Third window lesions of the inner ear: A pictorial review.

PURPOSE: Radiographic review of pathologies that associate with third window syndrome. METHODS: Case series and literature review. RESULTS: Eight unique third window conditions are described and illustrated, including superior, lateral, and posterior semicircular canal dehiscence; carotid-cochlear, facial-cochlear, and internal auditory canal-cochlear dehiscence, labyrinthine erosion from endolymphatic sac tumor, and enlarged vestibular aqueduct. CONCLUSION: The present study highlights the characteristic imaging features and symptoms to differentiate third window pathologies for expedient diagnosis and management planning.

A mouse model of autoimmune inner ear disease without endolymphatic hydrops.

Autoimmune inner ear disease (AIED) is an organ-specific disease characterized by irreversible, prolonged, and progressive hearing and equilibrium dysfunctions. The primary symptoms of AIED include asymmetric sensorineural hearing loss accompanied by vertigo, aural fullness, and tinnitus. AIED is divided into primary and secondary types. Research has been conducted using animal models of rheumatoid arthritis (RA), a cause of secondary AIED. However, current models are insufficient to accurately analyze vestibular function, and the mechanism underlying the onset of AIED has not yet been fully elucidated. Elucidation of the mechanism of AIED onset is urgently needed to develop effective treatments. In the present study, we analyzed the pathogenesis of vertigo in autoimmune diseases using a mouse model of type II collagen-induced RA. Auditory brain stem response analysis demonstrated that the RA mouse models exhibited hearing loss, which is the primary symptom of AIED. In addition, our vestibulo-oculomotor reflex analysis, which is an excellent vestibular function test, accurately captured vertigo symptoms in the RA mouse models. Moreover, our results revealed that the cause of hearing loss and vestibular dysfunction was not endolymphatic hydrops, but rather structural destruction of the organ of Corti and the lateral semicircular canal ampulla due to an autoimmune reaction against type II collagen. Overall, we were able to establish a mouse model of AIED without endolymphatic hydrops. Our findings will help elucidate the mechanisms of hearing loss and vertigo associated with AIED and facilitate the development of new therapeutic methods.

Dehiscencia del canal semicircular superior, un nuevo diagnóstico en pacientes con vértigo / Superior semicircular canal dehiscence, a new diagnosis in patients with vertigo

Introduction: The superior semicircular canal dehiscence syndrome (SSCD) is a pathology described in 1998, which presents several symptoms including sound induced vertigo, hearing loss and autophony due to bone dehiscence of this semicircular canal. Material and Methods: A retrospective and descriptive study was carried out, reviewing the medical records of patients with computed tomography suggestive of SSCD between 2006 and 2010 from the Radiology department of the Clinical Hospital of the University of Chile. Results: We obtained six cases of SSCD (4 female) with a mean age of 52.7 years. SSCD was observed in four cases bilaterally and in two cases on the left ear. We confirmed a clinical syndrome in two patients, based on the presence of hearing loss and sound induced vertigo. Conclusions: The diagnosis of SSCD syndrome should be supported on both clinical and imaging studies. We should maintain a high level of suspicion, particularly in cases of sound induced vertigo and of conductive hearing loss with normal otoscopy.

Da eletrococleografia transtimpânica em pacientes com e sem hydrops endolinfático e limiares auditivos iguais ou maiores que 50 decibéis / Transtympanic electrocochleography in patients with and without endolymphatic hydrops and hearing thresholds equal or major than 50 decibels

OBJETIVOS: Por meio da análise de eletrococleografias transtimpânicas realizadas em indivíduos controles, em pacientes com diagnóstico clínico definido de hydrops endolinfático e limiares auditivos iguais ou maiores que 50 decibéis e em pacientes com labirintopatias sem evidência clínica de hydrops endolinfático e limiares auditivos iguais ou maiores que 50 decibéis, este estudo tem como objetivos determinar diferenças estatísticas entre os três grupos em relaçäo aos parâmetros estudados; avaliar qual o parâmetro mais sensível na identificaçäo do grupo com hydrops endolinfático e analisar se a associaçäo de parâmetros é útil para a caracterizaçäo laboratorial do grupo com hydrops endolinfático. FORMA DE ESTUDO: Clínico retrospectivo. MÉTODO: Estudo retrospectivo de 60 eletrococleografias. Foram analisadas a relaçäo percentual entre o potencial de somaçäo e o potencial de açäo (SP/AP), a amplitude entre o primeiro pico positivo do segundo componente do potencial de açäo e a linha de base (I/BSL) e a amplitude entre o segundo pico positivo do segundo componente do potencial de açäo e a linha de base (II/BSL). RESULTADOS: A análise estatística revelou comportamento diferente entre os três grupos quanto à relaçäo SP/AP, mas näo quanto aos outros dois parâmetros. O valor da relaçäo SP/AP equivalente a 46,0 por cento apresentou índices de 75,0 por cento de sensibilidade e 60,0 por cento de especificidade para a identificaçäo do grupo com hydrops endolinfático. CONCLUÖES: Os três grupos apresentaram comportamentos estatísticos diferentes entre si; a relaçäo SP/AP foi o parâmetro mais sensível e específico para identificaçäo dos pacientes com diagnóstico de hydrops endolinfático e a análise da associaçäo dos parâmetros näo foi possível