Combined ocular and cervical vestibular evoked myogenic potential in individuals with vestibular hyporeflexia and in patients with Ménière's disease / Potencial evocado miogênico vestibular ocular e cervical simultâneo em indivíduos com hiporreflexia vestibular e em indivíduos com doença de Ménière

Abstract Introduction: The vestibular evoked myogenic potential is a potential of mean latency that measures the muscle response to auditory stimulation. This potential can be generated from the contraction of the sternocleidomastoid muscle and also from the contraction of extraocular muscles in response to high-intensity sounds. This study presents a combined or simultaneous technique of cervical and ocular vestibular evoked myogenic potential in individuals with changes in the vestibular system, for use in otoneurologic diagnosis. Objective: To characterize the records and analyze the results of combined cervical and ocular VEMP in individuals with vestibular hyporeflexia and in those with Ménière's disease. Methods: The study included 120 subjects: 30 subjects with vestibular hyporeflexia, 30 with Ménière's disease, and 60 individuals with normal hearing. Data collection was performed by simultaneously recording the cervical and ocular vestibular evoked myogenic potential. Results: There were differences between the study groups (individuals with vestibular hyporeflexia and individuals with Ménière's disease) and the control group for most of wave parameters in combined cervical and ocular vestibular evoked myogenic potential. For cervical vestibular evoked myogenic potential, it was observed that the prolongation of latency of the P13 and N23 waves was the most frequent finding in the group with vestibular hyporeflexia and in the group with Ménière's disease. For ocular vestibular evoked myogenic potential, prolonged latency of N10 and P15 waves was the most frequent finding in the study groups. Conclusion: Combined cervical and ocular vestibular evoked myogenic potential presented relevant results for individuals with vestibular hyporeflexia and for those with Ménière's disease. There were differences between the study groups and the control group for most of the wave parameters in combined cervical and ocular vestibular evoked myogenic potential.

Resumo Introdução: O potencial evocado miogênico vestibular é um potencial de média latência que avalia a resposta muscular decorrente de estimulação auditiva. Pode ser gerado a partir da contração do músculo esternocleidomastóideo e também a partir da contração de músculos extraoculares em resposta a sons de elevada intensidade. Este estudo apresenta uma técnica combinada ou simultânea de potencial evocado miogênico vestibular cervical e ocular em indivíduos com alterações no sistema vestibular para que possa ser usada no diagnóstico otoneurológico. Objetivo: Caracterizar o registro e analisar os resultados do potencial evocado miogênico vestibular cervical e ocular combinado em indivíduos com hiporreflexia vestibular e em indivíduos com doença de Ménière. Método: Participaram do estudo 120 indivíduos, 30 com hiporreflexia vestibular, 30 com doença de Ménière e 60 com audição dentro dos padrões de normalidade. A coleta de dados foi feita por meio do potencial evocado miogênico vestibular cervical e ocular registrados simultaneamente. Resultados: Houve diferença entre o grupo de estudo (indivíduos com hiporreflexia vestibular e indivíduos com doença de Ménière) e o grupo controle para a maioria dos parâmetros das ondas no potencial evocado miogênico vestibular cervical e ocular combinado. Para o potencial evocado miogênico vestibular cervical observou-se que o prolongamento da latência das ondas P13 e N23 foi a alteração mais encontrada no grupo de indivíduos com hiporreflexia vestibular e no grupo de indivíduos com doença de Ménière. Para o potencial evocado miogênico vestibular ocular o prolongamento da latência das ondas N10 e P15 foi a alteração mais encontrada no grupo de estudo. Conclusão: O potencial evocado miogênico vestibular cervical e ocular combinado apresentou resultados relevantes para os indivíduos com hiporreflexia vestibular e para os indivíduos com doença de Ménière. Houve diferença entre o grupo de estudo e o grupo controle para a maioria dos parâmetros das ondas no potencial evocado miogênico vestibular cervical e ocular combinado.

Perfil audiológico de idosos submetidos à reabilitação vestibular / Audiologic profile of older adults subjected to vestibular rehabilitation therapy

OBJETIVO: caracterizar o perfil auditivo de idosos com tontura submetidos à Reabilitação Vestibular e comparar os resultados obtidos nas avaliações auditivas de idosos sem tontura. MÉTODOS: estudo observacional analítico transversal com 87 idosos, sendo 35 no grupo com tontura e 52 no grupo sem tontura. Foram realizadas anamnese, audiometria tonal limiar e vocal. Para a análise estatística foi utilizado o programa estatístico Statistical Package for the Social Sciences versão 17.0, com nível de significância de 5% nas análises. RESULTADOS: a perda auditiva neurossensorial de grau leve e moderada esteve presente em 72,4% da amostra, com piora dos limiares de audibilidade por via aérea a partir de 4000Hz em ambos os grupos. O zumbido foi a queixa mais frequente observada na amostra. CONCLUSÃO: o perfil auditivo de idosos com tontura não se diferencia daquele encontrado em idosos sem tontura, sendo observada com maior frequência a perda auditiva neurossensorial leve bilateral de configuração descendente. .

PURPOSE: to characterize the auditory profile of older adults with dizziness undergoing vestibular rehabilitation therapy and to compare the results with the profile of older adults without dizziness. METHODS: a cross-sectional, observational, and analytical study conducted with 87 older adults, 35 in the group with dizziness and 52 in the group without dizziness. The participants were interviewed and subjected to pure-tone threshold audiometry and speech audiometry. Statistical analysis was performed using the software Statistical Package for the Social Sciences version 17.0, at 5% significance. RESULTS: approximately 72.4% of the sample exhibited mild sensorineural hearing loss, with the air conduction threshold of audibility beginning to be affected at 4,000 Hz in both groups. Tinnitus was the complaint most frequently reported by the participants. CONCLUSION: the auditory profile of older adults with dizziness did not differ from the profile exhibited by older adults without dizziness; bilateral mild sensorineural hearing loss with a downward sloping configuration was the most frequent finding. .

Protective Effect of Metformin on Gentamicin-Induced Vestibulotoxicity in Rat Primary Cell Culture

OBJECTIVES: One of the antidiabetic drugs, metformin, have shown that it prevented oxidative stress-induced death in several cell types through a mechanism involving the opening of the permeability transition pore and cytochrome c release. Thus, it is possible that the antioxidative effect of metformin can also serve as protection against gentamicin-induced cytotoxicity related to reactive oxygen species (ROS). The aim of this study was to examine the protective effect of metformin on gentamicin-induced vestibulotoxicity in primary cell culture derived from rat utricle. METHODS: For vestibular primary cell culture, rat utricles were dissected and incubated. Gentamicin-induced cytotoxicity was measured in both the auditory and vestibular cells. To examine the effects of metformin on gentamicin-induced cytotoxicity in the primary cell culture, the cells were pretreated with metformin at a concentration of 1 mM for 24 hours, and then exposed to 2.5 mM gentamicin for 48 hours. The intracellular ROS level was measured using a fluorescent dye, and also measured using a FACScan flow cytometer. Intracellular calcium levels in the vestibular cells were measured with calcium imaging using Fura-2 AM. RESULTS: Vestibular cells were more sensitive to gentamicin-induced cytotoxicity than auditory hair cells. Metformin protects against gentamicin-induced cytotoxicity in vestibular cells. Metformin significantly reduced a gentamicin-induced increase in ROS, and also reduced an increase in intracellular calcium concentrations in gentamicin-induced cytotoxicity. CONCLUSION: Metformin significantly reduced a gentamicin-induced increase in ROS, stabilized the intracellular calcium concentration, and inhibited gentamicin-induced apoptosis. Thus, Metformin showed protective effect on gentamicin-induced cytotoxicity in vestibular primary cell culture.