COCHLEAR NERVE APLASIA AND COCHLEAR IMPLANTATION: AUTHOR'S REPLY

Congenital aural atresia (CAA) is usually accompanied by an anomalous course of facial nerves, which may run over the round window niche toward the promontory in some cases of CAA. Very rarely, cochlear malformation might coexist at the same ear which has CAA, in which case cochlear implantation can be difficult due to anomalous facial nerve. Herein we present a case of cochlear implantation performed in a child who had CAA along with cochlear hypoplasia and cochlear nerve aplasia. The mastoid segment of facial nerve was displaced anteriorly, running over the round window niche. The surgery was done successfully using the round window approach without facial nerve injury.

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Vestibular dysfunction after cochlear and auditory brainstem implantation: Madras ENT Research Foundation experience

International Journal of Otorhinolaryngology and Head and Neck Surgery ◽

10.18203/issn.2454-5929.ijohns20210687 ◽

2021 ◽

Vol 7 (3) ◽

pp. 513

Author(s):

Kiran Natarajan ◽

Sathiya Murali ◽

Santhosh Kumar M. ◽

Manjunatha H. A. ◽

Adarsh Panicker ◽

...

Keyword(s):

Cochlear Implantation ◽

Vestibular Function ◽

Auditory Brainstem ◽

Cochlear Nerve ◽

Vestibular Evoked Myogenic Potentials ◽

Caloric Test ◽

Cerebellar Flocculus ◽

Cochlear Nerve Aplasia ◽

Invasive Techniques ◽

The Impact

Background: Cochlear implantation is an established procedure for patients with bilateral severe to profound sensorineural hearing loss. CI may, in some implantees, have a detrimental impact on vestibular function. Auditory brainstem implantation is a safe and effective procedure in children with bilateral cochlear and cochlear nerve aplasia. The aim of the study was to assess the impact of cochlear implantation and auditory brainstem implantation on the vestibular function.Methods: Three hundred and twenty patients who underwent CI surgery over a four years period from November 2016 to November 2020 were studied for symptoms of vestibular disturbance. Twenty three patients complained of giddiness and underwent vestibular function testing including videooculography, caloric test and vestibular evoked myogenic potentials. 48 patients with cochlear and cochlear nerve aplasia underwent ABI surgery from September 2009 to March 2019. The correlation between the size of the flocculus and the presence of vestibular symptoms was studied.Results: After CI, vestibular disturbances were seen in 23 patients (7.2%) and were transient. In auditory brainstem implantees, vestibular disturbances were seen in eight patients (16.7%) and were found to correlate with the size of the cerebellar flocculus.Conclusions: Vestibular disturbances are rare after cochlear and auditory brainstem implant surgery. During CI, the preservation of vestibular function should be attempted using minimally invasive techniques. ABI surgery requires meticulous dissection, especially of a large cerebellar flocculus to minimize the possibility of vestibular disturbances.

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Cochlear Implantation in Children With Cochlear Nerve Absence or Deficiency

Otology & Neurotology ◽

10.1097/mao.0b013e31821f473b ◽

2011 ◽

Vol 32 (6) ◽

pp. 956-961 ◽

Cited By ~ 50

Author(s):

Joe Walter Kutz ◽

Kenneth H. Lee ◽

Brandon Isaacson ◽

Timothy N. Booth ◽

Melissa H. Sweeney ◽

...

Keyword(s):

Cochlear Implantation ◽

Cochlear Nerve

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Brain Stem Responses Evoked by Stimulation With an Auditory Brain Stem Implant in Children With Cochlear Nerve Aplasia or Hypoplasia

Ear and Hearing ◽

10.1097/aud.0b013e3181fc9f17 ◽

2011 ◽

Vol 32 (3) ◽

pp. 300-312 ◽

Cited By ~ 17

Author(s):

Martin OʼDriscoll ◽

Wael El-Deredy ◽

Ahmet Atas ◽

Gonca Sennaroglu ◽

Levent Sennaroglu ◽

...

Keyword(s):

Brain Stem ◽

Cochlear Nerve ◽

Auditory Brain Stem ◽

Cochlear Nerve Aplasia

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EABR of Inner Ear Malformation and Cochlear Nerve Deficiency After Cochlear Implantation in Children

Cochlear Implantation in Children with Inner Ear Malformation and Cochlear Nerve Deficiency ◽

10.1007/978-981-10-1400-0_8 ◽

2016 ◽

pp. 97-109

Author(s):

Shujiro Minami ◽

Kimitaka Kaga

Keyword(s):

Inner Ear ◽

Cochlear Implantation ◽

Cochlear Nerve ◽

Inner Ear Malformation ◽

Cochlear Nerve Deficiency

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The Narrow Internal Auditory Canal in Children: A Contraindication to Cochlear Implants

Otolaryngology ◽

10.1177/019459988910000310 ◽

1989 ◽

Vol 100 (3) ◽

pp. 227-231 ◽

Cited By ~ 107

Author(s):

Clough Shelton ◽

William M. Luxford ◽

Lisa L. Tonokawa ◽

William W. M. Lo ◽

William F. House

Keyword(s):

High Resolution ◽

Cochlear Implants ◽

Cochlear Implantation ◽

Electric Stimulation ◽

Internal Auditory Canal ◽

Auditory Stimulation ◽

Cochlear Nerve ◽

X Ray ◽

Computed Tomographic ◽

Auditory Response

We suggest a new explanation for the lack of auditory response to electric stimulation in children with cochlear implants: The very narrow internal auditory canal, 1 to 2 mm in diameter, and the probable absence of the cochlear nerve. This defect can be seen on high-resolution computed tomographic x-ray studies and may represent aplasia of the auditory-vestibular nerve. We report on eight children with this anomaly, three of whom have received implants and failed to respond with a sensation of sound. Identification of this problem on screening x-ray films is a contraindication to cochlear Implantation for auditory stimulation.

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Familial Unilateral Cochlear Nerve Aplasia

Otology & Neurotology ◽

10.1097/00129492-200604000-00025 ◽

2006 ◽

Vol 27 (3) ◽

pp. 443-444 ◽

Cited By ~ 6

Author(s):

Nimish Patel ◽

John S. Oghalai

Keyword(s):

Cochlear Nerve ◽

Cochlear Nerve Aplasia

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A New Classification of Cochleovestibular Malformations and Implications for Predicting Speech Perception Ability after Cochlear Implantation

Audiology and Neurotology ◽

10.1159/000365584 ◽

2015 ◽

Vol 20 (2) ◽

pp. 90-101 ◽

Cited By ~ 12

Author(s):

Sung-Wook Jeong ◽

Lee-Suk Kim

Keyword(s):

Speech Perception ◽

Cochlear Implantation ◽

Test Scores ◽

Type A ◽

Cochlear Nerve ◽

Type B ◽

New Classification ◽

Type D ◽

Type C

Objectives: The aims of this study were to introduce a new classification of cochleovestibular malformation (CVM) and to investigate how well this classification can predict speech perception ability after cochlear implantation in children with CVM. Methods: Fifty-nine children with CVM who had used a cochlear implant for more than 3 years were included. CVM was classified into 4 subtypes based on the morphology of the cochlea and the modiolus on temporal bone computed tomography (TBCT): normal cochlea and normal modiolus (type A, n = 16), malformed cochlea and partial modiolus (type B, n = 31), malformed cochlea and no modiolus (type C, n = 6), and no cochlea and no modiolus (type D, n = 6). Speech perception test scores were compared between the subtypes of CVM using analysis of covariance with post hoc Bonferroni test. Univariate and multivariate regression analyses were used to identify the significant predictors of the speech perception test scores. Results: The speech perception test scores after implantation were significantly better in children with CVM type A or type B than in children with CVM type C or type D. The test scores did not differ significantly between the implanted children with CVM type A or type B and those without CVM. In univariate regression analysis, the type of CVM was a significant predictor of the speech perception test scores in implanted children with CVM. Multivariate regression analysis revealed that the age at cochlear implantation, cochlear nerve size and preimplantation speech perception test scores were significant predictors of the postimplantation speech perception test scores. The chance of cochlear nerve deficiency increased progressively from CVM type A to type D. Conclusion: The new classification of CVM based on the morphology of the cochlea and the modiolus is simple and easy to use, and correlated well with postimplantation speech perception ability and cochlear nerve status. This simple classification of CVM using TBCT with cochlear nerve assessment by magnetic resonance imaging is helpful in the preoperative evaluation of children with CVM.

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