Air, bone and soft tissue excitation of the cochlea in the presence of severe impediments to ossicle and window mobility.

Clinical conditions have been described in which one of the two cochlear windows is immobile (otosclerosis) or absent (round window atresia), but nevertheless bone conduction (BC) thresholds are relatively unaffected. To clarify this apparent paradox, experimental manipulations which would severely impede several of the classical osseous mechanisms of BC were induced in fat sand rats, including discontinuity or immobilization of the ossicular chain, coupled with window fixation. Effects of these manipulations were assessed by recording auditory nerve brainstem evoked response (ABR) thresholds to stimulation by air conduction (AC), by osseous BC and by non-osseous BC (also called soft tissue conduction-STC) in which the BC bone vibrator is applied to skin sites. Following the immobilization, discontinuity and window fixation, auditory stimulation was also delivered to cerebro-spinal fluid (CSF) and to saline applied to the middle ear cavity. While the manipulations (immobilization, discontinuity, window fixation) led to an elevation of AC thresholds, nevertheless, there was no change in osseous and non-osseous BC thresholds. On the other hand, ABR could be elicited in response to fluid pressure stimulation to CSF and middle ear saline, even in the presence of the severe restriction of ossicular chain and window mobility. The results of these experiments in which osseous and non-osseous BC thresholds remained unchanged in the presence of severe restriction of the classical middle ear mechanisms and in the absence of an efficient release window, while ABR could be recorded in response to fluid pressure auditory stimulation to fluid sites, indicate that it is possible that the inner ear may be activated at low sound intensities by fast fluid pressure stimulation. At higher sound intensities, a slower passive basilar membrane traveling wave may serve to excite the inner ear.

[Fluoroscopic assisted cochlear implantation in children with inner ear malformations].

BACKGROUND: Cochlear implants are the treatment of choice for individuals with severe to profound sensorineural hearing loss. In most cases, the anatomy is normal and the insertion of the electrode-array is straightforward, complete and in the correct position. In the presence of inner-ear malformations, the risk of an intra or extra-cochlear malpositioned electrode-array increases. OBJECTIVES: To describe the technique of fluoroscopic assisted cochlear implantation in children with severe inner-ear malformations and present the results with respect to the number of active electrodes and function. METHODS: Fifteen fluoroscopy assisted implantations in 9 children were conducted at the Shaare Zedek Cochlear Implant Center between 2009-1014. All implanted ears had severe anatomic malformations. Mean implantation age was 3.5 years (range 1-11). Six children underwent sequential bilateral implantation. Two children underwent revision surgery due to a malpositioned electrode initially implanted without fluoroscopy at other centers. RESULTS: There was no radiologic or electro-physiologic evidence of kinking, bending or electrode damage in all 15 implantations. Complete insertion was achieved in all ears except one with partial insertion. There were no extra-cochlear or intrameatal placements. In 9 ears, all electrodes were active at switch-on and in the remaining, 15-20 were active. In all ears the Ling-6 sounds were detected and in 13 they were also identified. CONCLUSION: Fluoroscopy is an effective tool in complex cochlear implant surgeries and its use is simple and safe. As demonstrated in this study, with fluoroscopy assistance, good results are achieved in children with inner-ear malformations.

Cochlear implant in a patient with mondini's deformity of the cochlea: pilot patient in Pakistan.

Autosomal-recessive genes account for about 80% of the patients of non-syndromic deafness, and a major portion of those lead to cochlear pathology. Given the strong cultural practice of consanguineous marriages and the lack of awareness regarding screening modalities, a high prevalence of hereditary pre-lingual deafness is seen in Pakistan. Considering the situation, cochlear implant surgery was introduced by Aga Khan University Hospital (AKUH), Karachi, Pakistan, in 2003. Recently we decided to expand the profile and services available and conducted the first ever cochlear implant on an anatomically-challenged cochlea. The case report relates to the experience of our pilot patient who was suffering from Mondini's deformity.

A new phenomenon of cochlear otosclerosis: an acquired or congenital disease? - A clinical report of cochlear otosclerosis.

BACKGROUND: No cochlear otosclerosis in infants with congenital bilateral SNHL has been reported. AIMS/OBJECTIVES: We report an infant male with bilateral cochlear otosclerosis, suggesting that cochlear otosclerosis may be a congenital disease and to further analyze the etiology of and genetic expression in congenital bilateral cochlear otosclerosis. We also describe the clinical characteristics and experience of patients with bilateral cochlear otosclerosis treated with cochlear implants (CIs). MATERIALS AND METHODS: Seven patients, including an infant, who were diagnosed with cochlear otosclerosis underwent CI surgery. Their medical records, audiological and radiological results, surgical procedures, and CI outcomes were collected and reviewed. RESULTS: The median age at hearing loss was 38 years, ranging from 0 to 47 years. The child had bilateral hearing loss at birth and received a CI at 1 year of age. He also had growth retardation and was diagnosed with 3q+/3p- syndrome. All patients (8 ears) had better postoperative auditory performance than that preoperatively. CONCLUSIONS AND SIGNIFICANCE: Although cochlear otosclerosis often starts at middle age and progresses slowly, it may be a congenital disease that is related to chromosome abnormality. This disease presents with SNHL or MHL, and treatment with a CI is beneficial.

Identification of MYO6 copy number variation associated with cochlear aplasia by targeted sequencing.

Copy number variation is an extensively studied cause of hereditary diseases. However, its role in hereditary sensorineural deafness has been rarely reported. Using targeted sequencing, SNP array and qPCR, we found a novel 622.2 kb duplication of 6q14.1 in a patient with congenital sensorineural hearing loss and cochlear aplasia. The duplication included MYO6 and IMPG1 genes. FISH study confirmed that this duplication was inherited from the patient's mosaic mother.

New Classification of Cochlear Hypoplasia Type Malformation: Relevance in Cochlear Implantation.

OBJECTIVES: This paper attempts to create a new classification type of cochlear hypoplasia (CH)-type malformation taking into consideration of vestibular section and internal auditory canal (IAC). MATERIALS AND METHODS: Preoperative computed-tomography (CT) scans of cochlear implant (CI) candidates (N=31) from various clinics across the world with CH type malformation were taken for analysis. CT dataset were loaded into 3D-slicer freeware for three-dimensional (3D) segmentation of the inner-ear by capturing complete inner-ear structures from the entire dataset. Cochlear size in terms of diameter of available cochlear basal turn and length of cochlear lumen was measured from the dataset. In addition, structural connection between IAC and cochlear portions was scrutinized, which is highly relevant to the proposed CH classification in this study. RESULTS: CH group-I has the normal presence of IAC leading to cochlear and vestibular portions, whereas CH group-II is like CH group-I but with some degree of disruption in vestibular portion. In CH group-III, a disconnection between IAC and the cochlear portion irrespective of other features. Within all these three CH groups, the basal turn diameter varied between 3.1 mm and 9.6 mm, and the corresponding cochlear lumen length varied between 3 mm and 21 mm for the CI electrode array placement. CONCLUSION: A new classification of CH mainly based on the IAC connecting the cochlear and vestibular portions is presented in this study. CI electrode array length could be selected based on the length of the cochlear lumen, which can be observed from the 3D image.

Congenital cholesteatoma extending into the internal auditory canal and cochlea: a case report.

We report here on a case of congenital cholesteatoma that extended into the internal auditory meatus and cochlea. A 17-year-old boy underwent surgery for a very large cholesteatoma, which was discovered behind an intact tympanic membrane. Pure tone audiometry revealed an unresponsive ear. High resolution temporal bone computed tomography showed perilabyrinthine extension with its absence in the vestibular area, and destruction of the bony cochlea at the basal turn, the tegmen and the posterior cranial fossa. Magnetic resonance imaging revealed no intracranial extension. Surgical exploration of the middle ear and the mastoid cavity revealed that both the vestibule and the basal turn of the cochlea were filled with a noninfected cholesteatoma. The cholesteatoma extended into the internal auditory meatus through translabyrinthine destruction; it extended into the basal turn of the cochlea through the infralabyrinthine route. The bony segment of the facial nerve canal demonstrated near total dehiscence. The cholesteatoma was removed by the transotic approach. Congenital cholesteatoma is characterized by no specific history. Therefore, early detection of this malady can be challenging, but it is important to prevent such complications as were observed in this reported case.

Rare case of bilateral aural atresia and cochlear dysplasia: when cochlear implantation is not the answer.

OBJECTIVE AND IMPORTANCE: Reports of patients with concurrent middle and inner ear anomalies are rare. These patients present a surgical challenge for cochlear implantation. The surgical risk must be weighed against the predicted benefit of the patient's hearing outcome and subsequent development of speech and language as well as their quality of life. CLINICAL PRESENTATION: Thirteen-year-old boy presented to the Otology clinic for auditory rehabilitation options. He has mild developmental delay, is non-verbal and communicates via American Sign Language. He was born with bilateral aural atresia and never wore amplification. On exam he has grade 1 microtia and complete ear canal atresia bilaterally. His behavioural hearing test shows profound sensorineural hearing loss of both ears. The computed tomography scan shows bilateral underdeveloped and completely opacified mastoid and middle ear, complete bony atresia of the ear canals, and an under-partitioned cochlea with poorly defined modiolus, among other abnormalities. The patient and his family were counselled on the available options as well as the need for any further studies. INTERVENTION: Counselling of patient and family. CONCLUSION: While there have been reports in the literature of performing cochlear implantations in patients with a concurrent atresia and cochlear dysplasia, these were patients whose degree of inner ear anomalies was relatively minor and their prognosis of a good audiological outcome was favourable. The presented case is that of a patient for whom the surgical approach to the cochlea alone would be difficult. More importantly, his quality of life would not significantly improve in light of the predicted limited hearing and language development outcomes, given the severity of his inner ear abnormalities, limited communication abilities, prolonged period of deafness and developmental delays.

Audiologic and radiologic findings in cochlear hypoplasia.

OBJECTIVE: The aim of the current study is to evaluate audiologic and radiologic findings of cochlear hypoplasia which is a subgroup of inner ear malformations. METHODS: This study was a prospective clinical study and based on voluntary participation from cases with cochlear hypoplasia diagnosis. The study was conducted at Hacettepe University, Department of Otolaryngology, Head and Neck Surgery and Department of Audiology. Subjects were selected from an inner ear malformations database. Inclusion criteria were having cochlear hypoplasia for at least one ear. There were 66 subjects with an age range of 12 months and 60 years 5 months. For each subject, pure tone audiometry and tympanometry were applied according to chronological and cognitive age. And also, auditory brainstem response test was applied to when it is need. Subjects' radiologic results were reevaluated to confirm cochlear hypoplasia, cochlear nerve and cochlear aperture. RESULTS: Cochlear hypoplasia types were statistically significantly different in terms of HL degree. This difference was caused by cochlear hypoplasia type IV group being was statistically different from the other three groups. Like with degree of HL, cochlear hypoplasia groups were statistically different from other three groups in terms of type of hearing loss. Cochlear aperture and cochlear nerve status showed variation according to cochlear hypoplasia type but these differences were not statistically approved. CONCLUSIONS: In the current study, incidence of cochlear hypoplasia was 23.5% in all inner ear malformation. With this study, it was seen that subtypes of cochlear hypoplasia showed variability in terms of degree and type of hearing loss and also cochlear aperture and cochlear nerve status. Especially cochlear hypoplasia type IV differs from other three cochlear hypoplasia types.

Human cochleae with three turns: an unreported malformation.

OBJECTIVE: The objective of this histologic study of archival temporal bone sections was to describe the morphology of human cochleae found with three turns, a previously unreported anomaly, found in three pairs of temporal bones. METHODS: The authors conducted histopathologic processing and measurement of basilar membrane length. Basilar membrane length was compared with that found in six normal control bones. RESULTS: Cochleae with three complete turns, rather than the usual two and a half turns, are described for the first time. All had longer than normal basilar membranes, with a mean length of 40.6 mm compared with a mean of 33.8 mm in the normal bones. CONCLUSIONS: Human cochleae with three turns exist as an unreported anomaly. This is a new category of anomaly, not likely based on interruption of development.

Inner ear morphology in a bilaterally deaf Dogo Argentino pup.

Two bilaterally deaf and three unilaterally deaf pups were identified from a litter of 10 Dogo Argentino pups presented for hearing evaluation by electrophysiological investigation. One pup, a bilaterally deaf female aged 43 days, was available for histopathology. Examination of both inner ears revealed bilateral cochlear degeneration with atrophy of the stria vascularis, collapse of the cochlear duct, degeneration of the organ of Corti, and abnormal tectorial membrane. The left vestibule, including the sacculus, was normal. The spiral and vestibular ganglia were essentially normal. This is the first histopathological description of lesions associated with deafness in a Dogo Argentino, but abnormalities were similar to those previously described in deaf Dalmatian pups and in other white hair-coated breeds. The defect was classified as a cochleosaccular degeneration. It was probably congenital and genetic causes were suspected.

[The use of magnetic resonance in the study of sensorineural hearing loss in children]. / Utilidad de la rm en el estudio de la hipoacusia neurosensorial unilateral infantil.

Although newborn screening of congenital hearing loss through otoacustic emissions allow prompt recognition, imaging techniques, such as CT and MRI are needed to get a morphological diagnosis. Furthermore they can be very useful in unilateral cases, whose clinical presentation is belated and more insidious. Our aim is to show the utility of MRI in the study of inner ear congenital anomalies, whose presentation is belated. Thus from a series of 88 consecutive patients in which a MRI was performed as screening of assymetric sensorineural hearing loss, we selected 6 cases aged between 6 and 20. Four of them showed an inner ear anomaly on MRI. We present these anomalies commenting the findings on CT and MRI. Imaging techniques are required to start hearing rehabilitation programs early on patients with bilateral inner ear anomalies. But also they are very useful in the evaluation of unilateral assymetric sensorineural hearing loss, in young patients, even if only some frequencies are damned, to determine the nature of hearing loss.

Congenital perilymph fistula causing recurrent meningitis: lessons learnt from a single-institution case series.

OBJECTIVE: To study the steps involved in definitive evaluation and successful management of patients with congenital perilymph fistula presenting with recurrent meningitis. STUDY DESIGN: Case series with chart review. SETTING: Tertiary care center. SUBJECTS AND METHODS: The case records of 11 patients (12 ears) treated for congenital perilymph fistula presenting with recurrent meningitis were reviewed to ascertain their clinical, radiological, and intraoperative features and outcome following surgery. RESULTS: Most patients presented after at least 3 episodes of meningitis (range, 2-10 episodes). Ipsilateral hearing loss was present in 9 of 12 ears, with normal hearing in 3 patients. High-resolution computed tomography and/or magnetic resonance imaging scanning of the temporal bone contributed to the diagnosis in 75% of cases but was normal in 3 cases (25%). Oval window and round window defects were the most common (66.7% and 63.6%, respectively). Four ears (33.3%) had more than 1 defect. The unusual presentations included 2 patients who presented in adulthood, a patient with a defect in the medial wall of the attic, and 3 patients with normal radiological findings. Follow-up ranged from 1 to 11 years (median, 2 years). There were 2 failures following simple fistula closure with cessation of symptoms after vestibular obliteration. No patient was readmitted with recurrent meningitis after definitive surgery. CONCLUSION: Up to 25% of patients with recurrent meningitis secondary to congenital perilymph fistula may have normal audiological and radiological assessment necessitating exploratory tympanotomy. Vestibular obliteration, rather than simple fistula closure, prevents recurrence.

Incomplete cochlear partition type II variants as an indicator of congenital partial deafness: a first report.

INTRODUCTION: The increased understanding on the impact of partial deafness (PD) with residual low-frequency hearing has led to new hearing rehabilitation strategies using hearing preservation techniques during cochlear implantation with the aim to make use of the combined electric acoustic stimulation (EAS) in the affected ear. As a first report, we describe minor forms of the incomplete cochlear partition type II (IP- II) involving the apical 1.5 turns, which were found in the majority of our patients presenting with congenital PD. We investigated the hearing preservation rates and hearing outcomes of these patients after EAS cochlear implantation (EAS-CI). MATERIALS AND METHODS: We present a review of a case series of 4 children and 1 adult with documented congenital PD. They all underwent audiologic and radiologic assessment for CI. Hearing preservation rates and speech perception outcomes were assessed at 1, 3, 6, 12, and 24 months after EAS-CI. RESULTS: Three (75%) of the 4 pediatric patients and 1 adult patient with congenital PD showed the pattern of isolated IP-II variants involving the apical 1.5 cochlear turns with a normal basal turn, without associated inner ear anomalies. Complete hearing was preserved in all patients. Speech performance improved significantly in all patients. CONCLUSION: As a first report, we describe minor IP-II variants identified in the majority of our patients with congenital PD; these IP-II variants could be useful as an indicator of malformation for congenital PD. Detection requires careful radiologic evaluation of the cochlea. EAS-CI is not a contraindication in these patients and should be considered early to prevent permanent speech and language deficits.