The natural history and genotype-phenotype correlations of TMPRSS3 hearing loss: an international, multi-center, cohort analysis.

TMPRSS3-related hearing loss presents challenges in correlating genotypic variants with clinical phenotypes due to the small sample sizes of previous studies. We conducted a cross-sectional genomics study coupled with retrospective clinical phenotype analysis on 127 individuals. These individuals were from 16 academic medical centers across 6 countries. Key findings revealed 47 unique TMPRSS3 variants with significant differences in hearing thresholds between those with missense variants versus those with loss-of-function genotypes. The hearing loss progression rate for the DFNB8 subtype was 0.3 dB/year. Post-cochlear implantation, an average word recognition score of 76% was observed. Of the 51 individuals with two missense variants, 10 had DFNB10 with profound hearing loss. These 10 all had at least one of 4 TMPRSS3 variants predicted by computational modeling to be damaging to TMPRSS3 structure and function. To our knowledge, this is the largest study of TMPRSS3 genotype-phenotype correlations. We find significant differences in hearing thresholds, hearing loss progression, and age of presentation, by TMPRSS3 genotype and protein domain affected. Most individuals with TMPRSS3 variants perform well on speech recognition tests after cochlear implant, however increased age at implant is associated with worse outcomes. These findings provide insight for genetic counseling and the on-going design of novel therapeutic approaches.

Hearing loss, cleft palate, and congenital hip dysplasia in female carriers of an intragenic deletion of AMMECR1.

Previously, mutations in the AMMECR1 gene have been described in six males with developmental delay, sensorineural hearing loss (SNHL) and/or congenital abnormalities, including fetal nuchal edema, fetal pericardial effusion, talipes, congenital hip dysplasia, elliptocytosis and cleft palate. In this report, we present three female relatives of a male fetus with an intragenic deletion in this X-linked gene. All three women reported hearing loss and one was born with a soft cleft palate and hip dysplasia. The audiograms showed mild to moderate SNHL with a variable pattern of the affected frequencies. Immunohistochemical analysis of fetal cochlea was performed confirming the expression of AMMECR1 in the human inner ear. Since hearing loss, cleft palate and congenital hip dysplasia were reported before in male AMMECR1 point mutation carriers and AMMECR1 is expressed in fetal inner ear, we suggest that female carriers may display a partial phenotype in this X-linked condition.

Assessment of the Clinical Benefit of Imaging in Children With Unilateral Sensorineural Hearing Loss: A Systematic Review and Meta-analysis.

IMPORTANCE: Imaging used to determine the cause of unilateral sensorineural hearing loss (USNHL) in children is often justified by the high likelihood of detecting abnormalities, which implies that these abnormalities are associated with hearing loss and that imaging has a positive contribution to patient outcome or well-being by providing information on the prognosis, hereditary factors, or cause of hearing loss. OBJECTIVES: To evaluate the diagnostic yield of computed tomography (CT) and magnetic resonance imaging (MRI) in children with isolated unexplained USNHL and investigate the clinical relevance of these findings. EVIDENCE REVIEW: Cochrane Library, Embase, PubMed, and Web of Science databases were searched for articles published from 1978 to 2017 on studies of children with USNHL who underwent CT and/or MRI of the temporal bone. Two authors (F.G.R. and E.N.B.P.) independently extracted information on population characteristics, imaging modality, and the prevalence of abnormalities and assessed the studies for risk of bias. Eligibility criteria included studies with 20 or more patients with USNHL who had CT and/or MRI scans, a population younger than 18 years, and those published in English. MAIN OUTCOMES AND MEASURES: The pooled prevalence with 95% CI of inner ear abnormalities grouped according to finding and imaging modality. FINDINGS: Of 1562 studies, 18 were included with a total of 1504 participants included in the analysis. Fifteen studies were consecutive case studies and 3 were retrospective cohort studies. The pooled diagnostic yield for pathophysiologic relevant findings in patients with unexplained USNHL was 37% for CT (95% CI, 25%-48%) and 35% for MRI (95% CI, 22%-49%). Cochleovestibular abnormalities were found with a pooled frequency of 19% for CT (95% CI, 14%-25%) and 16% for MRI (95% CI, 7%-25%). Cochlear nerve deficiency and associated cochlear aperture stenosis had a pooled frequency of 16% for MRI (95% CI, 3%-29%) and 44% for CT (95% CI, 36%-53%), respectively. Enlarged vestibular aqueduct (EVA) was detected with a pooled frequency of 7% for CT and 12% for MRI in children with USNHL. CONCLUSIONS AND RELEVANCE: Imaging provided insight into the cause of hearing loss in a pooled frequency of about 35% to 37% in children with isolated unexplained USNHL. However, none of these findings had therapeutic consequences, and imaging provided information on prognosis and hereditary factors only in a small proportion of children, namely those with EVA. Thus, there is currently no convincing evidence supporting a strong recommendation for imaging in children who present with USNHL. The advantages of imaging should be carefully balanced against the drawbacks during shared decision making.

De novo and inherited loss-of-function variants of ATP2B2 are associated with rapidly progressive hearing impairment.

ATP2B2 encodes the PMCA2 Ca2+ pump that plays an important role in maintaining ion homeostasis in hair cells among others by extrusion of Ca2+ from the stereocilia to the endolymph. Several mouse models have been described for this gene; mice heterozygous for loss-of-function defects display a rapidly progressive high-frequency hearing impairment. Up to now ATP2B2 has only been reported as a modifier, or in a digenic mechanism with CDH23 for hearing impairment in humans. Whole exome sequencing in hearing impaired index cases of Dutch and Polish origins revealed five novel heterozygous (predicted to be) loss-of-function variants of ATP2B2. Two variants, c.1963G>T (p.Glu655*) and c.955delG (p.Ala319fs), occurred de novo. Three variants c.397+1G>A (p.?), c.1998C>A (p.Cys666*), and c.2329C>T (p.Arg777*), were identified in families with an autosomal dominant inheritance pattern of hearing impairment. After normal newborn hearing screening, a rapidly progressive high-frequency hearing impairment was diagnosed at the age of about 3-6 years. Subjects had no balance complaints and vestibular testing did not yield abnormalities. There was no evidence for retrocochlear pathology or structural inner ear abnormalities. Although a digenic inheritance pattern of hearing impairment has been reported for heterozygous missense variants of ATP2B2 and CDH23, our findings indicate a monogenic cause of hearing impairment in cases with loss-of-function variants of ATP2B2.

Incus necrosis after irradiation.

OBJECTIVES: Osteoradionecrosis (ORN) of the temporal bone is a rare, late complication of radiotherapy to the temporal bone region for head and neck or skull base tumours. ORN can occur as a localized or a diffuse type, according to the extension of the affected temporal bone. It can lead to otitis externa, otitis media, aseptic labyrinthitis and may lead to serious intracranial complications. Hearing loss may be conductive, sensorineural, or mixed. A few case studies report of previously irradiated patients presenting with conductive hearing loss presumably caused by ORN of the ossicular chain. In only one case report of diffuse ORN, ORN of the ossicles was histologically proven, leading to the conclusion that ossicular chain involvement as the sole entity of ORN would not exist. However, the presented case report disputes this. PATIENTS: A 13-year-old boy presenting with a unilateral mixed hearing loss as the sole otological complaint, 10 years after radiotherapy for an anaplastic ependymoma. RESULTS: Middle ear inspection revealed ORN of the incus which was confirmed by histological investigation. CONCLUSION: ORN of the ossicular chain as a late complication can occur as an isolated entity and may present as conductive hearing loss predominantly in the low frequencies. Middle ear inspection and ossicular chain reconstruction should be attempted, bearing in mind the risk of iatrogenic lacerations of a thin tympanic membrane and possibly a delayed wound healing.

Cytomegalovirus DNA detection in dried blood spots and perilymphatic fluids from pediatric and adult cochlear implant recipients with prelingual deafness.

BACKGROUND: Congenital cytomegalovirus (CMV) infection is the leading cause of non-genetic congenital hearing loss. The contribution of congenital CMV to prelingual deafness and the pathophysiology is largely unknown. OBJECTIVE: (1) To analyze the prevalence of congenital CMV among cochlear implant (CI) recipients with prelingual deafness. (2) To genotype CMV present in dried blood spots (DBS) and in the inner ear years after birth. STUDY DESIGN: Children and adults with prelingual deafness who received a CI in 2010-2011 were included prospectively. Perilymphatic fluids were collected during CI surgery and, in the pediatric cases, DBS were retrieved for CMV DNA detection. Furthermore, a cohort of children with prelingual deafness who received a CI between 2003 and 2008 were included retrospectively. CMV detection in DBS and perilymph was followed by gB and gH genotyping. RESULTS: Seventysix pediatric CI recipients were included. Seventy DBS were tested for CMV DNA, resulting in a prevalence of congenital CMV of 14% (10/70). Perilymphatic fluid was available from 29 pediatric CI recipients. One perilymph fluid, of a 21-month old girl with congenital CMV, asymptomatic at birth, was CMV DNA positive. The CMV strain in the perilymph was genotypically identical to the strain present in her DBS (gB1/gH2). Perilymph samples from 21 adult CI recipients were CMV DNA negative. CONCLUSIONS: Our study stresses the important contribution of congenital CMV among pediatric CI recipients. Furthermore, our genotyping data support the hypothesis that CMV-related hearing loss is associated with ongoing viral replication in the inner ear up to years after birth.

Speech perception after cochlear implantation in 53 patients with otosclerosis: multicentre results.

OBJECTIVES: To analyse the speech perception performance of 53 cochlear implant recipients with otosclerosis and to evaluate which factors influenced patient performance in this group. The factors included disease-related data such as demographics, pre-operative audiological characteristics, the results of CT scanning and device-related factors. METHODS: Data were reviewed on 53 patients with otosclerosis from 4 cochlear implant centres in the United Kingdom and the Netherlands. Comparison of demographics, pre-operative CT scans and audiological data revealed that the patients from the 4 different centres could be considered as one group. Speech perception scores had been obtained with the English AB monosyllable tests and Dutch NVA monosyllable tests. Based on the speech perception scores, the patients were classified as poor or good performers. The characteristics of these subgroups were compared. RESULTS: There was wide variability in the speech perception results. Similar patterns were seen in the phoneme scores and BKB sentence scores between the poor and good performers. The two groups did not differ in age at onset of hearing loss, duration of hearing loss, progression, age at onset of deafness, or duration of deafness. CONCLUSIONS: The clinical presentation of the otosclerosis (rapid or slow progression) did not influence speech perception. Better performance was related to less severe signs of otosclerosis on CT scan, full insertion of the electrode array, little or no facial nerve stimulation and little or no need to switch off electrodes.

Cochlear implantation in 3 patients with osteogenesis imperfecta: imaging, surgery and programming issues.

Osteogenesis imperfecta (OI) is a heterogeneous disease of the connective tissue caused by a defective gene that is responsible for the production of collagen type I, leading to defective bone matrix and connective tissue. Hearing loss affects 35-60% of the patients and will progress to deafness in 2-11% of OI patients for whom cochlear implantation may become the only remaining treatment option. Three patients with OI were retrieved from the Nijmegen Cochlear Implant Centre's database. Most of the specific observations in ear surgery on patients with OI, such as brittle scutum, sclerotic thickening of the cochlea, hyperplastic mucosa in the middle ear and persistent bleeding, were encountered in these 3 patients. In case 3, with severe deformities on the CT scan, misplacement of the electrode array into the horizontal semicircular canal occurred. In all 3 cases, programming was hindered by nonauditory stimulation. Even after reimplantation, nonauditory sensations lead to case 3 becoming a nonuser. Averaged electrode voltages in case 3 were deviant in accordance with an abnormally conductive otic capsule. Spatial spread of neural excitation responses in cases 1 and 2 suggested intracochlear channel interaction for several electrodes, often in combination with facial nerve stimulation (FNS). In case 1, the estimated pitch of the electrodes that caused FNS varied consistently. Despite the electrophysiological changes, after 1-year follow-up, open set phoneme scores of 81% and 78% were reached in cases 1 and 2, respectively. When aware and prepared for the specific changes of the temporal bone in OI, cochlear implantation can be a safe and feasible procedure. Preoperative imaging is recommended to be fully informed on the morphology of the petrosal bone. In case of severe deformities on the CT scan, during counseling the possibility of misplacement should be mentioned. Rehabilitation is often hindered by FNS requiring frequent refitting.

Cochlear implantation in otosclerotic deafness.

The otosclerotic process commonly involves the otic capsule and may cause quite widespread demineralisation which leads to a progressive and often profound bilateral sensorineural hearing loss. In this situation cochlear implantation may be the only effective treatment. This chapter considers the pathology of this hearing loss, the effects of cochlear obliteration on implantation, and the effects of demineralisation of the otic capsule on placement of the electrode and nonauditory stimulation. A study is reported from 4 cochlear implant centres in the UK and the Netherlands of 53 patients with cochlear otosclerosis who received cochlear implantation. The CT features of their petrous bones are presented and a classification of the radiological features suggested. 38% of patients experienced facial nerve stimulation presumably due to spread of current through an otic capsule with lower than usual electrical impedance. The most common rogue electrodes were in the proximity of the geniculate ganglion. These could usually be successfully programmed out of the MAP.

Cochlear implantation in 53 patients with otosclerosis: demographics, computed tomographic scanning, surgery, and complications.

OBJECTIVES: To collect data from a large number of cochlear implant recipients with otosclerosis and to make an assessment of these patients' clinical characteristics, computed tomographic scans, surgical findings, and complications, and to quantify the occurrence of postoperative facial nerve stimulation. STUDY DESIGN: Retrospective multicenter study. PATIENTS: Fifty-three patients with otosclerosis from four cochlear implant centers in the United Kingdom and The Netherlands were reviewed. Sixty surgical procedures were performed in these patients: 57 devices were placed in 56 ears. RESULTS: The computed tomographic imaging demonstrated retrofenestral (cochlear) otosclerotic lesions in the majority of patients. Although not statistically significant, the extent of otosclerotic lesions on the computed tomographic scan as categorized in three types tends to be greater in patients with rapidly progressive hearing loss, in patients in whom there is surgically problematic insertion of the electrode array, and in patients with facial nerve stimulation. In four patients, revision surgery had to be performed. Twenty of 53 (38%) patients experienced facial nerve stimulation at various periods postoperatively. CONCLUSION: Cochlear implant surgery in patients with otosclerosis can be challenging, with a relatively high number of partial insertions and misplacements of the electrode array demanding revision surgery. A very high proportion of patients experienced facial nerve stimulation mainly caused by the distal electrodes. This must be discussed with patients preoperatively.

Congenital malformation of the inner ear and pediatric cochlear implantation.

OBJECTIVES: To study the surgical aspects and performance outcome of cochlear implantation in children with malformed inner ears. STUDY DESIGN: Clinical and audiometric evaluation in 13 patients. METHODS: Patient data concerning surgery, postoperative follow-up, and pre- and postimplantation audiometry were obtained from the cochlear implant center's database and evaluated. A review of the literature has been included. SETTING: Tertiary referral center. PATIENTS: The patients had a variety of inner ear malformations and profound hearing loss. One patient with recurrent meningitis had a severe cochlear malformation (common cavity). RESULTS: Major complications did not occur. In one patient with an abnormal position of the cochlea and concurring middle ear disease, it was difficult to find the scala tympani during surgery. A cerebrospinal fluid gusher was encountered in two patients and an aberrant facial nerve in another, which did not lead to any complications. The patients with mild cochlear malformation such as an incomplete partition demonstrated a good performance in speech perception tests. Even the child with the common cavity deformity had some open-set speech perception 1 year after implantation. CONCLUSIONS: Viewing the patients from this study and patients from a review of the literature concerning cochlear implantation in children with malformed inner ears including severe cochlear malformations, the occurrence of an aberrant facial nerve was 17%, which increases to 27% if one reviews the surgical findings in children with severe malformed cochleae such as a common cavity or a severe cochlear hypoplasia. In the latter patients, results in speech perception vary. Although the result of cochlear implantation may be promising, as in our patient with a common cavity, during preoperative counseling the child's parents must be informed that the result is uncertain.