Analyses of audiological examination in children without auditory brainstem response / 中华耳鼻咽喉头颈外科杂志

Objective@#To investigate residual hearing of children severe and profound sensorineural deafness in whom wave V was not found in auditory brainstem response(ABR) testing, and to emphasize the importance of objective audiological tests.@*Methods@#Two hundred and fifty-two children who were admitted to the Second Affiliated Hospital of Zhengzhou University between January 2015 and April 2018, with an average age of 20 months from 72 days to 4 years, received a full battery of objective audiological tests consisting of distortion product otoacoustic emission(DPOAEs), tympanometry, auditory brainstem responses(ABRs), 40 Hz auditory event related potential(40 HzAERP) and auditory steady-state response(ASSRs).There were 159 males(318 ears) and 93 females(186 ears). Residual hearing obtained by 40 HzAERP、ASSR of 252 children with sensorineural deafness was studied in relation to the absence of wave V in click ABR. SPSS 16.0 software was used to analyze the data.@*Results@#Four hundred and forty-four ears of 504 ears have residual hearing of different degrees at different frequencies(88.1%),60 ears (11.9%) were found in whom responses was not found in 40 HzAERP、ASSR testing; Seventy-two ears(14.3%) in 38 patients were tested cochlear microphonic potentials (CMs).@*Conclusion@#In children hearing evaluations,a full battery of objective audiological tests could better investigate residual hearing; The CMs were tested could provide the Audiotery Neuropathy diagnosis in infants with OAEs and ABR absent.

Role of Cochlear Microphonic in Newborn Hearing Test / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Cochlear microphonic (CM) is an electrical potential generated by outer hair cells in response to acoustic stimulation. The aim of this study is to evaluate the significance of CM in neonatal hearing loss. SUBJECTS AND METHOD: From April 2013 to April 2014, 64 neonates hospitalized in neonatal intensive care unit were enrolled. Subjects underwent transient evoked otoacoustic emission (TEOAE), auditory brain stem response (ABR) and CM. We analyzed the results of hearing tests and the correlation between CM and the other test modalities. RESULTS: Ninety two ears showed normal ABR waves whereas the other 36 ears had abnormal ABR. There were two neonates who were suspected of auditory neuropathy because of the presence of TEOAE and CM. Among 14 ears who showed abnormal OAE results, 12 ears (86%) were identified as having CM. The amplitudes of CMs were correlated with the reproducibility of TEOAE (p<0.005). Between the ears with positive TEOAE and others with negative TEOAE, the amplitudes of CMs were significantly different (p<0.005). CONCLUSION: Many ears were identified with the presence of CM without TEOAE response because of the the vulnerability of OAE from middle ear status and environment. We suppose that CM might provide information on outer hair cell function to complement the OAE in neonatal hearing test.

Eletrococleografia extratimpânica na neuropatia/dessincronia auditiva: [revisão] / Extratympanic electrocochleography in the diagnosis of auditory neuropathy/auditory dyssynchrony: [review]

O potencial evocado auditivo de tronco encefálico (PEATE) vem sendo amplamente utilizado como método para avaliação da função coclear em indivíduos com diagnóstico de neuropatia/dessincronia auditiva (NA/DA). Na ausência das emissões otoacústicas, muitos casos de NA/DA foram diagnosticados pela presença do microfonismo coclear (MC) identificado no PEATE. OBJETIVO: Demonstrar a aplicabilidade clínica da eletrococleografia extratimpânica (Ecog-ET) no diagnóstico diferencial da NA/DA quando comparada ao PEATE. MATERIAL E MÉTODO: Uma criança com 4 anos de idade, com diagnóstico de NA/DA atendida no Centro de Pesquisas Audiológicas realizou a Ecog-ET com tone burst de 2000Hz nas polaridades de rarefação e condensação. RESULTADOS: Ilustrou-se o registro da Ecog-ET. Com a utilização de protocolo apropriado, o MC pode ser evidenciado e confirmado na Ecog, com qualidade de registro superior ao obtido no PEATE. CONCLUSÃO: A Ecog-ET permitiu uma análise mais detalhada do MC quando comparada ao PEATE tendo, portanto aplicabilidade clínica na investigação da função coclear na NA/DA.

The brainstem auditory evoked potential (BAEP) is being extensively used as a method for the evaluation of cochlear function in individuals with diagnosis of auditory neuropathy/auditory dyssynchrony (AN/AD). In the absence of otoacoustic emissions, many cases of AN/AD have been diagnosed by the presence of CM identified in the BAEP. AIM: to demonstrate the clinical applicability of extratympanic electrocochleography (ET-Ecochg) in the differential diagnosis of AN/AD compared to the BAEP. METHOD: a 4-year-old child with a diagnosis of AN/AD seen at the Audiological Research Center was submitted to ET-Ecochg with a 2000 Hz tone burst in rarefaction and condensation polarities. RESULTS: the ET-Ecochg exam was illustrated. Using an appropriate protocol, it was possible to demonstrate CM and to confirm it in the Ecochg, with a recording quality superior to that obtained in the BAEP. CONCLUSION: ET-Ecochg permitted a more detailed analysis of CM compared to the BAEP, thus showing clinical applicability for the investigation of cochlear function in AN/AD.

The protective effect of dopamine on the noiseinduced hearing loss of guinea pigs / 中国耳鼻咽喉头颈外科

OBJECTIVE To investigate the protective effect and its frequency selection of dopamine on the inner cell in cochlea when exposed to white-noise;In order to offer an important step on understanding of negative protective modulation of dopamine in the cochlear auditory afferent nerve. METHODS Forty guinea pigs were randomly divided into 4 groups and whole intracochlear perfusions were performed. ① exposed to the 100dB white-noise; ② perfused with artificial perilymph solutions; ③exposed to the white-noise and perfused with artificial perilymph solutions; ④exposed to the white-noise and perfused with Artificial perilymph solutions containing 1mmol/L dopamine. Compound action potential(CAP)evoked by different frequencies tone pip, and cochlear mirophonics(CM)evoked by 4kHz tone burst were recorded from the round window of guinea pigs before and 2h after perfusion. RESULTS In the groups exposed to the white-noise, the CM amplitude and the linearity of input-output function both significantly decreased at 2h(P

Effect of nifedipine, a calcium channel blocker, on cochlear function and noise-induced hearing loss in guinea pigs / 中国耳鼻咽喉头颈外科

0.05). A rise in CAP threshold and reduction in CM amplitude after perfusion were found in the other three groups(P

Relationship among loudness recruitment, cochlear microphonics and prognosis of hearing loss / 中国耳鼻咽喉头颈外科

75dB SPL or no response. RESULTS The individual differences of CM absolute amplitudes among the normal hearing ones at different frequencies are distinct, but bilateral CM amplitudes in same person are almost uniform and stable. Enlargedand prolongated CM was found in ears with loudness recruitment .Of 104 cases with unilateral hearing loss, CM were enlarged and prolongated at corresponding frequencies with loudness recruitment in 95 cases(91.3 %).The prognosis of cases with CM type Ⅰ was better than those with types Ⅱ and Ⅲ. The effective rates of treatment were 78.19 % in type Ⅰ , 2.5 % in type Ⅱ, and none in type Ⅲ. There were significant differences among them. CM was slightly enlarged during sleep, and the detected threshold of CM is less than that of the awake condition. CONCLUSION CM offers the reliable information for the mechanism of loudness recruitment and is also useful for understanding the relationship among loudness recruitment, cochlear microphonics and prognosis. CM may be taken as a valuable parameter for evaluating prognosis.

Effects of N-methyl-D-aspartate on the cochlear potentials / 第二军医大学学报

Objective: To investigate the effect of N methyl D aspartate(NMDA) on cochlear potentials and to find out the possible neurotoxic effect of NMDA on cochlea function in guinea pigs. Methods: After basal compound action potentials (CAP) and cochlear microphonics (CM) were recorded by round window electrode, animals ( n =5) were treated with Hanks applied to the round window membrane (RWM) for 20 min as control. Then 100 ?mol/L NMDA was applied to the RWM for another 20 min. Results: Hanks produced no obvious changes in CAP threshold, CAP N1 and CM latency and amplitude. CAP thresholds at all frequencies of tone burst were significantly elevated by application of NMDA, threshold shifts ranged from 13 27 dB. NMDA significantly reduced the CAP N1 amplitudes at all intensities of stimulations. CAP amplitudes were suppressed by 50% 75%. NMDA also significantly increased the CAP latency, the latency of CAP evoked by 6 kHz tone burst at intensity of -90 dB(output attenuation) was (1.9?0.06) ms after Hanks treatment and (2.76?0.21) ms after NMDA treatment ( P