Congenital unilateral hearing loss from cochlear nerve canal stenosis

@#A 2-month-old baby girl presented with a failed neonatal otoacoustic emission (OAE) hearing screening in the left ear. Combined Auditory Brainstem Response/Auditory Steady-State Response (ABR/ASSR) testing confirmed the presence of a unilateral left moderate to severe hearing loss. No Joint Committee on Infant Hearing (JCIH) risk factors for early childhood hearing loss1 were identified. She subsequently underwent computed tomography (CT) of the temporal bones to determine the presence of any inner ear malformation. No abnormalities of the internal auditory canal, cochlea, semicircular canals and ossicles were noted by the radiologist, and the study was officially reported as a “normal temporal bone CT scan.” Independent review of the CT imaging revealed the presence of a visually apparent disparity in the width of the cochlear nerve canals. (Figure 1) Measurement of the cochlear nerve canal width in the axial plane parallel to the infraorbitomeatal line2 using the length measurement tool in the DICOM imaging software (RadiAnt DICOM Viewer, Version 2024.1, Medixant) indicated a cochlear nerve canal width of 2.18 mm on the right and 1.02 mm on the left. (Figure 2) Applying the suggested cutoff point of 1.2 mm as described by Lin et al.,2 we identified the presence of left cochlear nerve canal stenosis as the etiology of the congenital unilateral hearing loss. The cochlear nerve canal, which has also been referred to as the bony canal for the cochlear nerve (BCNC), cochlear aperture, and cochlear fosette, is the bony transition point between the internal auditory canal and the cochlear modiolus. A relationship between a hypoplastic cochlear nerve canal and congenital sensorineural hearing loss was first suggested by Fatterpekar et al. in 2000.3 Subsequent studies confirmed the association between cochlear nerve canal stenosis and sensorineural hearing loss that ranges from near-normal to profound, with a statistically significant relationship between the degree of hearing loss and the degree of stenosis.4 Various cutoff points to define stenosis of the cochlear nerve canal have been identified in the medical literature. These cutoff points range from 1.2 mm to 1.7 mm when the canal width is measured in the axial plane.2 This particular case demonstrated clear-cut evidence of cochlear nerve canal stenosis, as it satisfied the smallest cutoff criteria (< 1.2 mm) seen in the medical literature. The identification of cochlear nerve canal stenosis as the cause of congenital sensorineural hearing loss is important not only from a diagnostic point, but also from a prognostic perspective. Cochlear nerve deficiency has been noted to be highly prevalent among pediatric patients with cochlear nerve canal stenosis,5 and this has significant negative implications in relation to rehabilitation with external hearing devices and cochlear implants.

Ocorrência de alterações nos potenciais evocados auditivos de fumantes: revisão sistemática da literatura / Occurrence of changes in the auditory evoked potentials of smokers: systematic review of the literature

RESUMO Objetivo Verificar a ocorrência de alterações nos exames de potencial evocado (PEA) auditivo em adultos fumantes normo-ouvintes. Estratégia de pesquisa Revisão sistemática da literatura de acordo com recomendações do PRISMA, buscando responder à pergunta: "Há alterações nos resultados do exame de PEA em adultos fumantes?", estratégia PECOS. Pesquisa realizada nas bases de dados PubMed, Embase, CINAHL, LIVIVO, Scopus, Web of Science, LILACS e Scielo. Busca adicional da literatura cinzenta: Google Scholar e ProQuest e busca manual das referências dos estudos incluídos. Critérios de seleção Foram selecionados estudos com delineamento transversal, sem restrição do ano de publicação e idioma. Análise dos dados Primeiramente foram analisados os títulos e resumos de todos os estudos encontrados, seguido da leitura na íntegra dos estudos elegíveis. Resultados Foram obtidos 898 artigos, que após remoção dos duplicados e análise cega por três pesquisadores, foram selecionados oito trabalhos. Grande parte dos estudos encontrou uma associação entre tabagismo ativo e alterações nos testes eletrofisiológicos. Conclusão Adultos fumantes normo-ouvintes apresentam alterações nos exames de PEA de curta e longa latência. No potencial evocado auditivo de tronco encefálico, os principais componentes alterados foram o aumento das latências das ondas I e III e nos interpicos I - III e III - V, bem como diminuição da amplitude das ondas. No Mismatch Negativity, houve aumento significativo da amplitude da onda e da latência. No potencial de longa latência, P300, houve aumento das latências e redução das amplitudes nos componentes N1 (em Fz) e P3.

ABSTRACT Purpose To verify the occurrence of abnormal auditory evoked potentials (AEP) tests in adult smokers. Research strategies Systematic review of the literature according to the PRISMA guidelines, to answer the question: "Are there any changes in the AEP results in adult smokers?", PECOS strategy. Research carried out on PubMed, Embase, CINAHL, LIVIVO, Scopus, Web of Science, LILACS and Scielo databases. Additional search of gray literature: Google Scholar and ProQuest hand searching of reference lists of the included studies. Selection criteria Cross-sectional studies were selected, without restriction on the year of publication and language. Data analysis First, the titles and abstracts of all the studies were analyzed, followed by the full reading of the eligible studies. Results 898 articles were collected, after the duplicate studies were removed and after blind analysis by three researchers, 8 studies of the observational type were selected. Most studies have found an association between active smoking and changes in electrophysiological tests. Conclusion Normal hearing adult smokers present alterations in short and long AEP. In the auditory brainstem response, the main altered components were the increase in waves latencies of I and III and in the interpeaks I - III and III - V, as well as a decrease in the amplitude of the waves. In Mismatch Negativity, there was a significant increase in wave amplitude and latency. In the long latency potential, P300, there was an increase in latencies and decreased amplitudes in the components N1 (in Fz) and P3.

Does size of the cochlear nerve affect postoperative auditory performance in pediatric cochlear implant patients with normal cochlear nerves? / O tamanho do nervo coclear afeta o desempenho auditivo pós-operatório em pacientes pediátricos com implante coclear e nervos cocleares normais?

Abstract Introduction Cochlear implantation is an effective treatment method for severe to profound hearing loss. Many factors that may influence cochlear implantation success have been explained in previous studies. Apart from those, minor differences in size of normal cochlear nerves may affect postoperative performance. Objective To investigate whether the minor differences in cochlear nerve size in normal cochlear nerves affect postoperative cochlear implant performance. Methods 30 pediatric prelingually deaf patients who were treated with cochlear implantation were included in this study. From the reconstructed parasagittal magnetic resonance images, the diameter and cross-sectional area of the cochlear nerve on the ipsilateral and contralateral side were measured. Auditory evaluations were performed 1, 3, 6 and 12 months following the first fitting. All the analysis was performed by using EARS®, evaluation of auditory responses to speech tool. Correlation between cochlear nerve diameter, cross-sectional area and postoperative auditory perception was analyzed to determine whether variation in cochlear nerve size contributes to postoperative auditory performance. Results The mean diameter of the cochlear nerve on the ipsilateral side was 718.4 μm (504.5 − 904.3 μm) and mean cross sectional area was 0.015 cm2 (0.012 − 0.018 cm2). On the contralateral side the mean cochlear nerve diameter was 714.4 μm (502.6 − 951.4 μm) and mean cross sectional area was 0.014 cm2 (0.011 − 0.019 cm2). The correlation between the diameter and cross-sectional area of the ipsilateral and contralateral cochlear nerve revealed no significance. Mean score at first month monosyllable-trochee-polysyllable test, MTP1, was 0.17 (0.08 − 0.33), at 6th month with 6 words test, 6th month MTP6 was 0.72 (0.39 − 1.0), at 6th month with 12 words, 6th month MTP 12 was 0.46 (0.17 − 0.75) and at 12th month with 12 words, 12th month MTP12 was 0.73 (0.25 − 1.0). There was no correlation between the monosyllable-trochee-polysyllable test, values at any time with the diameter of the ipsilateral cochlear nerve. However, the first month MTP, 6th month MTP6 and 12th month MTP12 correlated with the cross-sectional area of the ipsilateral cochlear nerve. Conclusion Measuring the cross sectional area of the normal- appearing cochlear nerve may give important prognostic knowledge on cochlear implant outcomes. In patients with a larger cross sectional area the auditory performance was better and faster. Although normal appearing, slight differences on cross sectional area of the cochlear nerve may affect performance. Measuring the size of the cochlear nerve on parasagittal magnetic resonance images may provide beneficial information on the postoperative rehabilitation process.

Resumo Introdução O implante coclear é um método de tratamento eficaz para a perda auditiva grave a profunda. Muitos fatores que podem influenciar o sucesso do implante coclear foram explicados em estudos anteriores. Além desses fatores, pequenas diferenças no tamanho dos nervos cocleares normais podem afetar o desempenho pós-operatório. Objetivo Investigar se pequenas diferenças no tamanho dos nervos cocleares normais afetam o desempenho pós-operatório do implante coclear. Método Foram incluídos neste estudo 30 pacientes pediátricos surdos pré-linguais, tratados com implante coclear. A partir de imagens de ressonância magnética parassagitais reconstruídas, foram medidos o diâmetro e a área de seção transversal do nervo coclear no lado ipsilateral e contralateral. As avaliações auditivas foram feitas 1, 3, 6 e 12 meses após a primeira adaptação. Todas as análises foram feitas com a ferramenta EARS® (do inglês evaluation of auditory responses to speech). A correlação entre o diâmetro do nervo coclear, a área transversal e a percepção auditiva pós-operatória foi analisada para determinar se a variação no tamanho do nervo coclear contribui para o desempenho auditivo pós-operatório. Resultados O diâmetro médio do nervo coclear no lado ipsilateral foi de 718,4 μm (504,5 a 904,3 μm) e a área da seção transversal média foi de 0,015 cm2 (0,012-0,018 cm2). No lado contralateral, o diâmetro médio do nervo coclear foi de 714,4 μm (502,6 a 951,4 μm) e a área da seção transversal média foi de 0,014 cm2 (0,011 a 0,019 cm2). A correlação entre o diâmetro e a área transversal do nervo coclear ipsilateral e contralateral não revelou qualquer significância. O escore médio do teste monosyllable-trochee-polysyllable no primeiro mês, denominado MTP1, foi de 0,17 (0,08-0,33), no sexto mês com teste de 6 palavras, MTP6, foi de 0,72 (0,39-1,0), no sexto mês com 12 palavras, MTP12, foi de 0,46 (0,17-0,75) e no 12° mês com 12 palavras, MTP12, foi de 0,73 (0,25-1,0). Não houve correlação entre os valores do teste monosyllable-trochee-polysyllable em qualquer momento com o diâmetro do nervo coclear ipsilateral. Entretanto, o teste monosyllable-trochee-polysyllable do primeiro mês, do 6° mês, e o do 12° mês correlacionaram-se com a área transversal do nervo coclear ipsilateral. Conclusão Medir a área da secção transversal do nervo coclear de aparência normal pode fornecer conhecimento prognóstico importante sobre os resultados do implante coclear. Em pacientes com área da secção transversal maior, o desempenho auditivo foi melhor e mais rápido. Embora o nervo coclear pareça normal, pequenas diferenças na área da secção transversal do nervo coclear podem afetar o desempenho, de forma que a medida do tamanho do nervo coclear nas imagens de ressonância magnética na projeção parassagital pode fornecer informações benéficas sobre o processo de reabilitação pós-operatória.

Clinical implications of intraoperative eABRs to the Evo®-CI electrode array recipients / Implicações clínicas do eABR intraoperatório para usuários do feixe de eletrodos Evo

Abstract Introduction Electrically evoked auditory brainstem responses provide reliable clinical information to assist professionals in the auditory rehabilitation of cochlear implant users. Objective This study aimed to investigate intraoperative evoked auditory brainstem response recordings in Evo®-cochlear implant electrode array recipients and its correlation with their behavioral levels and auditory performance. Methods This is a retrospectivey study. Intraoperative evoked auditory brainstem responses were recorded in adult Evo®-cochlear implant electrode array recipients. Wave V latencies, amplitudes and interpeak III-V intervals were recorded in three different electrode locations and compared to the sentence recognition scores obtained from subjects after six months of device use. Evoked auditory brainstem responses thresholds were also recorded and compared to the behaviorally determined levels of the subjects in the sound processor activation. Results Evoked auditory brainstem responses thresholds were significantly correlated with both, behavioral T- and C-levels and they were recorded at audible electrical stimulation levels in all subjects. There was a significant correlation between interpeak III-V interval recorded in the apical electrode and sentence recognition scores of the subjects. Conclusions Intraoperative evoked auditory brainstem responses can be used to establish audible levels for fitting the sound processor in Evo®-cochlear implant recipients and it could help professionals to plan further actions aiming to improve their auditory performance.

Resumo Introdução Os potenciais auditivos de tronco encefálico evocados eletricamente fornecem informações clínicas confiáveis que auxiliam no processo de reabilitação auditiva de usuários de implante coclear. Objetivo Investigar o registro intraoperatório dos potenciais auditivos de tronco encefálico evocados eletricamente em usuários do feixe de eletrodos Evo® e sua correlação com os níveis comportamentais e desempenho auditivo dos indivíduos. Método Estudo retrospectivo. Os potenciais auditivos de tronco encefálico intraoperatórios foram registrados em usuários adultos de implante coclear com feixe de eletrodos Evo®. As latências e amplitudes da onda V e os intervalos interpico III-V foram registrados em três diferentes eletrodos e comparados às pontuações de reconhecimento de sentenças após 6 meses de uso do implante coclear. Os limiares dos eABRs foram comparados aos níveis comportamentais dos indivíduos na ativação do processador de som. Resultados Os limiares do eABR foram significativamente correlacionados aos níveis comportamentais T e C e registrados em níveis de estimulação elétrica audíveis em todos os indivíduos. Houve uma correlação significativa entre o intervalo interpico III-V no eletrodo apical e a pontuação de reconhecimento de sentenças dos indivíduos. Conclusões O eABR intraoperatório pode ser usado para estabelecer níveis audíveis de estimulação elétrica na ativação do processador sonoro em usuários de implante coclear‐Evo® e pode auxiliar os profissionais no planejamento de ações visando melhorar o desempenho auditivo nesses pacientes.

Implante coclear y terapia auditivo verbal en el Hospital Pediátrico Provincial Pepe Portilla / Cochlear implant and auditory-verbal therapy at Pepe Portilla Provincial Pediatric Teaching Hospital

RESUMEN Introducción: el lenguaje oral está basado principalmente en la información acústica. La hipoacusia es la pérdida parcial de la capacidad auditiva. A partir de los 40 decibelios en adelante, su presencia repercute en la adquisición de las funciones del lenguaje y el desarrollo integral del niño. Objetivo: describir la evolución de un caso clínico hipoacúsico con implante coclear, tras la aplicación de una terapia auditivo-verbal. Presentación de caso: se presenta un niño de 10 años y siete meses de edad, con retraso en el desarrollo del lenguaje debido a una Hipoacusia Neurosensorial Bilateral Profunda de presunto origen congénito. Después de ser diagnosticado tempranamente con esta enfermedad, fue incluido en el Programa Nacional de Implante Coclear con vistas a mejorar sus capacidades auditivas y facilitar así la retroalimentación auditiva. Luego de la cirugía se le comenzó a aplicar una terapia auditivo verbal para propiciar la adquisición adecuada de las funciones del lenguaje. Conclusiones: los niños con problemas de audición pueden aprender a escuchar y a hablar mediante un diagnóstico y una intervención temprana, la tecnología apropiada y con la dedicación de padres y terapeutas que comparten la visión de darle voz al futuro del niño. Es importante tener en cuenta que el tratamiento adecuado, la capacidad intelectual de los niños y el ambiente familiar, condicionan la evolución exitosa de las terapias aplicadas.

ABSTRACT Introduction: oral language is mainly based on acoustic information. Hypoacusis is the partial loss of hearing capacity; from 40 decibels and above, its presence has an impact on the acquisition of language functions and the overall development of the child. Objective: to describe the evolution of a clinical case of a hearing impaired patient with cochlear implant after the application of an auditory-verbal therapy. Case report: a 10-year-old and 7 months boy with delayed language development due to a Deep Bilateral Sensorineural Hearing Loss of presumed congenital origin, after being diagnosed early with this disease he was included in the National Cochlear Implant Program in order to improve his hearing abilities and thus facilitate auditory feedback. After surgery, he began to undergo auditory-verbal therapy to promote the proper acquisition of language functions. Conclusions: hearing impaired children can learn to listen and speak through early diagnosis and intervention, appropriate technology and with the perseverance of parents and therapists who share the vision of giving voice to the future of the child. It is important to keep in mind that the appropriate treatment, the intellectual capacity of children and the family environment condition the successful evolution of the therapies applied.

Bilateral Narrow Internal Auditory Canal With Duplication: High Resolution CT And MRI Findings

Inner ear malformations account for only 20 % of cases of congenital sensorineural hearing loss.A narrow internal auditory canal (IAC) with duplication is a very rare congenital anomaly that can be associated with other malformative ear abnormalities. Identification and characterization of these abnormalities will be crucial for the proper management of patients.We report two cases of bilateral duplicated internal auditory canal with other associated inner ear anomalies.

High-resolution CT combined MR T2-DRIVE sequence imaging in diagnosis of children cochlear nerve dysplasia / 中国介入影像与治疗学

Objective: To investigate the value of high-resolution CT (HRCT) combined with MR T2-DRIVE in diagnosis of cochlear nerve dysplasia (CND) of children. Methods: HRCT and MR T2-DRIVE image data of 43 children (28 unilateral and 15 bilateral) with CND were retrospectively analyzed. The diameters of cochlear nerve canal (CNC) and cochlear nerve were measured with HRCT and T2-DRIVE,respectively. The correlation between CNC diameter and cochlear nerve diameter was analyzed by using Spearman correlation. Results: A total of 58 diseased ears, including 27 pure CND ears and 31 CND accompanied with malformation of inner ear ones, as well as 28 normal ears were found among 43 CND children. HRCT showed CNN stenosis in 45 ears, CNC atresia or absence in 13 ears, internal auditory canal stenosis in 15 ears, including CNC stenosis 12 ears, CNC atresia 2 ears and CNN absence 1 ear. MRI showed abnormal facial nerve morphology in 7 ears, vestibular nerve absence in 1 ear and slender in 1 ear. Among 15 ears of internal auditory canal stenosis, vestibulocochlear nerve was absence in 8 ears and slender in 3 ears, while was normal in 4 ears. Among 58 diseased ears, CNC was demonstrated normal on both HRCT and MRI in 7 ears. The diameters of CNC and cochlear nerve of CND ears were all smaller than those of normal ears (both P=0.001), while no statistically difference of diameters of CNC and cochlear nerve between pure CND ears and CND accompanied with malformation of inner ear ones (P=0.185, 0.140). CNC diameter of all 86 ears was positively correlated with diameter of cochlear nerve (rs=0.773, P<0.001). Taken CNC diameter=1.5 mm as cut-off value, the sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of CND was 84.48% (49/58), 100% (28/28), 100% (49/49) and 75.68% (28/37), respectively. Conclusion: HRCT combined with MR T2-DRIVE can provide diagnostic references for CND of children.

MR three-dimension brain volume imaging enhanced scanning in diagnosis of internal auditory canal lesions / 中国介入影像与治疗学

Objective: To investigate the value of MR three-dimension brain volume imaging (3D-BRAVO) enhanced scanning in diagnosis of internal auditory canal lesion. Methods: Eighty-one patients with internal auditory canal disease (totally 116 lesions) underwent 3D-BRAVO enhanced and conventional enhanced MR scanning. The sensitivity of methods was compared. Results: Conventional MR enhanced scanning found 86 lesions, the diagnostic sensitivity was 71.55% (83/116), and the misdiagnose rate was 28.45% (33/116). All 116 lesions were detected with 3D-BRAVO enhanced scanning, and the diagnostic sensitivity was 100% (116/116). The diagnostic sensitivity of 3D-BRAVO scanning was higher than that of conventional enhanced scanning (Z=-3.74, P<0.001). Conclusion: 3D-BRAVO enhanced scanning can sensitively detect lesions in the internal auditory canal area and provide imaging evidences for clinical diagnosis and treatment of these lesions.

Frequency-following response (FFR) com estímulo de fala em jovens adultos normo-ouvintes / Frequency-following response (FFR) with speech stimulus in normal-hearing young adults

RESUMO Objetivo: Analisar o slope e as latências e amplitudes das ondas V, A, C, D, E, F e da Frequency-Following Response, com estímulo de fala, em adultos com audição normal, tendo como base referência internacional. Método: Onze adultos normo- ouvintes com idade entre 18 e 30 anos, sem queixas auditivas, foram avaliados na pesquisa. O equipamento utilizado foi o Intelligent Hearing System. O estímulo de fala /da/ foi apresentado por meio de fone de inserção na orelha direita e a resposta foi captada por meio de eletrodos posicionados no vértex, na mastoide direita e eletrodo terra na fronte. Resultados: Os valores descritivos de latência dos componentes foram: V 6,50, A 7,87, C 17,74, D 22,77, E 32,07, F 40,03 e O 48,07 ms. As médias de amplitude foram V 0,17, A -0,12, C -0,14, D -0,14, E -0,20, F -0,22 e O -0,14 µV. A média do valor do slope encontrada foi 0,23. Na comparação com estudo de referência internacional, Krizman et al. (2012) mostraram que a maioria dos resultados se encontra dentro de um desvio padrão positivo e negativo para a faixa etária estudada tanto para o slope quanto para as latências e amplitudes. Conclusão: A resposta eletrofisiológica da Frequency Following Response, utilizando o estímulo de fala /da/, em adultos com audição normal e sem queixas auditivas, apresentou valores de slope e de latência e amplitude de todos os componentes dentro do padrão de normalidade apresentado pela literatura internacional.

ABSTRACT Purpose: Analyze the slope, latency and amplitude values of the waveforms V, A, C, D, E, F and O from Frequency-following Response (FFR) with speech stimulus in normal-hearing adults based on a recent international reference study. Method: Eleven normal-hearing adults aged 18-30 years, without hearing complaints, were evaluated in this study using an Intelligent Hearing Systems device. The speech stimulus /da/ was presented to the right ear via insertion phone and the responses were captured by electrodes placed on the vertex, right mastoid bone, and forehead (ground). Results: The descriptive latency values of the components were V 6.50, A 7.87, C 17.74, D 22.77, E 32.07, F 40.03 and O 48.07 ms. The mean amplitude measures of the waves were V 0.17, A -0.12, C -0.14, D -0.14, E -0.20, F -0.22 and O -0.14 µV. The mean slope value was 0.23. Comparison with an international study, Krizman et al. (2012), showed that most of the results are within positive and negative standard deviation values for the assessed age group for slope, latency and amplitude. Conclusion: The electrophysiological measures obtained from Frequency-following Response using the speech stimulus / da/ in normal-hearing adults without hearing complaints showed slope, latency and amplitude values of all FFR components within the normality standard described in the international literature.

Analyzing The Age Related Changes In The Human Cochlear Nerve: A Qualitative Microscopic Study

Background: Cochlear nerve serves as one of the nodal point for enabling the passage of sound in both directions.The knowledge of age related morphological changes in human cochlear nerve is important to understand itsrole in the manifestation of sensori-neural presbycusis.Materials and Methods: The study was conducted in 21 human cochlear nerve samples, collected in 3 differentage groups (0-30 years, 31-50 years, 51 years and above). Resin embedding of cochlear nerves was done. Semithin (1 µm) cross sections of the nerves were cut by glass knife on Reichert Ultra-microtome. Under light microscope,toluidine blue stained nerve sections were studied for shape, organization of connective tissue and number offascicles.Results: Cochlear nerve was comma-shaped across all the age groups studied. Majority of the nerve sections hada blunt round head and sharp tail. Few sections had blunt tail also. Nerve fascicles were well defined in all the21 samples studied. The approximate number of fascicles across the various age groups varied from 60 to 85 pernerve. Numerous Schwann cells and numerous small sized blood vessels were found in the endoneurium of olderage group compared to younger and middle aged groups.Conclusion: However, we didn’t observe major qualitative changes across different age groups, but the presentstudy provides novel baseline morphological data on the human cochlear nerve.

Combined application and evaluation of two types of auditory monitoring in acoustic neuroma surgery / 中国耳鼻咽喉头颈外科

OBJECTIVE To explore the significance of intraoperative auditory monitoring(IAMA) in surgery of acoustic neuroma and to compare the value of auditory brainstem response(ABR) and cochlear nerve action potential(CNAP) in auditory monitoring.METHODS Retrospective analysis of 12 cases of acoustic neuroma from January 2016 to December 2016 was performed.All patients have a practical hearing(AAO-HNS,grade class a,b),the ABR waveform can be elicited,wave v differentiation,All tumors were removed via posterior sigmoid sinus approach.RESULTS ABR waveform of all patients were prolonged with different degrees of change(0.68±0.41) ms compared with the preoperative data.Amplitude of CNAP diverse in different individuals,with an average prolong compared to the data before operation(0.25±0.16) ms.In all 12 cases,8 (66.7％) patients remained usable hearing after the operation,4 cases(33.3％) failed to have a usable hearing.Among these 4 patients,3 showed disappearance of wave v,1 patient showed wave v latency prolong in the ABR,meanwhile,2 patients showed P1 dissapear,2 patients showed P1 latency prolong in CNAP.The intraoperative auditory monitoring could play a role in preventing the hearing damage in the procedure.Drilling,noise,surgical nerve stretch or thermal injury may cause the hearing damage.A 5 minutes pause could get some degree of regain,with the amplitude rise again.CONCLUSION A combination use of the ABR and CNAP monitoring has a certain significance in surgery of acoustic neuroma.ABR waveform is stable and reliable,but costs longer time;CNAP stack quickly and improve monitoring sensitivity,but waveform varies.Vibration and noise caused by drilling,nerve stretch during operation and heat damage can be monitored timely.Combined use of ABR and CNAP monitoring can enhance the auditory preservation rate during acoustic neuroma surgery.

Analysis of electrically evoked compound action potential of the auditory nerve in children with bilateral cochlear implants / Análise do potencial de ação composto do nervo auditivo evocado eletricamente em crianças usuárias de implante coclear bilateral

ABSTRACT INTRODUCTION: The cochlear implant device has the capacity to measure the electrically evoked compound action potential of the auditory nerve. The neural response telemetry is used in order to measure the electrically evoked compound action potential of the auditory nerve. OBJECTIVE: To analyze the electrically evoked compound action potential, through the neural response telemetry, in children with bilateral cochlear implants. METHODS: This is an analytical, prospective, longitudinal, historical cohort study. Six children, aged 1-4 years, with bilateral cochlear implant were assessed at five different intervals during their first year of cochlear implant use. RESULTS: There were significant differences in follow-up time (p = 0.0082) and electrode position (p = 0.0019) in the T-NRT measure. There was a significant difference in the interaction between time of follow-up and electrode position (p = 0.0143) when measuring the N1-P1 wave amplitude between the three electrodes at each time of follow-up. CONCLUSION: The electrically evoked compound action potential measurement using neural response telemetry in children with bilateral cochlear implants during the first year of follow-up was effective in demonstrating the synchronized bilateral development of the peripheral auditory pathways in the studied population.

RESUMO INTRODUÇÃO: O implante coclear tem a capacidade de medir o potencial de ação composto eletricamente evocado do nervo auditivo (ECAP). Para esta verificação utiliza-se uma medida chamada telemetria de respostas neurais. OBJETIVO: Analisar o potencial de ação composto evocado eletricamente, por meio da neurotelemetria de respostas neurais, em crianças usuárias de implante coclear bilateral. MÉTODO: Trata-se de um estudo analítico, prospectivo, de coorte histórica longitudinal. Foram recrutadas seis crianças, com idades entre de 1-4 anos, usuárias de implante coclear bilateral. Estas crianças foram avaliadas em cinco momentos durante o primeiro ano de uso do implante coclear. RESULTADOS: Houve diferença significativa no tempo de acompanhamento (p = 0,0082) e posição do eletrodo (p = 0,0019) na medida de T-NRT. Houve diferença significativa na interação entre tempo de acompanhamento e posição do eletrodo (p = 0,0143) na medida da amplitude das ondas N1-P1 entre os três eletrodos a cada tempo de acompanhamento. CONCLUSÃO: A mensuração do ECAP por meio da NRT nas crianças com implante coclear bilateral durante o primeiro ano de acompanhamento foi uma medida importante para apresentar o desenvolvimento bilateral da via auditiva periférica de forma sincronizada nesta população estudada.

Analysis of Auditory Rehabilitation Outcomes of the Cochlear Neural Canal Stenosis Patients after Cochlea Implantation / 听力学及言语疾病杂志

Objective To study the analysis of auditory rehabilitation outcomes of patients with cochlear nerve canal stenosis after cochlear implantation(CI).Methods A cohort of 30 patients with bilateral profound senso-rineural hearing loss who were diagnosed with cochlear neural canal stenosis by high-resolution CT were tested with evoked compound action potential (ECAP)and evoked auditory brainstem response (EABR)during and 3 ,6 , 9 months after CI.Audiometry in sound field was also assessed before and 3 ,6 ,9 months after CI.Among the co-hort,1 7 patients over 3 years old underwent postoperative speech recognition rate test.All the auditory rehabilita-tion outcomes were analyzed.Results ① For all 30 patients,there were no obvious differences of ECAP and EABR waveforms tested in 3,6 and 9 months after CI.②The thresholds in sound field in 3,6,9 months after CI were 65 ±8 dB HL,62 ±4 dB HL and 61 ±7 dB HL,respectively.The thresholds in sound field were significantly im-proved after than before CI (100 ±5 dB HL).③ The single vowel recognition rates of 17 patients in 3 ,6 and 9 months after CI were 55%±7%,56%±8% and 80%±4%,respectively.The single vowel recognition rate was significantly improved in 9 months after than before CI(52%±8%).The single consonant recognition rates of 17 pa-tients in 3 ,6 and 9 months after CI were 9%±3%,8%±4% and 9%±2%,respectively.The single consonant recognition rates were not significantly improved after than before CI (8%±2%).Conclusion ① For patients with bi-lateral cochlear neural canal stenosis,neither ECAP nor EABR waves were produced during or after CI.The language com-munication of patients is limited as a result of their poor subjective thresholds in sound field and speech recognition rates.

Measurement of the diameter of the cochlear nerve and the age-variation in normal hearing children using MRI / 中华放射学杂志

Objective To measure the diameter of cochlear nerve(CN) in normal hearing children with different ages,and evaluate the diameter variations with age.Methods A total of 156 normal-hearing children were assessed with 3D-FIESTA sequence scanning of the inner ear.All the subjects were divided into 13 groups according to age,witha group of ≤6 months,a group of ≤1 year,and 11 groups from one year to 12 years.Each group had 12 cases,including 6 boys and 6 girls.The diameter of CN was measured at the entrance of the cochlea,the middle of internal auditory canal(IAC) and the fundus of IAC respectively on the axial and oblique sagittal images of 3.0 T MRI by two independent observers.The average values measured by them were the final results.The intraclass correlation coefficient was used to determine the consistency between the two independent observers.The t test was used to access differencesin CN diameter by sex and sides.One-way analysis of variance(ANOVA) and two-way ANOVA were used for comparisons among different groups.Spearman correlation coefficient was applied to find a correlation between the CN diameter and age.Results The diameters of normal-hearing children's CN at the middle of the IAC,IAC fundus and the entrance of the cochlea were (1.12 ± 0.08),(1.05 ± 0.06),(0.87 ± 0.14) mm respectively,and there was significant difference among the three measuring points (F=527.57,P＜0.05).The diameters of the CN had no significant differenc (P＞0.05) in age-groups,gender and sides(P＞0.05),and there was no correlation between the diameters of normal children's CN and age.Conclusions The diameters of normal-hearing children's CN change with different points of the IAC,of which the maximum value is at the middle of the IAC,followed by the IAC fundus,and the entrance of the cochlea is at the minimum,more over the normal size doesn't change with age.

Value of MRI in evaluating facial and cochlear nerve development / 实用放射学杂志

Objective To evaluate facial nerve(FN),cochlear nerve(CN)development by magnetic resonance hydrography of the inner ear.Methods 91 cases with normal hearing infants from 0 to 36 months underwent MR head scan and magnetic resonance hydrography of the inner ear.FN,CN long diameter (LD)and short diameter (SD)in oblique sagittal reconstruction imaging were measured.Results 91 cases(182 ears)were divided to 0-12 months as 1st,group (N=35),13-24 months as the 2ed,group (N=36),25-36 months as the 3rd,group (N=20)according to age,in which FN (154 ears,84.6%),CN(170 ears,93.4%)were showed clearly.FN’s LD, SD and Cross-section area(CSA)were 0.76 mm± 0.14 mm,0.50 mm± 0.12 mm,0.30 mm± 0.11 mm,and CN ’s LD,SD and CSA were 0.98 mm± 0.14 mm,0.63 mm± 0.11 mm,0.49 mm± 0.13 mm respectively comparison between groups it was showed that in hearing normal infant growth process,CN,FN development did not vary and change for the left and right side,gender and age.Conclusion MRI measurement of FN,CN diameter and cross-sectional area size provides an important reference on the assess-ment of CN,FN growth condition in infants with normal hearing.

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.

Change in Tinnitus after Treatment of Vestibular Schwannoma: Microsurgery vs. Gamma Knife Radiosurgery

PURPOSE: Tinnitus is a very common symptom of vestibular schwannoma, present in 45 to 80% of patients. We evaluated changes in tinnitus after translabyrinthine microsurgery (TLM) or gamma knife radiosurgery (GKS). MATERIALS AND METHODS: Among 78 patients with vestibular schwannoma who underwent TLM or GKS at Severance Hospital from 2009-2012, 46 patients with pre- or postoperative tinnitus who agreed to participate were enrolled. Pure tone audiometry, tinnitus handicap inventory (THI), visual analogue scale (VAS) scores for loudness, awareness, and annoyance were measured before and after treatment. Changes of THI and VAS were analysed and compared according to treatment modality, tumour volume, and preoperative residual hearing. RESULTS: In the TLM group (n=27), vestibulocochlear nerves were definitely cut. There was a higher rate of tinnitus improvement in TLM group (52%) than GKS group (16%, p=0.016). The GKS group had a significantly higher rate of tinnitus worsening (74%) than TLM group (11%, p<0.001). Mean scores of THI and VAS scores significantly decreased in the TLM group in contrast to significant increases in the GKS group. Tumor volume and preoperative hearing did not affect the changes in THI or VAS. CONCLUSION: GKS can save vestibulocochlear nerve continuity but may damage the cochlea, cochlear nerve and can cause worsening tinnitus. In cases where hearing preservation is not intended, microsurgery with vestibulocochlear neurectomy during tumor removal can sometimes relieve or prevent tinnitus.

Imaging analysis of simple cochlear nerve canal stenosis / 实用放射学杂志

Objective To study the imaging manifestations and clinical significance of simple cochlear nerve canal(CNC)stenosis. Methods The HRCT findings of 14 patients(1 7 ears)with simple CNC stenosis diagnosed sensorineural hearing loss(SNHL)were retrospectively analyzed.The width of CNC and internal auditory canal was measured and compared with the normal ears,the data were statisti-cally analyzed by SPSS1 6.0.Thin-sliced MRI of internal auditory canal (axial and oblique sagittal position)was performed in 8 cases. Results HRCT displayed obvious CNC stenosis in all 14 patients(1 7 ears),2 ears with cochlear nerve canal atresia.Width of CNC and internal auditory canal was (0.5±0.3)mm and (4.6±1.0)mm,it was (2.1±0.2)mm and (5.1 ±1.3)mm in normal ears (1 1 ears),the width of CNC was of significant difference between normal ears and ears with SNHL,and there was no statistical sig-nificant difference in width of internal auditory canal.12 ears(from 1 7 ears with simple CNC stenosis)were lacking of fissure in the cribriform area,1 1 ears(normal ear)were existence of fissure in the cribriform area;cochlear nerves were not shown in 8 patients with MRI examination.Conclusion CNC stenosis can be isolated from internal auditory canal stenosis,MRI could display cochlear nerve dysplasia(CND).

A Case with the Bilateral Narrow Bony Cochlear Nerve Canals Associated with Near Normal Hearing Thresholds

The narrow bony cochlear nerve canal in high resolution temporal bone computed tomography is frequently found in patients of congenital sensorineural hearing loss. But this bony structural anomaly could not conclude the functional outcome of cochlear nerve. Here, we present a case of a 14-month-old girl having bilateral narrow bony cochlear nerve canals. In magnetic resonance imaging, both the cochlear nerves were identified to be intact. Moreover, acoustic brainstem response threshold and auditory steady state response revealed nearly normal hearing thresholds. Therefore, we suggest that the narrow bony cochlear nerve canal itself does not necessarily indicate a substantial degree of hearing loss.

A Case with the Bilateral Narrow Bony Cochlear Nerve Canals Associated with Near Normal Hearing Thresholds

The narrow bony cochlear nerve canal in high resolution temporal bone computed tomography is frequently found in patients of congenital sensorineural hearing loss. But this bony structural anomaly could not conclude the functional outcome of cochlear nerve. Here, we present a case of a 14-month-old girl having bilateral narrow bony cochlear nerve canals. In magnetic resonance imaging, both the cochlear nerves were identified to be intact. Moreover, acoustic brainstem response threshold and auditory steady state response revealed nearly normal hearing thresholds. Therefore, we suggest that the narrow bony cochlear nerve canal itself does not necessarily indicate a substantial degree of hearing loss.