Avaliação do processamento auditivo temporal em trabalhadores rurais expostos a agrotóxicos organofosforados

Audiological findings of family farmers exposed to pesticides

PURPOSE

To analyze the possible differences among the hearing of farmers and their families when compared to the population not exposed to pesticides.

METHODS

Cross-sectional study with 70 smallholder family farmers (research group), with the mean age of 39.7 years, of both sexes and a mean of 23.7 years of exposure to pesticides. We included a control group with 71 participants of both sexes with the mean age of 39.5 years, not exposed to either noise or chemical substances, to compare the results. In stage 1, both groups were submitted to conventional and high-frequency audiometry, and acoustic immittance. In stage 2, only people with normal hearing were submitted to the evoked otoacoustic emissions and suppression effect on transient otoacoustic emissions.

RESULTS

Significant differences were observed between the groups in the conventional pure-tone and in the high-frequency audiometry, as well as in the acoustic reflex. The most affected frequencies in the conventional pure-tone audiometry ranged from 3 to 6 kHz and, in the high-frequency audiometry, from 9000 to 11200 Hz. As for the transient otoacoustic emissions, the worse suppression effect results were found in the research group.

CONCLUSION

There were differences among the hearing of family farmers and the control group. The conventional auditory thresholds are related to the group, age and sex. Farming is associated with impairments in the basal region of the cochlea, absence of acoustic reflex, reduced signal-to-noise ratio of the transient otoacoustic emissions, and dysfunction in the olivocochlear efferents of the auditory system.

Findings on the Central Auditory Functions of Endemic Disease Control Agents

This study aimed to assess the central auditory functions of endemic disease control agents. This cross-sectional cohort study comprised two groups: the exposed group, with 38 male endemic disease control agents with simultaneous occupational noise and pesticide exposure; and the control group, with 18 age- and sex-matched workers without occupational noise and/or pesticide exposure. All participants underwent pure-tone audiometry, brainstem auditory evoked potentials, dichotic digits test, and transient-evoked otoacoustic emissions suppression effect. There was a significant inter-group difference in waves III and V absolute latencies, and interpeak I-III and I-V latencies bilaterally, with worse results found in the exposed group. Abnormal dichotic digits test results occurred more often in the exposed group, with a significant association between pesticide- and noise-exposure and the abnormal results (p = 0.0099). The transient-evoked otoacoustic emissions with suppression effect did not yield significant inter-group differences. It was concluded that pesticide and noise exposure induce harmful effects on the central auditory functions, particularly on the brainstem and figure-ground speech-sound auditory skills.

Study on hearing loss and its relationship with work in pesticide-exposed tobacco growers

ABSTRACT The Purpose of this case report is to present four cases of tobacco growers with hearing loss due to occupational exposure to pesticides. A qualitative case study comprising three cases of sensorineural hearing loss with causal nexus (Cases 1, 2 and 4), and one (Case 3) of sensorineural hearing loss compatible with ototoxicity by pesticides, with causal nexus mainly based on minor neuropsychiatric disorders. The sample was composed of rural workers with health problems, in working age, having started working early in life, exposed to various pesticides, including organophosphates. The auditory and neurovegetative symptoms reported were noise discomfort (n = 2), speech perception difficulty (n = 3), dizziness (n = 2), and imbalance (n = 2). The pure-tone audiometry revealed a sensorineural hearing loss in one or more high frequencies, and one of the cases presented alteration in the brainstem auditory evoked potentials. There is evidence, in this study, of an association between hearing loss and work in tobacco growers exposed to pesticides, with peripheral auditory damage in four cases, and central damage in one of them. Thus, the need for a complete audiological evaluation of pesticide-exposed populations is highlighted.

Prenatal organophosphate insecticide exposure and infant sensory function

BACKGROUND

Occupational studies suggest that exposure to organophosphate insecticides (OPs) can lead to vision or hearing loss. Yet the effects of early-life exposure on visual and auditory function are unknown. Here we examined associations between prenatal OP exposure and grating visual acuity (VA) and auditory brainstem response (ABR) during infancy.

METHODS

30 OPs were measured in umbilical cord blood using gas chromatography tandem mass spectrometry in a cohort of Chinese infants. Grating visual acuity (VA) (n = 179-200) and auditory brainstem response (ABR) (n = 139-183) were assessed at 6 weeks, 9 months, and 18 months. Outcomes included VA score, ABR wave V latency and central conduction time, and head circumference (HC). Associations between sensory outcomes during infancy and cord OPs were examined using linear mixed models.

RESULTS

Prenatal chlorpyrifos exposure was associated with lower 9-month grating VA scores; scores were 0.64 (95% CI: -1.22, -0.06) points lower for exposed versus unexposed infants (p = 0.03). The OPs examined were not associated with infant ABR latencies, but chlorpyrifos and phorate were both significantly inversely associated with HC at 9 months; HCs were 0.41 (95% CI: 0.75, 0.6) cm and 0.44 (95% CI: 0.88, 0.1) cm smaller for chlorpyrifos (p = 0.02) and phorate (p = 0.04), respectively.

CONCLUSIONS

We found deficits in grating VA and HC in 9-month-old infants with prenatal exposure to chlorpyrifos. The clinical significance of these small but statistically significant deficits is unclear. However, the disruption of visual or auditory pathway maturation in infancy could potentially negatively affect downstream cognitive development.

Adverse effects of pesticides on central auditory functions in tobacco growers

OBJECTIVE

To investigate the effects of exposure to pesticides on the central auditory functions (CAF) of Brazilian tobacco growers.

DESIGN

This was a cross-sectional study carried out between 2010 and 2012. Participants were evaluated with two behavioural procedures to investigate CAF, the random gap detection test (RGDT) and the dichotic digit test in Portuguese (DDT).

STUDY SAMPLE

A total of 22 growers exposed to pesticides (study group) and 21 subjects who were not exposed to pesticides (control group) were selected.

RESULTS

No significant differences between groups were observed for pure-tone thresholds. A significant association between pesticide exposure and the results for RGDT and DDT was found. Significant differences between pesticide-exposed and nonexposed subjects were found for RGDT frequency average and DDT binaural average, when including age and hearing level as covariates. Age was significantly associated with RGDT frequency average, DDT left ear score, DDT binaural average and DDT right ear advantage. Hearing levels were not significantly associated with any of the test scores. The relative risk of failing the DDT and RGDT for the study group was 1.88 (95% CI: 1.10-3.20) and 1.74 (95% CI: 1.06-2.86), respectively, as compared with the control group.

CONCLUSIONS

The results showed that tobacco growers exposed to pesticides exhibited signs of central auditory dysfunction characterised by decrements in temporal processing and binaural integration processes/abilities.

Habilidade de ordenação temporal e nível de especificidade nos diferentes testes tonais

RESUMO Objetivo: Avaliar a habilidade de ordenação temporal com diferentes testes, verificar a especificidade desses testes e comparar o resultado com o grau de facilidade/dificuldade relatado pelos sujeitos. Métodos: Os indivíduos realizaram avaliação audiológica básica e Teste Dicótico de Dígitos, para triagem do processamento auditivo, e foram submetidos ao Teste Padrão de Frequência (TPF) e ao Teste Padrão de Duração (TPD), nas versões de Taborga-Lizarro, Musiek e Auditec®, para avaliar a habilidade de Ordenação Temporal. Após, foi apresentada a Escala Visual Analógica (EVA), para que os sujeitos identificassem a dificuldade de cada teste. Resultados: Foram avaliados 33 sujeitos, 29 do gênero feminino e quatro do gênero masculino, com idade entre 17 e 27 anos. Houve maior número de indivíduos que atingiram valores normais no teste Auditec® e de Taborga-Lizarro, para o TPD e TPF. No teste de Musiek, houve um número de sujeitos com resultados normais muito próximos aos de sujeitos com alteração de processamento. Na distribuição do teste mais difícil, houve significância estatística para o teste de Musiek. Quanto à especificidade dos testes, o Auditec® mostrou-se melhor, porém, a análise foi realizada apenas em TPF. Conclusão: Embora os indivíduos não tenham apresentado alteração e queixa de processamento auditivo, houve diferença nos resultados dos testes de ordenação temporal. Quanto ao grau de dificuldade relatado para o teste de Musiek, verificou-se que houve influência deste fator nos resultados dos testes. Na análise de especificidade dos testes, pôde-se observar melhores resultados para o teste Auditec®.

Testes tonais de padrão de frequência e duração no Brasil: revisão de literatura

Este estudo tem como tema o teste de padrão de frequência e de duração no Brasil e como objetivo revisar e explanar sobre a avaliação do processamento auditivo temporal no Brasil, mais especificamente sobre os testes tonais de ordenação temporal (teste de padrão de frequência e duração). Para atingir tal objetivo foi realizado um trabalho de revisão sistemática da literatura em periódicos nacionais, acessados eletronicamente na base de dado Scielo e Lilacs, sem restrição ao ano de publicação. A pesquisa foi estruturada por meio dos descritores: processamento temporal, processamento auditivo temporal, testes temporais, testes tonais de padrão de frequência e testes tonais de padrão de duração, percepção auditiva e testes auditivos. A pesquisa retornou 33 publicações nacionais sendo 28 artigos de periódicos, uma dissertação de mestrado e quatro teses de doutorado. Com isso, pode-se perceber que a utilização de testes que avaliem a habilidade de ordenação temporal no Brasil é recente, sendo notável o aumento significante das publicações nos últimos cinco anos. Desta forma, o emergente conhecimento possibilitado pelo acesso aos testes no Brasil permite ampliar um campo de pesquisa a todos os profissionais comprometidos com este tema.

Applicability of the P300 frequency pattern test to assess auditory processing

Temporal ordering and auditory attention are important skills in information processing, being evaluated by a behavioral test, as the frequency pattern test (FPT) in temporal ordering (TO) and electrophysiological testing, as the P300 in auditory attention.

OBJECTIVE

To analyze the applicability of FPT and P300 as testing for auditory processing.

METHOD

We performed an integrative literature review, with papers that met the inclusion criteria, using the MedLine, LILACS and SciELO databases, with the keywords: hearing attention, P300 evoked potential, P300 and electrophysiology, temporal ordering, processing and FPT. We found 13 papers concerning the use of the TPF and 16 regarding the use of P300.

RESULTS

The TPF was the most used test in the evaluation of TO, presented in a diotic way in individuals with language disorders, musicians, blind people, rural workers and different age groups. The P300 is used in the frequency of 1000 Hz in the frequent stimulus and 2000 Hz for the rare stimulus, applicable in individuals of both genders, different age groups, and in patients with Down syndrome, liver cirrhosis, AIDS and Sleep Apnea Syndrome.

CONCLUSION

The FPT and P300 are efficient instruments used to assess the intended skills.