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.

Computer scientists are increasingly aware of the power of ubiquitous computing systems that can display information in and about the user's environment. One sub category of ubiquitous computing is persuasive ambient information systems that involve an informative display transitioning between the periphery and center of attention. The goal of this ambient technology is to produce a behavior change, implying that a display must be informative, unobtrusive, and persuasive. While a significant body of research exists on ambient technology, previous research has not fully explored the different measures to identify behavior change, evaluation techniques for linking design characteristics to visual effectiveness, nor the use of short-term goals to affect long-term behavior change. This study uses the unique context of noise-induced hearing loss (NIHL) among collegiate musicians to explore these issues through developing the MIHL Reduction Feedback System that collects real-time data, translates it into visuals for music classrooms, provides predictive outcomes for goalsetting persuasion, and provides statistical measures of behavior change.

Noise exposure is one of the most prevalent causes of irreversible occupational disease in Sweden and in many other countries. In hearing conservation programs, aimed at preventing noise-induced hearing loss, audiometry is an important instrument to highlight the risks and to assess the effectiveness of the program. A hazardous working environment and persons affected by it can be identified by monitoring the hearing thresholds of individual employees or groups of employees over time. However, in order to evaluate the prevalence of occupational noise-induced hearing loss, relevant reference data of unexposed subjects is needed. The first part of this dissertation concerns the changes in hearing thresholds over three decades in two occupational environments with high noise levels in the province of Östergötland, Sweden: the mechanical and the wood processing industries. The results show a positive trend, with improving median hearing thresholds from the 1970s into the 1990s. However, the hearing loss present also in the best period, during the 1990s, was probably greater than if the occupational noise exposure had not occurred. This study made clear the need for a valid reference data base, representing the statistical distribution of hearing threshold levels in a population not exposed to occupational noise but otherwise comparable to the group under study. In the second part of the dissertation, reference data for hearing threshold levels in women and men aged from 20 to 79 years are presented, based on measurements of 603 randomly selected individuals in Östergötland. A mathematical model is introduced, based on the hyperbolic tangent function, describing the hearing threshold levels as functions of age. The results show an age-related gender difference, with poorer hearing for men in age groups above 50 years. The prevalence of different degree of hearing loss and tinnitus is described for the same population in the third part of the dissertation. The overall prevalence of mild, moderate, severe or profound hearing loss was 20.9% collectively for women and 25.0% collectively for men. Tinnitus was reported by 8.9% of the women and 17.6% of the men. Approximately 2.4% of the subjects under study had been provided with hearing aids. However, about 7.7% were estimated to potentially benefit from hearing aids as estimated from their degree of hearing loss. Noise-induced hearing loss primarily causes damage to the outer hair cells of the inner ear. The fourth and last part of the dissertation evaluates the outer hair cell function, using otoacoustic emission measurements (OAE). Prevalence results from three different measuring techniques are presented: spontaneous otoacoustic emissions (SOAE), transient evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE). Gender and age effects on the recorded emission levels were also investigated. Women showed higher emission levels compared to men and for both women and men the emission levels decreased with increasing age. The results from the OAE recordings were shown to be somewhat affected by the state of the middle ear. The study included tympanometry, and the relation of the outcome ofthis test to the otoacoustic emissions is described, where high middle ear compliance resulted in low emission level. Reference data for the tympanometric measurements are also presented. The results of this project form an essential part of the important work against noiseinduced hearing loss, which needs continuous monitoring. The reference data presented here will provide a valid and reliable data base for the future assessment of hearing tests performed by occupational health centres in Sweden. This data base will in turn prove useful for comparison studies for Sweden as a responsible fellow EU member country setting high standards for work force safety. The statistical distribution of hearing threshold levels as a function of age for men and women in tabulated form is available on the Swedish Work Environment Authority (Arbetsmiljöverket) web site: http://www.av.se/publikationer/bocker/fysiskt/h293.shtm.

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.

Thesis (MAud)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: In developing countries, like Namibia, there is limited data pertaining to the number of individuals with hearing loss and its associated factors. This study aimed to determine the prevalence of potential hearing loss in Namibian Class A mines and to describe the extrinsic and intrinsic factors associated with hearing loss. A cross-sectional design was utilised and data were collected from 132 respondents (mining employees) from five different Class A mines throughout the country. A questionnaire and a retrospective review of respondents’ medical records were utilised to determine the risk factors. The most recent audiogram found in the respondents’ records was used to determine the presence of potential hearing loss. Three definitions of potential hearing loss were used in this study and included all major frequency hearing loss (AFHL), high frequency hearing loss (HFHL) and low frequency hearing loss (LFHL). Potential hearing loss was identified when the pure tone average (PTA) of 0.5, 1, 2, & 4kHz, 0.5, 1 & 2kHz and 4 & 8kHz respectively was greater than 25dBHL in either one or both ears. Chi-square measurements or, where necessary, Fisher’s exact tests, as well as Odds Ratios were used for the analysis of data. In general a significance level of 5% was applied for all analyses. Results indicated the prevalence of potential hearing loss in Namibian mining employees to be 27% and that both extrinsic and intrinsic factors were associated with hearing loss. The extrinsic factors significantly associated with potential hearing loss were both occupational and medical. The occupational factors found to be significant were the number of years employed in whole life >10 years (p=0.012; OR=3.1, 95% CI=1.3-7.9), the number of years employed in current job > 10 years (p=0.01; OR=3.9, 95% CI1.7-8.8) and the non-availability of formal training in prevention of hearing loss (p=0.022; OR=0.3, 95% CI (0.1-0.9). Diabetes was the sole significant extrinsic medical factor (p=0.035, OR=5, 95% CI 1.1-22.1). The only intrinsic factor which was found to be significantly associated with hearing loss was Age, specifically being older than 40 years (p=0.002; OR=3.5, 95% CI 1.6-7.8) and 50 years (p=0.001, OR=5.5, 95% CI1.9-15.8). A multiple logistic regression model of all significant factors found that only no formal training of prevention of hearing loss was found to be significant in the presence of all other factors (p=0.036, OR=0.036, 95% 0.1-0.92). Findings from this study suggest that multiple factors may be associated with potential hearing loss and not just the exposure to hazardous occupational conditions. Recommendations for future research and clinical practice should, therefore, include thorough investigations into the aetiology of hearing loss. As this study focused on Class A mines, it is recommended that future research be conducted in other mines that are not categorised as Class A mines. Keywords: prevalence, extrinsic factors, intrinsic factors, extrinsic occupational factors, extrinsic social factors, extrinsic medical factors, potential hearing loss, mining industry, Class A mine, Namibia. / AFRIKAANSE OPSOMMING: In ontwikkelende lande, soos Namibië, is daar beperkte data met betrekking tot die aantal individue met gehoorverlies en sy verwante faktore. Hierdie studie het gepoog om die voorkoms van gehoorverlies in Namibiese Klas A myne te bepaal en die ekstrinsieke en intrinsieke faktore wat verband hou met potensiale gehoorverlies te beskryf. 'n Deursnee-ontwerp is gebruik en data is ingesamel uit 132 respondente (mynbou werknemers), uit vyf verskillende Klas A myne regdeur die land. 'n Vraelys en 'n retrospektiewe oorsig van die respondente se mediese rekords is gebruik om die risiko faktore te bepaal. Die mees onlangse oudiogram wat in die respondente se rekords gevind is, is gebruik om die teenwoordigheid van potensiale gehoorverlies te bepaal. Drie definisies van potensiale gehoorverlies is gebruik in hierdie studie, ingesluit al die groot frekwensie gehoorverliese (AFHL), hoë frekwensie gehoorverlies (HFHL) en 'n lae frekwensie gehoorverlies (LFHL). ‘n Gehoorverlies was teenwoordig wanneer die suiwer toon gemiddelde (PTA van 0.5 , 1 , 2, & 4kHz , 0.5, 1 & 2kHz en 4 & 8kHz onderskeidelik , groter was as 25dBHL in een of albei ore. Chi -square metings of, waar nodig, Fisher se presiese toetse, asook kans verhoudings is gebruik vir die ontleding van data. In die algemeen is 'n beduidendeidsvlak van 5% gebruik en toegepas vir al die ontledings. Resultate het aangedui die voorkoms van gehoorverlies in Namibiese mynbouwerknemers tot 27 % was en dat beide ekstrinsieke en intrinsieke faktore ‘n verband toon met potensiaal gehoorverlies. Die ekstrinsieke faktore wat ‘n beduidende verband getoon het met gehoorverlies was albei beroeps- en mediese faktore. Die beroepsfaktore wat betekenisvol was, was die aantal jare diens in hele lewe > 10 jaar ( p = 0,012 ; OR = 3.1 , 95 % CI = 1.3-7.9) , die aantal jare in huidige pos> 10 jaar diens (p = 0,01 ; OF = 3.9 , 95 % CI1.7-8.8 ) en die onbeskikbaarheid van formele opleiding in die voorkoming van potensiaal gehoorverlies (p = 0,022 ; OF = 0,3 , 95 % CI ( 0,1-0,9 ). Diabetes was die enigste beduidende ekstrinsieke mediese faktor (p = 0,035 , OR = 5 , 95 % CI 1,1-22,1 ). Die enigste intrinsieke faktor watbeduidend was en verband hou met gehoorverlies was ouderdom, spesifiek om ouer as 40 jaar ( p = 0,002 ; OF = 3.5 , 95 % CI 1,6-7,8 ) en 50 jaar ( p = 0.001 , OR = 5.5 , 95 % CI1.9-15.8 ) te wees. 'n Veelvuldige regressie model van alle beduidende faktore het bevind dat slegs geen formele opleiding in die voorkoming van gerhoor verlies beduidende was in die teenwoordigheid van al die ander faktore ( p = 0,036 , OR = 0,036 , 95 % 0,1-0,92 ) . Bevindinge van hierdie studie dui daarop dat verskeie faktore geassosieer kan word met gehoorverlies en nie net die blootstelling aan gevaarlike beroepstoestande nie. Aanbevelings vir toekomstige navorsing en kliniese praktyk moet dus 'n grondige ondersoek na die etiologie van gehoorverlies uitvoer. Aangesien hierdie studie gefokus het op die Klas A- myne , word dit aanbeveel dat toekomstige navorsing gedoen word in ander myne wat nie gekategoriseer is as Klas A myne nie. Sleutelwoorde: Voorkoms, ekstrinsieke faktore, instrinsieke faktore, ekstrinsieke beroepsfaktore, ekstrinsieke sosiale faktore, ekstrinsieke mediese faktore, potensiale gehoorverlies, Klas A myn, Namibië.

published_or_final_version / Speech and Hearing Sciences / Master / Master of Science in Audiology

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.

The need for hearing protection in industry has evolved from the growing awareness of the detrimental effects of noise on hearing and recent legislation enacted to protect the hearing of noise-exposed employees through the use of hearing conservation programs. In lieu of expensive or impractical engineering and administrative controls, personal hearing protection devices (HPDs) are considered to be the most practical and effective means of protecting employees from the damaging effects of noise in industry today.