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.

CDK5RAP2 primary microcephaly is associated with hypothalamic, retinal and cochlear developmental defects.

BACKGROUND: Primary hereditary microcephaly (MCPH) comprises a large group of autosomal recessive disorders mainly affecting cortical development and resulting in a congenital impairment of brain growth. Despite the identification of >25 causal genes so far, it remains a challenge to distinguish between different MCPH forms at the clinical level. METHODS: 7 patients with newly identified mutations in CDK5RAP2 (MCPH3) were investigated by performing prospective, extensive and systematic clinical, MRI, psychomotor, neurosensory and cognitive examinations under similar conditions. RESULTS: All patients displayed neurosensory defects in addition to microcephaly. Small cochlea with incomplete partition type II was found in all cases and was associated with progressive deafness in 4 of them. Furthermore, the CDK5RAP2 protein was specifically identified in the developing cochlea from human fetal tissues. Microphthalmia was also present in all patients along with retinal pigmentation changes and lipofuscin deposits. Finally, hypothalamic anomalies consisting of interhypothalamic adhesions, a congenital midline defect usually associated with holoprosencephaly, was detected in 5 cases. CONCLUSION: This is the first report indicating that CDK5RAP2 not only governs brain size but also plays a role in ocular and cochlear development and is necessary for hypothalamic nuclear separation at the midline. Our data indicate that CDK5RAP2 should be considered as a potential gene associated with deafness and forme fruste of holoprosencephaly. These children should be given neurosensory follow-up to prevent additional comorbidities and allow them reaching their full educational potential. TRIAL REGISTRATION NUMBER: NCT01565005.

Pattern of cochlear obliteration after vestibular Schwannoma resection according to surgical approach.

OBJECTIVES/HYPOTHESIS: To investigate the prevalence and course of cochlear obliteration according to microsurgical approach to inform clinical decision making regarding optimal timing of cochlear implantation. STUDY DESIGN: Retrospective radiologic review and chart review. METHODS: Patients who underwent microsurgical resection of vestibular schwannoma (VS) with a minimum of two available postoperative magnetic resonance imaging (MRI) scans were analyzed. The prevalence and timing of cochlear and labyrinthine obliteration was classified using relevant MRI sequences. RESULTS: MRI studies in 60 patients were analyzed: 20 translabyrinthine (TL), 20 retrosigmoid, and 20 middle fossa (MF) cases. The first and last postoperative MRI was obtained a median of 3.4 months (interquartile range (IQR), 3.0-3.7 months) and 35 months (IQR, 27-83 months) after surgery, respectively. At the time of the first postoperative MRI, 21 (35%) patients had partial basal turn obliteration, and none of the patients had complete basal turn obliteration. At the time of the last postoperative MRI, six (10%) patients had partial basal turn obliteration and 17 (28%) patients had complete basal turn obliteration. The pattern of partial or complete basal turn obliteration differed significantly among all three surgical approaches (P < .001). Specifically, the risk of partial or complete obliteration of the basal turn was highest in the TL cohort and lowest in the MF cohort. CONCLUSIONS: The prevalence and timing of cochlear obliteration after VS microsurgery varies significantly according to surgical approach. The risk of early and complete obliteration is highest in the TL group and lowest in the MF cohort. These data may inform clinical decision making regarding optimal timing of cochlear implantation in patients with advanced hearing loss after microsurgical resection. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:474-481, 2020.

Carotid-cochlear dehiscence: a dangerous mimicker of inner ear pathologies.

A 67-year-old woman was referred to the otolaryngology service after presenting to the emergency department for dizziness and loss of balance. She reported several similar episodes over the past years. Physical examination was unremarkable. A temporal bone CT scan revealed dehiscence between the bony carotid canal and the cochlea resulting in the diagnosis of carotid-cochlear dehiscence (CCD). CCD is an extremely rare condition involving the thinning of the bony canal separating the internal carotid artery from the cochlea. CCD is best diagnosed with temporal bone CT scan. Treatment options include observation as well as chemical or surgical labyrenthectomy. Despite similar clinical and diagnostic characteristics of reported CCD cases, general trends and consensus on treatment options cannot be ascertained due to the extreme rarity of this condition. Regardless of these limitations, CCD is a critical diagnosis as it mimics other inner ear conditions and poses a potential, significant surgical risk for the otolaryngologist.

Cochlear patency following translabyrinthine vestibular schwannoma resection: implications for hearing rehabilitation.

OBJECTIVE: To examine when cochlear fibrosis occurs following a translabyrinthine approach for vestibular schwannoma resection, and to determine the safest time window for potential cochlear implantation in cases with a preserved cochlear nerve. METHODS: This study retrospectively reviewed the post-operative magnetic resonance imaging scans of patients undergoing a translabyrinthine approach for vestibular schwannoma resection, assessing the fluid signal within the cochlea. Cochleae were graded based on the Isaacson et al. system (from grade 0 - no obstruction, to grade 4 - complete obliteration). RESULTS: Thirty-nine patients fulfilled the inclusion criteria. The cochleae showed no evidence of obliteration in: 75 per cent of patients at six months, 38.5 per cent at one year and 27 per cent beyond one year. Most changes happened between 6 and 12 months after vestibular schwannoma resection, with cases of an unobstructed cochlear decreasing dramatically, from 75 per cent to 38.5 per cent, within this time. CONCLUSION: The progress of cochlear obliteration that occurred between 6 and 12 months following vestibular schwannoma resection indicates that the first 6 months provides a safer time window for cochlear patency.

Cochlear Erosion due to a Facial Nerve Schwannoma.

Facial nerve schwannomas are rare benign neoplasms. We report a case of a 60-year-old woman who initially presented with vestibular complaints. Magnetic resonance imaging (MRI) revealed a facial nerve schwannoma centered on the right geniculate ganglion extending in the labyrinthine segment. The patient consulted again after 2 months because she developed a sudden and severe right-sided sensorineural hearing loss. MRI showed no progression or pathological enhancement in the membranous labyrinth. A cone beam computed tomography (CT) of the temporal bone was performed and revealed a large erosion at the region of the geniculate ganglion in open communication with the middle turn of the cochlea. This case report demonstrates the importance of CT in facial nerve schwannomas for evaluating the impact on the surrounding structures.

Inner ear and retrocochlear pathology on magnetic resonance imaging for sudden and progressive asymmetrical sensorineural hearing loss.

BACKGROUND: In sudden and asymmetrical progressive sensorineural hearing loss (SNHL), magnetic resonance imaging (MRI) is required to evaluate retrocochlear pathology and, with recent advances in MRI techniques, inner ear pathology. Given the limited literature regarding inner ear pathology associated with SNHL, we aimed to assess the incidence of retrocochlear and inner ear pathology, and congenital malformation on MRI in sudden SNHL (SSNHL) and progressive SNHL. METHODS: A total of 987 acoustic neuroma (AN) protocol MRI internal acoustic meatus studies performed at our institution to investigate SNHL between January 2013 and December 2015 inclusive were identified. Following categorization for indication of SSNHL versus progressive asymmetrical SNHL, MRIs with retrocochlear or inner ear abnormality, congenital malformation or other otology-related abnormality were identified, and further data were collected for these patients including patient demographics, associated symptomatology, management and outcomes. RESULTS: In SSNHL, aetiological abnormality on MRI was identified for 6.9% patients with AN present on 4% overall. 3.2% of MRIs for progressive asymmetrical SNHL identified a causative lesion with 2.3% of scans overall diagnosing AN. The incidence of congenital inner ear malformation on MRI in the setting of SSNHL and progressive asymmetrical SNHL are 1.7% and 0.6%, respectively. CONCLUSION: This is the first retrospective study of inner ear MRI abnormalities in both SSNHL and progressive asymmetrical SNHL in Australia and one of the largest cohorts published in the literature to date. MRI must be performed in the setting of SNHL to ensure aforementioned and rarer causative lesions are identified.

Cochlear implantation in patients with ossified cochleas.

PURPOSE: The timing of CI for postmeningitic deafness is controversial and differential outcomes have been reported. To review and share our surgical and auditory outcomes. MATERIALS AND METHODS: 17 patients with ossified cochleas who received CI were enrolled. Clinical data including the cause of cochlear ossification, preoperative examination, onset of deafness, age at implantation, surgical findings, and relevant auditory outcomes was analysed. RESULTS: Cochlear ossification was observed in 53% of patients with HRCT, whereas the corresponding value for MRI was 59%. Patients in both stage I and II received complete insertion of the electrode array, however, stage III patients only received partial insertion. 1 patient in stage II received bilateral CI. Hearing tests showed increased average hearing threshold for stage III patients than those in stage I and II (P < 0.05). CAP scores were much lower for stage III patients than those in stage I and II (P < 0.05). Postlingual deafness patients showed higher SIR scores than prelingual deafness children (P < 0.05). CONCLUSIONS: HRCT and MRI have comparable value in predicting the occurrence of ossification in cochleas. We recommend fast surgical intervention in the patients with bilateral profound postmeningitic deafness. If possible, bilateral cochlear implantation is recommended.

Cochlear obliteration following a translabyrinthine approach and its implications in cochlear implantation.

The most frequent sequelae following a translabyrinthine approach for vestibular schwannoma resection is complete hearing loss on the affected side. Such patients could benefit from a cochlear implant, provided that two essential requisites are met before surgery: a preserved cochlear nerve and a patent cochlea to accommodate the electrode array. The goal of our study is to determine the prevalence and extent of cochlear ossification following a translabyrinthine approach. Postoperative MRI of 41 patients were retrospectively reviewed. Patients were classified according to the degree of cochlear obliteration into three groups (patent cochlea, partially obliterated cochlea and totally obliterated cochlea). The interval between surgery and the first MRI was studied as well as its relationship with the rate of cochlear ossification. At first postoperative MRI (mean interval of 20 months), 78% of patients showed some degree of cochlear ossification. Differences were found in the time interval between surgery and first MRI for each group, showing a smaller interval of time the patent cochlea group (p > 0.05). When MRI was performed before the first year after surgery, a larger rate of patent cochlea was found (p > 0.05). The present study suggests that cochlear ossification is a time-depending process, whose grounds are still to be defined.

Etiologic and Audiologic Characteristics of Patients With Pediatric-Onset Unilateral and Asymmetric Sensorineural Hearing Loss.

Importance: Pediatric-onset unilateral and asymmetric sensorineural hearing loss (SNHL) is a common condition, but in most patients, the cause remains unclear; thus, determination of the hearing outlook is difficult. Objective: To analyze the etiologic and audiologic characteristics of pediatric-onset unilateral and asymmetric SNHL. Design, Setting, and Participants: In this retrospective cohort study performed from January 1, 2008, through December 31, 2016, patients at a tertiary referral center who were diagnosed with pediatric-onset unilateral or asymmetric SNHL were divided into 3 groups according to their hearing levels: unilateral hearing loss with scaled-out levels (UHL-SO), unilateral hearing loss with residual hearing (UHL-RH), and asymmetric hearing loss (AHL). Main Outcomes and Measures: Basic demographic data, family and medical histories, audiologic results, imaging findings, and genetic results were ascertained and compared among patients of the 3 groups. Results: A total of 133 patients (mean [SD] age, 9.1 [10.9] years; 63 [47.4%] male and 70 [52.6%] female), including 50 with UHL-SO, 42 with UHL-RH, and 41 with AHL, were enrolled for analyses. Of 50 patients with UHL-SO, 49 (98.0%) had stable hearing levels with time, whereas 10 of 42 patients with UHL-RH (23.8%) and 18 of 41 patients with AHL (43.9%) revealed progressive or fluctuating hearing loss. Inner ear malformations detected with temporal bone high-resolution computed tomography, particularly cochlear aperture stenosis, were detected at higher rates in patients with UHL-SO (9 of 31 [29.0%]) and UHL-RH (6 of 24 [25.0%]) than in those with AHL (1 of 30 [3.3%]). In contrast, screening for mutations in 3 common deafness genes-GJB2, SLC26A4, and MTRNR1-achieved definite diagnosis in a higher percentage of patients with AHL (10 of 37 [27.0%]) than patients with UHL-SO (0 of 33) and UHL-RH (1 of 25 [4.0%]). Conclusions and Relevance: The UHL-SO and UHL-RH conditions share a common or similar etiopathogenesis different from that of AHL. Imaging studies and genetic testing might be prioritized during the respective general etiologic workups for patients with UHL and AHL. Regular hearing checkups are warranted for patients with UHL and AHL because a certain proportion of patients might sustain progression in SNHL.

Endolymphatic hydrops imaging: Differential diagnosis in patients with Meniere disease symptoms.

PURPOSE: The goal of this retrospective study was to investigate the differential diagnosis of endolymphatic hydrops in patients with Meniere's disease (MD) symptoms by using magnetic resonance imaging (MRI) with intravenous injection of gadolinium chelate and delayed acquisition. MATERIAL AND METHOD: Two hundred patients (133 women, 67 men; mean age=67.2±11 ([SD] years) with unilateral MD underwent MRI at 3-T, between 4.5 and 5.5hours after intravenous administration of gadoterate meglumine at a dose of 0.1mmol/kg. MR images were analyzed for the presence of saccular hydrops, perilymphatic fistulae, inner ear malformations, semicircular canal (SCC) abnormal enhancement and brain lesions. We also tested the potential relationship between past history of gentamicin intratympanic administration and perilymphatic fistula presence and SCC aspect. RESULTS: Saccular hydrops were found in 96/200 patients with MD (48%). Three patients (1.5%) had perilymphatic fistulas associated with saccular hydrops, as confirmed by surgery. There was a correlation between the presence of perilymphatic fistula and past history of intratympanic gentamicin administration (P=0.02). We detected inner ear malformations in 5 patients (2.5%), SCC local enhancement in 15 patients (7.5%) always on the same side than the clinical symptoms of MD. There was a correlation between the presence of SCC abnormal enhancement and past intratympanic gentamicin administration (P=0.001). Five patients (2.5%) had brain lesions along central cochleovestibular pathways. CONCLUSION: MRI may reveal brain lesions, SCC abnormalities and perilymphatic fistulae in patients with clinical MD.

Auditory and audio-visual processing in patients with cochlear, auditory brainstem, and auditory midbrain implants: An EEG study.

There is substantial variability in speech recognition ability across patients with cochlear implants (CIs), auditory brainstem implants (ABIs), and auditory midbrain implants (AMIs). To better understand how this variability is related to central processing differences, the current electroencephalography (EEG) study compared hearing abilities and auditory-cortex activation in patients with electrical stimulation at different sites of the auditory pathway. Three different groups of patients with auditory implants (Hannover Medical School; ABI: n = 6, CI: n = 6; AMI: n = 2) performed a speeded response task and a speech recognition test with auditory, visual, and audio-visual stimuli. Behavioral performance and cortical processing of auditory and audio-visual stimuli were compared between groups. ABI and AMI patients showed prolonged response times on auditory and audio-visual stimuli compared with NH listeners and CI patients. This was confirmed by prolonged N1 latencies and reduced N1 amplitudes in ABI and AMI patients. However, patients with central auditory implants showed a remarkable gain in performance when visual and auditory input was combined, in both speech and non-speech conditions, which was reflected by a strong visual modulation of auditory-cortex activation in these individuals. In sum, the results suggest that the behavioral improvement for audio-visual conditions in central auditory implant patients is based on enhanced audio-visual interactions in the auditory cortex. Their findings may provide important implications for the optimization of electrical stimulation and rehabilitation strategies in patients with central auditory prostheses. Hum Brain Mapp 38:2206-2225, 2017. © 2017 Wiley Periodicals, Inc.

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.

Phenotype of a Belgian Family With 6p25 Deletion Syndrome.

BACKGROUND: The 6p25 deletion syndrome is one of the many syndromes with both hearing impairment as well as vision impairment. However, the audiometric characteristics and radiological findings of patients with 6p25 deletions are only scarcely described in literature. This study focused on characterizing the audiometric and radiological features of a Belgian family with a chromosome 6p25 deletion. OBJECTIVE: To evaluate the hearing impairment, audiometric testing and radiological examination of the temporal bones in 3 family members with a 3.4 Mb deletion in chromosome band 6p25. RESULTS: All 3 family members demonstrated slowly progressive sensorineural or mixed hearing impairment. Radiologic examination revealed thickened and sclerotic stapes in all patients and a minor internal partition type II of the cochlea in 2 patients. CONCLUSION: There is a significant phenotypic variability within and among families with the 6p25 deletion syndrome. A thorough genotype-phenotype correlation is difficult because of the small number of affected patients and the limited clinical data available. More clinical data of families with 6p25 deletions need to be published in order to create a reliable and precise phenotypic characterization. However, our findings can facilitate counseling of hearing impairment caused by 6p25 deletions.

Endolymphatic hydrops in superior canal dehiscence and large vestibular aqueduct syndromes.

OBJECTIVES/HYPOTHESIS: Pathologic third window lesions, such as superior semicircular canal dehiscence syndrome (SCDS) or large vestibular aqueduct syndrome (LVAS), cause several auditory and vestibular symptoms, which might affect perilymphatic pressure and induce endolymphatic hydrops (EH). In this study, the existence of EH in subjects with SCDS or LVAS was investigated using contrast-enhanced magnetic resonance imaging (MRI). STUDY DESIGN: Case series at university hospital. METHODS: Seventeen ears from nine subjects who were diagnosed as having SCDS (five ears from three cases) or LVAS (12 ears from six cases) were studied. Ears were evaluated by 3-T MRI performed 4 hours after intravenous injection of gadodiamide hydrate. Imaging data concerning the degree of EH in the cochlea and the vestibule were compared with clinical symptoms and hearing levels for all ears. RESULTS: All ears showed air-bone gaps at low frequencies on pure tone audiometry. None of the subjects with SCDS had episodes of acute sensorineural hearing loss (SNHL) or vestibular symptoms, except for one patient who complained of head vibration induced by loud noise. Conversely, five of six subjects with LVAS had episodes of acute SNHL or vestibular symptoms. Four of five ears with SCDS showed severe EH in the cochlea, and two ears showed mild EH in the vestibule. All ears with LVAS showed mild to severe EH in both the cochlea and vestibule. CONCLUSIONS: The present study demonstrated the existence of EH in ears with pathologic third window lesions, which might affect patients' auditory or vestibular symptoms. LEVEL OF EVIDENCE: 4 Laryngoscope, 126:1446-1450, 2016.

Kanamycin-furosemide ototoxicity in the mouse cochlea: a 3-dimensional analysis.

OBJECTIVE: Administration of an aminoglycoside antibiotic and loop diuretic causes damage to hair cells in the organ of Corti, resulting in their death and the death of their corresponding spiral ganglion neurons. While this phenomenon has been studied previously, analysis of its effects in the whole cochlea has not been reported. The authors sought to evaluate the effects of a combination dose of kanamycin and furosemide in mice cochlea using an imaging system and computer analysis that allowed for nondestructive, whole-cochlea visualization. STUDY DESIGN: Study using an animal model. SETTING: Cochlear analysis laboratory. SUBJECTS AND METHODS: Five mice received kanamycin and furosemide and 3 mice received saline. Cochleas were harvested and imaged with scanning thin-sheet laser imaging microscopy (sTSLIM) to analyze sensory cells and cochlea structures. RESULTS: The drug-treated animals showed substantial loss of inner hair cells and complete outer hair cell loss. All treated mice showed spiral ganglion neuron loss with fewer neurons than control animals and decreased cell density in the middle turn of the cochlea. The spiral ligament and spiral limbus in the treated animals also showed a decrease in fibrocyte cell density in the middle to apical portion of the cochlea. The stria vascularis appeared normal in all animals. CONCLUSION: Imaging methods that allow for whole-cochlea analysis provide insight into changes that occur in the cochlea after ototoxic insult. Trends that may not be apparent in cross-section samples of the cochlea can be observed. Computer analysis of these trends allows them to be assessed accurately.

A new computed tomography method to identify meningitis-related cochlear ossification and fibrosis before cochlear implantation.

OBJECTIVE: To develop a new method to determine the presence of intracochlear ossification and/or fibrosis in cochlear implantation candidates with bilateral profound deafness following meningitis. STUDY DESIGN: Diagnostic test assessment. SETTING: A university hospital. SUBJECTS AND METHODS: This study involved 15 ears from 13 patients with profound deafness following meningitis who underwent cochlear implantation. These ears showed normal structures, soft tissue, partial bony occlusion, and complete bony occlusion in 4, 3, 2, and 6 ears, respectively. We measured radiodensity in Hounsfield units (HU) using 0.5-mm-thick axial high-resolution computed tomography image slices at 3 different levels in the basal turn, the fenestration, and inferior and ascending segment sites, located along the electrode-insertion path. Pixel-level analysis on the DICOM viewer yielded actual computed tomography values of intracochlear soft tissues by eliminating the partial volume effect. The values were compared with the intraoperative findings. RESULTS: Values for ossification (n = 12) ranged from +547 HU to +1137 HU; for fibrosis (n = 11), from +154 HU to +574 HU; and for fluid (n = 22), from -49 HU to +255 HU. From these values, we developed 2 presets of window width (WW) and window level (WL): (1) WW: 1800, WL: 1100 (200 HU to 2000 HU) and (2) WW: 1500, WL: 1250 (500 HU to 2000 HU). The results using these 2 presets corresponded well to the intraoperative findings. CONCLUSION: Our new method is easy and feasible for preoperative determination of the presence of cochlear ossification and/or fibrosis that develops following meningitis.