Normative values of vestibulo-ocular reflex gain obtained through Video Head Impulse Test: an integrative literature review / Valores normativos para la ganancia del reflejo vestíbulo ocular obtenidos a través de test de impulso cefálico asistido por video: una revisión integrativa de la literatura

ABSTRACT Purpose: to identify and analyze the available evidence on the reference values of the vestibulo-ocular reflex gain obtained with the video head impulse test. Methods: an integrative review based on the PRISMA protocol, searching the ProQuest, EBSCO, PubMed, ScienceDirect, Cochrane Library, LILACS, and SciELO databases with keywords. The studies included were original research articles, systematic reviews, and meta-analyses published since 2009, involving humans, written in English, Spanish and/or Portuguese. Results: 10,250 studies related to the keywords were found. Of these, 10 articles met the inclusion criteria and were analyzed following the CADE protocol. On the horizontal plane, the values ranged from 0.80 to 1.06, while on the right anterior/left posterior and on the left anterior/right posterior planes, the values ranged from 0.80 to 1.03. Other relevant data for obtaining the gain were analyzed, such as the number of impulses, the assessor's experience, the patient-object distance, and the percentage of asymmetry. Conclusion: little research on the theme, recently developed and published, mostly in European countries, was found. This shows the need for a greater number of studies to strengthen the scientific evidence.

RESUMEN Objetivo: identificar y analizar la evidencia disponible sobre los valores de referencia para la ganancia del reflejo vestíbulo ocular, obtenido a través del test de impulso cefálico asistido por video. Método: se realizó una revisión integrativa guiada por protocolo PRISMA en las bases de datos Proquest, Ebsco, Pubmed, ScienceDirect, Cochrane Library, LILACS y Scielo de acuerdo a términos claves. Fueron incluídos artículos originales de investigación, revisiones sistemáticas y metaanálisis, publicados desde el año 2009, realizados en humanos y en idiomas inglés, español y portugués. Resultados: se encontraron 10.250 estudios relacionados con los términos claves utilizados. 10 artículos cumplieron con los criterios de inclusión y fueron analizados según protocolo CADE. Para plano horizontal los valores varían entre 0.80 y 1.06; mientras que para los planos DerechoAnterior/IzquierdoPosterior e IzquierdoAnterior/DerechoPosterior, los valores oscilan entre 0.80 y 1.03. Se analizaron también otros datos relevantes para la obtención de la ganancia, como la cantidad de impulsos, experiencia del evaluador, distancia paciente-objetivo y porcentaje de asimetría. Conclusión: la investigación en torno al tema es escasa, ha sido desarrollada y publicada de manera reciente en países principalmente europeos; demostrando la necesidad de contar con un mayor número de estudios para fortalecer la evidencia científica.

Aplicações dos potenciais evocados miogênicos vestibulares: revisão sistemática de literatura / Applications of vestibular-evoked myogenic potentials: a systematic literature review

RESUMO Objetivos Revisar a literatura científica sobre as principais técnicas usadas para gerar o potencial evocado miogênico vestibular (VEMP) e suas aplicações clínicas. Estratégia de pesquisa Os artigos que descrevem os métodos de registro e as aplicações do VEMP foram localizados nas bases de dados PubMed, Web of Science, MEDLINE, Scopus, LILACS e SciELO. O levantamento realizado limitou-se aos artigos publicados nos idiomas Inglês, Português e Espanhol, entre janeiro de 2012 e maio de 2018. Critérios de seleção Artigos sobre os aspectos técnicos para a realização do VEMP ocular, cervical ou do músculo sóleo, com estimulação auditiva ou galvânica e artigos sobre as aplicações clínicas do VEMP foram incluídos; artigos repetidos nas bases de dados, artigos de revisão de literatura, relato de casos, cartas e editoriais foram excluídos. Resultados A estratégia de busca resultou na seleção de 28 artigos. Os estudos evidenciaram três métodos de registro do VEMP: cervical, ocular e no músculo sóleo. As aplicações clínicas do VEMP incluíram doença de Ménière, neurite vestibular, síndrome da deiscência do canal semicircular superior, doença de Parkinson, lesões centrais isquêmicas e mielopatias motoras. Conclusão Independentemente da técnica de registro, o VEMP mostrou-se útil como ferramenta complementar para o diagnóstico de doenças vestibulares periféricas e centrais.

ABSTRACT Purpose To review the scientific literature on the main techniques used to generate vestibular-evoked myogenic potential (VEMP) and its clinical applications. Research strategy A search for articles describing VEMP recording methods and applications was conducted in the PubMed, Web of Science, MEDLINE, Scopus, LILACS and SciELO databases. The search was limited to articles published in English, Portuguese, and Spanish between January 2012 and May 2018. Selection criteria Articles addressing the technical aspects for performing ocular, cervical or soleus VEMP with auditory or galvanic stimulation and articles on the clinical applications of VEMP were included in this review, whereas articles repeated in the databases, literature reviews, case reports, letters, and editorials were excluded. Results The search strategy resulted in the selection of 28 articles. The studies evidenced three methods of VEMP recording: responses from the cervical, ocular and soleus muscle. Clinical applications of VEMP included Meniere's disease, vestibular neuritis, superior semicircular canal dehiscence syndrome, Parkinson's disease, central ischemic lesions, and motor myelopathies. Conclusion Regardless of the recording technique, VEMP has proved to be useful as a complementary tool for the diagnosis of peripheral and central vestibular diseases.

Effect of caffeine on vestibular evoked myogenic potential: a systematic review with meta-analysis / Efeito da cafeína no potencial evocado miogênico vestibular: uma revisão sistemática com metanálise

Abstract Introduction: Caffeine can be considered the most consumed drug by adults worldwide, and can be found in several foods, such as chocolate, coffee, tea, soda and others. Overall, caffeine in moderate doses, results in increased physical and intellectual productivity, increases the capacity of concentration and reduces the time of reaction to sensory stimuli. On the other hand, high doses can cause noticeable signs of mental confusion and error induction in intellectual tasks, anxiety, restlessness, muscle tremors, tachycardia, labyrinthine changes, and tinnitus. Objective: Considering that the vestibular evoked myogenic potential is a clinical test that evaluates the muscular response of high intensity auditory stimulation, the present systematic review aimed to analyze the effects of caffeine on vestibular evoked myogenic potential. Methods: This study consisted of the search of 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 intervention (caffeine or coffee consumption) and the primary outcome (vestibular evoked myogenic potential). Results: Based on the 253 potentially relevant articles identified through the database search, only two full-text publications were retrieved for further evaluation, which were maintained for qualitative analysis. Conclusion: Analyzing the articles found, caffeine has no effect on vestibular evoked myogenic potential in normal individuals.

Resumo Introdução: A cafeína pode ser considerada a droga mais consumida por adultos em nível mundial, podendo ser encontrada em inúmeros alimentos, como no chocolate, café, chá, refrigerante e outros. Em geral, a cafeína em doses moderadas, produz ótimos rendimentos físico e intelectual, aumenta a capacidade de concentração e diminui o tempo de reação aos estímulos sensoriais. Por outro lado, doses elevadas podem causar sinais perceptíveis de confusão mental e indução de erros em tarefas intelectuais, ansiedade, nervosismo, tremores musculares, taquicardia, alterações labirínticas e zumbido. Objetivo: Considerando que o potencial evocado miogênico vestibular é um teste clínico que avalia a resposta muscular decorrente de estimulação auditiva de alta intensidade, a presente revisão sistemática objetivou analisar o efeito da cafeína sobre o potencial evocado miogênico vestibular. Método: A formulação deste trabalho consistiu na busca dos estudos nas seguintes bases de dados: MEDLINE, CENTRAL, ScienceDirect, Scopus, Web of Science, LILACS, SciELO e Clinical-Trials.gov. Adicionalmente, a literatura cinzenta também foi pesquisada. A estratégia de busca incluiu termos relacionados à intervenção (consumo de cafeína ou café) e ao desfecho primário (potencial evocado miogênico vestibular). Resultados: A partir de 253 registros potencialmente relevantes identificados através da busca nas bases de dados, apenas duas publicações em texto completo foram recuperadas para avaliação mais aprofundada, sendo estas mantidas para a análise qualitativa. Conclusão: Diante dos artigos encontrados a cafeína não tem efeito sobre o potencial evocado miogênico vestibular em sujeitos normais.

Pitfalls in the Diagnosis of Vertigo

Vertigo/dizziness is a common complaint in patients who are seeking a primary health clinic. Vertigo is traditionally attributed to damage of the vestibular system. Many peripheral and central vestibular disorders are usually presented with vertigo. However, patients with benign paroxysmal positional vertigo (BPPV), a leading cause of vertigo, may present with postural lightheadedness, near faint, imbalance rather than true vertigo. On the contrary, patients with orthostatic hypotension may present with true spinning vertigo, not dizziness. Persistent postural perceptual dizziness, a second most common cause of dizziness (after BPPV), is mainly occurred after organic vestibular disorders such as BPPV or vestibular neuritis, and classified as a chronic functional vestibular disorder. This article describes non-vestibular disorders presenting dizziness and/or vertigos, which conditions may be misdiagnosed as structural vestibular disorders.

Paroxismia vestibular: reporte de un caso / Vestibular paroxysmia: case report

Presentamos el caso de un paciente joven quien presenta 4 a 5 crisis diarias de vértigo espontáneo de segundos de duración, todos o casi todos los días desde hace 9 meses. Estas crisis no tienen gatillo posicional, y hay completa ausencia de sintomatologia entre crisis. Como discutimos en el artículo, este cuadro coíncide con los recientemente publicados criterios para una paroxismia vestibular, entidad supuestamente secundaria a la compresión neurovascular del nervio vestibular. El paciente respondió de forma inmediata y completa a carbamazepina a dosis bajas, el tratamiento de elección en la paroxismia vestibular.

We present the case of a young patient, with a 9-month long history of 4 to 5 daily spells of spontaneous vertigo, each lasting only seconds. There is no positional trigger, and there is a complete lack of symptoms between attacks. As is discussed in the article, this matches the recently published criteria for Vestibular Paroxysmia, an entity allegedly secondary to neurovascular compression of the vestibular nerve. The patient responded immediately and completely to carbamazepine at low dosage, the preferred treatment for vestibular paroxysmia.

Labyrinthectomy and Vestibular Neurectomy for Intractable Vertiginous Symptoms

Abstract Introduction Labyrinthectomy and vestibular neurectomy are considered the surgical procedures with the highest possibility of controlling medically untreatable incapacitating vertigo. Ironically, after 100 years of the introduction of both transmastoid labyrinthectomy and vestibular neurectomy, the choice of which procedure to use rests primarily on the evaluation of the hearing and of the surgical morbidity. Objective To review surgical labyrinthectomy and vestibular neurectomy for the treatment of incapacitating vestibular disorders. Data Sources PubMed, MD consult and Ovid-SP databases. Data Synthesis In this review we describe and compare surgical labyrinthectomy and vestibular neurectomy. A contrast between surgical and chemical labyrinthectomy is also examined. Proper candidate selection, success in vertigo control and complication rates are discussed on the basis of a literature review. Conclusions Vestibular nerve section and labyrinthectomy achieve high and comparable rates of vertigo control. Even though vestibular neurectomy is considered a hearing sparing surgery, since it is an intradural procedure, it carries a greater risk of complications than transmastoid labyrinthectomy. Furthermore, since many patients whose hearing is preserved with vestibular nerve section may ultimately lose that hearing, the long-term value of hearing preservation is not well established. Although the combination of both procedures, in the form of a translabyrinthine vestibular nerve section, is themost certain way to ablate vestibular function for patients with no useful hearing and disabling vertigo, some advocate for transmastoid labyrinthectomy alone, considering that avoiding opening the subarachnoid space minimizes the possible intracranial complications. Chemical labyrinthectomy may be considered a safer alternative, but the risks of hearing loss when hearing preservation is desired are also high.

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.

Cardiovascular Risk Factors in Total or Divisional Vestibular Neuritis / 대한평형의학회지

OBJECTIVES: In vestibular neuritis (VN), the lesion preferentially affects the superior vestibular nerve because of the anatomic arrangement. It is well known that VN patients have a higher score of metabolic syndrome or a higher incidence of vertebral artery hypoplasia than controls. However, it is unclear whether the frequency of cardiovascular risk factors can affect the selective involvement of the branch of the vestibular nerve. Thus, we investigated the influence of cardiovascular risk factors on the development of total- or divisional VN. METHODS: 61 patients with VN were enrolled. Video head impulse tests and caloric tests were performed to determine which vestibular divisionswere affected. The patients were divided into divisional-VN (superior or inferior) and total-VN groups. Statistical analysis of the frequency of cardiovascular risk factors was performed only in superior and total VN groups because the number of inferior VN patients was too small to be statistically analyzed. RESULTS: Nineteen (31.1%) patients were classified as the total-VN group. In the divisional-VN group (42 patients, 65.6%), 40 were superior VN. The frequency of cardiovascular risk factors are not significantly different in superior VN and total-VN groups (All patients 50/61 [82.0%], superior-VN 36/40 [90.0%], total-VN 13/19 [68.4%]). The frequency of having more than one cardiovascular risk factor was slightly higher in the superior VN group, (13 [68.4%] vs. 36 [90.0%], p=0.062) but did not show any significant difference. CONCLUSIONS: The number of cardiovascular risk factors did not differ in superior VN patients compared to total VN patients.

Potencial evocado miogênico vestibular ocular e cervical simultâneo em indivíduos normais / Ocular and cervical vestibular evoked myogenic potential simultaneous in normal individuals

RESUMO Objetivo: Caracterizar o registro e analisar os resultados do potencial evocado miogênico vestibular cervical e ocular combinado em indivíduos sem queixas auditivas e vestibulares. Métodos: Participaram da pesquisa 30 indivíduos sem queixa auditiva e com audição dentro dos padrões de normalidade. A coleta de dados foi realizada por meio do potencial evocado miogênico vestibular cervical e ocular registrados simultaneamente. Resultados: Houve diferença entre as orelhas direita e esquerda para a amplitude das ondas P13 e N23 do potencial evocado miogênico vestibular cervical e para a latência da onda N10 do potencial evocado miogênico vestibular ocular. No gênero feminino não houve diferença entre as orelhas direita e esquerda para a amplitude das ondas P13, N23, N10, P15, interamplitude no potencial evocado miogênico vestibular cervical e interamplitude no potencial evocado miogênico vestibular ocular e para a latência das ondas P13, N23, N10 e P15. No gênero masculino houve diferença entre as orelhas direita e esquerda para a amplitude da onda P13. Conclusão: Os resultados do potencial evocado miogênico vestibular cervical e ocular combinado foram consistentes, uma vez que as respostas geradas pelos potenciais evocados miogênicos vestibulares apresentaram morfologia, latência e amplitude adequadas, o que permite a avaliação da via vestibular ipsilateral descendente e da via vestibular contralateral ascendente.

ABSTRACT Purpose: To characterize the recording and analyze the results of the combined cervical and ocular vestibular evoked myogenic potential in individuals without hearing and vestibular complaints. Methods: In this study, 30 individuals without hearing complaints and hearing within normal limits were evaluated. Data were collected through the simultaneous recording of cervical and ocular vestibular evoked myogenic potential. Results: Differences were observed between the right and left ears for the amplitude of waves P13 and N23 of the cervical vestibular evoked myogenic potential and the latency of wave N10 of the ocular vestibular evoked myogenic potential. For female subjects, there was no difference between the right and left ears for the amplitude of waves P13, N23, N10, and P15; interamplitude in cervical vestibular evoked myogenic potential and interamplitude in ocular vestibular evoked myogenic potential; and latency in waves P13, N23, N10, and P15. For male subjects, there was a difference between the right and left ears for the amplitude of wave P13. Conclusion: The results of the combined cervical and ocular vestibular evoked myogenic potentials were consistent, because the responses generated by the vestibular evoked myogenic potentials presented an adequate morphology, latency, and amplitude, allowing for the evaluation of the ipsilateral descending vestibular pathways and the contralateral ascending vestibular pathways.

A Case of Patient with Meniere's Disease Who Presented Periodic Alternating Nystagmus / 대한평형의학회지

Periodic alternating nystagmus (PAN) is a spontaneous horizontal jerky nystagmus that reverses its direction periodically with a quiescent interval. PAN has been reported in acquired and congenital forms. The main lesion site of the acquired form of PAN has been attributed to the caudal brainstem or cerebellum. Herein we report a 63-year-old male patient with Meniere's disease, who presented PAN during a vertigo attack. The patient demonstrated no abnormality on neurologic evaluation and brain imaging, which is different feature compared to the central or congenital form of PAN. It should be kept in mind that peripheral vestibular disorders such as Meniere's disease can produce PAN.

Potencial evocado miogênico vestibular ocular: revisão de literatura / Ocular vestibular evoked myogenic potential: literature review

RESUMO Objetivo Identificar e sistematizar os principais estudos sobre o potencial evocado miogênico vestibular ocular e suas aplicações no diagnóstico das diversas doenças vestibulares. Estratégia de pesquisa Foram localizados artigos que descrevem a utilização do potencial evocado miogênico vestibular ocular na avaliação de doenças vestibulares nas bases PubMed, Web of Science, MEDLINE, Scopus, LILACS e SciELO. Critérios de seleção Foram incluídos estudos originais, com resumo disponível, publicados no período de janeiro de 2010 a março de 2016. Análise dos dados Foi realizada a descrição do delineamento do estudo e elencados os achados para a avaliação de potencial evocado miogênico vestibular ocular. Resultados Foram encontrados 265 estudos, dos quais 14 contemplaram os critérios de seleção propostos. Em relação à população/amostra de pacientes com alterações vestibulares incluída nos estudos, observou-se que as doenças mais investigadas foram a neurite vestibular, a vertigem posicional paroxística benigna, o Schwanoma vestibular e a doença de Ménière. Conclusão A maior parte das pesquisas realizadas nos últimos anos e publicadas nas bases de dados PubMed, Web of Science, MEDLINE e Scopus revelou que o potencial evocado miogênico vestibular ocular representa um método eficaz para avaliar a função utricular nas mais diversas doenças vestibulares.

ABSTRACT Purpose To identify and systematize the main studies on the ocular vestibular evoked myogenic potentials and their applications in the diagnosis of various vestibular diseases. Research strategy Articles that describe the use of ocular vestibular evoked myogenic potentials the evaluation of vestibular diseases were located in PubMed, Web of Science, MEDLINE, Scopus, LILACS e SciELO. Selection criteria Original studies, with available abstract, published in the period 2010 to March 2016 were included. Data analysis The study design was described, and the characteristics for the evaluation of ocular vestibular evoked myogenic potentials were listed. Results 265 studies were found, but just 14 contemplated the proposed selection criteria. In relation to the population / sample of patients with vestibular disorders included in the study, it was observed that the most researched diseases were the vestibular neuritis, benign paroxysmal positional vertigo, vestibular Schwanoma and Meniere's disease. Conclusion The most of the research realized in recent years and published in the databases PubMed, Web of Science, MEDLINE and Scopus revealed that the ocular vestibular evoked myogenic potentials is an effective method to evaluate the utricular function in various vestibular disorders.

Reproducibility (test-retest) of vestibular evoked myogenic potential / Reprodutibilidade (teste-reteste) do potencial evocado miogênico vestibular

INTRODUCTION: There is still no consensus in the literature as to the best acoustic stimulus for capturing vestibular evoked myogenic potential (VEMP). Low-frequency tone bursts are generally more effective than high-frequency, but recent studies still use clicks. Reproducibility is an important analytical parameter to observe the reliability of responses. OBJECTIVE: To determine the reproducibility of p13 and n23 latency and amplitude of the VEMP for stimuli with different tone-burst frequencies, and to define the best test frequency. METHODS: Cross-sectional cohort study. VEMP was captured in 156 ears, on the sternocleidomastoid muscle, using 100 tone-burst stimuli at frequencies of 250, 500, 1000, and 2000 Hz, and sound intensity of 95 dB nHL. Responses were replicated, that is, recorded three times on each side. RESULTS: No significant difference was observed for p13 and n23 latencies of the VEMP, captured at three moments with tone-burst stimuli at 250, 500, and 1000 Hz. Only the frequency of 2000 Hz showed a difference between captures of this potential (p < 0.001). p13 and n23 amplitude analysis was also similar in the test-retest for all frequencies analyzed. CONCLUSION: p13 and n23 latencies and amplitudes of VEMP for tone-burst stimuli at frequencies of 250, 500, and 1000 Hz are reproducible. .

INTRODUÇÃO: Ainda não existe consenso quanto ao melhor estímulo acústico utilizado para a captação do potencial evocado miogênico vestibular (PEMV). Respostas amplas são observadas para estímulos de baixa frequência, porém estudos recentes ainda utilizam cliques. A reprodutibilidade dos traçados é um importante parâmetro de análise para observar a confiabilidade das respostas. OBJETIVO: Verificar a reprodutibilidade dos parâmetros ''latência e amplitude das ondas p13 en23'' do PEMV para estímulos com diferentes frequências de estímulos do tipo tone burst, e definir a melhor frequência de teste. MÉTODO: Estudo de coorte-transversal. Captou-se PEMV em 156 orelhas, no músculo esternocleidomastóideo, com 100 estímulos do tipo tone burst nas frequências de 250, 500, 1.000 e 2.000 Hz e nível sonoro 95 dB NAn, registrados três vezes de cada lado. RESULTADOS: Foram constatadas similaridades para latências de p13 e n23 do potencial estudado nos três momentos com estímulos tone burst em 250, 500, 1.000 Hz, e diferenças entre as captações desse potencial (p < 0,001) para a frequência de 2.000 Hz. A análise da amplitude de p13 e n23 se mostrou semelhante, no teste-reteste, para todas as frequências analisadas. CONCLUSÃO: Existe reprodutibilidade das latências e amplitudes de p13 e n23 do PEMV para estímulos tone burst nas frequências de 250, 500 e 1.000 Hz. .

Ruptured Total Intrameatal Anterior Inferior Cerebellar Artery Aneurysm

Among the distal anterior inferior cerebellar artery (AICA) aneurysms, a unique aneurysm at the meatal loop inside the internal auditory meatus is extremely rare. The authors report a case of surgically treated total intrameatal AICA aneurysm. A 62-year-old female patient presenting with sudden bursting headache and neck pain was transferred to our department. Computed tomography and digital subtraction angiography showed subarachnoid hemorrhage at the basal, prepontine cistern and an aneurysm of the distal anterior inferior cerebellar artery inside the internal auditory meatus. Surgery was performed by retrosigmoid craniotomy with unroofing of the internal auditory meatus. The aneurysm was identified between the seventh and eighth cranial nerve in the meatus and was removed from the canal and clipped with a small straight Sugita clip. After operation the patient experienced transient facial paresis and tinnitus but improved during follow up.

Vestibular Paroxysmia in a 7-Year-Old Child / 대한평형의학회지

Neurovascular cross-compression of the eighth cranial nerve is characterized by brief attacks of vertigo, unilateral audiologic symptoms such as tinnitus, ear fullness and hearing disturbance and relatively rare disease, in particular, in children. We report a 7-year-old female patient who presented with recurrent spontaneous vertigo, lasting 15 seconds and occuring up to 40 times per day and often associated with physical activity. Her symptoms were developed by hyperventilation. Associated aural symptoms are not founded. Magnetic resonance image showed the eighth cranial nerve compression caused by the vascular loop. She was treated with oxcarbazepine and showed improving symptoms. Therefore we report our clinical experience with a brief review of literature.

Evaluation of Internal Auditory Canal Structures in Tinnitus of Unknown Origin

OBJECTIVES: The aim of the present study was to evaluate the internal auditory canal (IAC) and the nerves inside it to define possible structural differences in cases with subjective tinnitus of unknown origin. METHODS: Cases applying to the ear, nose and throat department with the complaint of tinnitus with unknown origin and having normal physical examination and test results were included in the study (n=78). Patients admitted to the radiology clinic for routine cranial magnetic resonance imaging (MRI) and whose MRI findings revealed no pathologies were enrolled as the control group (n=79). Data for the control group were obtained from the radiology department and informed consent was obtained from all the patients. Diameters of the IAC and the nerves inside it were measured through enhanced images obtained by routine temporal bone MRIs in all cases. Statistical evaluations were performed using Student t-test and statistical significance was defined as P<0.05. RESULTS: Measurements of IAC diameters revealed statistically significant differences between the controls and the tinnitus group (P<0.05). Regarding the diameters of the cochlear nerve, facial nerve, inferior vestibular nerve, superior vestibular nerve, and total vestibular nerve, no statistically significant difference was found between the controls and the tinnitus group. CONCLUSION: Narrowed IAC has to be assessed as an etiological factor in cases with subjective tinnitus of unknown origin.

Potencial evocado miogênico vestibular a baixas frequências de estimulação / Vestibular evoked myogenic potentials using low frequency stimuli

Os potenciais evocados miogênicos vestibulares são reflexos vestíbulo-cervicais, decorrentes da estimulação do sáculo com sons de forte intensidade. São necessários parâmetros de normalidade para indivíduos jovens normais, utilizando-se estímulos a baixas frequências, as quais configuram a região de maior sensibilidade desse órgão sensorial. OBJETIVO: Realizar normatização do potencial evocado miogênico vestibular para baixas frequências de estimulação. MATERIAL E MÉTODO: Captou-se o potencial evocado miogênico vestibular em 160 orelhas, no músculo esternocleidomastoideo, de forma ipsilateral, por meio da promediação de 200 tone bursts, frequência de 250 Hz, intensidade de 95 dB NAn. FORMA DE ESTUDO: Estudo de coorte contemporânea com corte transversal. RESULTADOS: Aplicando-se o teste T de Student ou o Teste de Mann-Whitney, não foi constatada diferença significativa para parâmetros do potencial evocado miogênico vestibular entre os gêneros, para p <; 0,05. Verificamos, independente do gênero, latências de p13, n23 e interpicos p13-n23 iguais a 13,84ms (± 1,41), 23,81ms (±1,99) e 10,62ms (± 6,56), respectivamente. Observamos índices de assimetria iguais a 13,48 por cento para mulheres e 3,81 por cento para homens. CONCLUSÃO: Estímulos de baixa frequência geram respostas de potenciais evocados miogênicos vestibulares, com morfologia e amplitudes adequadas, sendo determinados, valores de normalidade para essa frequência, em indivíduos normais.

Vestibular evoked myogenic potentials are vestibulocervical reflexes resulting from sacculus stimulation with strong intensity sounds. Normality parameters are necessary for young normal individuals, using low frequency stimuli, which configure the most sensitive region of this sensory organ. AIM: To establish vestibular evoked myogenic potential standards for low frequency stimulation. MATERIAL AND METHOD: Vestibular evoked myogenic potential was captured from 160 ears, in the ipsilateral sternocleidomastoid muscle, using 200 averaged tone-burst stimuli, at 250 Hz, with an intensity of 95 dB NAn. CASE STUDY: Clinical observational cross-sectional. RESULTS: Neither the student's t-test nor the Mann-Whitney test showed a significant difference in latency or vestibular evoked myogenic potential amplitudes, for p <; 0.05. Irrespective of gender, we found latencies of p13-n23 and p13-n23 interpeaks of 13.84 ms (± 1.41), 23.81 ms (±1.99) and 10.62 ms (± 6.56), respectively. Observed values for amplitude asymmetry between the ears were equal to 13.48 percent for females and 3.81 percent for males. CONCLUSION: Low frequency stimuli generate vestibular evoked myogenic potentials, with adequate morphology and amplitude, thereby enabling the establishment of standard values for normal individuals at this frequency.

Contralateral Suppression of Transient Evoked Otoacoustic Emission in Vestibular Neuritis / 대한평형의학회지

BACKGROUND AND OBJECTIVES: The etiology of vestibular neuritis is unknown. Many investigators have suggested that this condition spares the inferior vestibular nerve system. However, others have reported that the lesion sometimes affects the inferior vestibular nerve system based on vestibular evoked myogenic potential. The function of the inferior vestibular nerve was studied in acute vestibular neuritis by monitoring medial olivocochlear bundle (MOCB) function. Under normal conditions, contralateral acoustic stimulation has inhibitory effects on ipsilateral otoacoustic emissions through the MOCB. MATERIALS AND METHODS: Twenty patients that presented with dizziness and spontaneous nystagmus, and were confirmed to have acute vestibular neuritis by rotatory chair and caloric testing were enrolled in this study. We evaluated the evoked otoacoustic emissions with and without contralateral acoustic stimulation in both ears in all patients. The percent loss of normal inhibitory action on otoacoustic emissions was determined in the normal and affected ears. RESULTS: All patients showed inhibitory effects in response to contralateral acoustic stimulation on evoked otoacoustic emissions in normal ears. Fifteen patients (75%) had an absence of contralateral suppression of otoacoustic emissions on the affected side. CONCLUSION: The findings of this study suggest the presence of dysfunction of the MOCB in patients with acute vestibular neuritis.

Herpes Zoster Oticus Involving Superior And Inferior Vestibular Nerve Without Facial Nerve Palsy

Herpes zoster oticus (HZO) is characterized by auricular vesicles, facial palsy and vestibulocochlear dysfunction. The 8th cranial nerve can be most frequently involved. Rarely, it may be associated with the involvement of 5th, 6th, 9th, 11th or 12th cranial nerve. However, only few cases of HZO involving vestibular nerve without facial nerve palsy have been previously reported. We experienced an unusual case of 38-year-old woman who presented with auricular vesicles, otalgia, and vertigo of whilrling nature but not with facial palsy. Vestibular evoked myogenic potential (VEMP) and caloric tests that were performed to determine which division of vestibular nerve was involved demonstrated that decreased responses in this case. We report a case of HZO involving superior and inferior vestibular nerve without facial palsy that was confirmed by VEMP and caloric tests with a review of literature.

A Case of Herpes Zoster Oticus Involving Vestibular Nerve without Facial Nerve Palsy

Herpes zoster oticus (Ramsay Hunt syndrome) is characterized by facial nerve paralysis associated with vesticular eruptions and cochleovestibular symptoms. Many evidences have supported that it is caused by the reactivation of latent varicella-zoster virus in the geniculate ganglion. Recently we experienced a case 49-year-old man presented severe vertigo and a vesicular eruptions of auricle and external ear canal. It is an unusual variant of herpes zoster oticus that involves only vestibular nerve without facial nerve palsy and hearing loss. We believe this case results from reactivation of latent varicella zoster virus in the vestibular ganglion and report with a review of literatures.

Changes in Vestibular Nerve Activity Following Acute Hypotension in Rats

The basic mechanism for the excitation of the peripheral vestibular receptors following acute hypotension induced by sodium nitroprusside (SNP) or hemorrhage was investigated in anesthetized rats. Electrical activity of the afferent vestibular nerve was measured after pretreatment with kynurenic acid, an NMDA receptor antagonist. The activity of the vestibular nerve at rest following acute hypotension induced by SNP or simulating hemorrhage was a greater increase than in control animals. The gain of the vestibular nerve with sinusoidal rotation following acute hypotension increased significantly compared to control animals. The acute hypotension induced by SNP or hemorrhage did not change the activity of the afferent vestibular nerve after kynurenic acid injection. These results suggest that acute hypotension produced excitation of the vestibular hair cells via glutamate excitotoxicity in response to ischemia.