Hearing Of Workers Research Articles

Time domain localization technique with sparsity constraint for imaging acoustic sources

This paper addresses source localization technique in time domain for broadband acoustic sources. The objective is to accurately and quickly detect the position and amplitude of noise sources in workplaces in order to propose adequate noise control options and prevent workers hearing loss or safety risk. First, the generalized cross correlation associated with a spherical microphone array is used to generate an initial noise source map. Then a linear inverse problem is defined to improve this initial map. Commonly, the linear inverse problem is solved with an l2-regularization. In this study, two sparsity constraints are used to solve the inverse problem, the orthogonal matching pursuit and the truncated Newton interior-point method. Synthetic data are used to highlight the performances of the technique. High resolution imaging is achieved for various acoustic sources configurations. Moreover, the amplitudes of the acoustic sources are correctly estimated. A comparison of computation times shows that the technique is compatible with quasi real-time generation of noise source maps. Finally, the technique is tested with real data.

Liberal Individualism and Deleuzean Relationality in Intellectual Disability

Successful critiques of health policies for people with impaired cognition identify a need for alternatives that go beyond individualism. ‘Choice’ policy was examined as young people with severe intellectual disabilities moved from special schools to adult services. We draw on three cases from a longitudinal cohort study to examine the way decisions with and for these young people were made and accounted for. It was not a simple matter of parents and transition workers hearing about these young people’s choices and facilitating what they wanted. The data raise questions about discourses of choice in ID when referring to people with severe intellectual disabilities: few ‘choices’ could be considered informed nor made by young people with capacity to make them and many decisions were informed by other ethics. Findings were interpreted through a Deleuzean ethical–relational lens. We identify implications for theory and practice to show how Deleuzean thinking can reinvigorate intellectual disability.

Prevalence of Onihl in Manufacturing Industry

Objective: To find out the prevalence of occupational noise induced hearing loss (ONIHL) among the workers in a manufacturing engineering industry and to observe the effect of duration of noise exposure on hearing of workers. Study design:Observational case control study. Study sample: Of 236 subjects, 118 cases each in noise (>85dB) exposed (group A) and control (group B). All the subjects were subjected to audiometry and pure tone averages for frequencies 500Hz, 1kHz, 2kHz and 4kHz were calculated and compared. Results: Showed an overall prevalence of 41.5% hearing loss in the exposed study group A out of which 77.5% had mild while 22.5% had moderate hearing loss as compared to only 2.5% overall prevalence in unexposed group B, which was found to be statistically significant (p<0.005).The present study also compared the audiometry results with duration of exposure which revealed a hearing loss of 3.7% among workers exposed for duration of 5-9yrs, 51.6% for duration of 10- 14yrs and 100% for duration of ≥15yrs. Conclusion: ONIHL is prevalent in form of mild to moderate hearing loss within the manufacturing industry.

Assessment of Impulse Noise Hazard and the Use of Hearing Protection Devices in Workplaces Where Forging Hammers are Used

Abstract The impulse noise is agent harmful to health not only in the case of shots from firearms and the explosions of explosive materials. This kind of noise is also present in many workplaces in the industry. The paper presents the results of noise parameters measurements in workplaces where four different die forging hammers were used. The measured values of the C-weighted peak sound pressure level, the A-weighted maximum sound pressure level and A-weighted noise exposure level normalized to an 8 h working day (daily noise exposure level) exceeded the exposure limit values. For example, the highest measured value of the C-weighted peak sound pressure level was 148.9 dB. In this study possibility of the protection of hearing with the use of earplugs or earmuffs was assessed. The measurement method for the measurements of noise parameters under hearing protection devices using an acoustical test fixture instead of testing with the participation of subjects was used. The results of these measurements allows for assessment which of two tested earplugs and two tested earmuffs sufficiently protect hearing of workers in workplaces where forging hammers are used.

Trends in worker hearing loss by industry sector, 1981-2010.

The purpose of this study was to estimate the incidence and prevalence of hearing loss for noise-exposed U.S. workers by industry sector and 5-year time period, covering 30 years. Audiograms for 1.8 million workers from 1981-2010 were examined. Incidence and prevalence were estimated by industry sector and time period. The adjusted risk of incident hearing loss within each time period and industry sector as compared with a reference time period was also estimated. The adjusted risk for incident hearing loss decreased over time when all industry sectors were combined. However, the risk remained high for workers in Healthcare and Social Assistance, and the prevalence was consistently high for Mining and Construction workers. While progress has been made in reducing the risk of incident hearing loss within most industry sectors, additional efforts are needed within Mining, Construction and Healthcare and Social Assistance.

Stop gambling with your hearing

In 2014, the National Hearing Conservation Association took its chances and held its 39th annual conference, titled Stop Gambling with your Hearing, in Las Vegas. The authors who contributed to this issue of the International Journal of Audiology demonstrated that they could be relied upon to deliver a royal flush when it comes to advancing research and knowledge for worker hearing loss prevention. The papers that we were privileged to shepherd through the review process share common themes: epidemiologic and workplace assessments of hearing and new methods to better assess hearing and the effects of wearing hearing protection upon the speech intelligibility and localization. Hearing loss prevention starts with education and testing. The study by Flamme et al. has expanded the work from last year’s supplement, considering how audiometric testing may be changed. Will pure-tone audiometry become passe? The potential to integrate hearing testing with hearing protector fit-testing seems natural, and combining testing with training in the use of personal protection technology makes sense. Without question, occupational hearing conservation programs must begin with engineering noise controls to reduce exposures for at risk workers. Cantley et al. explored the relationship between hearing loss and tinnitus and workplace injury. They found an increased risk of acute injury among workers with tinnitus and high-frequency hearing loss. Although their research does not draw strong correlations between tinnitus and increased incidence of workplace injury, the communication needs of hearing impaired workers cannot be overlooked. Helleman et al. considered the effects of interrupted exposures to loud music at night clubs - often cited as a potential cause of hearing loss. Their research suggests that quiet zones within clubs little effect on the hearing of the subjects they evaluated. However, providing club patrons a place to get out of the noise was still thought to be important because high noise levels present a risk in and of themselves. Hong et al. investigated the relationships between occupational exposures and hearing among elderly Latino Americans. They concluded that a reduction of occupational exposure to noise and chemicals will have a positive impact on better hearing later in life. Worker adoption of hearing protection use is challenged by the effect of attenuation on communication. When passive hearing protection is worn properly, it further degrades the ability of a hearing impaired worker to communicate. Giguere et al. investigated the effect of hearing protection on communication for persons with various degrees of hearing impairment. Sound restoration hearing protection had positive benefits for both impaired and normal hearing persons. Whereas Giguere used the Hearing in Noise Test (HINT) to estimate Speech Reception Threshold, Hiselius et al. utilized the Call-sign Acquisition Test (CAT) to determine the effect of different amounts of hearing protection on communication ability. Hiselius’ approach proved to be an efficient means of assessing several products. Both methods are useful for determining worker communication needs and abilities with a system that could be implemented in conjunction with hearing protection fit testing. In addition to affecting speech intelligibility, hearing protection use can critically impact localization ability. Casali and Robinette investigated the performance of different electronic hearing protectors on localization for groups who received varying amounts of training. They demonstrate that localization ability improved after listeners acclimated to hearing the world through a new set of filters. Finally, we consider the effect of diet and dietary supplements on hearing. Rosenhall provides evidence that high quality diet is associated with better hearing and high frequency hearing. Although establishing such correlations is complex and not conclusive, good dietary habits appear to be important to maintaining hearing health. We invite you to read this special supplement and consider how you may implement new techniques within your practice of hearing loss prevention. We wish to highlight and thank our sponsors who contributed to the supplement: National Hearing Conservation Association, National Institute for Occupational Safety and Health, and Safe-in-Sound Excellence in Hearing Loss Prevention Award™ along with Roger Angelelli, Council for Accreditation in Occupational Hearing Conservation (CAOHC), Honeywell Inc., and HTI Inc..

Effect of noise emitted by forestry equipment on workers' hearing capacity

Forest logging involves the use of various noise-producing equipment, which may be harmful to the hearing capabilities of operators in the immediate area. Yet, little research has been performed to determine the long term effect of noise on forest loggers. Therefore, the purpose of this study was to determine how noise from forestry work affects operators' hearing capabilities at different frequencies, in relation to their age, years of experience as forest loggers, and whether or not they regularly wore hearing protection equipment (HPE). Twenty-six male forest loggers who were directly involved with logging equipment operations participated in this study. They were divided into different groups depending on age (20–29, 30–39, 40–49, and 50–59), years of experience (1–10, 11–20, 21–30, and 31–40), and whether they used HPEs. A Beltone audiometer was used to measure hearing thresholds at different frequencies (125, 250, 500, 750, 1000, 2000, 4000, and 8000 Hz). To determine whether the loggers experienced threshold shifts, their hearing thresholds were compared with average persons’ hearing thresholds. The hearing threshold and threshold shift were found at 4000 Hz, and the lowest hearing thresholds were found at 500, 750, and 1000 Hz. According to results, as age increased, hearing threshold either increased or remained the same. This study also concluded that the years of experience or exposure to forestry equipment can adversely affect hearing. Participants that used HPE had lower hearing thresholds than participants that did not use HPE. By wearing HPE, forest workers may prevent hearing loss at 4000 Hz. Relevance to industryForest logging has adverse effect on the hearing of workers. Specifically the loggers who do not use hearing protection equipment are more susceptible to hearing loss. Therefore, the hearing of workers needs to be monitored on a regular basis and the use of HPE should be made mandatory.

A Case Study of Cairo Airport Noise for Preserving Worker's Hearing in Egypt

A Case Study of Cairo Airport Noise for Preserving Worker's Hearing in Egypt

Auditory effects of exposure to noise and solvents: a comparative study.

Introduction Industry workers are exposed to different environmental risk agents that, when combined, may potentiate risks to hearing. Objective To evaluate the effects of the combined exposure to noise and solvents on hearing in workers. Methods A transversal retrospective cohort study was performed through documentary analysis of an industry. The sample (n = 198) was divided into four groups: the noise group (NG), exposed only to noise; the noise and solvents group (NSG), exposed to noise and solvents; the noise control group and noise and solvents control group (CNS), no exposure. Results The NG showed 16.66% of cases suggestive of bilateral noise-induced hearing loss and NSG showed 5.26%. The NG and NSG had worse thresholds than their respective control groups. Females were less susceptible to noise than males; however, when simultaneously exposed to solvents, hearing was affected in a similar way, resulting in significant differences (p < 0.05). The 40- to 49-year-old age group was significantly worse (p < 0.05) in the auditory thresholds in the NSG compared with the CNS. Conclusion The results observed in this study indicate that simultaneous exposure to noise and solvents can damage the peripheral auditory system.

Estimation of noise exposure level for subjects wearing hearing protector devices

Industrial workers are exposed to noise levels that could damage their hearing. The Field-MIRE (F-MIRE) method has been developed to quantify earplug and earmuff attenuations with two microphones located under and outside of the HPD. This technique has been designed to be used in the field, but does not give a direct access to the noise exposure level, that is, the noise level at the head location without the subject. In this article, we present a combination of the F-MIRE method with a proposed technique to estimate the sound pressure level without subject, in order to quantify both the ambient and protected noise exposure levels and deduce the effects on worker hearing. Several experiments have been conducted on four subjects with three types of earplugs and with five types of earmuffs. First, the best location for the microphone outside of the HPD has been determined. Second, correction factors that need to be applied on the outside microphone measurement to estimate the sound pressure level without subject have been quantified. Finally, the proposed technique has been validated with measurements taken in a simulated workplace.

The epidemiology of noise exposure in the Australian workforce

This work considers an alternate methodology for the estimation of the noise exposed population of the Australian workforce. Previous methods relied on the statistics from the annual rate of application for worker's hearing loss compensation claims, the generalization of small scale surveys to the broader population or larger scale telephone surveys. This proposed method takes measured noise exposure data from sampled industries and combines that with official demographic information on the numbers employed in the respective industries. From the Australian data, it is estimated that around 20.1% of the workforce regularly work in noise above the recommended exposure standard (L Aeq, 8 h = 85 dB) and 9.4% above and exposure of 90 dB. These figure lie within the range of estimates derived from other methodologies.

Audição de Trabalhadores Antes e Após o Programa de Conservação Auditiva

Introduction: It is still limited the acceptance and participation of companies in the implementation of the Hearing Conservation Program (HCP), which intends to prevent the evolution of hearing loss as a result of occupational noise exposure. Objective: To check the HCP effects from the analysis of the hearing profile of workers exposed to noise before and after the implementation of this program in a tiles factory in the city of Recife, PE. Methods: This was an observational, descriptive and cross-sectional study. A total of 71 workers’ medical records were used through which occupational history and audiological findings were investigated. It was considered the reference audiometry, the sequential audiometry before the HCP implementation and the sequential audiometry after the HCP. Results: There were significant changes in the threshold of reference audiometry more often than those regarding the audiometry done before the HCP. Also, there were fewer changes in the reference audiometry compared to the sequential audiometry done after the HCP implementation. Furthermore, some positive changes were observed for audiometric thresholds after the HCP, which suggests an improvement in the workers’ hearing condition. Conclusion: The preventive means adopted and encouraged by the HCP brought benefits to these workers hearing. DESCRIPTORS: Hearing. Occupational Health. Occupational Noise.

A survey on effect of industrial impulse noise on hearing in workers for punching

Objective To explore the effect of industrial impulse noise on hearing in workers for punching.Methods 442 workers for punching and 128 workers for grinding were assigned to impulse noise group and steady-state noise group； 208 assembly workers without noise exposure were selected as control group.The results of pure-tone air conduction threshold audiometry were analyze.Results High-frequency hearing loss was detectable in 44.3％ of the workers for punching observed objects was in 4.1％; and noise-induced deafness was in 2.0％.Rate of hearing loss was higher in the impulse noise group than in the steady-state noise group ( P ＜ 0.01 ).With an elevation in CNE of 1dB ( A ) ·year,the risk of hearing loss in the workers for punching increased 12.3％ ( P＜ 0.01 ) and the risk in those for grinding increased 9.3％ ( P ＜ 0.05 ).Conclusions Industrial impulse noise is worse than steady-state noise in damage to hearing. Key words: Impulse noise; Steady-state noise; Hearing loss; Cumulative noise exposure

Effect of combined occupational exposure to noise and organic solvents on hearing

Noise exposure has been commonly regarded as the main hazard of occupational hearing loss. Recent studies indicate that several chemicals, including organic solvents have ototoxic effects. This study aimed at evaluating the hearing of workers exposed to both noise and a mixture of organic solvents at concentrations anticipated as safe. The study comprised three groups. The first one included 70 workers exposed to noise only, the second group consisted of 93 workers exposed to organic solvents and noise, and the control group included 59 individuals exposed to neither noise nor organic solvents. The three groups were matched for age, socioeconomic status, and smoking habit. The results of this study revealed that there was no statistically significant difference between the two exposed groups as regards the duration of exposure. There was a highly statistically significant difference between the two exposed groups as regards the different types of hearing loss (conductive deafness, sensory neural hearing loss, and mixed type) compared with the control one. Our study reported that sensory neural hearing loss occurred earlier in subjects with combined exposure to noise and solvents at a mean duration of exposure (16.38±9.44 years) compared to (24.53±9.59 years) the subjects with sole exposure to noise. The difference between the two groups was statistically significant regarding this type of hearing impairment (p < 0.05). There was a positive significant correlation between hearing impairment and duration of exposure in the two exposed groups. As regards the results of the environmental monitoring, both noise exposure levels (dB) and levels of different organic solvents measured (mg/m(3)) in different work departments were less than the levels recommended by Egyptian Environmental Law No. 4 for 1994. It is recommended that in the case of combined exposure, noise and solvent levels should be lowered than the permissible limits recommended for either alone.

A case study of construction noise exposure for preserving worker's hearing in Egypt

Every day, approximately half a million workers in the construction sector in Egypt are exposed to excessive noise. Noise is one of the most prevalent physical contaminants in the construction sector. The most negative effects of noise exposure are related to the hearing system and may produce occupational deafness or even permanent deafness. These effects have a very important influence on people’s health and well-being. The goals of this study are to carry out measurements to evaluate construction noise levels, which exceed the permissible level set by Egyptian noise standards and policy to protect the public health of workers, to assess noise exposure, and to develop controls for proposing preventive solutions. The noise levels to which the workers in the construction sector are exposed have been studied. A number of representative measurements have been carried out using a sound level meter and a dosimeter to collect data from workers devoted to different tasks in the construction process. The most important levels and indexes have been analyzed with those data.

A survey on hearing of workers exposed to noisy environment in a cotton spinning mill

Objective To explore the effect of high intensity noise on the hearing in the workers in a cotton spinning mill. Methods A hygienic survey on the workplaces in a cotton mill was conducted. The results of hearing examination on 195 workers exposed to the noisy environment were compared with those from 108 controls. Results A total of 110 noisy spots were detected, whose intensity ranged from 80.1 to 96.0 dB, with an average of (85.3 ± 2.6) dB. 42 detected spots (38.2%) exceeded the national hygienic standards. The incidence of hearing loss was significantly higher in the workers exposed to the noisy environment than in the controls (26.2% vs. 5.6%, P<0.01); and the degree of hearing loss increased with the length of the exposure time. Conclusions The workers exposed to such a noisy environment in the cotton spinning mill have a marked hearing loss. Key words: Cotton spinning mill; Noise; Hearing

N-Acetyl L-Cysteine does not protect mouse ears from the effects of noise*

BackgroundNoise-induced hearing loss (NIHL) is one of the most common occupational injuries in the United States. It would be extremely valuable if a safe, inexpensive compound could be identified which protects worker hearing from noise. In a series of experiments, Kopke has shown that the compound N-acetyl-L-cysteine (L-NAC) can protect the hearing of chinchillas from the effects of a single exposure to noise. L-NAC is used in clinical medicine and is very safe. Although L-NAC was reported to be promising, it has not been successful in other studies (Kramer et al., 2006; Hamernik et al., 2008). The present study was undertaken to determine if L-NAC could protect C57BL/6J (B6) mice from the permanent effects of noise.MethodTwo groups of five B6 mice were injected with either 300 or 600 mg/kg L-NAC approximately 1 hr prior to a 104 dB broadband noise exposure and again immediately after the exposure. A control group (N = 7) was exposed to the same noise level but injected with vehicle (sterile saline). Auditory brainstem response measurements were made at 4, 8, 16 and 32 kHz one week prior to and 12 days after exposure.ConclusionsThere were no statistically significant differences in ABR threshold shifts between the mice receiving L-NAC and the control mice. This indicates that L-NAC was not effective in preventing permanent threshold shift in this mouse model of NIHL.

Comparative study of audiometrics tests on metallurgical workers exposed to noise only as well as noise associated to the handling of chemical products

SummaryExposure to ototoxic chemical products in the presence or absence of noise can cause irreversible injury to the hearing of workers for a significantly short period of exposure period. Aim: to perform a comparative study, through audiometric tests, in workers exposed to noise only and noise associated with chemical products. Materials and Methods:155 steel workers (18 - 50 years) exposed to noise (group I), and exposed to noise and chemical products (group II) for a period that varies from 3 to 20 years. Results: significant difference in the rate of occupational hearing loss in the right ear between groups I (3.6%) and II (15.5%). A significantly higher rate of occupational hearing loss in group II (18.3%) and I (6%). With respect to the average time of exposure to aggressive agents, group I was exposed by a significantly higher time. Retrospective study. Discussion: The fact that the right ear was more affected in group II is controversial and should be better investigated in the future, since some studies show that the left ear would be more prone to noise-induced hearing loss. Conclusion: group II had proportionally a higher rate of hearing loss when compared with group I, even after having been exposed to aggressive agents for a lower average time.

Association of work-related accidents with noise exposure in the workplace and noise-induced hearing loss based on the experience of some 240,000 person-years of observation

This retrospective study explores the association between occupational noise exposure at the time of hearing tests, permanent noise-induced hearing loss and work-related accident risk. Log-binomial analysis was used to first ascertain the association between study variables according to activity sector (North American Industry Classification System, NAICS) and accident context while controlling for age. Second part of the paper estimates the overall number of accidents attributable to occupational noise or the associated hearing loss (excess fraction). Study was carried on a sample of 52,982 male workers exposed to a minimum of 80 dBA on a daily basis and whose hearing was examined at least once between 1983 and 1996 by public health authorities of Quebec. These participants evidenced bilateral average hearing threshold levels at 3, 4 and 6 kHz ranging from normal (≤15 dB) to hearing loss in excess of 50 dB as a result of chronic occupational noise exposure (subjects otherwise otologically normal). The occupational accident count of these workers was derived from the individual histories registered with the Quebec workers’ compensation board for the 1983–1998 period. Results show an association between accident risk and worker's hearing sensitivity. For example, a hearing loss of 20 dB corresponds to a rise of accident risk equal to 1.14 when controlling for age and occupational noise exposure at the time of hearing tests. NAICS economic activity sectors where association is the most noticeable are “Metal Transformation”, “Metal Product Manufacturing” and “Transportation Equipment Manufacturing”. “Passive accidents” (PR per decibel of hearing loss = 1.008; CI 95 (1.007; 1.010)) and “same-level falls” (1.007; CI 95 (1.003; 1.010)) are the two accidents categories most strongly associated with hearing loss. Overall, 12.2% of accidents considered in this study were attributable to a combination of noise exposure in the workplace (≥90 dBA) and noise-induced hearing loss.

Industrial noise control—Technical and economic feasibility

Industrial noise control is too often considered technically not possible or economically infeasible. The use of ear protection devices becomes the fallback approach to attempt to reduce the risk of worker hearing loss. In reality there are noise control opportunities in industrial settings than are low cost and provide significant noise reduction without affecting production and maintenance practices. This paper will present mechanical and pneumatic noise controls that can be successfully applied to industrial environments. This paper will also present information on OSHAs approach to determine whether engineering noise controls are considered economically feasible.