Umbrales auditivos en pacientes con enfermedad de Méniere manejados con corticoides transtimpánicos / Hearing thresholds in Ménière's disease patients managed with transtympanic dexametasone

Introducción: Pese a que el uso de corticoides transtimpánicos en pacientes con enfermedad de Méniere es habitual en muchos centros, la evidencia respecto de su efecto sobre los umbrales auditivos es aún controversial. Objetivo: Estudiar los umbrales auditivos de pacientes con enfermedad de Méniere que recibieron corticoides transtimpánicos en el Servicio de Otorrinolaringología del Hospital Clínico de la Universidad de Chile. Material y Método: Estudio retrospectivo de pacientes con enfermedad de Méniere que consultaron entre los años 2015 y 2021. Se estudiaron los umbrales auditivos, antes y después de 3 inyecciones de dexametasona transtimpánica. Resultados: Se obtuvieron datos completos de 27 pacientes. Al comparar el promedio tonal puro antes y después del tratamiento, no se observaron diferencias significativas. A nivel individual, la variación de cambio de los umbrales auditivos con dexametasona se correlaciona en forma significativa con los umbrales auditivos previos a las inyecciones y con el tiempo transcurrido desde la última inyección, pero no con la edad. Conclusión: La terapia con dexametasona transtimpánica en pacientes con enfermedad de Méniere no altera los umbrales auditivos. Sin embargo, se requieren más estudios, para comprobar, si existe un efecto transitorio en los umbrales auditivos de los primeros días posterior al procedimiento.

Introduction: Although transtympanic corticosteroids are proposed in Méniere's disease patients refractory to standard medical therapy, the evidence regarding the effect of transtympanic corticosteroids on hearing thresholds is still controversial. Aim: To study the hearing thresholds of patients with Méniere's disease who were administrated with transtympanic corticosteroids at the Otorhinolaryngology Service of the University of Chile's Clinical Hospital. Material and Method: Retrospective study of Méniere's disease patients who consulted between 2015 and 2021. Demographic variables and hearing thresholds were studied before and after three transtympanic injections of dexamethasone. Results: A total of 27 patients were studied. There were non-significant differences in pure-tone hearing threshold averages before and after the injections. Individual variation in hearing thresholds correlates significantly with the pre-injection hearing thresholds and the period since the last injection, but not with age. Conclusion: Transtympanic dexamethasone therapy in patients with Meniere's disease does not alter hearing thresholds. However, more studies are needed to verify whether there is a transitory effect on hearing thresholds in the first days after the procedure.

The Effects of Riluzole on Cisplatin-induced Ototoxicity

Abstract Introduction Riluzole (2-amino-6-trifluoromethoxy benzothiazole) is known as a neuroprotective, antioxidant, antiapoptotic agent. It may have beneficial effects on neuronal cell death due to cisplatin-induced ototoxicity. Objective To evaluate the effect of riluzole on cisplatin-induced ototoxicity in guinea pigs. Methods Twenty-four guinea pigs, studied in three groups, underwent auditory brainstem response evaluation using click and 8 kHz tone burst stimuli. Subsequently, 5 mg/kg of cisplatin were administered to all animals for 3 days intraperitoneally (i.p.) to induce ototoxicity. Half an hour prior to cisplatin, groups 1, 2 and 3 received 2 ml of saline i.p., 6 mg/kg of riluzole hydrochloride i.p., and 8 mg/kg of riluzole hydrochloride i.p., respectively, for 3 days. The auditory brainstem responses were repeated 24 hours after the last drug administration. The cochleae were analyzed by transmission electron microscopy (TEM). Results After drug administiration, for 8,000 Hz stimulus, group 1 had significantly higher threshold shifts when compared with groups 2 (p < 0.05) and 3 (p < 0.05), and there was no significant difference in threshold shifts between groups 2 and 3 (p > 0.05). Transmission electron microscopy findings demonstrated the protective effect of riluzole on the hair cells and the stria vascularis, especially in the group treated with 8 mg/kg of riluzole hydrochloride. Conclusion We can say that riluzolemay have a protective effect on cisplatin- induced ototoxicity. However, additional studies are needed to confirm these results and the mechanisms of action of riluzole.

Effect of antioxidant supplementation on the auditory threshold in sensorineural hearing loss: a meta-analysis / Efeito da suplementação de antioxidantes sobre o limiar auditivo na perda auditiva neurosensorial: uma metanálise

Abstract Introduction: Hearing loss is conceptualized as any impairment of the ability to hear and/or detect speech or environment sounds, regardless of cause, type, or degree. It may occur at different stages of life; during pregnancy or childbirth, in childhood, adulthood or old age. It should be noted that aging is the most common cause of sensorineural hearing loss followed by noise-induced hearing loss, and both are closely related to the formation of reactive oxygen species. Dietary antioxidant supplementation has been employed as a therapeutic strategy to prevent and/or delay the risks of major human diseases. Objective: To assess randomized clinical trials to determine the effect of antioxidant supplementation on the auditory thresholds in patients of different age groups with sensorineural hearing loss. Methods: This systematic review consisted of a search in the following databases: MEDLINE, CENTRAL, ScienceDirect, Scopus, Web of Science, LILACS, SciELO and ClinicalTrials.gov. Additionally, the gray literature was also searched. The search strategy included terms related to the intervention (antioxidant supplementation), primary outcome (sensorineural hearing loss), as well as terms related to randomized clinical trials to improve search sensitivity. Results: Based on 977 potentially relevant records identified through the search in the databases, ten full-text publications were retrieved for further evaluation. The increase in threshold at the 4 kHz frequency was statistically higher in the control group (1.89 [1.01-2.78], p < 0.0001) when compared to the NAC group and the ginseng group, whereas at 6 kHz, the threshold increase was higher in the control group (1.42 [−1.14-3.97], p = 0.28), but no statistically significant differences were found between groups. Conclusion: Ginseng was the antioxidant agent that showed the best effect in preventing auditory threshold worsening at the frequency of 4 kHz, but not at 6 kHz in patients with sensorineural hearing loss caused by exposure to high sound pressure levels. There was no improvement in the thresholds with vitamin E supplementation.

Resumo Introdução: A perda auditiva é conceituada como qualquer diminuição da capacidade de ouvir e/ou detectar sons da fala ou do ambiente, independentemente da causa, tipo ou grau e pode ocorrer em diversos estágios da vida, durante a gestação ou parto, na infância, vida adulta ou na terceira idade. Convém destacar que o envelhecimento é a primeira causa de perda auditiva do tipo sensorioneural e em segundo lugar a perda auditiva induzida pelo ruído, ambas estão intimamente relacionadas com a formação de espécies reativas de oxigênio. Evidências têm sido acumuladas indicando que a suplementação com antioxidantes via alimentação tornou-se estratégia terapêutica para prevenir e/ou retardar os riscos das principais doenças humanas. Objetivo: Avaliar ensaios clínicos aleatórios para determinar qual o efeito da suplementação com antioxidantes sobre o limiar auditivo na perda auditiva sensorioneural em pacientes de diversas faixas etárias. Método: A formulação desta revisão sistemática consistiu na busca dos estudos nas seguintes bases de dados: MEDLINE, CENTRAL, ScienceDirect, Scopus, Web of Science, LILACS, SciELO e ClinicalTrials.gov. Adicionalmente, a literatura cinzenta também foi pesquisada. A estratégia de busca incluiu termos relacionados à intervenção (suplementação de antioxidantes), o desfecho primário (perda auditiva sensorioneural), bem como termos relacionados aos ensaios clínicos randomizados para melhorar e a sensibilidade da busca. Resultados: A partir de 977 registros potencialmente relevantes identificados através da busca nas bases de dados, dez publicações em texto completo foram recuperadas para avaliação mais aprofundada. O aumento no limiar na frequência de 4 kHz foi estatisticamente maior no Grupo Controle (1,89 [1,01-2,78], p < 0,0001) quando comparados com o Grupo NAC e o Grupo Ginseng, já na frequência de 6 kHz o aumento no limiar foi maior no Grupo Controle (1,42 [-1,14-3,97], p = 0,28), porém, não foram encontradas diferenças estatisticamente significativas entre grupos. Conclusão: O Ginseng foi o antioxidante que evitou a piora do limiar auditivo na frequência de 4 kHz, mas não em 6 kHz, em pacientes com perda auditiva sensorioneural causada por exposição a elevados níveis de pressão sonora. Não foi observada melhora nos limiares com a suplementação com Vitamina E.

Sequential analysis as a tool for detection of amikacin ototoxicity in the treatment of multidrug-resistant tuberculosis / Análise sequencial como ferramenta na detecção da ototoxicidade da amicacina no tratamento da tuberculose multirresistente

ABSTRACT Objective: To investigate early detection of amikacin-induced ototoxicity in a population treated for multidrug-resistant tuberculosis (MDR-TB), by means of three different tests: pure-tone audiometry (PTA); high-frequency audiometry (HFA); and distortion-product otoacoustic emission (DPOAE) testing. Methods: This was a longitudinal prospective cohort study involving patients aged 18-69 years with a diagnosis of MDR-TB who had to receive amikacin for six months as part of their antituberculosis drug regimen for the first time. Hearing was assessed before treatment initiation and at two and six months after treatment initiation. Sequential statistics were used to analyze the results. Results: We included 61 patients, but the final population consisted of 10 patients (7 men and 3 women) because of sequential analysis. Comparison of the test results obtained at two and six months after treatment initiation with those obtained at baseline revealed that HFA at two months and PTA at six months detected hearing threshold shifts consistent with ototoxicity. However, DPOAE testing did not detect such shifts. Conclusions: The statistical method used in this study makes it possible to conclude that, over the six-month period, amikacin-associated hearing threshold shifts were detected by HFA and PTA, and that DPOAE testing was not efficient in detecting such shifts.

RESUMO Objetivo: Verificar a detecção precoce de ototoxicidade causada pelo uso de amicacina numa população tratada para tuberculose multirresistente (TBMR) por meio da realização de três testes distintos: audiometria tonal liminar (ATL), audiometria de altas frequências (AAF) e pesquisa de emissões otoacústicas por produto de distorção (EOAPD). Métodos: Estudo longitudinal de coorte prospectiva incluindo pacientes de ambos os sexos, com idade entre 18 e 69 anos, com diagnóstico de TBMR pulmonar e que necessitaram utilizar amicacina por seis meses em seu esquema medicamentoso antituberculose pela primeira vez. A avaliação auditiva foi realizada antes do início do tratamento e depois de dois e seis meses do início do tratamento. A análise dos resultados foi realizada por meio de análise estatística sequencial. Resultados: Foram incluídos 61 pacientes, mas a população final foi constituída de 10 pacientes (7 homens e 3 mulheres), em razão da análise sequencial. Ao se comparar os valores das respostas dos testes com aqueles encontrados na avaliação basal, foram verificadas mudanças nos limiares auditivos compatíveis com ototoxicidade após dois meses de tratamento através da AAF e após seis meses de tratamento através da ATL. Entretanto, essas mudanças não foram verificadas através da pesquisa de EOAPD. Conclusões: Ao se considerar o método estatístico utilizado nessa população, é possível concluir que mudanças nos limiares auditivos foram associadas ao uso da amicacina no período de seis meses por meio de AAF e ATL e que a pesquisa de EOAPD não se mostrou eficiente na identificação dessas mudanças.

Study of the protective effect of dexamethasone on cisplatin-induced ototoxicity in rats

Abstract Purpose: To evaluate the ability of dexamethasone to protect against cisplatin (CDDP)-induced ototoxicity. Methods: Male Wistar rats were divided into the following three groups: 1) Control (C): 6 animals received intraperitoneal (IP) saline solution, 8 ml/kg/day for four days; 2) C + CDDP: 11 animals received 8 ml/kg/day of IP saline and, 90 min after saline administration, 8 mg/kg/day of IP CDDP for four days; and 3) DEXA15 + CDDP: 11 animals received IP dexamethasone 15 mg/kg/day and, 90 min after dexamethasone administration, received 8 mg/kg/day of IP CDDP for four days. Results: It was found that dexamethasone did not protect against weight loss in CDDP-exposed animals. The mortality rate was comparable with that previously reported in the literature. The auditory threshold of animals in the DEXA15 + CDDP group was not significantly altered after exposure to CDDP. The stria vascularis of animals in the DEXA15 + CDDP group was partially preserved after CDDP exposure. Conclusions: Dexamethasone at the dose of 15 mg/kg/day partially protected against CDDP-induced ototoxicity, based on functional evaluation by brainstem evoked response audiontry (BERA) and morphological evaluation by optical microscopy. However, dexamethasone did not protect against systemic toxicity.

Hearing thresholds in patients with drug-resistant tuberculosis: baseline audiogram configurations and associations / Limiares auditivos em pacientes com tuberculose resistente: configurações do audiograma basal e associações

ABSTRACT Objective: To use baseline audiogram parameters in order to ascertain whether drug-resistant tuberculosis (DR-TB) has effects on hearing, as well as to describe the configurations of the audiograms and to determine whether there are parameters that can be associated with those configurations. Methods: This was a prospective study involving patients diagnosed with DR-TB at a tuberculosis treatment center in the state of Ogun, in Nigeria. The patients included in the study were submitted to pure tone audiometry at baseline (within two weeks after treatment initiation). For comparative analyses, data regarding demographic and clinical characteristics were collected from the medical records of the patients. Results: The final sample comprised 132 patients. The mean age of the patients was 34.5 ± 12.6 years (range, 8-82 years), and the male:female ratio was 2:1. Of the 132 patients, 103 (78.0%) resided in neighboring states, 125 (94.7%) had previously experienced antituberculosis treatment failure, and 18 (13.6%) were retroviral-positive. Normal audiograms were found in 12 patients (9.1%), whereas sensorineural hearing loss was identified in 104 (78.8%), the two most common configurations being ascending, in 54 (40.9%), and sloping, in 26 (19.7%). Pure-tone averages at low frequencies (0.25-1.0 kHz) and high frequencies (2.0-8.0 kHz) were 33.0 dB and 40.0 dB, respectively. Regarding the degree of hearing loss in the better ear, 36 patients (27.3%) were classified as having normal hearing and 67 (50.8%) were classified as having mild hearing loss (26-40 dB), whereas 29 (21.9%) showed moderate or severe hearing loss. Among the variables studied (age, gender, retroviral status, previous treatment outcome, and weight at admission), only male gender was associated with audiometric configurations. Conclusions: In this sample of patients with DR-TB, most presented with bilateral, mild, suboptimal sensorineural hearing loss, and ascending/sloping audiometric configurations were associated with male gender.

RESUMO Objetivo: Utilizar parâmetros do audiograma basal para verificar se a tuberculose resistente (TB-R) tem efeitos na audição, descrever as configurações dos audiogramas e determinar se há parâmetros que possam ser associados a essas configurações. Métodos: Estudo prospectivo com pacientes diagnosticados com TB-R em um centro de tratamento de tuberculose no estado de Ogun, Nigéria. Os pacientes incluídos no estudo foram submetidos à audiometria de tons puros em até duas semanas após o início do tratamento (audiometria basal). Características demográficas e clínicas foram coletadas dos prontuários médicos dos pacientes para análises comparativas. Resultados: A amostra final envolveu 132 pacientes. A média de idade dos pacientes foi de 34,5 ± 12,6 anos (variação, 8-82 anos), e a razão homem:mulher foi de 2:1. A maioria dos pacientes (n = 103; 78,0%) residia nos estados vizinhos e tinha história de falha de tratamento antituberculose (n = 125; 94.7%); 18 (13.6%) apresentavam status retroviral positivo. Doze pacientes (9,1%) apresentaram audiogramas normais, e 104 (78,8%) apresentaram perda auditiva neurossensorial, sendo as configurações mais comuns do tipo ascendente, em 54 (40,9%), e descendente, em 26 (19,7%). As médias de tons puros em frequências baixas (0,25-1,0 kHz) e altas (2,0-8,0 kHz) foram de 33,0 dB e 40,0 dB, respectivamente. Quanto ao grau de perda auditiva no melhor ouvido, 36 pacientes (27,3%) apresentaram audição normal, e 67 (50,8%) apresentaram perda auditiva leve (26-40 dB), enquanto 29 (21,9%) mostraram perda auditiva moderada ou grave. Entre as variáveis estudadas (idade, gênero, status retroviral, desfecho de tratamento anterior e peso na admissão), somente o gênero masculino foi associado às configurações audiométricas. Conclusões: Nesta amostra de pacientes com TB-R, a maioria apresentou perda auditiva neurossensorial leve e subótima bilateralmente, com configurações audiométricas ascendentes/descendentes associadas ao gênero masculino.

Caracterização audiológica de crianças em tratamento oncológico / Audiological characterization of children under oncologic treatment

Objetivo Investigar os efeitos do tratamento oncológico no sistema auditivo de crianças. Métodos A amostra foi constituída por 12 crianças de 2 a 12 anos de idade, com diagnóstico de câncer e indicação para radioterapia associada ou não à quimioterapia. Foram realizadas pesquisas das emissões otoacústicas produto de distorção (EOA-PD) e emissões otoacústicas transientes (EOA-TE), antes e após seis meses de tratamento. Resultados Das 24 orelhas, apenas duas (8,3%) falharam para as EOA-TE e EOA-PD e não foi observada alteração significativa após o tratamento oncológico. Conclusão O tratamento oncológico, durante um período de seis meses, não ocasionou alterações auditivas nesta amostra. .

Purpose To investigate the effects of cancer treatment on the auditory system of children. Methods The study population comprised 12 children, aged 2 to 12 years, who had been diagnosed with cancer and recommended radiotherapy with/without chemotherapy. Distortion product otoacoustic emissions (DP-OAE) and transient evoked otoacoustic emissions OAE (TE-OAE) were measured before treatment and after six months of treatment. Results Out of the 24 ears, only two ears (8.3%) failed the TE-OAE and DP-OAE tests, and no significant change was observed after cancer treatment. Conclusion Cancer treatment over a period of six months did not cause hearing impairment in this group of patients. .

Lack of protection against gentamicin ototoxicity by auditory conditioning with noise / Falta de proteção contra a ototoxicidade da gentamicina pelo condicionamento auditivo com ruído

INTRODUCTION: Auditory conditioning consists of the pre-exposure to low levels of a potential harmful agent to protect against a subsequent harmful presentation. OBJECTIVE: To confirm if conditioning with an agent different from the used to cause the trauma can also be effective. METHOD: Experimental study with 17 guinea pigs divided as follows: group Som: exposed to 85 dB broadband noise centered at 4 kHz, 30 minutes a day for 10 consecutive days; group Cont: intramuscular administration of gentamicin 160 mg/kg a day for 10 consecutive days; group Expt: conditioned with noise similarly to group Som and, after each noise presentation, received gentamicin similarly to group Cont. The animals were evaluated by distortion product otoacoustic emissions (DPOAEs), brainstem auditory evoked potentials (BAEPs) and scanning electron microscopy. RESULTS: The animals that were conditioned with noise did not show any protective effect compared to the ones that received only the ototoxic gentamicin administration. This lack of protection was observed functionally and morphologically. CONCLUSION: Conditioning with 85 dB broadband noise, 30 min a day for 10 consecutive days does not protect against an ototoxic gentamicin administration of 160 mg/kg a day for 10 consecutive days in the guinea pig. .

INTRODUÇÃO: O condicionamento auditivo consiste da pré-exposição de um agente lesivo em baixos níveis para proteger contra uma posterior apresentação lesiva. OBJETIVO: Confirmar se o condicionamento com um agente diferente do utilizado para causar o trauma pode ser efetivo. MÉTODO: Estudo experimental com 17 cobaias albinas divididas como a seguir- grupo Som: exposto a um ruído branco de 85 dB centrado em 4 kHz, 30 minutos por dia, por 10 dias consecutivos; grupo Cont: administração intramuscular de gentamicina 160 mg/kg por dia, por 10 dias consecutivos; grupo Expt: condicionado com ruído como o grupo Som. Após cada exposição ao ruído, recebeu gentamicina similarmente ao grupo Cont. Os animais foram avaliados por emissões otoacústicas produto de distorção (EOAPDs), potencial evocado auditivo de tronco encefálico (PEATE) e microscopia eletrônica de varredura (MEV). RESULTADOS: Os animais que foram condicionados com ruído não mostraram qualquer efeito protetor quando comparados com os que receberam apenas a gentamicina em doses ototóxicas. Esta ausência de proteção foi observada tanto funcionalmente quanto morfologicamente. CONCLUSÃO: Os autores concluíram que o condicionamento com ruído branco a 85 dB por 30 minutos, por dia por 10 dias consecutivos, não protege contra uma administração de gentamicina 160 mg/kg/dia, por 10 dias consecutivos. .

First report onoototoxicity of meglumine antimoniate / Primeiro relato de ototoxicidade pelo antimoniato de meglumina

Introduction: Pentavalent antimonials are the first drug of choice in the treatment of tegumentary leishmaniasis. Data on ototoxicity related with such drugs is scarcely available in literature, leading us to develop a study on cochleovestibular functions. Case Report: A case of a tegumentary leishmaniasis patient, a 78-year-old man who presented a substantial increase in auditory threshold with tinnitus and severe rotatory dizziness during the treatment with meglumine antimoniate, is reported. These symptoms worsened in two weeks after treatment was interrupted. Conclusion: Dizziness and tinnitus had already been related to meglumine antimoniate. However, this is the first well documented case of cochlear-vestibular toxicity related to meglumine antimoniate.

Introdução: Antimoniais pentavalentes são os fármacos de primeira escolha no tratamento da leishmaniose tegumentar. Dados de ototoxicidade relacionados a tais fármacos são escassos na literatura, o que nos levou a desenvolver um estudo de funções cócleo-vestibulares. Relato de caso: Relatamos caso de paciente masculino de 78 anos com leishmaniose tegumentar, que apresentou aumento significativo dos limiares auditivos com zumbido e tontura rotatória grave durante o tratamento com antimoniato de meglumina. Os sintomas pioraram até duas semanas após a interrupção do tratamento. Conclusão: Tontura e zumbido já tinham sido associados ao antimoniato de meglumina. Entretanto, este é o primeiro caso bem documentado de toxicidade cócleo-vestibular relacionado ao antimoniato de meglumina.

Effect of the ketamine/xylazine anesthetic on the auditory brainstem response of adult gerbils

The auditory brainstem response (ABR) is a test widely used to assess the integrity of the brain stem. Although it is considered to be an auditory-evoked potential that is influenced by the physical characteristics of the stimulus, such as rate, polarity and type of stimulus, it may also be influenced by the change in several parameters. The use of anesthetics may adversely influence the value of the ABR wave latency. One of the anesthetics used for e ABR assessment, especially in animal research, is the ketamine/xylazine combination. Our objective was to determine the influence of the ketamine/xylazine anesthetic on the ABR latency values in adult gerbils. The ABRs of 12 adult gerbils injected with the anesthetic were collected on three consecutive days, or a total of six collections, namely: pre-collection and A, B, C, D, and E collections. Before each collection the gerbil was injected with a dose of ketamine (100 mg/kg)/xylazine (4 mg/kg). For the capture of the ABR, 2000 click stimuli were used with rarefaction polarity and 13 stimuli per second, 80 dBnHL intensity and in-ear phones. A statistically significant difference was observed in the latency of the V wave in the ABR of gerbils in the C and D collections compared to the pre-, A and E collections, and no difference was observed between the pre-, A, B, and E collections. We conclude that the use of ketamine/xylazine increases the latency of the V wave of the ABR after several doses injected into adult gerbils; thus clinicians should consider the use of this substance in the assessment of ABR.

Temporal auditory processing in rural workers exposed to pesticide / Processamento auditivo temporal de trabalhadores rurais expostos a agrotóxico

PURPOSE: The objective of this research was to assess the ordering and temporal resolution auditory abilities in rural workers exposed to pesticides and compare them with laborers exposure index. METHODS: A sectional study assessed 33 individuals of both genders, aged 18-59 years, who were exposed to pesticides during their daily routine. The procedures were: questionnaire, meatoscopy, basic audiological evaluation and Temporal Auditory Processing tests: pattern test duration and Gaps-in-Noise. In order to analyse the results, a variable called 'index of exposure' was set up through a simple sum of variables present in the questionnaire. The tests' results on Temporal Auditory Processing were categorized according to the tercis of distribution, based on the results observed - in this study, tertile 1, tertile 2, and tertile 3 - and then compared with the exposure index. RESULTS: Difference was verified in all tertiles, with a dose-response relationship, i.e. increased average exposure was associated to worse performance on pattern test duration (p=0.001) and Gaps-in-Noise (p=0.001) in all tertiles. The highest correlation was observed between tertiles 3 and 1. CONCLUSION: Workers exposed to pesticide performed bellow average on Temporal Auditory Processing tests. There was association between the index of exposure to pesticides and worse performance in Temporal Auditory Processing tests, suggesting that the pesticides may be harmful to central auditory pathways.

OBJETIVO: Investigar as habilidades auditivas de ordenação e resolução temporal, em trabalhadores rurais expostos ocupacionalmente a agrotóxicos, e correlacionar estes resultados com o grau de exposição dos laboriosos a estas substâncias. MÉTODOS: Foi realizado um estudo seccional, por meio da avaliação de 33 indivíduos de ambos os gêneros, com idades entre 18 e 59 anos, expostos ocupacionalmente a agrotóxicos. Aplicou-se os seguintes procedimentos: questionário, meatoscopia, audiometria, imitanciometria e testes do Processamento Auditivo Temporal: Teste de Padrão de Duração e Gaps-in-Noise. Para análise dos resultados criou-se uma variável denominada índice de exposição, por meio de um somatório de variáveis presentes no questionário. Os resultados dos testes de Processamento Auditivo Temporal aplicados foram categorizados segundo os tercis de distribuição, de acordo com o resultado observado - sendo neste estudo denominado de Tercil 1, Tercil 2 e Tercil 3 - e então, comparado com o índice de exposição. RESULTADOS: Verificou-se diferença em todos os tercis, havendo relação dose-resposta: conforme foi aumentada a média de exposição, pior foi o desempenho no Teste de Padrão de Duração (p=0,001) e no Gaps-in-Noise (p=0,001), em todos os tercis. A maior correlação foi observada entre o Tercil 3 e o Tercil 1. CONCLUSÃO: Os trabalhadores expostos ao agrotóxico apresentaram desempenho inferior ao esperado para os padrões de normalidade nos testes de Processamento Auditivo Temporal. Houve associação entre o índice de exposição a agrotóxico e pior desempenho nos testes de Processamento Auditivo Temporal, sugerindo que o agrotóxico pode ser uma substância nociva às vias auditivas centrais.

Limiares auditivos em crianças expostas a mercúrio no período pré-natal / Hearing thresholds in children exposed to mercury in the prenatal period

OBJETIVO: Avaliar os limiares auditivos de crianças com histórico de exposição ao mercúrio durante o período pré-natal. MÉTODOS: Foram avaliadas 90 crianças com idades entre 8 e 10 anos, de ambos os gêneros, categorizadas em dois grupos de acordo com os níveis de exposição pré-natal ao mercúrio. O grupo de estudo foi composto por 57 crianças que apresentaram níveis de mercúrio no cordão umbilical iguais ou superiores a 8 µg/L, e o grupo de comparação por 33 crianças que apresentaram níveis de mercúrio no cordão umbilical inferiores a 8µg/L. Os procedimentos incluíram um questionário, audiometria tonal liminar, pesquisa do limiar de recepção de fala e análise das doses de mercúrio no cordão umbilical coletadas ao nascimento. RESULTADOS: O grupo de estudo apresentou mediana de mercúrio no cordão umbilical de 14,63 µg/L, e mediana dos limiares tonais das frequências de 500 Hz, 1 kHz e 2 kHz de 10 dB em ambas orelhas. O grupo de comparação apresentou mediana de mercúrio no cordão umbilical de 4,88 µg/L, e mediana dos limiares tonais das frequências de 500 Hz, 1 kHz e 2 kHz de 10 dB em ambas orelhas. Quando comparados os limiares auditivos, tanto pela média tritonal quanto para cada frequência isoladamente, não foram observadas diferenças significativas entre os grupos. CONCLUSÃO: As crianças apresentaram limiares auditivos dentro dos padrões de normalidade e não foi observada diferença significativa entre os limiares auditivos das crianças expostas e não-expostas ao mercúrio no período pré-natal.

PURPOSE: To evaluate hearing thresholds in children with a history of exposure to mercury during the prenatal period. METHODS: Participants were 90 children of both genders with ages from 8 to 10 years, divided into two groups according to prenatal mercury exposure levels. The study group was composed by 57 children who had mercury levels in the umbilical cord equal or above 8 µg/L, and the comparison group comprised 33 children who had mercury levels in the umbilical cord below 8 µg/L. Investigation procedures included the application of a questionnaire, pure-tone audiometry, speech reception threshold, and mercury level analysis in cord blood collected at birth. RESULTS: The study group showed a median mercury level in the umbilical cord of 14.63 µg/L, and the median threshold for 500 Hz, 1 kHz and 2 kHz in pure-tone audiometry was 10 dB for both ears. The comparison group had a median cord blood mercury level of 4.88 µg/L, and the median threshold for 500 Hz, 1 kHz and 2 kHz in pure-tone audiometry was 10 dB for both ears. When the hearing thresholds were compared, both by the tritonal mean and by each frequency separately, there were no significant differences between groups. CONCLUSION: The children had hearing thresholds within normal limits and there was no significant difference between the hearing thresholds of children exposed and not exposed prenatally to mercury.

Efeito do metilfenidato no processamento auditivo em crianças e adolescentes com transtorno do deficit de atenção/hiperatividade / Effects of methylphenidate in auditory processing evaluation of children and adolescents with attention deficit hyperactivity disorder

OBJETIVO: Comparar o desempenho em teste de avaliação do processamento auditivo (PA) num grupo de crianças e adolescentes com transtorno do déficit de atenção e hiperatividade (TDAH) pré e pós-metilfenidato. MÉTODO: Foram aplicados testes comportamentais padronizados de avaliação do PA em 29 indivíduos com TDAH na faixa etária de 7 a 15 anos, de ambos os sexos. Utilizou-se um grupo de comparação de 29 indivíduos sem déficit de atenção, com e sem transtornos de aprendizado. RESULTADOS: O grupo com TDAH apresentou desempenho nos testes de PA semelhante ao grupo controle sem transtornos do aprendizado sendo seus resultados ainda melhores na ocasião pós-medicação. O grupo sem déficit de atenção e com problemas de aprendizagem apresentou o pior desempenho nos testes de PA e o grupo sem déficit de atenção e sem problemas de aprendizagem foi o que apresentou o melhor desempenho. CONCLUSÃO: O teste de PA não permitiu diferenciar portadores de TDAH de controles pareados; o metilfenidato se associou a melhora do desempenho nos testes de PA nos portadores de TDAH.

PURPOSE: To compare the performance of a group of children and adolescents diagnosed with attention deficit hyperactivity disorder (ADHD) pre and post-methylphenidate use in a behavioral auditory processing test battery (AP). METHOD: Twenty-nine subjects, male and female, ranging from 7 to 15 years old have undergone different behavioral auditory processing tests. A control group composed of 29 subjects with and without learning disabilities was also evaluated. RESULTS: The group with ADHD had a performance similar to the control group without learning disabilities which improved after medication. The group with learning disabilities and without ADHD had the worst performance in tests while the group without learning disabilities and without ADHD exhibited the best ones. CONCLUSION: The AP battery was unable to distinguish ADHD patients from paired controls; the use of methylphenidate improved the performance on AP tests of ADHD group in the post-medication evaluation.

A comparison of the protective effects of systemic administration of a pro-glutathione drug and a Src-PTK inhibitor against noise-induced hearing loss.

Both the antioxidant, n-l-acetyl cysteine (L-NAC) and the Src inhibitor, KX1-004, have been used to protect the cochlea from hazardous noise. To date, KX1-004 has only been used locally on the round window. In the current study, the two drugs were administered systemically. LNAC was delivered intraperitoneally at a dose of 325 mg/kg while KX1-004 was administered subcutaneously at a dose of 50 mg/kg. The noise exposure consisted of a 4 kHz octave band of noise at 100 dB SPL for 6 hours/day for 4 days. The drugs were administered once each day, 30 minutes prior to the onset of the noise exposure. The animals' hearing was estimated using the evoked response records from surgically-implanted chronic electrodes in the inferior colliculi. Animals treated with LNAC and KX1-004 had from 10 to 20 dB less temporary threshold shift at day 1 and an average 10 dB less permanent threshold shift by day 21 when compared to control saline treated animals. There were no significant side effects (i.e.: appetite loss, weight loss, lethargy, etc.) related to either of the drug treatments. KX1-004 produced at least as much protection as L-NAC, but at a significantly lower concentration.

Critical period for styrene ototoxicity in the rat.

The current experiments were undertaken to determine whether or not styrene-induced hearing loss in the rat depends more on the existence of a critical period between 14 and 21 weeks of age than on body weight. For these purposes, two experiments were carried out with mature Long-Evans rats. In the first experiment, two groups of 5-month old rats, but having different body weight (slim: 314 g vs. fat: 415 g) were exposed to 700 ppm styrene for 4 consecutive weeks, 5 days per week, 6 hours per day. In the second experiment, two groups of rats having the same weight: 345 g, but different ages (14- vs. 21- week old) were exposed to styrene in strictly identical experimental conditions. Auditory sensitivity was tested by recording evoked potentials from the inferior colliculus. Surface preparations of the organ of Corti were also performed to complete the investigation. At the end of the six week recovery period following the styrene exposure, a 7 dB permanent threshold shift (PTS) was obtained with the same age animals regardless of the body weight. Consequently, weight was not a major factor in styrene-induced hearing loss. Age was a more critical factor in determining higher sensitivity to styrene. Indeed, the three months old group had 23.5 dB PTS, whereas the five months old group had only a 7.7 dB PTS at 16 kHz. Thus, a 15 dB difference of PTS was obtained between the rats having the same weight but different age. While the weight does not play a major role in styrene ototoxicity, there is a critical period whose duration lasts more than three months and for which the susceptibility to styrene is enhanced.

Ototoxicidade induzida por cis-diamminedichloroplatinum (NSC - 119875): relato de dois casos / Ototoxicity induced by cis-diamminedichloroplatinum (NSC -119875): report of two cases

Este trabalho relata alteraçöes ototóxicas encontradas em dois pacientes portadores de neoplasias malignas e que foram submetidos a esquema quimioterápico com Cis-diamminedichloroplatinum (NSC 119875), tendo apresentado perda auditiva após o uso desta droga. Discutimos as causas, o tipo de lesäo e os danos cocleares ocasionados por esta droga. Outrossim, salientamos a importância do estudo da ototoxicidade dos agentes terapêuticos