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Int Arch Otorhinolaryngol 2015; 19(02): 135-140
DOI: 10.1055/s-0034-1544115
Original Research
Thieme Publicações Ltda Rio de Janeiro, Brazil

Mercury Exposure in a Riverside Amazon Population, Brazil: A Study of the Ototoxicity of Methylmercury

Ana Hoshino
1   Universidade Federal do Rio de Janeiro, Instituto de Estudos em Saúde Coletiva, Rio de Janeiro, Brazil
2   Department of Otorhinolaryngology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
,
Heloisa Pacheco-Ferreira
3   Universidade Federal do Rio de Janeiro, Faculdade de Medicina, Rio de Janeiro, Brazil
,
Seisse Gabriela G. Sanches
4   Universidade de São Paulo, FOFITO, São Paulo, Brazil
,
Renata Carvallo
5   FMUSP, FOFITO, São Paulo, São Paulo, Brazil
,
Nathália Cardoso
1   Universidade Federal do Rio de Janeiro, Instituto de Estudos em Saúde Coletiva, Rio de Janeiro, Brazil
,
Maurício Perez
1   Universidade Federal do Rio de Janeiro, Instituto de Estudos em Saúde Coletiva, Rio de Janeiro, Brazil
,
Volney de Magalhães Câmara
1   Universidade Federal do Rio de Janeiro, Instituto de Estudos em Saúde Coletiva, Rio de Janeiro, Brazil
› Author Affiliations
Further Information

Publication History

06 November 2014

11 December 2014

Publication Date:
19 February 2015 (online)

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Abstract

Introduction Mercury poisoning causes hearing loss in humans and animals. Acute and long-term exposures produce irreversible peripheral and central auditory system damage, and mercury in its various forms of presentation in the environment is ototoxic.

Objective We investigated the otoacoustic emissions responses in a riverside population exposed to environmental mercury by analyzing the inhibitory effect of the medial olivocochlear system (MOCS) on transient otoacoustic emissions (TEOAE).

Methods The purpose of the research was to evaluate the entire community independently of variables of sex and age. All of the participants were born and lived in a riverside community. After otolaryngologic evaluation, participants were received tympanometry, evaluation of contralateral acoustic reflexes, pure tone audiometry, and recording of TEOAEs with nonlinear click stimulation. Hair samples were collect to measure mercury levels.

Results There was no significant correlation between the inhibitory effect of the MOCS, age, and the level of mercury in the hair.

Conclusions The pathophysiological effects of chronic exposure may be subtle and nonspecific and can have a long period of latency; therefore, it will be important to monitor the effects of mercury exposure in the central auditory system of the Amazon population over time. Longitudinal studies should be performed to determine whether the inhibitory effect of the MOCS on otoacoustic emissions can be an evaluation method and diagnostic tool in populations exposed to mercury.

Keywords

mercury - methylmercury compounds - auditory pathways - medial olivocochlear system - otoacoustic emissions - ototoxicity
 

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