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Evaluation of Noise Exposure and Hearing Threshold Levels Among Call Centre Operators

Pawlaczyk-Łuszczyńska Małgorzata, Zamojska-Daniszewska Małgorzata, Zaborowski Kamil, Dudarewicz Adam

Archives of Acoustics

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2019

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Vol. 44, No. 4

747--759

EN

The aim of this study was to evaluate the hearing status of call centre operators in relation to their noise exposure. Conventional pure-tone audiometry and extended high-frequency audiometry were performed in 49 workers, aged 22-47 years (mean ± SD: 32.0 ± 6.0 years), working in call centre from 1.0 to 16.5 years (mean ± SD: 4.7 ± 2.9 years). Questionnaire inquiry aimed at collecting personal data, the information on communication headset usage habits, self-assessment of hearing ability and identification of risk factors for noise-induced hearing loss were also carried out. Sound pressure levels generated by the communication headset were determined using the artificial ear technique specified in CSA Z107.56-13 (2013) standard. The background noise prevailing in offices was also measured according to PN-N-01307 (1994) and PN-EN ISO 9612 (2011). Personal daily noise exposure levels in call centre operators varied from 66 to 86 dB (10-90th percentile). About half of the study subjects had normal hearing in the standard frequencies (from 250 to 8000 Hz) in both ears, while only 27.1% in the extended high-frequencies (9-16 kHz). Moreover, both high-frequency and speech-frequency hearing losses were observed in less than 10% of audiograms, while the extended high-frequency threshold shift was noted in 37.1% of analysed ears. The hearing threshold levels of call centre operators in the frequency of 0.25-11.2 kHz were higher (worse) than the expected median values for equivalent (due to age and gender) highly screened population specified in ISO 7029 (2017). Furthermore, they were also higher than predicted for 500-4000 Hz according to ISO 1999 (2013) based on the results of noise exposure evaluation.

2

The Hearing Threshold of Employees Exposed to Noise Generated by the Low-Frequency Ultrasonic Welding Devices

Dudarewicz A., Zaborowski K., Rutkowska-Kaczmarek P., Zamojska-Daniszewska M., Śliwińska-Kowalska M., Zamysłowska-Szmytke E., Pawlaczyk-Łuszczyńska M.

Archives of Acoustics

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2017

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Vol. 42, No. 2

199--205

EN

The aim of the study was to assess the hearing threshold levels (HTLs) in employees exposed to noise generated by low-frequency ultrasonic technological equipment in comparison with the HTLs of workers exposed to audible noise at the similar A-weighted equivalent-continuous sound pressure level. The study includes measurements of ultrasonic and audible noise at workplaces and hearing tests, i.e. conventional pure-tone audiometry and extended high-frequency audiometry. The study group comprised 90 workers, aged 41.4 ± 10.0 years (mean±SD), exposed for 17.3 ± 9.8 years to noise generated by ultrasonic devices at mean daily noise exposure level (‹LEX,8h›) of 80.6 ± 2.9 dB. The reference group consists of 156 subjects, exposed to industrial noise (without ultrasonic components) at similar A-weighted equivalent-continuous sound pressure level (‹LEX,8h› = 81.8 ± 2.7 dB), adjusted according to age (39.8 ± 7.7 years), gender and job seniority (14.0 ± 7.0 years). This group was selected from database collected in the Nofer Institute of Occupational Medicine. Audiometric hearing threshold levels in the frequency range of 0.5–6 kHz were similar in both groups, but in the frequency range of 8–12.5 kHz they were higher in the group of employees exposed to ultrasonic noise. The findings suggest that differences in the hearing threshold (at high frequencies) in analyzed groups may be due to differences in spectral composition of noise and show the need to continue the undertaken studies.

3

Hearing Status in Young People Using Portable Audio Players

Pawlaczyk-Łuszczyńska M., Zaborowski K., Zamojska-Daniszewska M., Rutkowska-Kaczmarek P., Dudarewicz A., Śliwinska-Kowalska M.

Archives of Acoustics

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2017

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Vol. 42, No. 1

113--120

EN

The aim of this study was to evaluate the hearing status in young adults using portable audio players (PAPs) in relation to their listening habits. The study included 58 subjects, aged 22.8±2.8 years, non-occupationally exposed to noise. Questionnaire inquiry aimed at collecting personal data, the information on PAPs usage habits, self-assessment of hearing status and identification of risk factors for noise-induced hearing loss (NIHL) were performed in study subjects. Hearing tests included pure-tone audiometry (PTA) and transient-evoked optoacoustic emission (TEOAE). All subjects were PAPs users. Depending on listening habits they were divided into the subgroups of “frequent” users (>1 h/day) and “non-frequent” users (≤1 h/day). There were no significant differences between subgroups in prevalence of NIHL risk factors and self-assessment of hearing status. However, frequent users more often complained of tinnitus and hyperacusis. Majority (81.9 %) of participants had normal hearing. Nevertheless, 6.9 % of audiograms showed high-frequency notches typical for NIHL. Both, the PTA and TEOAE indicated worse hearing in non-frequent users compared to frequent users. No significant differences in prevalence of high-frequency notches between subgroups were noted. The outcomes do not support some previous studies results that the excessive exposure to music listened through PAPs might result in accelerating of development of NIHL loss in young adults.

4

Determining the effect of worker exposure conditions on the risk of hearing loss in noisy industrial workroom using Cox proportional hazard model

Aliabadi M., Fereidan M., Farhadian M., Tajik L.

International Journal of Occupational Safety and Ergonomics

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2015

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Vol. 21, No. 2

201--206

EN

In noisy workrooms, exposure conditions such as noise level, exposure duration and use of hearing protection devices are contributory factors to hearing loss. The aim of this study was to determine the effect of exposure conditions on the risk of hearing loss using the Cox model. Seventy workers, employed in a press workshop, were selected to study their hearing threshold using an audiometric test. Their noise exposure histories also were analyzed. The results of the Cox model showed that the job type, smoking and the use of protection devices were effective to induce hearing loss. The relative risk of hearing loss in smokers was 1.1 times of non-smokers The relative risk of hearing loss in workers with the intermittent use of protection devices was 3.3 times those who used these devices continuously. The Cox model could analyze the effect of exposure conditions on hearing loss and provides useful information for managers in order to improve hearing conservation programs.

5

Applications and Comparison of Continuous Wavelet Transforms on Analysis of A-wave Impulse Noise

Qin J., Sun P.

Archives of Acoustics

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2015

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Vol. 40, No. 4

503--512

EN

Noise induced hearing loss (NIHL) is a serious occupational related health problem worldwide. The A-wave impulse noise could cause severe hearing loss, and characteristics of such kind of impulse noise in the joint time-frequency (T-F) domain are critical for evaluation of auditory hazard level. This study focuses on the analysis of A-wave impulse noise in the T-F domain using continual wavelet transforms. Three different wavelets, referring to Morlet, Mexican hat, and Meyer wavelets, were investigated and compared based on theoretical analysis and applications to experimental generated A-wave impulse noise signals. The underlying theory of continuous wavelet transform was given and the temporal and spectral resolutions were theoretically analyzed. The main results showed that the Mexican hat wavelet demonstrated significant advantages over the Morlet and Meyer wavelets for the characterization and analysis of the A-wave impulse noise. The results of this study provide useful information for applying wavelet transform on signal processing of the A-wave impulse noise.

6

Occupational Exposure to Impulse Noise Associated With Shooting

Lwow F., Jóźków P., Mędraś M.

International Journal of Occupational Safety and Ergonomics

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2011

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Vol. 17, No. 1

69--77

EN

Shooting training is associated with exposure to a considerable amount of unique noise. We wanted to evaluate noise exposure during such training. Our observations especially apply to professional sport shooters, but they are also valid for shooting coaches/instructors. We collected acoustic signals in 10-, 25- and 50-m as well as open-air shooting ranges. The recorded material was analysed with orthogonal, adaptive parameterization by Shur. The mean duration of a single acoustic signal was 250–800 ms with the C-weighted sound peak pressure level of 138.2–165.2 dB. Shooters may be exposed to as many as 600–1350 acoustic impulses during a training unit. The actual load for the hearing organ of a professional shooter or a shooting coach is ~200 000 acoustic stimuli in a year-long training macrocycle. Orthogonal, adaptive parameterization by Shur makes safe scheduling of shooters’ training possible.

7

Noise Variability in Underground Room and Pillar Coal Mines

Szary M. L., Chugh Y. P., Hirschi J.

International Journal of Occupational Safety and Ergonomics

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2011

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Vol. 17, No. 3

301--308

EN

Noise in an underground coal mine has dominant components generated mainly from 3 sources: (a) continuous mining machines, (b) roof bolters, and (c) cars/vehicles used to transport personnel and/or coal. Each of these 3 noise sources also has a number of well-defined sub-sources with their own noise characteristics. Sound level meters were used to collect noise data in the form of instantaneous readings and also to check calibration of other sound measuring instruments. The most useful information was obtained from a spectrum analysis of continuous digital recordings of noise over time. This paper discusses the variability or dynamics of generated noise in both frequency and time domains in relation to several independent variables related to coal extraction and transportation processes.

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The Influence of Selected Risk Factors on the Hearing Threshold Level of Noise Exposed Employees

Dudarewicz A., Toppila E., Pawlaczyk-Łuszczyńska M., Śliwińska-Kowalska M.

Archives of Acoustics

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2010

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Vol. 35, No. 3

371-382

EN

The aim of the study was to evaluate the combined effect of noise exposure and additional risk factors on permanent hearing threshold shift. Three additional risk factors were: exposure to organic solvents, smoking and elevated blood pressure. The data on exposure and health status of employees were collected in 24 factories. The study group comprised of 3741 noise male exposed workers of: mean age 39§8 years, mean tenure 16§7 years and LEX;8h = 86 § 5 dB. For each subject, hearing level was measured with pure tone audiometry, blood pressure and noise exposure were assessed from the records of local occupational health care and obligatory noise measurements performed by employers. Smoking and solvent exposure were assessed with questionnaire. The study group was divided into subgroups with respect to the considered risk factors. In the analysis, the distribution of hearing level of each subgroup was compared to the predicted one which the standard calculation method described in ISO 1999:1990. For each of the considered risk factors, the difference between measured and calculated hearing level distribution was used to establish, by the least square method, a noise dose related correction square function for the standard method. The considered risk factors: solvent exposure, smoking and elevated blood pressure combined with noise exposure, may increase degree of hearing loss.

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Noise-Induced Hearing Loss and Efficiency of Communication by Means of Speech

Rzymełka S.

Molecular and Quantum Acoustics

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2001

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Vol. 22

213-219

EN

The work presents studied on perception of speech, which is the essence of social efficiency of hearing, depending on degree of noise-induced hearing loss. The applied method consisted in processing verbal tests by a computer system that simulated noise-inducted hearing loss. A group of young people with normal hearing was used in the study and their intelliginility of speech was determined with apprpriately filtered verbal tests. It was found that hearing lodd characteristic of noise-inducted changes consideably impair understanding of speech.