exposed to similar acoustical environments. This individual susceptibility issue has been acknowledged and reported in the literature. Apart from the environmental factors (e.g. noise level,exposure duration, years of working etc.), individual susceptibility to noise damage is also contributed by biological factors including age, gender, race, eye color, degree of hearing loss, ear laterality and genetic [3,4]. Even though NIHL typically shows a symmetrical pattern in noise-exposed workers, the left ear can be more vulnerable to hearing damage than the right ear in some individuals [3]. By utilizing PTA, left and right ear information can be obtained separately in a convenient manner. More recently, a well-controlled genetic study has identified a key gene for susceptibility to NIHL [4]. This further supports the notion that some individuals are more genetically susceptible to noise damage than others. Notwithstanding, we agree with the authors that PTA is not easily accessible and an optimum testing environment (e.g., sound proof room or booth) is required for conducting PTA. In this regard, if a similar study to be expanded in future, perhaps a simpler hearing test such as Otoacoustic Emission (OAE) can be considered for screening NIHL. OAE is a rapid objective test that has been used widely for hearing screening. In fact, OAE can be reliably conducted even in less optimum testing conditions (i.e., background noise levels of up to 70dBA) [5].More studies are warranted to further explore the potential use of HDI in NIHL testing. For example, studies on determining the correlation between HDI and hearing tests (PTA and/or OAE) should be conducted to justify the usefulness of HDI as an indirect screening method for NIHL. Finally, we fully agree with the authors that awareness and preventive programmes are required for reducing the occurrence of NIHL among the drivers. In fact, the HDI values can also be considered when developing guidelines in the NIHL preventive programmes

Basic and applied aspects of noise-induced hearing loss: R.J. Salvi, D. Henderson, R.P. Hamernik and V. Colletti (Eds.) (Plenum, New York, 1986, 666 p., U.S. $97.50)

Noise-induced hearing loss has a high incidence among Brazilian workers, causing socioeconomic and cognitive impairments. To describe noise-induced hearing loss according to professional occupation between 2012 and 2021. This was a cross-sectional and descriptive study of Brazilian workers affected by noise-induced hearing loss. Data were collected from noise-induced hearing loss notifications filed with the Sistema de Informação de Agravos de Notificação in Brazil. The absolute and relative frequencies of sociodemographic variables and occupational characteristics were assessed. A total of 7,413 cases of noise-induced hearing loss were notified in Brazil. Workers in industrial production were the most affected (56.4%). There was a higher prevalence in White (45.4%), male (87.3%) participants aged between 50 and 59 years (42.5%) from the Southeast region (43%). In this study, 3.5% of participants were temporarily removed from their position, 42.6% reported using personal protective equipment, and 65.7% did not use collective protective equipment. The most prevalent type of noise was continuous noise (33%). Noise-induced hearing loss is prevalent among Brazilian workers and varies according to each occupational group. Cases of noise-induced hearing loss are underreported in Brazil.

The Ca2+/calmodulin-dependent protein kinase kinases (CaMKKs) are serine/threonine-directed protein kinases that are activated following increases in intracellular calcium, playing a critical role in neuronal signaling. Inner-ear-trauma-induced calcium overload in sensory hair cells has been well documented in the pathogenesis of traumatic noise-induced hair cell death and hearing loss, but there are no established pharmaceutical therapies available due to a lack of specific therapeutic targets. In this study, we investigated the activation of CaMKKβ in the inner ear after traumatic noise exposure and assessed the prevention of noise-induced hearing loss (NIHL) with RNA silencing. Treatment with short hairpin RNA of CaMKKβ (shCaMKKβ) via adeno-associated virus transduction significantly knocked down CaMKKβ expression in the inner ear. Knockdown of CaMKKβ significantly attenuated noise-induced hair cell loss and hearing loss (NIHL). Additionally, pretreatment with naked CaMKKβ small interfering RNA (siCaMKKβ) attenuated noise-induced losses of inner hair cell synapses and OHCs and NIHL. Furthermore, traumatic noise exposure activates CaMKKβ in OHCs as demonstrated by immunolabeling for p-CaMKI. CaMKKβ mRNA assessed by fluorescence in-situ hybridization and immunolabeling for CaMKKβ in OHCs also increased after the exposure. Finally, pretreatment with siCaMKKβ diminished noise-induced activation of AMPKα in OHCs. These findings demonstrate that traumatic-noise-induced OHC loss and hearing loss occur primarily via activation of CaMKKβ. Targeting CaMKKβ is a key strategy for prevention of noise-induced hearing loss. Furthermore, our data suggest that noise-induced activation of AMPKα in OHCs occurs via the CaMKKβ pathway.

Objectives:Studies have shown that in addition to energy, kurtosis plays an important role in the assessment of hearing loss caused by complex noise. The objective of this study was to investigate how to use noise recordings and audiometry collected from workers in industrial environments to find an optimal kurtosis-adjusted algorithm to better evaluate hearing loss caused by both continuous noise and complex noise.Design:In this study, the combined effects of energy and kurtosis on noise-induced hearing loss (NIHL) were investigated using data collected from 2601 Chinese workers exposed to various industrial noises. The cohort was divided into three subgroups based on three kurtosis (β) levels (K1: 3 ≤ β ≤ 10, K2: 10 <β ≤ 50, and K3: β > 50). Noise-induced permanent threshold shift at test frequencies 3, 4, and 6 kHz (NIPTS346) was used as the indicator of NIHL. Predicted NIPTS346 was calculated using the ISO 1999 model for each participant, and the actual NIPTS was obtained by correcting for age and sex using non-noise-exposed Chinese workers (n = 1297). A kurtosis-adjusted A-weighted sound pressure level normalized to a nominal 8-hour working day (LAeq,8h) was developed based on the kurtosis categorized group data sets using multiple linear regression. Using the NIPTS346 and the LAeq.8h metric, a dose-response relationship for three kurtosis groups was constructed, and the combined effect of noise level and kurtosis on NIHL was investigated.Results:An optimal kurtosis-adjusted LAeq,8h formula with a kurtosis adjustment coefficient of 6.5 was established by using the worker data. The kurtosis-adjusted LAeq,8h better estimated hearing loss caused by various complex noises. The analysis of the dose-response relationships among the three kurtosis groups showed that the NIPTS of K2 and K3 groups was significantly higher than that of K1 group in the range of 70 dBA ≤ LAeq,8h < 85 dBA. For 85 dBA ≤ LAeq,8h ≤ 95 dBA, the NIPTS346 of the three groups showed an obvious K3 > K2 > K1. For LAeq,8h >95 dBA, the NIPTS346 of the K2 group tended to be consistent with that of the K1 group, while the NIPTS346 of the K3 group was significantly larger than that of the K1 and K2 groups. When LAeq,8h is below 70 dBA, neither continuous noise nor complex noise produced significant NIPTS346.Conclusions:Because non-Gaussian complex noise is ubiquitous in many industries, the temporal characteristics of noise (i.e., kurtosis) must be taken into account in evaluating occupational NIHL. A kurtosis-adjusted LAeq,8h with an adjustment coefficient of 6.5 allows a more accurate prediction of high-frequency NIHL. Relying on a single value (i.e., 85 dBA) as a recommended exposure limit does not appear to be sufficient to protect the hearing of workers exposed to complex noise.

N-acetylcysteine attenuates noise-induced permanent hearing loss in diabetic rats

One of the most important occupational diseases encountered in mining is the noise induced hearing loss (NIHL). In this study, analyses were carried out to examine the NIHL in the open pit lignite mine in Turkey. The NIHL was evaluated in accordance with the miners’ age, experience, occupation, exposure value (Lex), and maximum noise level (Lpeak). Noise levels exposed the employees were measured with noise dosimeters and a hearing test was applied to the employees by a special hearing center. To determine the parameters that could be effective in NIHL, all of the obtained data were evaluated by the logistic regression analysis (LRA) and hierarchical log-linear analysis (HLA) methods. It was determined that the NIHL probability of field staff is approximately 6 times higher than operators and drivers. According to the 21-29 age group, it was found that the probability of NIHL in the 57-65 and in the 48-56 age group was 11.4 and 4.41 times higher, respectively. Experience and maximum noise levels were found to be the most important parameters in hearing loss. Besides these, it was determined that the interactions of age×experience, occupation×maximum noise levels, and occupation×average noise exposure levels increased the likelihood of NIHL. A logistic regression model has been developed for the NIHL estimation of employees and hearing loss was found to be a problem mostly for those working in the field. It was determined that hearing loss increased with age and experience, and varied according to occupational groups.

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

Background This study was focused on impulse noise induces hidden hearing loss. Objectives This study was designed to determine the morphology changes of noise-induced hidden hearing loss (NIHHL). Method Fifteen guinea pigs were divided into three groups: noise-induced hidden hearing loss (NIHHL) group, noise-induced hearing loss (NIHL) group, and normal control group. For the NIHHL group, guinea pigs were exposed to 15 times of impulse noise with peak intensity of 163 dB SPL at one time. For the NIHL group, animals were exposed to two rounds of 100 times impulse noise, and the time interval is 24 h. Auditory brain response (ABR) was tested before, immediately, 24 h, one week, and one month after noise exposure to evaluate cochlear physiology changes. One month after noise exposure, all guinea pigs in three groups were sacrificed, and basement membranes were carefully dissected immediately after ABR tests. The cochlea samples were observed by transmission electron microscopy (TEM) to find out the morphology changes. Result The ABR results showed that 15 times of impulse noise exposure could cause NIHHL in guinea pigs and 200 times could cause completely hearing loss. Impulse noise exposure could cause a dramatic increase of mitochondria in the inner hair cell. The structures of ribbon synapse and heminode were also obviously impaired compared to the normal group. The nerve fiber and myelin sheath remained intact after impulse noise exposure. Conclusion This research revealed that impulse noise could cause hidden hearing loss, and the changes in inner hair cells, ribbon synapse, and heminode all played a vital role in the pathogenesis of hidden hearing loss.

Noise-induced hearing loss in chinchillas pre-treated with glutathione monoethylester and R-PIA