Audiological Tests Used in the Evaluation of the Effects of Solvents on the Human Auditory System: A Mixed Methods Review.

This study aimed to scope the literature, identify knowledge gaps, appraise results, and synthesize the evidence on the audiological evaluation of workers exposed to solvents. We searched Medline, PubMed, Embase, CINAHL, and NIOSHTIC-2 up to March 22, 2021. Using Covidence, two authors independently assessed study eligibility, risk of bias, and extracted data. National Institute of Health Quality Assessment Tools was used in the quality evaluation of included studies; the Downs and Black checklist was used to assess the risk of bias. Of 454 located references, 37 were included. Twenty-five tests were studied: two tests to measure hearing thresholds, one test to measure word recognition in quiet, six electroacoustic procedures, four electrophysiological tests, and twelve behavioral tests to assess auditory processing skills. Two studies used the Amsterdam Inventory for Auditory Disability and Handicap. The quality of individual studies was mostly considered moderate, but the overall quality of evidence was considered low. The discrepancies between studies and differences in the methodologies/outcomes prevent recommending a specific test battery to assess the auditory effects of occupational solvents. Decisions on audiological tests for patients with a history of solvent exposures require the integration of the most current research evidence with clinical expertise and stakeholder perspectives.

Temporary and Permanent Auditory Effects Associated with Occupational Coexposure to Low Levels of Noise and Solvents.

This study aimed to assess temporary and permanent auditory effects associated with occupational coexposure to low levels of noise and solvents. Cross-sectional study with 25 printing industry workers simultaneously exposed to low noise (<80 dBA TWA) and low levels of solvents. The control group consisted of 29 industry workers without the selected exposures. Participants answered a questionnaire and underwent auditory tests. Auditory fatigue was measured by comparing the acoustic reflex threshold before and after the workday. Workers coexposed to solvents and noise showed significantly worse results in auditory tests in comparison with the participants in the control group. Auditory brainstem response results showed differences in III−V interpeak intervals (p = 0.046 in right ear; p = 0.039 in left ear). Mean dichotic digits scores (exposed = 89.5 ± 13.33; controls = 96.40 ± 4.46) were only different in the left ear (p = 0.054). The comparison of pre and postacoustic reflex testing indicated mean differences (p = 0.032) between the exposed (4.58 ± 6.8) and controls (0 ± 4.62) groups. This study provides evidence of a possible temporary effect (hearing fatigue) at the level of the acoustic reflex of the stapedius muscle. The permanent effects were identified mainly at the level of the high brainstem and in the auditory ability of binaural integration.

Auditory system dysfunction in Brazilian gasoline station workers.

Objective: To examine the auditory system of Brazilian gasoline station workers using an extensive audiological test battery. Design: This was a cross-sectional study. The audiological evaluation included a questionnaire, pure-tone audiometry, acoustic immittance tests, transient-evoked otoacoustic emissions (TEOAEs), distortion product otoacoustic emissions (DPOAEs), auditory brainstem response (ABR) and P300 auditory-evoked potentials. Study sample: A total of 77 Brazilian gasoline station workers were evaluated, and their results were compared with those of 36 participants who were not exposed to chemicals or noise at work. The gasoline station employees worked in 18 different gas stations, and the noise area measurements from all gas stations revealed time-weighted averages below 85 dBA. Results: Of the 77 gasoline station workers evaluated, 67.5% had audiometric results within the normal range, but 59.7% reported difficulties in communication in noisy places. Gasoline station workers showed significantly poorer results than non-exposed control participants in one or more conditions of each of the audiological tests used, except P300. Conclusions: The results suggest that the gasoline station workers have both peripheral and central auditory dysfunctions that could be partly explained by their exposure to gasoline.

The maturation state of the auditory nerve and brainstem in rats exposed to lead acetate and supplemented with ferrous sulfate / Estado de maturação do nervo auditivo e tronco encefálico em ratos expostos a acetato de chumbo e suplementados com sulfato ferroso

Abstract Introduction The literature has reported the association between lead and auditory effects, based on clinical and experimental studies. However, there is no consensus regarding the effects of lead in the auditory system, or its correlation with the concentration of the metal in the blood. Objective To investigate the maturation state of the auditory system, specifically the auditory nerve and brainstem, in rats exposed to lead acetate and supplemented with ferrous sulfate. Methods 30 weanling male rats (Rattus norvegicus, Wistar) were distributed into six groups of five animals each and exposed to one of two concentrations of lead acetate (100 or 400 mg/L) and supplemented with ferrous sulfate (20 mg/kg). The maturation state of the auditory nerve and brainstem was analyzed using Brainstem Auditory Evoked Potential before and after lead exposure. The concentration of lead in blood and brainstem was analyzed using Inductively Coupled Plasma-Mass Spectrometry. Results We verified that the concentration of Pb in blood and in brainstem presented a high correlation (r = 0.951; p < 0.0001). Both concentrations of lead acetate affected the maturation state of the auditory system, being the maturation slower in the regions corresponding to portion of the auditory nerve (wave I) and cochlear nuclei (wave II). The ferrous sulfate supplementation reduced significantly the concentration of lead in blood and brainstem for the group exposed to the lowest concentration of lead (100 mg/L), but not for the group exposed to the higher concentration (400 mg/L). Conclusion This study indicate that the lead acetate can have deleterious effects on the maturation of the auditory nerve and brainstem (cochlear nucleus region), as detected by the Brainstem Auditory Evoked Potentials, and the ferrous sulphate can partially amend this effect.

Resumo Introdução A literatura relatou a associação entre o chumbo e os efeitos auditivos, com base em estudos clínicos e experimentais. No entanto, não há consenso em relação aos efeitos do chumbo no sistema auditivo, ou sua correlação com a concentração do metal no sangue. Objetivo Investigar o estado de maturação do sistema auditivo, especificamente do nervo auditivo e do tronco encefálico, em ratos expostos ao acetato de chumbo e suplementados com sulfato ferroso. Método 30 ratos machos desmamados (Rattus norvegicus, Wistar) foram distribuídos em seis grupos de cinco animais e expostos a uma de duas concentrações de acetato de chumbo (100 ou 400 mg/L) e suplementados com sulfato ferroso (20 mg/kg). O estado de maturação do nervo auditivo e do tronco encefálico foi analisado pelo Potencial Evocado Auditivo do Tronco Encefálico antes e após a exposição ao chumbo. A concentração de chumbo no sangue e tronco encefálico foi analisada utilizando-se Espectrometria de Massa com Plasma Indutivamente Acoplado. Resultados Verificamos que as concentrações de Pb no sangue e no tronco encefálico apresentaram alta correlação (r = 0,951, p < 0,0001). Ambas as concentrações de acetato de chumbo afetaram o estado de maturação do sistema auditivo, a maturação foi mais lenta nas regiões correspondentes à porção do nervo auditivo (onda I) e dos núcleos cocleares (onda II). A suplementação com sulfato ferroso reduziu significativamente a concentração de chumbo no sangue e no tronco encefálico no grupo exposto à menor concentração de chumbo (100 mg/L), mas não para o grupo exposto à maior concentração (400 mg/L). Conclusão Esse estudo indica que o acetato de chumbo pode ter efeitos deletérios na maturação do nervo auditivo e do tronco encefálico (região do núcleo coclear), como detectado pelos potenciais evocados auditivos do tronco encefálico, e que o sulfato ferroso pode diminuir parcialmente esse efeito.

The maturation state of the auditory nerve and brainstem in rats exposed to lead acetate and supplemented with ferrous sulfate.

INTRODUCTION: The literature has reported the association between lead and auditory effects, based on clinical and experimental studies. However, there is no consensus regarding the effects of lead in the auditory system, or its correlation with the concentration of the metal in the blood. OBJECTIVE: To investigate the maturation state of the auditory system, specifically the auditory nerve and brainstem, in rats exposed to lead acetate and supplemented with ferrous sulfate. METHODS: 30 weanling male rats (Rattus norvegicus, Wistar) were distributed into six groups of five animals each and exposed to one of two concentrations of lead acetate (100 or 400mg/L) and supplemented with ferrous sulfate (20mg/kg). The maturation state of the auditory nerve and brainstem was analyzed using Brainstem Auditory Evoked Potential before and after lead exposure. The concentration of lead in blood and brainstem was analyzed using Inductively Coupled Plasma-Mass Spectrometry. RESULTS: We verified that the concentration of Pb in blood and in brainstem presented a high correlation (r=0.951; p<0.0001). Both concentrations of lead acetate affected the maturation state of the auditory system, being the maturation slower in the regions corresponding to portion of the auditory nerve (wave I) and cochlear nuclei (wave II). The ferrous sulfate supplementation reduced significantly the concentration of lead in blood and brainstem for the group exposed to the lowest concentration of lead (100mg/L), but not for the group exposed to the higher concentration (400mg/L). CONCLUSION: This study indicate that the lead acetate can have deleterious effects on the maturation of the auditory nerve and brainstem (cochlear nucleus region), as detected by the Brainstem Auditory Evoked Potentials, and the ferrous sulphate can partially amend this effect.

Peripheral and central auditory dysfunction induced by occupational exposure to organic solvents.

OBJECTIVE: To examine the effects of solvent exposure on hearing function, through an audiological test battery, in a population not occupationally exposed to high levels of noise. METHODS: One hundred ten workers from a coating factory were studied. Jobs at the factory were divided into three different levels of solvent exposure. Hearing status was assessed with a test battery including pure-tone hearing thresholds (0.5-8 kHz), high-frequency hearing thresholds (12 and 16 kHz), and dichotic listening measured through dichotic digits test. Multiple linear regression models were created to explore possible association between solvent exposure and each of the hearing outcomes. RESULTS: Significant associations between solvent exposure and the three hearing outcomes were found. Covariates such as age, gender, race, and ethnicity were also significantly associated with the studied hearing outcomes. CONCLUSIONS: Occupational exposure to solvents may induce both peripheral and central auditory dysfunction. The dichotic digits test seems as a sensible tool to detect central auditory dysfunction associated with solvent exposure. Hearing loss prevention programs may use this tool to monitor hearing in solvent-exposed workers.

Audiological findings among workers from Brazilian small-scale fisheries.

OBJECTIVE: The aim of this study was to examine the noise exposure and hearing of fishermen from small-scale fisheries from the state of Paraná in Brazil. DESIGN: Participants of this cross-sectional study included 141 male fishermen, ages ranging from 18 to 77 yr old and 136 controls matched by socioeconomic level, age, and gender. We conducted personal noise dosimetry and interviewed the fishermen regarding their hearing and their job. Audiological testing performed included pure-tone audiometry in the 0.5 to 8 kHz frequency range, extended high-frequency audiometry in the 9 to 16 kHz range, and transient and distortion-product otoacoustic emissions. Testing was preceded by a period of at least 14 hr without exposure to noise. Participants were subdivided in subgroups according to their noise exposure history. RESULTS: Sound level measurement results ranged from 38 to 58 Leq dB (A) in vessels without an engine and between 90 and 108 Leq dB (A) in vessels with an engine. Results from additional area sound level measurements conducted in five different seating locations in the 9HP engine boat ranged from 86 to 105 dB (A). Statistical analysis of the pure-tone audiometry results showed that fishermen with current or a history of occupational noise exposure had significantly poorer thresholds than controls or unexposed fishermen in several of the tested audiometric frequencies. Results of the otoacoustic emissions testing showed differences between exposed and unexposed groups regarding the presence of responses in bilateral amplitude and reproducibility at all frequency bands tested. CONCLUSIONS: Because of the fishermen's increased risk of hearing disorders, a variety of solutions are recommended, which include dissemination of information on control of noise emissions generated by the boat engines, audiological care, and hearing loss prevention services tailored to workers from small-scale fisheries.

Conhecimento de trabalhadores sobre ruído e seus efeitos em indústria alimentícia / Knowledge of workers in the food industry about noise and its effects

A atuação na área da saúde do trabalhador envolve o monitoramento do ambiente de trabalho, desenvolvimento de programas preventivos, treinamento e educação. O conhecimento que os trabalhadores possuem sobre riscos laborais pode influenciar na sua participação efetiva nas campanhas e ações preventivas e repercutir no sucesso das mesmas...

Work in the field of workers'health involves monitoring of the work environment, the development of preventive programs and training and education. Workers'knowledge of the worplace risks can influence their effective participation in preventive programs and the success of such iniciatives...

Audiology in Brazil.

The profession of audiology took root in Brazil nearly a half a century ago and has since blossomed into a flourishing, well-developed field. Currently, audiologists in Brazil work at private institutions, including private medical practices and dedicated speech and hearing clinics. They are also employed in a wide array of public institutions, including community clinics, elementary schools, colleges, and universities. In both the private sector and health clinics, audiologists perform diagnostic evaluations of auditory and vestibular disorders, select and fit hearing aids, and provide aural rehabilitation. At the public level, they assist with workers' health programs, dispense hearing aids, and aural rehabilitation. There is always room to grow, however, and the future of audiology in Brazil holds both challenges and opportunity. The following article will sketch the development of audiology training and practice in Brazil, provide a picture of how the field stands today, and summarize the unique challenges which the profession faces in this large and diverse nation.

Music exposure and audiological findings in Brazilian disc jockeys (DJs).

The aim of this study was to examine the music exposure and hearing of disc jockeys (DJs). We conducted personal noise dosimetry on 30 DJs and interviewed them regarding their hearing and their job. We conducted pure-tone audiometry, and transient and distortion product otoacoustic emissions before their exposure to music during their work. This first test was preceded by a period of at least 12 hours without exposure to music or noise. We repeated the pure-tone audiometry and otoacoustic emissions after their music exposure, and poorer performances were registered in all retests. The nightclubs' average sound level ranged between 93.2 to 109.7 dB(A). Statistical analysis showed significant bilateral temporary threshold shifts at all frequencies between audiometry performed pre- and post-exposure to amplified music. Transient otoacoustic emissions showed a significant difference in bilateral amplitude and reproducibility at all frequency bands tested. The comparison of distortion product otoacoustic emissions results pre- and post-music exposure showed there was a significant difference in amplitude. Music exposure was associated with temporary and permanent auditory dysfunction among professional DJs.

Análise da conduta de médicos do trabalho diante de trabalhadores com perda auditiva / The analysis of professional conduct of occupational physicians regarding workers with hearing loss

Entrevistas com médicos do trabalho da Região Sul do país, com o objetivo de identificação de sua visão e de suas condutas com relação à saúde auditiva dos trabalhadores expostos a níveis elevados de pressão sonora, susceptíveis a danos auditivos

Auditoria dos programas de prevenção de perdas auditivas em Curitiba (PPPA) / Hearing loss prevention programs control of Curitiba (HLPP)

OBJETIVO: O presente trabalho teve como objetivo examinar se medidas práticas de prevenção de perdas auditivas, adotadas por indústrias de Curitiba e região metropolitana, atendem às exigências da legislação trabalhista vigente e recomendações científicas que abordam este tema. FORMA DE ESTUDO: Coorte transversal. MATERIAL E MÉTODO: Um questionário elaborado pelo instituto americano National Institute for Occupational Safety and Health (NIOSH) em 1996, para auditoria de programas de prevenção de perdas auditivas (PPPA), nos serviu de instrumento para a coleta de dados. O instrumento original possui 89 questões divididas em oito temas relacionados à prática dos programas: treinamento e educação, envolvimento do supervisor, medição do ruído, controle de Engenharia e Administrativo, monitoração audiométrica e manutenção dos registros, encaminhamentos, equipamento de proteção individual e questões administrativas. A coleta de dados foi realizada com Médicos do Trabalho, Engenheiros e/ou Técnicos de Segurança das indústrias. As empresas foram divididas em dois grupos: o das empresas que possuem um PPPA e o das que não possuem. CONCLUSÃO: Com base nos dados obtidos concluímos que não houve diferença significativa de conduta entre os grupos e que ambos cumprem parcialmente a legislação trabalhista relacionada à prevenção dos efeitos do ruído. Quanto às questões que abordam aspectos que se excedem às exigências legais, concluímos que as empresas que possuem PPPA dedicam maiores esforços à prevenção de perdas auditivas. Com estes dados identificamos pontos fortes e fracos das medidas que vêm sendo adotadas pelas indústrias da região, os quais poderão nos direcionar à elaboração de medidas preventivas mais efetivas e de propostas para revisão da legislação vigente.

Prevençäo de perdas auditivas no trabalho em uma indústria cervejeira de Lages: comparaçäo com a Portaria 19, 1998, e com as recomendaçöes contidas no guia prático do Niosh, 1996 / Prevention of hearing losses on a beer manufacturing plant on Lages: comparison between Portaria 19, 1998, and Niosh Practical Guide, 1996

Objetiva comparar a prática preventiva de perdas auditivas, adotada por uma empresa brasileira, com a exigência da legislaçäo nacional pertinente.

[Hearing health of workers exposed to noise and insecticides]. / Saúde auditiva de trabalhadores expostos a ruído e inseticidas.

OBJECTIVE: To examine the peripheral auditory disorders in a group of workers exposed to organophosphate and pyrethroid insecticides, used in vector control campaigns. METHODS: The prevalence study examined a population of 98 individuals who sprayed insecticides in campaigns for the prevention of Dengue, Chagas disease and Yellow fever. The sampling approach was finalistic, and included the workers in a health district of Pernambuco, during the year 2000. A questionnaire was used to collect data on occupational and non-occupational risks, safety measures utilized, family history of auditory problems and health symptoms. Previous noise exposure history was also investigated, since noise can be a confounding factor for hearing loss. Hearing sensitivity and middle ear function were assessed by pure tone audiometry. RESULTS: Among those exposed to insecticides, 63.8% demonstrated a hearing loss. For the group of workers exposed to both noise and insecticides, hearing loss was observed in 66.7% of the cases. The median exposure time necessary to detect high-frequency losses was 3.4 years for workers exposed to both agents and 7.3 years for workers exposed to insecticides only. Hearing thresholds were poorest among workers exposed to both agents. Auditory damage for those with combined exposures to the two factors was more severe than the hearing losses observed among those exposed only to insecticides. CONCLUSIONS: There is evidence that exposure to insecticides was associated with peripheral sensorioneural hearing loss and that noise exposure can potentiate the ototoxic effects of insecticides. It is necessary to evaluate this possible association through epidemiological studies.

Saúde auditiva de trabalhadores expostos a ruído e inseticidas / Hearing health of workers exposed to noise and insecticides

OBJETIVO: Avaliar as alteraçöes auditivas periféricas em um grupo de trabalhadores exposto a inseticidas, organofosforados e piretróides, utilizados em campanhas de controle de vetores. MÉTODOS: Estudo de prevalência de uma populaçäo de 98 indivíduos que pulverizavam venenos nas campanhas de prevençäo do dengue, da febre amarela e da doença de Chagas. A amostra foi de tipo finalística, considerando o universo dos trabalhadores de um distrito sanitário, em Pernambuco, no ano de 2000. Utilizou-se questionário contendo questöes de identificaçäo de riscos ocupacional e näo ocupacional, medidas de segurança utilizadas, antecedentes de problemas auditivos e sintomas referidos. Foi investigada a historia pregressa de exposiçäo ao ruído, por ser um fator de confusäo para a perda auditiva. Todos os indivíduos foram avaliados pelo teste de audiometria tonal. RESULTADOS: Dos expostos apenas aos inseticidas, 63,8por cento apresentaram perda auditiva. Para o grupo com exposiçäo concomitantemente aos inseticidas e ao ruído, a perda auditiva foi de 66,7por cento. O tempo mediano para o desenvolvimento de alteraçöes auditivas nas freqüências médias altas, para as exposiçöes combinadas de inseticidas e ruído, foi de 3,4 anos e para as exposiçöes apenas aos inseticidas foi de 7,3 anos. A perda auditiva para as exposiçöes concomitantes aos dois fatores foi de maior intensidade nessas freqüências, do que o observado na exposiçäo apenas aos inseticidas. CONCLUSOES: Há evidência de que a exposiçäo aos inseticidas induz dano auditivo periférico e que o ruído é um fator que interage com os inseticidas, potencializando seus efeitos ototóxicos. Faz-se necessário avaliar essa possível associaçäo através de estudos epidemiológicos de caráter analítico