Fifty-six subjects performed a decision and data-entry task (for 40 minutes) to determine the influence of realistic noises on task performance. Implementation of a mixed two-by-seven complete factorial design was used to investigate the influence of noise on a) objective performance measures (number of questions answered, and errors) and b) subjective perceptions of the noises. The task involved both high and low complexity levels. Seven noises with different characteristics and spectra were investigated: continuous high frequency industrial, intermittent high frequency industrial, continuous low frequency industrial, computer printer noise, office noise, music, and white noise. Analysis of covariance performed on the task performance data showed a significant main effect of complexity and noise-by-complexity interaction. As expected, for all noise conditions, the high complexity condition was more detrimental to performance than low complexity. Also, Newman-Keuls test of the noise-by-complexity interaction showed that subjects who performed the high complexity task while exposed to printer noise were hindered more than subjects performing any complexity level under any other noise condition. Analysis of variance on the subjective rating data showed both main effects of noise and complexity to be significant. Regardless of the noise, the high complexity condition was consistently perceived as more difficult than the low. Subjects perceived the music condition to be more enhancing than the low-frequency industrial noise. All other noises were perceived to be similar. Subject gender was not found to have any significant effect on objective task performance measures or subjective perception of noise. / M.S.

Hearing protection devices (HPDs), a widely used countermeasure against noise-induced hearing loss, are laboratory-tested for their attenuation (noise reduction) capabilities. Unfortunately, laboratory tests overestimate the in-workplace performance of the devices, potentially leading to inadequate protection for the user. Many factors affect in-field effectiveness, including the physical design and "wearability" of the protector. Wearability, a highly subjective aspect which encompasses such characteristics as user comfort, ease of use, and acceptability, directly affects performance by influencing the regularity of use and the manner in which a protector is worn. This research investigated the influence of the user's work-related activities over a prolonged wearing period, and of variations in headband compression force and cushion material (liquid- or foam-filled) on achieved noise attenuation and wearability (comfort and acceptability) of earmuff hearing protectors. REAT (real-ear attenuation at threshold) testing procedures were used to collect attenuation data on 24 subjects, both prior-to and following completion of a simulated work task. Bipolar rating scales were utilized to collect pre- and post-task wearabi1ity data. Statistical analyses demonstrated that the work-related movement and wearing time significantly reduced achieved attenuation and, for higher compression earmuffs, also degraded perceived comfort and acceptability. A high headband compression force was 1inked to increased attenuation and to poorer user comfort and acceptance. The data revealed no significant difference in achieved attenuation or wearability between cushion types. The results illustrate the powerful influence of physical activity on HPD effectiveness and the criticality of certain earmuff design parameters to both attenuation and wearability. Furthermore, the existing tradeoff in earmuff design between comfort and attenuation was clearly demonstrated. / Master of Science

This study was made to find the effects of noise on the human body, to measure sound levels that exist in school power laboratories, and to design and evaluate the effectiveness of two noise control devices. An accurately calibrated testing device was used to measure sound levels in an attempt to determine if excessive noise exists in school power laboratories and to find the extent to which such noise can be reduced by shielding or enclosing the engine test area. It was found that noise has undesirable physical and psychological effects on the human organism. Sixty-two and one-half per cent of the engines tested registered sound levels above 90 dBA; even so, simple, inexpensive noise control devices do control the noise levels generated in the school power laboratories.

A study was conducted to determine the dependency of sound attenuation capabilities of earmuffs and earcaps on various application instruction techniques including: (1) no instruction, (2) no instruction with 70 dBA auditory feedback, (3) manufacturers' package instruction, (4) detailed instruction, and (5) modeled instruction. The hearing protection devices (HPDs) studied were: two earcaps (Willson #20 Sound-Ban, Flents #055 Peace & Quiet Headband), and four earmuffs (E-A-R model 1000, Siebe Norton Industrial model 4540, Peltor H6A/v, and Willson 365A Sound Barrier). HPD comfort and wearer preferences were also assessed. Furthermore, typical excessive industrial machinery noises were sampled and analyzed across the 1/3 octave frequencies. Finally, an example is provided as to how these machinery noise spectra can be matched with HPD attenuation spectra to ascertain the protector which would afford optimal protection for a given noise situation. Fifty subjects (twenty-five males and twenty-five females) participated in the experiment. Attenuation characteristics of the HPDs were evaluated utilizing the real-ear attenuation at threshold (REAT) method. A three-way mixed factorial design was used for data collection and analysis of attenuation results. Bipolar scales were used to assess individual HPD comfort, and the HPDs examined were ranked to obtain user preferences. In the analysis of attenuation results, analysis of variance CANOVA) and pairwise comparisons were utilized to detect statistical significance. The comfort scales and ranking scores were evaluated using the Friedman one-way block design. Attenuation results for the earmuffs and earcaps tested showed that they were much less susceptible than earplugs (from a previous study by Epps, 1984) to changes in user insertion/donning instruction technique and also not as dependent on user gender. The main effect of gender was not significant, and in general, any instruction was better than no instruction at all but the effects of those instructions did not differ significantly among each other. As expected, there were main effect differences among the HPDs as to their attenuation capabilities, rated discomfort, and user preference. Because the main objective was on assessing donning instruction effects on HPD attenuation, the comfort/preference assessment was based on only a short (25 minutes) wearing time during the attenuation tests. Therefore, the comfort/preference ratings could likely vary given longer wearing periods and different work environments. All results found are discussed on the basis of the sample data obtained and conclusions drawn from these results should be limited to these experimental conditions and subsequent analyses, as actual attenuation achieved in practice may differ. The example of HPD-machinery noise matching illustrates that the attenuation/spectral matching procedure may indeed be a feasible way of selecting optimal protection for workers. / Master of Science

Submitted in fulfillment of the requirements for the degree of Doctor of Technology: Quality Management, Durban University of Technology, 2014. / Hearing conservation in the industrial setting has mainly focussed on the harmful effects of noise exposure on the auditory system. This study investigated the co-exposure to noise and ototoxic chemicals on the auditory system of workers engaged by labour brokers. It examined the adequacy of current occupational health and safety legislation to address chemically induced hearing loss and makes recommendations at a policy level to protect workers’ hearing at the workplace. This study is an exploratory cross-sectional field case study in an industrial setting. A sample of 300 workers was drawn from a rubber factory involved in the manufacture of components for the motor, shoe and plumbing industries in the metropolitan area of Durban. Purposive sampling was undertaken amongst a cohort of day shift workers which constituted the research subjects. The research tools used in the study included the completion of the NoiseChem questionnaire, conducting pure tone audiometric testing on research subjects, monitoring noise exposure levels and performing chemical air monitoring of the ambient environment. This study confirms that a segment of the research subjects were exposed to both ototoxic chemicals and noise. Chemical exposure of research subjects was within legal permissible limits in most instances. Noise exposure exceeded the noise rating limit of 85 dBA in certain work areas. Multiple regression analysis revealed that there was a slight trend towards co-exposure to chemicals and noise being risk factors for hearing loss with an odds ratio of 1.7 (95% CI = 0.34 – 8.57) but the p value was not significant. No significant association with hearing loss was evident for workers exposed to chemical only with odds ratio of 0.41 (95% CI = 0.11 – 1.53, p = 0.19) and noise only with odds ratio of 0.87 (95% CI = 0.32 – 2.31, p = 0.78). The study indicated that workers exposed to both ototoxic chemicals and noise may be more susceptible to hearing loss in their current jobs. The study draws attention to policy gaps in the Occupational Health and Safety Act and proposes changes to address the shortcomings. / D

The study investigated the feasibility of including DPOAEs in the annual medical surveillance test battery for the identification of NIHL in a group of employees in a manufacturing industry in KwaZulu-Natal. Feasibility was investigated by exploring the sensitivity, specificity and predictive efficiency of DPOAEs, the ability of DPOAEs to detect subtle noise-induced cochlea changes, the test-retest reliability of DPOAEs and lastly, the duration of time taken to conduct the DPOAE test bilaterally. A cross-sectional and repeated measures within-in participant design was utilized in the study. A purposive convenience sampling technique was used, as well as a stratified sampling approach in order to realize objective two of the study. The study consisted of 60 participants, which were further stratified into four test groups, i.e. Group A: 0-3 years, Group B: 3.1-6 years and Group C: 6.1-9 years and Group D: 9.1-13 years of working within the beverage manufacturing industry. A high sensitivity and negative predictive value was reported in the current study, suggesting that DPOAEs may be able to identify those who present with subtle cochlea changes as a result of exposure to occupational noise. The sensitivity of DPOAEs was 100% at 1, 2, 4, 6 and 8kHz in the right ear and at 4 and 6kHz in the left ear. The specificity of DPOAEs in the current study ranged between 55%-97% across the frequency range in the right ear and 49%-88% in the left ear. A negative predictive value of 100% was obtained bilaterally across the frequency range, except at 8kHz in the left ear. Visual inspection of the DPgram in the current study revealed a bilateral reduction in DPOAE amplitudes for all test groups in the high frequency region of the DP-Gram, namely, 5477Hz and 7303Hz, in the absence of a statistically significant difference (p>0.05). A greater frequency range appears to be affected in this group of workers, indicating that the type of noise, namely, impulse noise, may result in cochlea changes. Corresponding changes on the pure tone audiogram were not observed, however, noise notch configurations were observed for the groups with a longer history of noise exposure. This was not seen bilaterally as is typically expected with NIHL. Good test-retest reliability across the frequency range obtained in the current study further indicates the feasibility of including DPOAEs in the annual medical surveillance test battery. Additionally, the current study calculated an average of 86 seconds (1 minute 26 seconds) to conduct the DPOAE test bilaterally, confirming that DPOAEs are a quick test to administer. The findings of this study suggest that DPOAEs may be used to monitor early subtle noise-induced cochlea changes for workers exposed to noise in the beverage manufacturing industry as part of the annual medical surveillance test battery. / Thesis (M.Comm.Path.)-University of KwaZulu-Natal, Westville, 2013.

CAPES / O alto nível de ruído ocupacional é um problema presente em todas as regiões do mundo. O ruído é um agente ambiental que afeta diariamente uma grande parte de trabalhadores em indústrias e geram inúmeras consequências negativas. Pesquisas sobre o ruído ocupacional e os efeitos na saúde do trabalhador são publicados, porém, a análise da percepção individual do trabalhador sobre o seu comportamento constitui ainda um tema pouco abordado. Esta pesquisa buscou avaliar a influência do nível de maturidade dos Programas de Conservação Auditiva sobre a percepção de risco pelos trabalhadores. O presente estudo avaliou cinco empresas metalúrgicas com uma amostra de 243 trabalhadores expostos a níveis de pressão sonora superiores ao nível de ação na legislação nacional 85 dB (A). Tendo como base a revisão bibliográfica, foram aplicados dois questionários para avaliação das variáveis de natureza qualitativa. O primeiro questionário foi desenvolvido e aplicado às empresas para avaliar os níveis de maturidade em programas de conservação auditiva. Posteriormente foi aplicado um questionário para o trabalhador considerando a percepção individual do risco, a percepção dos efeitos do ruído, cultura de segurança e o comportamento de risco. Os dados foram analisados estatisticamente, onde foram utilizadas ferramentas de análise de confiabilidade, análise de variância – ANOVA, Teste de Tukey e estatística descritiva para relacionar os dados. Concluiu-se que os diferentes níveis de maturidade não apresentam diferenças significativas na percepção do trabalhador, entretanto, foi possível constatar um maior percepção de risco nos diferentes níveis de exposição ao ruído. / The high level of occupational noise is a problem present in all regions of the world. Noise is an environmental agent that daily affects a large number of workers in industries and generate countless negative consequences. Research on occupational noise and the health effects of the worker is published, however, the analysis of individual perception of the worker on his behavior is still a subject little addressed. This research aimed to evaluate the influence of the level of maturity of the Hearing Conservation Programs on the perception of risk by the workers. The present study evaluated five metallurgical companies with a sample of 243 workers exposed to sound pressure levels above the action level in national legislation 85 dB (A). Based on the bibliographic review, two questionnaires were used to evaluate qualitative variables. The first questionnaire was developed and applied to companies to evaluate maturity levels in auditory conservation programs. Subsequently a questionnaire was applied to the worker considering the individual perception of risk, perception of the effects of noise, safety culture and risk behavior. The data were analyzed statistically, where tools of reliability analysis, analysis of variance - ANOVA, Tukey test and descriptive statistics were used to relate the data. It was concluded that the different levels of maturity do not present significant differences in the perception of the worker, however, it was possible to verify a greater perception of risk in the different levels of exposure to noise.

A constante mudança nos meios de trabalho ocorre devido a evolução tecnológica e industrial. Entretanto, com o advento de tais inovações, dificilmente o trabalhador da indústria não é submetido aos mais variados riscos ocupacionais resultantes dos processos produtivos. Diante deste contexto, o presente estudo teve como objetivo principal avaliar os níveis de vibração e de ruído aos quais os trabalhadores de uma empresa do setor da construção civil, especializada na manutenção e reformas de pisos industriais, estavam expostos durante suas jornadas de trabalho em duas frentes de trabalho. As medições foram realizadas em locais e dias distintos nos municípios de Curitiba e de São José dos Pinhais, ambos no estado do Paraná. Para a avaliação da vibração ocupacional, utilizou-se um acelerômetro junto ao trabalhador e um sensor triaxial acoplado na empunhadura dos equipamentos objeto de estudo, que foram duas diferentes fresadoras de piso. Posteriormente os dados foram processados e comparados com o novo texto do Anexo no 08 da Norma Regulamentadora NR-15, apresentado para consulta pública pelo Ministério do Trabalho e Emprego entre os meses de janeiro e fevereiro de 2014. Já para a medição do ruído utilizou-se um dosímetro de ruído junto ao trabalhador, cujo resultado final possibilitou a comparação com o Anexo no 01 da mesma Norma Regulamentadora. Os resultados finais indicaram níveis de exposição excessivos, superiores aos limites de tolerância determinados pela Legislação, tanto para vibração quanto para o ruído, gerando insalubridade para os trabalhadores expostos, em todos os locais onde foram realizadas as medições. / The constant change in the means of work is done by technological and industrial developments. However, with the advent of such innovations, hardly the work of the industry is not subject to a variety of occupational hazards resulting from production processes. Given this context, the present study aimed to monitor the working hours of the employees of a company in the construction industry, specializing in industrial floor maintenance and renovations, as exposure of vibration and noise on two fronts work in the cities of Curitiba - PR and São José dos Pinhais – PR. The program took place in two locations and on different days. The workday adopted by the company is six hours daily. For the evaluation of vibration, we used accelerometer with the worker and coupled to the handle of the equipment object of study, a mill floor, triaxial sensor subsequently the data were processed and compared with the new text of Annex No. 08, NR 15, submitted for public consultation by the Ministry of Labour and Employment in the months of January and February 2014. As for noise measurement used a dosimeter with the worker, whose final results enabled comparison with the regulatory norm 15 - Annex No. 01. The final results indicate excessive exposure to the tolerance specified by the legislation, both vibration and sound pressure level, featuring unhealthy at all locations where measurements were performed.

Indiana University-Purdue University Indianapolis (IUPUI) / Highway noise can cause annoyance, affect sleep patterns, and reduce the property value for people in the proximity. Current methods for analyzing the effectiveness of sound barriers only take loudness into consideration. This paper introduces new methods that can be used to analyze the effectiveness of the sound barriers. Our approach uses psychoacoustic measures including sharpness, roughness, fluctuation, strength, and annoyance. Highway noise is non-stationary, therefore each of these metrics are calculated over a short time. Finally analysis is performed the distribution and change over time. We used nth nearest neighbor algorithm to remove sounds that are not a part of the experiment. In the future, this data can be combined with human surveys to see if the change in sound quality due to the presence of sound barriers has a meaningful impact on people's lives.

Thesis (MScMedSc (Interdisciplinary Health Sciences. Speech-Language and Hearing Therapy))--University of Stellenbosch, 2007. / Noise is a noxious stimulus with possible negative physiological effects on the infant, especially in the Neonatal Intensive Care Unit (NICU). The present study conducted a detailed noise assessment in a NICU of a state hospital in the Cape Metropole and documented 6 infants’ physiological responses to noise levels. Noise levels ranged from 62.3-66.7dBA (LAeq), which exceed all American and British standards (50dBA -60dBA) for a NICU. Continuous exposure to noise of these levels is potentially harmful to the infants’ auditory system and health stability. The general well-being of the staff working in the NICU may also be compromised. Analysis of the noise events revealed that staff conversations were the largest single contributor to the number of noise events, while the largest single non-human contributor was the alarm noise of the monitors. No significant correlations were found between the heart rates and noise levels and the respiratory rates and the noise levels for any of the participants in either room. The NICU was found to be an extremely reverberant environment, which suggested that the NICU noise levels were largely a result of reverberant noise reinforcements. NICU nursing staff’s most common suggestion for noise abatement strategies was reduction of staff conversation. Results of this study highlight the need for NICU noise abatement to optimise newborn patient care, reduce the risk of acoustic trauma and to improve the neonate’s quality of life, thus enhancing the infant’s physiologic stability, growth and health.