Management of occupational noise induced hearing loss in the mining sector in South Africa: Where are the audiologists?

Development of an artificial intelligence based occupational noise induced hearing loss early warning system for mine workers

Introduction

Occupational Noise Induced Hearing Loss (ONIHL) is one of the most prevalent conditions among mine workers globally. This reality is due to mine workers being exposed to noise produced by heavy machinery, rock drilling, blasting, and so on. This condition can be compounded by the fact that mine workers often work in confined workspaces for extended periods of time, where little to no attenuation of noise occurs. The objective of this research work is to present a preliminary study of the development of a hearing loss, early monitoring system for mine workers.

Methodology

The system consists of a smart watch and smart hearing muff equipped with sound sensors which collect noise intensity levels and the frequency of exposure. The collected information is transferred to a database where machine learning algorithms namely the logistic regression, support vector machines, decision tree and Random Forest Classifier are used to classify and cluster it into levels of priority. Feedback is then sent from the database to a mine worker smart watch based on priority level. In cases where the priority level is extreme, indicating high levels of noise, the smart watch vibrates to alert the miner. The developed system was tested in a mock mine environment consisting of a 67 metres tunnel located in the basement of a building whose roof top represents the "surface" of a mine. The mock-mine shape, size of the tunnel, steel-support infrastructure, and ventilation system are analogous to deep hard-rock mine. The wireless channel propagation of the mock-mine is statistically characterized in 2.4-2.5 GHz frequency band. Actual underground mine material was used to build the mock mine to ensure it mimics a real mine as close as possible. The system was tested by 50 participants both male and female ranging from ages of 18 to 60 years.

Results and discussion

Preliminary results of the system show decision tree had the highest accuracy compared to the other algorithms used. It has an average testing accuracy of 91.25% and average training accuracy of 99.79%. The system also showed a good response level in terms of detection of noise input levels of exposure, transmission of the information to the data base and communication of recommendations to the miner. The developed system is still undergoing further refinements and testing prior to being tested in an actual mine.

Evaluation of Lung Functions, Blood Pressure, and Hearing Deterioration in Tile Setters

INTRODUCTION

Tile setters in construction industries are exposed to a potent risk of silicosis as they are constantly exposed to crystalline silica dust during concrete finishing, cutting and fixing of the ceramic tiles. The noise produced by instruments used in tile settings may lead to noise-induced hearing loss. Noise above the permissible limit of 85 dB may lead to autonomic changes and alteration in blood pressure. These facts gave us an impetus to evaluate the pulmonary functions, blood pressure and hearing deterioration in tile setters and correlate these parameters for their present functional status with duration of exposure to tile cutting profession.

METHODS

The pulmonary functions were evaluated with spirometer, autonomic status by recording the blood pressure and hearing loss by calculating the Hearing Deterioration Index (HDI) for hearing loss.

RESULTS

There was significant decline in forced vital capacity (FVC), forced expiratory volume 1 sec (FEV1) and forced expiratory volume 1% (FEV1%) in tile setters. The decline in FVC, FEV1 and FEV1% was significantly higher in subjects with exposure of more than five years. There was increased systolic and diastolic blood pressure in those having more than five years of exposure in the tile setting profession as compared to less than five years. There was a positive correlation between years of service in the tile setting profession as well as sound exposure level with HDI and blood pressure in our subjects.

CONCLUSION

Prolonged exposure to the tile setting profession may lead to compromised lung function, hypertension and hearing deterioration in tile setters.

Barriers to access to ear and hearing care services in low- and middle- income countries: A scoping review

People living in low- and middle- income countries (LMICs) meet significant challenges in accessing ear and hearing care (EHC) services. We conducted a scoping review to identify and summarise such barriers, to recognise gaps in the literature, and to identify potential solutions. Reviewers independently screened titles, abstracts and full-text articles and charted data. We undertook thematic analysis of supply and demand side dimensions of access, and summarised findings mapped against the Levesque framework. Of 3048 articles screened, 62 met inclusion criteria for review. Across the five access dimensions, supply-side constraints were more frequently described, the most common being a shortage of EHC workforce or appropriate facilities, despite high demand. We identified a thin geographical spread of literature on barriers to accessing EHC services in LMICs, reflecting low availability of such services. LMICs face a diverse range of demand and supply side challenges including workforce, equipment and resource shortages, and challenges for the majority of the population to pay for such services. There is a need for many LMICs to develop health policy and programmes in EHC, including integration into primary care, scaling up the EHC workforce through increased training and education, and improving EHC literacy through public health measures.

Workplace noise exposure and the prevalence and 10-year incidence of age-related hearing loss

There is paucity of population-based data on occupational noise exposure and risk of age-related hearing loss. Therefore, we assessed cross-sectional and longitudinal associations of past workplace noise exposure with hearing loss in older adults. At baseline, 1923 participants aged 50+ years with audiological and occupational noise exposure data included for analysis. The pure-tone average of frequencies 0.5, 1.0, 2.0 and 4.0 kHz (PTA_0.5-4KHz) >25 dB HL in the better ear, established the presence of hearing loss. Participants reported exposure to workplace noise, and the severity and duration of this exposure. Prior occupational noise exposure was associated with a 2-fold increased odds of moderate-to-severe hearing loss: multivariable-adjusted OR 2.35 (95% CI 1.45–3.79). Exposure to workplace noise for >10 years increased the odds of having any hearing loss (OR 2.39, 95% CI 1.37–4.19) and moderate-to-severe hearing loss (OR 6.80, 95% CI 2.97–15.60). Among participants reporting past workplace noise exposure at baseline the 10-year incidence of hearing loss was 35.5% versus 29.1% in those who had no workplace noise exposure. Workplace noise exposure was associated with a greater risk of incident hearing loss during the 10-year follow-up: multivariable-adjusted OR 1.39 (95% CI 1.13–1.71). Prior occupational noise exposure was not associated with hearing loss progression. Workplace noise exposure increased the risk of incident hearing loss in older adults. Our findings underscore the importance of preventive measures which diminish noise exposure in the workplace, which could potentially contribute towards reducing the burden of hearing loss in later life.

Noise Exposure and Hearing Loss among Brewery Workers in Lagos, Nigeria

The health risks of exposure to loud noises are a well-established fact and are widely addressed in modern industries. Yet, in less developed countries, it is thought these hazards receive less attention, both in the workplace and in private life. (1) Background: The aim of this study is to assess the occupational noise exposure in a developing country and identify possible risk groups for whom intervention is needed. (2) Methods: A cross-sectional study was performed among brewery employees in Lagos, Nigeria. Pure-tone audiometry (PTA) was performed, paired with a self-report questionnaire. Personal noise dosimetry (PND) was also performed with an additional group of participants. (3) Results: A total of 458 employees were submitted to PTA. The Packaging and Utilities department reported the largest shifts in hearing thresholds (18 dB [sd = 15] and 16 dB [sd = 15] @4kHz, respectively). No significant effect of department type on auditory health could be found. PND results were obtained from 39 employees. Packaging and Sales were identified as the most exposed departments. (4) Conclusions: A healthy hearing profile was found for a large proportion of the brewery employees (91.7%). However, NIHL (noise-induced hearing loss) proportions specifically among Bottling and Sales employees were elevated.

Engineering noise control for mines: Lessons from the world

OBJECTIVE

The main objective of this article was to present some of the engineering noise control methods that are currently being used across the world in the mining industry, while at the same time interrogating noise control measures that could be applied to effectively reduce noise emissions from the equipment utilised within South African mines.

BACKGROUND

A brief summary of the hearing conservation programmes used in South Africa is presented. Summarised research on the use of engineering noise control in South Africa is also presented, with an overview of the various engineering noise control methods applied across the world in dealing with occupational noise.

METHOD

For illustrative purposes, case studies were used to show how engineering noise controls could be used to reduce the noise levels and risks within this context.

RESULTS

Some of the case studies used have cited a reduction in the noise intensity emitted by machinery from a range of 93 dBA - 104 dBA to a range of 90 dBA - 94 dBA, demonstrating quite a significant reduction in the noise emission of the equipment. This article further provides recommendations on how South African mines could contextualise these methods.

CONCLUSION

One of the key recommendations is encouraging the South African mining industry towards the documenting and publishing of those engineering noise control methodologies that have proven to be effective for shared best practice. A need was identified for extensive research to be conducted and documented evidence to be made available to assist the South African mining industry with locating and assessing current engineering controls available in South Africa. Machines and processes that require noise control should be identified and, lastly, the current barriers to the use of engineering noise control methodologies should be identified, with the main goals of finding ways to overcome the noise challenges in the mines.

Occupational noise induced hearing loss in the mining sector in South Africa: Perspectives from occupational health practitioners on how mineworkers are trained

Background

Historically, occupational health concerns associated with mining, particularly occupational noise-induced hearing loss (ONIHL), were ignored by the mining sector, policy-makers and academic researchers. As such, there is a dearth of literature related to ONIHL, especially in low- and middle-income countries such as South Africa. Consequently, mineworkers were not aware of the latent effects of excessive exposure to hazardous noise and the resultant hearing loss thereof.

Objectives

The aim of this study was to explore the perspectives of occupational health practitioners (OHPs) regarding education and training of mineworkers on occupational noise-induced hearing loss (ONIHL) and its impact on mineworkers’ health.

Method

Qualitative, in-depth telephonic and face-to-face interviews were conducted with 16 OHPs. Purposive and snowball sampling methods were utilised to recruit participants. Data were analysed using inductive thematic analysis.

Results

Three themes emerged from the data: ‘seeing is believing’, ‘not my department!’ and ‘barriers and facilitators to raising awareness’ with two subthemes: ‘blame it on the language and level of education’ and ‘compensation pay-outs’. Superficially, OHPs believe that mineworkers are aware of the impact of noise on health; however, the OHPs are not aware on how the mineworkers are educated on ONIHL and its latent consequences. Furthermore, language, low levels of education and literacy, as well as financial constraints, are the factors found to affect education and training of the mineworkers about the risks of ONIHL.

Conclusion

If the mining industry is committed in eliminating ONIHL, they should prioritise health literacy, and mines need to have an effective awareness-raising plan in place to eliminate ONIHL from every mine. This plan must consider diversity of workforce, including linguistic, as well as educational level diversity.

Middle ear pathologies in adults within the mining industry: A systematic review

BACKGROUND

Literature suggests that risk factors for middle ear pathologies, such as traumatic injuries and human immunodeficiency virus (HIV), exist in mines. However, studies on hearing health in mines seem to focus primarily on occupational noise-induced hearing loss and ignore middle ear pathologies. As a result, there is little documented evidence on the trends of middle ear pathologies in mine workers.

OBJECTIVES

The aim of this study was to explore and document published evidence reflecting trends in middle ear pathologies in mine workers.

METHOD

A systematic literature review of studies that reported middle ear pathologies in mine workers was conducted. Medline, CINAHL, PubMed, PsychInfo and Google Scholar databases were searched for studies in English published between January 1994 and December 2018 and reporting on trends in middle ear pathologies in mine workers.

RESULTS

Two research studies met the selection criteria and were included for analysis. One research study used tympanometry with 226 Hz probe tone, while another study used interviews to determine the presence of middle ear pathologies. While these studies indicate that middle ear pathologies exist in individuals working in mines, the evidence is limited.

CONCLUSION

While current data indicate that individuals working in mines may present with middle ear pathologies of varying severities, the evidence is too small to provide a clear trend of middle ear pathologies in individuals working in mines. Therefore, the current limited data suggest a need for further studies to examine middle ear pathologies in individuals working in mines.

Estimating miners at risk for occupational noise-induced hearing loss: A review of data from a South African platinum mine

Background

Occupational noise-induced hearing loss (ONIHL) is a complex, but preventable, health problem for South African miners. Meticulously collected data should be made use of to design interventions to address this health issue.

Objectives

A single mine’s electronic data were reviewed in a secondary data review to determine, from the records, factors that hearing conservation practitioners deemed useful for identifying ‘at risk’ miners and to establish factors that would pave the way for the integration of the 2014 hearing conservation programme (HCP) milestones into the mine’s current proactive data management system (PDMS). The objectives of this article were to establish how miners with published risk factors associated with ONIHL were managed by the mine’s hearing conservation practitioners as part of the HCP; to determine if the mine’s hearing conservation practitioners could estimate miners’ risk of ONIHL using baseline percentage loss of hearing (PLH) as a hearing conservation measure; and to estimate the contribution of noise exposure to ONIHL risk.

Method

In a secondary data review design, records in a platinum mine’s two electronic data sets were reviewed: the first contained diagnostic audiometry records (N = 1938) and the second comprised a subset of miners diagnosed with ONIHL (n = 73). Data were available for the period 2014–2017 and included demographic, occupational, audiometry and ONIHL diagnosis data. Miners’ risk factors associated with ONIHL were identified using the functional risk management structure. A logistic regression model was used for the baseline PLH margins of 0% – 40% (in 5% increments) to estimate the adjusted predictions for miners at risk of developing ONIHL. The contribution of noise exposure as a risk for ONIHL was estimated using a two-way sample proportion test.

Results

The mean age of the miners (all male candidates) was 47 ± 8.5 years; more than 80% had worked for longer than 10 years. Valid baseline audiometry records were available for only 34% (n = 669) of the miners. Miners with a 0% baseline PLH had a 20% predicted risk of ONIHL, and a 45% predicted risk if they had a 40% baseline PLH – these employees were referred. The noise exposure risk rankings revealed that 64.9% (n = 1250) of the miners were exposed to 91 dBA – 105 dBA noise exposure levels and that 59 (80.8%) diagnosed with ONIHL were exposed to noise levels of up to 104 dBA.

Conclusion

These findings indicate significant gaps in the mine’s PDMS, requiring attention. Nonetheless, the mine’s current data capturing may be used to identify miners at risk of developing ONIHL. The PLH referral cut-off point (≥2.5%) used by the mine’s hearing conservation practitioners, when used in conjunction with baseline PLH shifts, was the major factor in early identification of ONIHL in miners exposed to ≥85 dBA noise. An inclusive integrative data management programme that includes the medical surveillance data set of the miners’ noise exposure levels, occupations, ages and medical treatments for tuberculosis and human immunodeficiency syndrome is recommended, as these are important risk indicators for developing ONIHL, particularly within the South African context.

A critical analysis of the current South African occupational health law and hearing loss

BACKGROUND

Occupational health laws must recognise the constitutional requirement of substantive equality, and its role in 'the progressive realisation' of the rights provided by Section 27.

OBJECTIVES

Our main aim is to review current South African occupational health law (vis-à-vis workers' constitutional rights) in relation to hearing loss. We focus on gaps in the law regarding occupational hearing loss in South Africa.

METHOD

Our review of legal texts relies on experience as a methodological device augmented by the use of a critical science. Guided by literature or evidence synthesis methodologies, South African primary and secondary laws were reviewed along with unpublished (non-peer-reviewed) grey literature. An established six-step framework guided our thematic analysis. A semantic approach aided the critical interpretation of data using the Bill of Rights as a core analytical framework.

RESULTS

Four themes are discussed: (1) separate and unequal regulatory frameworks; (2) monologic foregrounding of noise; (3) minimisation of vestibular disorders; and (4) dilution of ototoxic agents. The highly divided legal framework of occupational health and safety in South Africa perpetuates a monologic 'excessive noise-hearing loss' paradigm that has implications for the rights of all workers to equal protections and benefits. There is a need to harmonise occupational health and safety law, and expand the scope of hearing-protection legislation to include the full range of established ototoxic hazards.

CONCLUSION

Occupational audiology is dominated by efforts to address noise-induced hearing loss. A 'noise' despite the reality of workers' exposures to a range of ototoxic stressors that act synergistically on the ear, resulting in audio-vestibular disorders.

Occupational noise and age: A longitudinal study of hearing sensitivity as a function of noise exposure and age in South African gold mine workers

BACKGROUND

A relationship exists between occupational noise exposure and age, which remains poorly understood.

OBJECTIVES

The aim of this study was to establish the relationship between hearing loss and age over time.

METHOD

Audiological data from 2583 mine workers in South Africa were utilised. Data were received from a non-noise exposed group (NNEG) (n = 951) and a noise exposed group (NEG) (≥85 dBA) (n = 1632). Data comprised a low-frequency average (LFA512) (average of audiological thresholds for 0.5 kHz, 1 kHz and 2 kHz) and high-frequency average (HFA346) (average of audiological thresholds for 3 kHz, 4 kHz and 6 kHz). Data were compared by using mixed-effects regression analysis.

RESULTS

Base threshold values were higher for the NEG than for the NNEG across frequencies. All year-to-year increases in mean hearing thresholds were statistically significant (p 0.01). When correcting for age, increases in mean hearing thresholds were higher for the NEG than for the NNEG for HFA346 (3.5 dB vs. 2.9 dB decline over a 4-year period) but similar for LFA512 (0.6 dB vs. 0.7 dB decline). Uncorrected for age, increases in mean hearing thresholds were higher than when age was corrected for.

CONCLUSION

Age and occupational noise exposure influence hearing thresholds over time. The continued increase in hearing thresholds of the NEG above that of the NNEG can be related to ineffective noise management programmes and/or the fact that early noise exposure leads to a higher burden of hearing loss over time - even after noise exposure had stopped.

South African hearing conservation programmes in the context of tele-audiology: A scoping review

BACKGROUND

The limited involvement of audiologists in occupational noise-induced hearing loss (ONIHL) management through hearing conservation programmes (HCPs) is a global issue. In low- and middle-income (LAMI) countries such as South Africa, this is also exacerbated by demand versus capacity challenges. Tele-audiology is an option requiring serious deliberation by the audiology community within HCPs in LAMI contexts.

OBJECTIVES

This scoping review explores if tele-audiology has a potential value in HCPs and reviews what has been documented in the literature on the use of tele-audiology in HCPs.

METHOD

A scoping review was conducted using the Arksey and O'Malley's framework. A search was conducted in five electronic bibliographic databases including Science Direct, PubMed, Scopus Medline, ProQuest and Google Scholar and the grey literature to identify publications presenting considerations around tele-audiology in the implementation of HCPs.

RESULTS

Findings revealed significant dearth of evidence specific to the use or application of tele-audiology in ONIHL and/or HCPs both within the African context and internationally, despite the purported potential benefit of this service delivery model, particularly in resource-constrained contexts such as LAMI countries. Of the publications deemed potentially relevant to this scoping review, none were found that specifically investigated or addressed the use of tele-audiology in ONIHL or HCPs as their main objective. Nuanced analysis of publications revealed that in the last decade, indication for potential growth in the use of tele-audiology within occupational audiology is indicated.

CONCLUSION

Because of the significant demand versus capacity challenges in LAMI countries, and because of the need for scaling up audiology professionals' management of HCPs, careful consideration of teleaudiology as a platform to deliver services in these contexts is required.

Risk versus benefit: Should not audiologists assess this in the context of occupational noise-induced hearing loss in the mining industry?

BACKGROUND

Hearing conservation programmes (HCPs) are an important aspect of occupational health efforts to prevent occupational noise-induced hearing loss (ONIHL). In low- and middle income (LAMI) countries, where the incidence of ONIHL is significant, it is important to deliberate on the risk or benefit of HCPs.

OBJECTIVES

This article is an attempt at highlighting important strategic indicators as well as important variables that the occupational health and audiology community need to consider to plan efficacious HCPs within the South African mining context.

METHOD

The current arguments are presented in the form of a viewpoint publication.

RESULTS

Occupational audiology vigilance in the form of engagement with HCPs in the mining industry has been limited within the South African research and clinical communities. When occupational audiology occurs, it is conducted by mid-level workers and paraprofessionals; and it is non-systematic, non-comprehensive and non-strategic. This is compounded by the current, unclear externally enforced accountability by several bodies, including the mining industry regulating body, with silent and/or peripheral regulation by the Health Professions Council of South Africa and the Department of Health. The lack of involvement of audiologists in the risk or benefit evaluation of HCPs during their development and monitoring process, as well as their limited involvement in the development of policies and regulations concerning ear health and safety within this population are probable reasons for this.

CONCLUSIONS

Increased functioning of the regulatory body towards making the employers accountable for the elimination of ONIHL, and a more central and prominent role for audiologists in HCPs, are strongly argued for.