Vestibular evoked myogenic potentials in the prognosis of sudden hearing loss - a systematic review / O potencial evocado miogênico vestibular no prognóstico da surdez súbita - uma revisão sistemática

Abstract Introduction: Sudden hearing loss is an otorhinolaryngological emergency that often leads to severe damage to the auditory and vestibular function. The vestibular evoked myogenic potential is a test that allows a noninvasive evaluation of the otolithic system function and vestibulospinal and vestibulo-ocular pathways. Objective: To evaluate the importance of vestibular evoked myogenic potential in determining the prognosis of patients with sudden hearing loss. Methods: A search for articles published up to December 2018 was performed in the PubMed, Cochrane, VHL and LILACS databases using MeSH descriptors. Retrospective and prospective articles were included containing cervical or ocular vestibular evoked myogenic potential in sudden hearing loss patients and information on associated vertigo and/or dizziness. Results: Sixteen of 62 initially selected articles met the inclusion criteria and were analyzed. Regarding the methodology of the evaluated studies, 8 studies were prospective, six were retrospective, one contained part of the data from a retrospective analysis and another part from a prospective analysis, and one study was cross-sectional. A total of 872 patients were evaluated (50.22% males and 49.77% females) with a mean age of 51.26 years. Four hundred and twenty-six patients (50.35%) had vertigo and/or dizziness associated with sudden hearing loss. The cervical vestibular evoked myogenic potential was performed in all studies, but only seven assessed the ocular vestibular evoked myogenic potential. The cervical vestibular evoked myogenic potential showed alterations in 38.65% of 846 evaluated ears, whereas ocular vestibular evoked myogenic potential showed alterations in 47.88% of 368 evaluated ears. The hearing recovery rate was analyzed by 8 articles, with 63.4% of 410 evaluated ears showing hearing recovery. Conclusions: The studies suggest that the assessment of the vestibular system using vestibular evoked myogenic potential seems to be important in the prognosis of sudden hearing loss. For better follow-up of patients with sudden hearing loss, the emphasis should not be limited to the cochlea, but also include the diagnosis and treatment of vestibular abnormalities, regardless of the presence of vertigo.

Resumo Introdução: A surdez súbita é uma emergência otorrinolaringológica que frequentemente cursa com graves danos à função auditiva e vestibular. O potencial evocado miogênico vestibular é um exame que permite a avaliação não invasiva da função do sistema otolítico e das vias vestíbulo-espinhal e vestíbulo-ocular. Objetivo: Avaliar a importância do potencial evocado miogênico vestibular na determinação do prognóstico dos pacientes com surdez súbita. Método: Uma busca de trabalhos publicados até dezembro de 2018 foi realizada nos bancos de dados PubMed, Cochrane, BVS e Lilacs com descritores cadastrados no MeSH. Foram incluídos artigos retrospectivos e prospectivos que contivessem o potencial evocado miogênico vestibular cervical ou ocular em pacientes com surdez súbita e informações sobre vertigem e/ou tontura associados. Resultados: Dezesseis de 62 artigos selecionados inicialmente preencheram os critérios de inclusão e foram analisados. Quanto à metodologia dos trabalhos avaliados, 8 estudos foram prospectivos, seis retrospectivos, um continha parte dos dados oriunda de uma análise retrospectiva e outra parte de uma análise prospectiva e um estudo foi transversal. Foram avaliados 872 pacientes (50,22% do gênero masculino e 49,77% feminino) com média de 51,26 anos. Do total de pacientes, 426 (50,35%) apresentavam vertigem e/ou tontura associada à surdez súbita. O potencial evocado miogênico vestibular cervical foi realizado em todos os estudos, porém o potencial evocado miogênico vestibular ocular em apenas sete. O potencial evocado miogênico vestibular cervical apresentou alteração em 38,65% de 846 orelhas avaliadas, enquanto o potencial evocado miogênico vestibular ocular estava alterado em 47,88% das 368 orelhas avaliadas. A taxa de recuperação auditiva foi analisada por 8 artigos, 63,4% de 410 orelhas avaliadas apresentavam recuperação auditiva. Conclusões: Os estudos demonstram que a avaliação do sistema vestibular com o uso do potencial evocado miogênico vestibular parece ter importância no prognóstico da surdez súbita. Para melhor acompanhamento do paciente com surdez súbita a ênfase não deve se restringir à cóclea, mas também no diagnóstico e tratamento de alterações vestibulares, independentemente da presença de vertigem.

Sordera súbita: estudio retrospectivo sobre 40 casos ingresados en nuestro hospital / Sudden deafness: a retrospective study of 40 cases admitted to our hospital

Introducción: La sordera brusca es una pérdida súbita de audición a nivel neuro-sensorial, por causas desconocidas, y con mal pronóstico funcional. Las causas son desconocidas, lo que genera múltiples hipótesis y discusiones sobre esta patología. Objetivo: Evaluar los factores asociados al pronóstico y determinar los aspectos terapéuticos que influyen en el pronóstico de estos pacientes. Material y método: Revisamos las historias clínicas de los pacientes diagnosticados de sordera brusca durante un período de estudio de 4 años, y calculamos las frecuencias de las diferentes variables consideradas como relevantes; realizamos análisis bivariante y una comparación de las distribuciones mediante test de ANOVA y un análisis multivariante con regresión logística y lineal múltiple. Resultados: Analizamos 40 casos. Consideramos factores como el oído afectado, antecedentes cardiovasculares, HTA, diabetes, dislipemia, tabaco, hemoglobina, hematocrito, las circunstancias temporales y geográficas, de las que ninguna de ellas resultaron significativas para la recuperación. Tras el análisis de otros factores, encontramos un predominio de casos en verano y otoño (90 por ciento) frente a invierno y primavera (10 por ciento). El uso del famciclovir estuvo asociado a mayor probabilidad de recuperación completa OR 21,164 [1,265-374,47]. Por el contrario, estuvieron ligados a una menor probabilidad de recuperación completa: el tratamiento con medicina hiperbárica OR 0,013 [0,001-0,433], la curva audiométrica descendente OR 0,164 [0,032-0,533], y la presencia de vértigo asociada a acúfenos OR 0,158 [0,08-1,015]. La aspirina mejoró la recuperación de decibelios media 24,3 db IC 95 por ciento [1,00-47,61]. Conclusiones: El estudio es una serie retrospectiva cuyo análisis multivariante muestra que el famciclovir y el AAS tienen un efecto estadísticamente beneficioso en el tratamiento de la sordera súbita...

Introduction: The sudden deafness is a sudden loss of hearing at the neuro-senso-rial, for unknown reasons, and bad functional prognosis. The cause is unknown, generating multiple hypotheses and discussions on this topic. Aim: To evaluate the factors associated with prognosis and determine therapeutic aspects that influence the prognosis of these patients. Matherial and method: We reviewed the medical records ofpatients diagnosed with sudden hearing loss during a study period of 4 years, and calculate the frequencies of the different variables considered relevant; performed bivariate analysis and a comparison of the distributions byANOVA and a multivariate analysis with logistic regression and multiple lineal. Results: We analyzed 40 cases. We consider factors like the affected ear, cardiovascular history, hypertension, diabetes, dyslipidemia, snuff, hemoglobin, hematocrit, temporal and geographical, of which none were significant for recovery. After analysis of other factors, we found a predominance of cases in summer and autumn (90 percent) compared to winter and spring (10 percent). Use of famciclovir was associated with greater likelihood of complete recovery OR 21.164 [1.265 to 374.47]. On the contrary, were linked to a lower linked to a lower likelihood of full recovery: treatment with hyperbaric OR 0.013 [0.0010.0433] OR descending audiometric curve [0.164 0.032 to 0.533] and the presence of vertigo associated with tinnitus OR o.158 [0.08 to 1.015]. Aspirin improved recovery of 24.3 db decibel half 95 percent CI [1.00 to 47.61]. Conclusions: The study is a retrospective multivariate analysis which shows that famciclovir and aspirin have a statisfically beneficial in the treatment of sudden deafness, which in our sample is more frequent in summer and autumn. Biased studies are needed on these results may provide new hypotheses for treatment.

Brainstem auditory evoked potentials and electrocochleographic findings in patients with idiopathic sudden sensorineural hearing loss

To determine the status of cochlea, auditory pathway and hearing threshold by recording brainstem auditory evoked potential [BAEP] and electrocochleography in patients with idiopathic sudden sensorineural hearing loss [ISSNHL]. Observational study. Department of Clinical Physiology at King Abdul Aziz University Hospital, Riyadh, Saudi Arabia, from May 2002 to November 2007. Patients diagnosed with idiopathic sudden sensorineural hearing loss [ISSNHL] based on clinical features and pure tone audiometry were studied. Brainstem auditory evoked potential [BAEP] and electrocochleography [ECOG] was performed in them according to standard protocols for assessment of auditory pathway and hearing threshold. Out of 23 patients [14 males and 9 females] left ear was affected in 9 [39.1%] patients, right ear in 13 [56.5%] and both in 1 [4.3%]. Absolute latency of wave I and wave V were significantly prolonged in affected ear compared to unaffected ears [p=0.0031], while interpeak I-V latency was significantly higher in affected ears versus unaffected ears [p=0.0544]. Six patients [26.1%] had type II Diabetes mellitus, five cases [21.7%] had hypertension and 5 cases [21.7%] had dyslipidemia. ECOG revealed absence of summation potential [SP] and action potential [AP] response even at 95 dB in 17 out of 23 cases [73.9%]. Patients with ISSNHL had significant abnormalities in BAEP and ECOG recordings showing predominantly cochlear involvement. Thus, these tests provide useful diagnostic information in patients with ISSNHL in addition to pure tone audiometry

Classification and hearing evolution of patients with sudden sensorineural hearing loss

The aim of this study was to analyze clinical aspects, hearing evolution and efficacy of clinical treatment of patients with sudden sensorineural hearing loss (SSNHL). This was a prospective clinical study of 136 consecutive patients with SSNHL divided into three groups after diagnostic evaluation: patients with defined etiology (DE, N = 13, 10%), concurrent diseases (CD, N = 63, 46.04%) and idiopathic sudden sensorineural hearing loss (ISSHL, N = 60, 43.9%). Initial treatment consisted of prednisone and pentoxifylline. Clinical aspects and hearing evolution for up to 6 months were evaluated. Group CD comprised 73% of patients with metabolic decompensation in the initial evaluation and was significantly older (53.80 years) than groups DE (41.93 years) and ISSHL (39.13 years). Comparison of the mean initial and final hearing loss of the three groups revealed a significant hearing improvement for group CD (P = 0.001) and group ISSHL (P = 0.001). Group DE did not present a significant difference inthresholds. The clinical classification for SSNHL allows the identification of significant differences regarding age, initial and final hearing impairment and likelihood of response to therapy. Elevated age and presence of coexisting disease were associated with a greater initial hearing impact and poorer hearing recovery after 6 months. Patients with defined etiology presented a much more limited response to therapy. The occurrence of decompensated metabolic and cardiovascular diseases and the possibility of first manifestation of auto-immune disease and cerebello-pontine angle tumors justify an adequate protocol for investigation of SSNHL.

Surdez súbita idiopática: aspectos etiológicos e fisiopatogênicos / Idiopathic sudden sensorineural hearing loss: etiopathogenic aspects

Vários fatores têm sido postulados como causa da surdez súbita idiopática. Por meio de uma revisão bibliográfica foi feita uma análise crítica quanto aos aspectos etiológicos e fisiopatogênicos desta manifestação clínica. Estudos atuais sugerem que os distúrbios vasculares, a ruptura de membranas da orelha interna e as doenças auto-imunes são possíveis causas, mas a afecção viral tem recebido maior atenção nos últimos anos, embora ainda pouco se conheça sobre os mecanismos da surdez súbita idiopática. Os vírus podem causar a perda súbita da audição na infecção aguda, mas a forma latente, com uma possível reativação viral, também tem sido considerada no mecanismo de agressão à cóclea. Apesar de uma alteração da viscosidade sangüínea poder explicar a perda auditiva, estudos experimentais e clínicos não mostram sinais de ossificação e de fibrose na cóclea ou de ruptura de membranas do labirinto. Estes fatos contrapõem, respectivamente, a teoria vascular e a da fístula labiríntica. A eventual presença de anticorpos contra a orelha interna sugere que a surdez súbita idiopática possa ser de natureza auto-imune, fato este também não confirmado pela falta de relação entre os aspectos clínicos e morfológicos da doença auto-imune e da perda auditiva. A surdez súbita idiopática é, ainda, um tema controverso e obscuro em diversos aspectos.

Several factors have been postulated to elicit the etiology of idiopathic sudden sensorineural hearing loss. Through a bibliographic review, we made a critical analysis of the different etiopathogenic aspects of its clinical manifestation. The most recent studies concerning the possible causes of sudden hearing loss suggest vascular disorders, rupture of the inner ear membrane and autoimmune diseases; however, viral infections have received a great deal of attention in recent years. Little is known about the mechanism of sudden hearing loss. Viruses can cause sudden hearing loss in an acute infection, however the latent form, and its possible reactivation have also been considered as explanations of the cochlear injury mechanism. Even though hearing loss can be explained by a blood viscosity change, experimental and clinical studies do not show any evidence of labyrinthine fibrosis and new bone formation, or labyrinthine membrane breaks. These findings are not in agreement with vascular and rupture membrane factors, respectively. The eventual presence of antibodies against the inner ear suggests that sudden hearing loss pathogenesis may be of autoimmune nature, but the difficulty in establishing the correlation of its morphological and clinical aspects to the hearing loss also do not help to support this statement. Sudden hearing loss is still a controversial and obscure subject in several aspects.

Valor pronóstico de la recuperación de la sordera súbita idiopática por medio del índice de acomodación vestibular / Pronostic value of the sudden idiophatic hearing loss by the vestibular accomodation index

El objetivo del trabajo es el de poder indicarle al paciente afectado por un cuadro de sordera súbita idiopática cuál sería la probabilidad de recuperar su audición, con o sin tratamiento médico. Dado que un gran porcentaje de pacientes presentan prodromos unas horas o días previos a la sensación del oído tapado, se supone que la afección podría ser centrífuga desde el ángulo pontocerebeloso hacia el receptor auditivo. En muchos casos además, los pacientes acusan una sensación débil o intensa de mareos. Por eso si la afección afectará exclusivamente al nervio auditivo tendría mejor pronóstico que si se afectara también el receptor. Esto porque el nervio tendría mas capacidad de recuperación o reparación. El uso del índice de acomodación vestibular ha demostrado ser muy sensible y confiable para diferenciar las afecciones de las fibras nerviosas de las del receptor tomando en cuenta, eso si, que la prueba se hace en la vía vestibular y que la afección es, principalmente, de la vía auditiva. La investigación se hizo en 63 pacientes que consultaron por sordera súbita idiopática, total o parcial, de horas a días e incluso semanas de haberse producido el hecho, con o sin vértigo. Se pudo separar dos grupos, uno de 41 pacientes cuyas respuestas al Indice de Acomodacion Vestibular indicaban lesión neural exclusiva y otro de 22 pacientes que presentaron respuesta que indicaban daño del receptor. En el primer grupo, con daño neural y mejor pronóstico, no se recuperaron 5 de los 41 pacientes. En el segundo grupo con daño del receptor y peor pronóstico se recuperaron sólo 2 de los 22 pacientes. Estadísticamente el método indica que la probabilidad de errar en el pronóstico es de un 11 por ciento lo que es mejor que el 35 por ciento de error de los métodos clínicos que se tienen en la actualidad

Síndrome de sordera por inhibición eferente retrococlear / Retrocochlear inhibition efferent deafness syndrome

Se presenta un cuadro clínico caracterizado por sordera sensorineural súbita o ráoidamente progresiva, acompañado de acúfenos y ocacionalmente de mareos, y todo esto relacionado con una situación estresante, que se produce en personas con personalidad tensa, perfeccionista e incapaces de relajarse. Se describe el posible mecanismo de esta inhibición activa eferente sobre uno o ambos oídos, por parte de la corteza vía geniculado medio al colículo inferior y desde esta al ramo olivo coclear, cuyas neuronas eferentes terminan en las células ciliadas externas. El posible modo de actuar de esta inhibición retrococlear eferente, sería a través de alterar el funcionamiento normal de las células ciliadas externas, las que cesarían en su función amplificadora y moduladora, causando sordera y acúfenos, posiblemente por alteración inmediata de la señal que se origina en las células internas y que va hasta la corteza por la vía aferente. Por el tipo de personalidad de los enfermos en que se manifiesta este síndrome de sordera por inhibición retrococlear eferente (SIRE), se postula que podría deberse a un trastorno en los neurotrasmisores similar al que se ve en la depresión endógena, y esta falta actuaría en los núcleos geniculado medio y colículo inferior, haciendo fallar el control eferente que éste ejerce sobre la cóclea.