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.

Made available in DSpace on 2015-05-14T12:47:12Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2059659 bytes, checksum: f3d773c696e3797e353a21eae5946320 (MD5) Previous issue date: 2012-03-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / INTRODUCTION: NIHL (Noise Induced Hearing Loss) is a condition that results from the accumulation of prolonged exposure to noise, causing a slow and progressive hearing impairment, sensorneural, not very deep, but irreversible. The dentist, individuals exposed to noise in their workplace, is susceptible to NIHL. OBJECTIVE: To analyze the auditory and possible risk factors that interfere with the hearing of the dentists from USFs (Unidades de Saúde da Família / Familiar Health Unities) in Joao Pessoa / PB. METHODOLOGY: There were interviews, audiological evaluations, instrumental and environmental noises within 65 dentists from Family Health Units in Joao Pessoa / PB to identify auditory characteristics and risk factors for hearing-surgeons dentists by using proportion measures calculation for categorical variables, and having the Statistical Logistic Regression Method. RESULTS: It was observed that 43.07% of the dentists who were evaluated had lower hearing in, at least, some of the characteristic frequencies of NIHL. It was found that the main ear symptoms cited by these professionals were to have the sensation of hearing loss (55%), and buzzer (50%), and also that the instruments which showed values above the allowed limits were turbine high rotation (61%) and the compressor (55%). The variables considered as risk factors for hearing loss based on logistic regression were: age over 45 years old, working time more than 10 years, a feeling of hearing loss, tinnitus and noise level of the compressor greater than 85 dB. CONCLUSION: The ear symptoms (tinnitus and hearing loss) are presented in a large number of dentists, and the noise emitted by the instruments used by these professionals is often high, presenting some risk factors for Noise Induced Hearing Loss and some of them may be prevented or controlled through specific strategies. / INTRODUÇÃO: A Perda Auditiva Induzida por Ruído (PAIR) é uma patologia decorrente do acúmulo de exposições a ruído prolongadas, gerando uma deterioração auditiva progressiva e lenta, sensorioneural, geralmente não muito profunda mas irreversível. Sabe-se que o cirurgião-dentista, indivíduo exposto ao ruído no ambiente de trabalho, é susceptível à PAIR. OBJETIVO: Analisar o perfil auditivo e possíveis fatores de risco que interferem na audição dos cirurgiões-dentistas das USFs (Unidades de Saúde da Família) de João Pessoa/PB. METODOLOGIA: Realizaram-se entrevistas, avaliações audiológicas e dos ruídos instrumental e ambiental com 65 cirurgiões-dentistas das Unidades de Saúde da Família de João Pessoa /PB, a fim de identificar características do perfil auditivo e de fatores de risco para a audição dos cirurgiões-dentistas, utilizando o cálculo de medidas de proporção para as variáveis categóricas, e tendo como método estatístico a Regressão Logística. RESULTADOS: Observou-se que 43,07% dos cirurgiões-dentistas avaliados apresentaram rebaixamento auditivo em pelo menos alguma das frequências características da PAIR. Verificou-se ainda que os principais sintomas otológicos citados por estes profissionais foram a sensação de déficit auditivo (55%), e o zumbido (50%). Os instrumentos que mais se apresentaram com valores de intensidade acima dos limites permitidos foram a turbina de alta rotação (61%) e o compressor (55%). As variáveis consideradas como fatores de risco para a perda auditiva com base na Regressão Logística foram: idade acima de 45 anos, tempo de trabalho maior que 10 anos e nível de ruído do compressor maior que 85 dB, além da presença dos sintomas de sensação de déficit auditivo e zumbido. CONCLUSÃO: A sintomatologia otológica (zumbido e diminuição auditiva) está presente em grande número dos cirurgiões-dentistas e o ruído emitido pelos instrumentos utilizados por estes profissionais é muitas vezes elevado. Constataram-se alguns fatores de risco para a Perda Auditiva Induzida por Ruído, podendo alguns destes ser prevenidos ou controlados por meio de estratégias específicas.

Millions of people across the world are suffering from noise induced hearing loss (NIHL), especially under working conditions of either continuous Gaussian or non-Gaussian noise that might affect human's hearing function. Impulse noise is a typical non-Gaussian noise exposure in military and industry, and generates severe hearing loss problem. This study mainly focuses on characterization of impulse noise using digital signal analysis method and prediction of the auditory hazard of impulse noise induced hearing loss by the Auditory Hazard Assessment Algorithm for Humans (AHAAH) modeling. A digital noise exposure system has been developed to produce impulse noises with peak sound pressure level (SPL) up to 160 dB. The characterization of impulse noise generated by the system has been investigated and analyzed in both time and frequency domains. Furthermore, the effects of key parameters of impulse noise on auditory risk unit (ARU) are investigated using both simulated and experimental measured impulse noise signals in the AHAAH model. The results showed that the ARUs increased monotonically with the peak pressure (both P+ and P-) increasing. With increasing of the time duration, the ARUs increased first and then decreased, and the peak of ARUs appeared at about t = 0.2 ms (for both t+ and t-). In addition, the auditory hazard of experimental measured impulse noises signals demonstrated a monotonically increasing relationship between ARUs and system voltages.

Occupational hearing loss resulting from noise exposures encountered in the workplace affects millions of workers and costs hundreds of millions of dollars annually in Workers’ Compensation costs in the United States alone. Some industries have been well studied, and the presence of hazardous noise in the work environment established and documented. The restaurant industry is one in which little current data exists, but in which there may be cause for concern. This work sought to quantify noise exposures for cooks, servers, and dishwashers and to determine whether or not any of these workers are at risk for Noise Induced Hearing Loss. Further, the researchers wanted to know what environmental factors present in the restaurants had the greatest impact on noise exposures for each exposure group. Statistical analysis was conducted on selected factors, and while nearly all were found to have significant effects on noise exposure for servers, only the number of minutes worked explained variance in exposures for cooks and dishwashers when all factors were included in analysis. These two groups are the ones most likely to be overexposed and they typically worked more than 480 minutes on the day the sample was collected. Efforts to control exposure must take these extended shifts into careful account. The study was limited by relatively small sample size, with 124 cooks, 119 servers, and 91 dishwashers employed at nine different restaurants participating. Future efforts to explain and characterize the sources of variation in noise exposure for these three groups should include greater numbers of participants and structure the data in a way that allows the effects of selected factors to be more clearly seen.

Abstract This research on military aviation noise was conducted because the personnel working with military aircraft were concerned about noise induced hearing damage. In addition, comprehensive data on hearing impairments and occupational exposure of military pilots in the Finnish Air Force was not available. Moreover, data on the effects of overflight noise of military jets was necessary for the evaluation of noise induced hearing deteriorations of members of the public who might be exposured accidentally for the low-level jets' overflights. The averaged noise exposure levels of pilots varied during a flight from 97 dB(A) to 106 dB(A) in the cockpit and from 83 dB(A) to 100 dB(A) at the entrance of the ear canal. Radio noise was 4–10 dB higher than background noise inside the helmet. The attenuation provided by air crew helmets varied from10 to 21 dB(A) in the laboratory, and was at the same level during real flights. The attenuation measured in the laboratory and in working conditions was about 30 dB(A) for earmuffs. An active noise cancellation (ANC) device decreased averaged noise exposure (LAeq8min) 4–8 dB over the noise attenuation of the same helmets when the ANC system was off. The noise of overflights by military jets were measured and the noise levels were lower than those known to cause the permanent threshold shifts. However, noise induced hearing damages might be possible in certain conditions. In order to assess the hearing loss risk of pilots, hearing thresholds were measured before and after one flight using both conventional and extended high frequency (EHF) audiometry. Minor temporary threshold shifts (TTS) were revealed. The risk of noise-induced damage at the studied exposure levels is, in all probability, rather small. A novel NoiseScan data management system proved to be an interesting tool in assessment of the risk of developing hearing impairment on the basis of known risk factors. Due to the small number of risk factors, the hearing of pilots was shown to be at considerably less risk than that of industrial workers in Finland.

Despite the preventability of noise-induced hearing loss (NIHL) a high prevalence is still reported in South African mines. The study aimed to describe the hearing of gold miners pertaining to the prevalence and degree of NIHL and effectiveness of current RSA impairment criteria to identify NIHL. The audiological data, collected between 2001 and 2008, of 57 714 mine workers were investigated in this retrospective cohort study. Data was accessed through the mine’s electronic database and exported to Microsoft Excel 2007 worksheets. Participants were categorised in terms of noise exposure (level and working years), age, race and gender. Noise exposure levels were described in terms of a specific occupation and categorized into four groups based on dosimeter data received from the mine’s noise hygienist, namely: 1) Below surface (underground) noise exposure, ≥85 dB A, classified according to the South African regulations on the daily permissible dose of noise exposure8, named Noise Group 1; 2) Surface noise exposure, ≥85 dB A, named Noise Group 2; 3) No known occupational noise exposure, named control group; and 4) Uncertain levels of noise exposure, e.g. students and trainees, named Noise Group 4. The control group was matched with participants of noise group 1 and 2 based on gender, race and age at the most recent audiogram test. Descriptive and inferential statistics were employed. Measures of central tendency and variability were used with analysis of covariance (ANCOVA) and pairwise comparisons according to Fisher’s Least Squares Differences Approach (F test). Results indicated that noise exposed groups had significantly higher prevalence of high and low frequency hearing loss than the control group. High-frequency hearing loss was also present in the control group. The greatest differences in prevalence of hearing loss were observed at 3, 4 kHz and age group 36 to 45 years. Thresholds at 8 kHz were worse than expected and decline slowed down with age. High-frequency thresholds showed a non-linear growth pattern with age with a greater decline at 2 kHz with age in the noise-exposed population compared to the control group. Hearing deteriorated more across age groups with more noise-exposed years, and this deterioration was most visible after 10 to 15 working years and at 3 kHz. Females had better hearing than males across the frequency spectrum. Black males had significantly better high-frequency hearing than white males but significantly worse low-frequency hearing than white male counterparts. PLH values showed poor correlation (through statistical analyses) with other well-accepted hearing impairment criteria. To date this was the largest study conducted on the hearing of gold miners and the sample included a very large number of black males exposed to occupational noise (N=17 933). Values supplied in distribution table format are therefore unique and contribute greatly to the knowledge base. / Thesis (PhD)--University of Pretoria, 2012. / Speech-Language Pathology and Audiology / unrestricted

<p>  </p> <p>Noise-induced hearing loss (NIHL) is a significant occupational health concern in the construction industry, necessitating effective hearing protection for workers. This project explores the detrimental consequences of environmental pollutants, specifically noise pollution common in construction settings. The research incorporates user interviews with construction workers and managers to identify challenges and motivations surrounding the use of hearing protection devices.</p> <p>My findings underscore the necessity of addressing pollution in the construction industry to safeguard the well-being of workers. Noise pollution emerges as a primary concern, leading to hearing loss, stress, decreased productivity, and safety hazards. The research revealed that workers grapple with obstacles, including discomfort, lack of awareness, and cost barriers, while also recognizing driving forces, including fear of hearing loss and the encouragement of supervisors. The design process involved thorough research, including a literature review, competitive analysis, and semi-structured user interviews, resulting in an advanced hearing protection device that prioritizes effective communication, cleanliness, and user comfort. The final product incorporates innovative features such as lighting indicators, a compact charging case, strategically positioned buttons, secure fit with magnets, and a range of color options. Furthermore, the accompanying application features customizable ambient sounds, performance feedback, and gamification elements.</p>

No description available.

No description available.