Myasthenia Gravis Presenting Hyperacusia and Ptosis

Myasthenia gravis (MG), which is the most common autoimmune neuromuscular junction disorder, is characterized by weakness of musdes and increased fatigability after repetitive use, and recovery after rest. The diagnosis is based on a detailed history, physical examination, and pharmacological, electrophysiological, and immunological testing. Stapedial reflex abnormalities are noted, so the stapedial reflex decay test (SRDT) can be attempted. There are no reports regarding the SRDT in Korea. We report a case of MG presenting hyperacusia and ptosis that was diagnosed by the SRDT. We recommend using the SRDT in the clinical diagnosis of MG.

Avaliação eletrofisiológica do nervo auditivo em pacientes normo-ouvintes com ausência do reflexo estapediano / Electrophysiological evaluation of the auditory nerve in normal hearing patients with absence of stapedial reflex

Introdução: O reflexo estapediano é uma contração do músculo estapédio, localizado na orelha média, induzido por um estímulo acústico intenso. É esperado que indivíduos com limiares auditivos dentro dos padrões de normalidade tenham reflexos estapedianos presentes, desde que haja integridade de orelha média. Entretanto, tem sido observada a existência de sujeitos ouvintes normais, com ausência de reflexo estapediano, o que pode sugerir a ausência do músculo estapédio ou até mesmo alteração do nervo auditivo (neuropatia). O Potencial Evocado de Tronco Encefálico (PEATE) é um exame objetivo e complementar da audição que avalia o funcionamento do nervo vestíbulo-coclear. Objetivo: O presente estudo foi realizado com o objetivo de se analisar os achados da avaliação eletrofisiológica do nervo auditivo, através do PEATE, em pacientes normo-ouvintes, sem queixas auditivas, com ausência do reflexo estapediano, confirmado pela Imitanciometria. Método: Foram estudados 68 sujeitos de ambos os sexos da faixa etária de 18 a 30 anos, sem queixas auditivas. Os procedimentos realizados compreenderam anamnese, inspeção do meato acústico interno, audiometria tonal liminar, logoaudiometria, imitanciometria e PEATE. Resultados: Os exames de PEATE da amostra populacional mostraram resultados dentro do padrão de normalidade com presença de onda I, III e V tendo os valores de latência absoluta e interpicos dentro dos padrões de normalidade, sugerindo integridade das vias auditivas centrais. Conclusão: A ausência dos reflexos estapedianos em pacientes normo-ouvintes, sem queixa auditiva por si só não é suficiente para diagnosticar a existência de neuropatia auditiva, necessitando ser empregado o exame de PEATE.

Introduction: The stapedial reflex is a stapedial muscle contraction located in the middle ear, induced by an intense acoustic stimulus. It is expected that individuals with auditory thresholds within the normality standards have stapedial reflexes once there is integrity of the middle ear. However, the existence of normal hearing persons, with absence of stapedial reflex, has been observed, which may suggest the absence of the stapedial muscle or even the alteration of the auditory nerve (neuropathy). The AEP (Encephalic Trunk Audition Evoked Potential) is an objective and complimentary exam of hearing that evaluates the functioning of the cochleovestibular nerve. Objective: This study was carried out aiming to review the auditory nerve electrophysiological evaluation findings, through AEP, in normal hearing patients without auditory complaints and with absence of the stapedial reflex, confirmed by imitanciometry. Method: We studied 68 individuals of both sexes and aged from 18 to 30 years without auditory complaints. The procedures carried out comprised anamnesis, internal acoustic meatus inspection, threshold tonal audiometry, logoaudiometry, imitanciometry and AEP. Results: The AEP exams of the population sample showed outcomes within the normality standard with presence of wave I, III and V, with absolute latency values and interpeaks within the normality standards, which suggested integrity of the central auditory passages. Conclusion: The absence of stapedial reflexes in normal hearing patients, without auditory complaint is not sufficient by itself to diagnose the existence of auditory neuropathy and requires application of the AEP exam.

Analysis of Nerve Excitability Test and Stapedial Reflex on the Prognosis of Facial Nerve Paralysis / 听力学及言语疾病杂志

Objective To evaluate the clinical application of nerve excitability test and stapedial reflex on the prognosis of facial nerve paralysis. Methods The threshold of excitability of the branches of facial nerves in both sides and stapedial reflex were tested in 50 patients.Results 34 patients out of 42 with differences of nerve excited threshold less than 3.5 mA showed complete recovery (81%),while only 2 patients out of 8 with the differences of nerve excited threshokd more than 3.5 mA showed recovery (25%), 32 patients out of 36 with positive response of stapedial reflex showed recovery (88.9%), but only 3 patients out of 14 recovered (21.4%) in non-response group.Conclusion The difference of nerve excited threshold of both sides less than 3.5 mA and positive response of stapedial refles showed a better prognosis, suggesting no severe injury to facial nerve and both nerve excitability test and stapedial reflex were useful chinical parameters to predict the prognosis of facial paralysis.