Emissões otoacústicas - produto de distorção em indivíduos expostos ao chumbo e ao ruído

Abstract

At ualmente, as legislações nacionais voltadas à saúde do trabalhador exigem que a audição seja monitorada apenas quando há exposição ocupacional ao ruído, não sendo considerada, assim, a exposição a produtos químicos. Entretanto, na literatura científica, é bastante clara a preocupação sobre os efeitos do chumbo no sistema auditivo, uma vez que foram observados efeitos negativos após a exposição ocupacional a este metal. Objetivo: O presente estudo teve como objetivo analisar a amplitude das emissões otoacústicas evocadas por produto de distorção, em indivíduos com histórico de exposição ao chumbo e ruído. Forma de estudo: Coorte Transversal. Material e método: Foram avaliados 69 indivíduos subdivididos em 3 grupos: Grupo I (GI): composto por 29 trabalhadores expostos ao chumbo com exposição simultânea ao ruído, em seu ambiente de trabalho; Grupo II (GII): composto por 11 trabalhadores expostos ao ruído ocupacional sem exposição simultânea ou pregressa a outros agentes nocivos à audição; e Grupo III (GIII): composto por 11 indivíduos com audição normal, sem histórico de exposição ao ruído ocupacional ou de outros fatores de risco para a ocorrência de perda auditiva. Resultado: Os resultados obtidos não evidenciaram o efeito tóxico do chumbo nos resultados das emissões otoacústicas, visto que as menores amplitudes das EOEPD foram observadas no grupo exposto somente ao ruído, mesmo considerando que os indivíduos expostos ao chumbo com exposição simultânea ao ruído apresentavam longo período de exposição a este metal bem como ampla variação do nível de chumbo sérico. Current ly, legislations concerning worker's health only require periodic monitoring of individuals who are noiseexposed at work, and exposure to chemicals are not taken into consideration. However, the scientific literature indicates a very clear concern regarding the effects of lead on the auditory system, demonstrating that there are negative effects to the auditory system following occupational exposure to this metal. Aim: The aim of this study was to evaluate the amplitude of distortion product otoacoustic emissions (DPOAEs) among individuals with a history of exposure to lead and noise. Study design: Transversal Cohort. Material and method: We evaluated 69 individuals divided in 3 groups: Group I (GI): composed by 29 workers occupationally exposed to both lead and noise; Group II (GII): composed by 11 noise-exposed workers with no other exposure to ototraumatic, and Group III (GIII): composed by 11 individuals with normal hearing and no history of exposure to noise or lead. Results: The results showed no effect of lead exposure on the otoacoustic emission results, since the smaller EOEPD amplitudes were observed in the noise-exposed group, despite the fact that the lead and noise exposed workers had a long history of lead exposure, and a wide variability in blood lead levels.Palavras-chave: chumbo, emissões otoacústicas, ruído, perda auditiva.

Avaliação audiológica em crianças com baixo nível de exposição cumulativa ao chumbo

“…In this study, the children subjected to evoked otoacoustic emissions through transient stimulus research presented normal result, bilaterally, demonstrating that there was no of outer hair cells in the cochlea, even sub-clinical. Considering the sensitivity of the procedure to detect this type of alteration, it is possible to assume that the lead did not cause cochlear alteration on the structure that was specifically analyzed, finding that corroborates with what is described in the literature 10,11 . were studied; in other words, what would be the lead level to be taken into account in the analyses: the blood lead level at the time of the evaluation, the cumulative level, or another proposal for calculation?…”

“…This argumentation is based on a study 11 in which a control group with equivalence on the factors age and level of exposure to noise is used. It found hearing alterations, however there was no difference in the amplitude of the evoked otoacoustic emissions, a product of the distortion between the lead-exposed group associated to noise and the group exposed solely to noise With reference to research done with children, various authors have discussed small changes on the thresholds found on intensities £10dBNA, that is, hearing thresholds that do not clinically represent hearing loss19,20.…”

“…Figure 1 shows a compilation of the studies presented in the field literature, which performed an auditory assessment of children and adults through behavioral methods. Another important aspect to be emphasized about this compilation is that only two studies demonstrated the absence of cochlear lesion 10,11 . seizures, IQ decrease, hearing loss, aggressive behavior, and mental retardation [5][6][7] .…”

Monitoramento auditivo na ototoxidade

“…Besides medication-related ototoxicity, damage to the hearing apparatus may occur from exposure to other physical agents such as noise, chemicals and heavy metals such as insecticides, toluene, styrene, ethylbenzene, carbon monoxide, carbon disulfide, lead and mercury, among others [2][3][4] . Notwithstanding, the present study will focus on the exposure to medication which are toxic for the human ear and the procedures currently available for the early diagnosis of hearing alterations caused by such exposure.…”

Evoked otoacoustic emissions in workers exposed to noise: A review

“…While some authors offered significant evidence of effects on EOAE results in workers exposed simultaneously to noise and chemicals compared to workers exposed only to noise12 24 28, other authors did not agree23.…”