ABSTRACT It is well documented that repetitive exposures to high intensity sound can cause acoustic trauma to the ear resulting in hearing loss, and that occupational noise is a significant cause of adult-onset hearing loss. Research world wide has indicated a significant number of workers with hearing loss attributed to noise exposure. Noise-Induced Hearing Loss (NIHL) claims are responsible for the majority of occupational disease payouts. The study was undertaken in order to determine the extent of hearing loss due to noise exposure that could be ascribed to excessive exposure to noise, and to describe the noise-induced hearing loss by severity, type of work, and area of work and duration of service. The cross-sectional study included 466 workers employed in a pulp and paper mill in KwaZulu Natal (KZN) South Africa. It involved the assessment of 932 individual audiograms to diagnose noise-induced hearing loss and the calculation of the percentage loss of hearing from pre placement to the year 2005. Audiometry results were presented for noise-induced hearing loss in relation to area of work, duration of service, categories of severity and age group. The prevalence of noise-induced hearing loss in the pulp and paper mill was 21% (98/466) and with 79% (368/466) of workers whose audiograms returned results not indicating NIHL. 75 workers were excluded due to workplace transfers. Type of work, area of work and years of service correlated significantly with a diagnosis of noise-induced hearing loss. As a department, the wood yard (which included the wood chipping facility, maintenance workers and workers with 10 – 20 years of service) showed the most significant association. In categories of severity 16.7% of workers suffering from NIHL fall in the ≤ 5 Percentage Loss of Hearing PLH category. This study has confirmed the findings of others that noise exposure is a significant hazard in industry and an effective noise control programme is the only way to reduce the risk of NIHL. _____________________________________________________________________

Noise Induced Hearing Loss (NIHL) is a sensorineural hearing loss resulting from excessive noise exposure (von Geirke, 1975). In New Zealand the Department of Labour stipulates that employees must not be exposed to more than an eight-hour equivalent continuous A-weighted sound pressure level (LAeq,8h) of 85 dB(A) or a peak sound pressure level (Lpeak) of 140 dB(A). Sandblasting is a process, whereby an abrasive is mixed with air at high pressures and exposes the operators to excessive noise (Blair, 1975). The protective equipment currently worn is a closed respirator system consisting of a helmet and cape, overseas research indicates noise levels inside the helmet are above the allowable levels (Blair, 1975; Environmental Medicine Unit, 1998; Irving, 1995; Patel and Irvings, 1999; Price and Whitaker, 1986 and Sussel 1992). There is disagreement in the literature as to the contribution of the noise created by the respirator system to the total noise exposure (Blair, 1975; Environmental Medicine Unit report, 1998; Irving, 1995 and Price and Whitaker, 1986). In some blasting sites additional hearing protection such as foam insert earplugs and/or earmuffs are worn in conjunction with the helmet. No research could be found investigating the resulting attenuation these combinations provide. It is well reported in the literature that the combined attenuation is more complex than the simple sum of the two components attenuation (Abel & Armstrong, 1991; Abel & Odell, 2006; Behar, 1990; Berger, 1983; Damongeot, Lataye & Kusy, 1989). The aims of the current study were to investigate noise levels during blasting inside booths and the operators’ helmets at two sites in New Zealand. The attenuation provided by the helmet alone and in combination with earmuffs was investigated in the laboratory. The contribution of the respirator airflow to the total noise exposure was also investigated. Finally the measured combined attenuation was compared to that calculated using three methods from the literature. Findings indicate that noise levels in blasting booths and inside operators’ helmets are above allowable levels. Laboratory findings indicate that the use of earmuffs in conjunction with the helmet increases the attenuation provided, therefore decreasing the risk of NIHL and that noise from the respirator airflow does not contribute to the total noise inside the helmet. The combined attenuation calculated from two methods in the literature was inaccurate while one was close. The findings, recommendations, limitations of the study and areas for further research are discussed.

The characteristics of Noise Induced Hearing Loss (NIHL) in gold miners of different ages and occupation types were examined and the incidence of tinnitus, vertigo/balance problems and nausea were determined. The results indicate that as a subject group these had symmetrical bilateral, mild hearing loss in the frequencies below 2000 Hz deteriorating to a moderate sloping hearing loss in the frequencies above 2000 Hz, and the loss did not demonstrate the expected “notch” at 4000 Hz that is usually found in NIHL. The average deterioration in the pure tone thresholds of gold miners was 3.5 dB at 500Hz; 2.75dB at 1000Hz, 15.37 dB at 2000Hz, 19.12 dB at 3000Hz; 20.87dB at 4000 Hz and 14.16dB at 6000 Hz for every ten years of age. The pattern of hearing loss varies for the different occupation types with machine operators being the most severely affected. The majority of tinnitus sufferers were in the age range 30-60 years and 57.8 % were in the under 60 years old category, while in the over 60 years the incidence was 4.8 %. The incidence of vertigo and nausea were found to be 27% in this population. The results of this study will equip the audiologist to better deal with diagnostic testing, successful hearing aid fitting and aural rehabilitation of this population. The study highlights the need for greater awareness and the imparting of detailed information to gold miners about the impact of noise on their hearing. / Dissertation (MCommunication Pathology)--University of Pretoria, 2009. / Speech-Language Pathology and Audiology / unrestricted

The purpose of this critical essay is two-fold. First, the essay presents a detailed critical analysis of my original composition, Blueline Concerto for bass trombone and wind ensemble. Second, using Blueline Concerto, the essay presents preliminary findings of my study to develop an approach to composing that takes into account the musicians' health, specifically regarding noise induced hearing loss (NIHL). Through various hypothesized composition- and orchestral-based approaches, I test effectiveness on changes in NIHL risk while also noting that artistic merit and compositional integrity is preserved.

Bakgrund: Studier visar att hörselskador kan uppstå till följd av yttre påfrestningar så som exponering av buller och kraftiga tryckförändringar. Fallskärmshoppare exponeras för bägge dessa faktorer, vilket skulle kunna innebära en ökad risk för att utveckla hörselskador. Trots detta är området mycket sparsamt studerat. En ökad kunskap inom området medför att eventuella behov av preventiva åtgärder kan identifieras. Syfte: Syftet med studien var att undersöka förekomsten av upplevda hörselbesvär hos fallskärmshoppare, samt om det finns något samband mellan upplevda hörselbesvär och antal hopp, användning av öronproppar eller akustiska höjdvarnare. Metod: Studien genomfördes i form av en kvantitativ tvärsnittsstudie. En webbenkät skickades ut till samtliga aktiva fallskärmshoppare med registrerad e-postadress i två fallskärmsklubbar i Mellansverige. Totalt 244 fallskärmshoppare deltog i studien (svarsfrekvens 47,6 %). Resultat: Hörselrelaterade besvär i form av hörselnedsättning, tinnitus och smärta/obehag i öronen förekom hos 20-30 % av de studerade fallskärmshopparna. Det fanns däremot inga statistiskt signifikanta samband mellan upplevda hörselbesvär och antal fallskärmshopp, användning av öronproppar eller användning av akustiska höjdvarnare. Andelen som uppgav att de upplevde svårigheter att höra vad som sägs i ett samtal mellan flera personer var högre bland de studerade fallskärmshopparna jämfört med en åldersmatchad population i SCB:s befolkningsundersökning. Slutsats: Inga samband mellan antal fallskärmshopp och hörselrelaterade besvär kan ses, men resultatet tyder på att fallskärmshoppare upplever hörselnedsättning i större utsträckning jämfört med övriga befolkningen. Vidare studier krävs för att med säkerhet kunna avgöra om fallskärmshoppning innebär en risk för att utveckla hörselskador. / Background: Studies have shown that hearing loss can be caused by environmental factors like noise and changes in the pressure. Skydivers are exposed to several risk factors for hearing impairment, but there is a lack of studies investigating hearing loss among skydivers. More knowledge among the phenomena is needed to identify potential need of preventive work.  Aims: The aim of the study was to investigate the prevalence of self-perceived hearing symptoms among skydivers. The study also examined the relationship between self-perceived hearing symptoms and the use of earplugs and audible altimeters. Methods: The study was executed as a quantitative cross-sectional study. Webb-based questionnaires were sent out to all skydivers with registered e-mail in two skydiving clubs in Sweden. A total of 244 skydivers were studied (response rate 47.6 %) Results: Hearing symptoms such as hearing loss, tinnitus and ear pain was found in 20-30 % of the skydivers. The proportion who experienced difficulty in hearing was higher among the skydivers than an age-matched population from a SCB survey. However, no statistically significant correlations between self-perceived hearing symptoms and number of parachute jumps, use of earplugs or use of audible altimeters were found. Conclusion: No relationship between amount of skydiving and hearing symptoms could be found, but the results indicate that hearing loss is more common among skydivers compared to the general population. Further studies are required to investigate if skydivers are in risk of developing hearing loss.

Student Number : 0213468X - MPh dissertation - School of Public Health - Faculty of Health Sciences / Background: Noise Induced Hearing Loss (NIHL) is increasingly being regarded as one of the most important Occupational diseases, especially in the mining industry. As most mining houses have put systems in place to try and control this problem it remains to be seen if existing controls are effective in achieving the intended objective of preventing hearing loss. This study was conducted in one of the big South African Diamond mines, which has a well resourced Hearing Conservation Program. Objectives: This study was conducted with the purpose of establishing if there has been additional incidence of NIHL in noise exposed workers during the observation period of five years. The other objective of this study was to determine the effect of age. Study design and method: The population in this study was made up of permanent employees of the mine. They were divided into low risk and high risk groups according to the noise/acoustic zoning of their work areas by the mine’s Occupation Hygiene Section, with the low exposure group acting as the control group. A retrospective record review was done using the Occupational Health records in the mine’s Occupational Health Centre. The period of observation spanned 1 January 1999 – 31 December 2004 (inclusive). Trends of the collated data were used to compare the two exposure groups with regard to the various outcomes that are commonly associated with hazardous noise exposure. Results: The outcomes that were analyzed in this study were: Incidence Rates for NIHL, Notching and Down-sloping. All these were observed to have occurred more among the exposed group during the period of observation. The incidence rates, in particular, were found to 92.8 per thousand person years in the high exposure group and 52.3 per thousand person years in the low exposure group. The statistical test that was used was the z-test and the results were z=5.844 with a p<0.05. Having decided on a significance level of 5% for the statistical test, this result was found to be statistically significant. This can be regarded as some proof that the exposed group had a worse outcome than their non-exposed counterparts. Another observation that was made was that the incidence of NIHL was proportionately higher among the older study subjects. Conclusion: Since the exposed group of workers was found to show statistically significant incidence of NIHL compared to the low exposure group it shows that the current Hearing Conservation Program (HCP) that is employed by the mine is not effective in preventing NIHL. However there were some limitations in the study design that preclude generalization of these results. Therefore a recommendation was made for a prospective cohort study to address these limitations.

Thesis (M. Sc. (Nursing Science)) --University of Limpopo, 2017. / Refer to the document

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Introdução: O zumbido é definido como uma sensação auditiva ilusória sem a presença de um som externo. Acomete homens e mulheres, mais comumente entre 40 e 70 anos de idade, às vezes podendo ocorrer em crianças. Análises de dados epidemiológicos indicam que a exposição ao ruído é uma das causas mais comuns de zumbido. Objetivos: Os objetivos gerais deste estudo foram verificar a prevalência do zumbido em trabalhadores expostos ao ruído ocupacional e avaliar a freqüência e a intensidade do zumbido. Os objetivos específicos foram avaliar a gravidade do zumbido; analisar a presença do zumbido por sexo, cor, idade e tempo de trabalho com exposição ao ruído e analisar a relação do zumbido com as freqüências mais acometidas na audiometria e com a presença e grau da perda auditiva, independente do nexo da perda. Materiais e Métodos: Trata-se de um estudo transversal para o qual foram selecionados 362 prontuários de trabalhadores expostos a ruído ocupacional ≥80dB(NA)/8h diárias. Estes trabalhadores haviam sido submetidos a meatoscopia, anamnese clínica e ocupacional, audiometria de via aérea, avaliação de freqüência e intensidade do zumbido e à escala de avaliação da gravidade do zumbido. Conclusão: A prevalência do zumbido foi de 9,9%. Nas análises de regressão conclui-se que trabalhadores com presença de perda auditiva em pelo menos um dos ouvidos têm 2,396 vezes mais chances de ter zumbido quando comparados com os que não tem perda auditiva. Os trabalhadores com faixa etária acima ou igual a 30 anos tem 5,353 vezes mais chances de ter perda auditiva em pelo menos um dos ouvidos quando comparados com os de faixa etária menor que 30 anos. Com relação ao tempo de trabalho em contato com o ruído, a analise estatística revela que trabalhadores com diferença de 1 ano no tempo de trabalho em contato com ruído tem um risco 5,3 % (OR=1,053) maior de apresentar perda auditiva. / Background: Tinnitus is an auditory phantom sensation experienced when no external sound is present. It occurs in both men and women, and is more prevalent between the age of 40 and 70; however, it may also occur in children. Analyses of epidemiologic data indicate that exposure to noise is its most common cause. Object: The aim of this study was to investigate the prevalence and characteristics of tinnitus in noise-exposed workers. Its specific objectives were to evaluate the severity of tinnitus, to compare the presence of tinnitus with the individual’s sex, race, age, and time of exposure to noise in the workplace, and to analyze the relation between tinnitus and the most affected frequencies in audiometric tests as well as the presence and level of hearing loss. Materials and Methods: The present was a cross-sectional study for which 362 files of workers exposed to noise (≥80dB(A)/8h per day) were selected. These workers had undergone otoscopy, clinical and occupational anamnesis, audiometric test of ear conduction, and an investigation of frequency, intensity, and severity of tinnitus. Conclusion: The prevalence of tinnitus found was 9.9%. After logistic regression analyses, it was concluded that workers with hearing loss in at least one ear have 2.396 times more chance of having tinnitus than those who do not have hearing loss. Workers aged 30 or older have 5.353 times more chance of having hearing loss in at least one ear than those younger than 30. As to time of exposure to noise in the workplace, statistical analysis showed that workers with a difference of 1 year in time of exposure to noise have a 5.3% (OR=1.053) higher risk of suffering hearing loss.

Millions of people across the world currently have noise induced hearing loss, and many are working in conditions with both continuous Gaussian and non-Gaussian noises that could affect their hearing. It was hypothesized that the energy of the noise was the cause of the hearing loss and did not depend on temporal pattern of a noise. This was referred to as the equal energy hypothesis. This hypothesis has been shown to have limitations though. This means that there is a difference in the types of noise a person receives to induce hearing loss and it is necessary to build a system that can easily mimic various conditions to conduct research. This study builds a system that can produce both non-Gaussian impulse/impact noises and continuous Gaussian noise. It was found that the peak sound pressure level of the system could reach well above the needed 120 dB level to represent acoustic trauma and could replicate well above the 85 dB A-weighted sound pressure level to produce conditions of gradual developing hearing loss. The system reached a maximum of 150 dB sound peak pressure level and a maximum of 133 dB A-weighted sound pressure level. Various parameters could easily be adjusted to control the sound, such as the high and low cutoff frequency to center the sound at 4 kHz. The system build can easily be adjusted to create numerous sound conditions and will hopefully be modified and improved in hopes of eventually being used for animal studies to lead to the creation of a method to treat or prevent noise induced hearing loss.