Leading Risk Factors for Congenital Deafness in the Context of Universal Neonatal Screening: Our Observations in a Four-Year Retrospective Study

It has been demonstrated that universal hearing neonatal screening (UHNS) is efficient at providing early diagnosis and rehabilitation for deafness. The risk factors of deafness in children have been identified, but less specifically in those diagnosed after UHNS. In this study, we aim to study these factors in infants who were referred after screening and to compare our experience to recent data. We studied infants referred to our department for diagnosis after screening between January 2018 and December 2021. Their medical history and neonatal hearing risk factors were assessed. Associations between factors were also analyzed. Sixty-six infants were included. A family history of deafness (47%), syndromic deafness (41%), intrauterine growth retardation or prematurity (19.7%), and prolonged NICU admission (18%) were the most observed factors. When analyzing according to these associations, family history of deafness and syndromic cases remained the most prevalent factors (74%), while only five cases (7.8%) presented with other neonatal risk factors only. The majority of congenital hearing loss cases are observed in infants with suspected genetic deafness. Parental counseling, the diagnostic pathway, as well as the healthcare system should be adapted according to these risk factors.

Congenital Deafness and Deaf-Mutism: A Historical Perspective

Hearing loss is the most common sensory deficit and one of the most common congenital abnormalities. The estimated prevalence of moderate and severe hearing loss in a normal newborn is 0.1-0.3%, while the prevalence is 2-4% in newborns admitted to the newborn intensive care unit. Therefore, early detection and prompt treatment are of utmost importance in preventing the unwanted sequel of hearing loss on normal language development. The problem of congenital deafness is today addressed on the one hand with hearing screening at birth, on the other with the early (at around 3 months of age) application of hearing aids or, in case of lack of benefit, by the cochlear implant. Molecular genetics, antibody tests for some viruses, and diagnostic imaging have largely contributed to an effective etiological classification. A correct diagnosis and timely fitting of hearing aids or cochlear implants is useful for deaf children. The association between congenital deafness and "mutism", with all the consequences on/the consideration that deaf mutes have had since ancient times, not only from a social point of view but also from a legislative point of view, continued until the end of the nineteenth century, with the development on one side of new methods for the rehabilitation of language and on the other of sign language. But we need to get to the last decades of the last century to have, on the one hand, the diffusion of "universal newborn hearing screening", the discovery of the genetic causes of over half of congenital deafness, and on the other hand the cochlear implants that have allowed thousands of children born deaf the development of normal speech. Below, we will analyze the evolution of the problem between deafness and deaf-mutism over the centuries, with particular attention to the nineteenth century.

Children then, adults now: long-term outcomes-performance at 15, 20, and 25 years of cochlear implant use

Motivation

Severe to profound sensorineural hearing loss interferes with a child's development at the cognitive, linguistic, academic, and social levels. Since the beginning of the pediatric auditory rehabilitation program through cochlear implantation in the Ear, Nose, and Throat (ENT) Service of the Coimbra Hospital and University Center (CHUC), Portugal, its mentors defended the early diagnosis of hearing loss followed by timely intervention, and this was considered the starting point to optimize (re)habilitation through this method. Three decades or so later, recently we conducted this study to evaluate the performance of patients implanted in the initial phase of the cochlear implantation program.

Objectives

The study aimed to evaluate the performance of individuals with severe to profound congenital hearing loss who underwent pediatric cochlear implantation and have used the cochlear implant for at least 25 years, to analyze the beneficial effect of early intervention in improving performance results.

Methods

The study sample is composed of 31 individuals with severe to profound congenital hearing loss and no other comorbidities, divided into two groups (Group 1: age at implantation was under 3 years; Group 2: age at implantation was over 3 years). All 31 subjects were evaluated at 15, 20, and 25 years of cochlear implant (CI) use with a comprehensive set of tests. In addition, data were collected regarding the academic level of each participant. The results of both groups were compared to find out if there is an effect of age at implantation on auditory performance, and if there is an improvement in the performance with CI over time (15, 20, and 25 years of use).

Results

The results show that there is a positive effect, with statistical significance, of early implantation on auditory performance, and telephone use. In both groups, there is an increase in performance over time, but it tends to stabilize after 20 years of CI use.

Discussion and conclusion

The results obtained in this work support the importance of early intervention in patients with severe to profound hearing loss who are cochlear implant users and show that CI is an effective and reliable method in the treatment of these patients, contributing to their improved socio-educational integration, and that the benefits last over time.

Time course from cochlear implant surgery to non-use for congenitally deaf recipients implanted as children over ten years ago

Objective

To determine the time-course from first cochlear implantation to non-use, to characterise non-users' receptive and expressive communication, and document known risk factors for inconsistent use, for congenitally deaf non-users of cochlear implants implanted as children at least ten years ago.

Methods

Retrospective service evaluation. All congenitally deaf patients who received a first cochlear implant as children at least ten years ago at a regional service, and were currently non-users, were identified. They were characterised in terms of ages at implantation and non-use, known risk factors for inconsistent CI use or CI non-use, and outcome measures were the Meaningful Auditory Integration Scale (MAIS) and Meaningful Use of Speech Scale (MUSS) scores.

Results

Seventeen patients met the inclusion criteria. They were implanted from 1990 to 2006. Median age at implantation was 4 years (range: 2-11), median age at non-use was 17 years (range: 9-31), and median duration of use was 8.5 years (range: 4-25). All used sign or gesture as their primary expressive and receptive communication modes. In addition, each child had at least one other known risk factor for inconsistent CI use. At 3 years post-implantation, mean Parent-rated MAIS scores were 76.5% (N = 14), and mean MUSS scores were 43.1% (N = 9).

Discussion

This cohort included cases where CI use was rejected following longer periods of time than previously reported, highlighting a need for long-term support, particularly around the ages of life transitions. Studies conducted when the earliest cohort of paediatric CI users were younger, and studies reliant on parent or patient reports, may under-estimate long-term non-use rates. No non-users were identified among congenitally-deaf children implanted 10-15 years ago. Further research is warranted to explore relationships between risk factors, including communication mode, and non-use to inform expectation setting and candidacy selection.

A Comparative Study of Voice Characteristics in Children With Cochlear Implants and Typically Hearing Children: Insights From an Indian Context

Purpose The aim of the study was to evaluate speech outcomes in children with cochlear implants compared to normally hearing children in terms of fundamental frequency, shimmer, and jitter. The study also aims to assess the intelligibility of speech in children with cochlear implants using a speech intelligibility rating scale. Methods This was a hospital-based comparative study conducted at JIPMER, a major tertiary referral center. A total of 25 prelingually deaf children with profound deafness, who underwent cochlear implantation at the institute, were recruited from the outpatient department of the Department of Otorhinolaryngology. Twenty-five children under seven years of age who underwent cochlear implantation and received a minimum of 36 speech therapy sessions were included in the study. Subjects with incomplete electrode array insertion and any neurological maldevelopment were excluded. Age- and gender-matched controls comprising 25 individuals were selected from the Ophthalmology Outpatient Department at JIPMER. Study procedure The study commenced in January 2019. Test subjects were asked to visit the Audiology and Speech and Language Pathology Department at JIPMER. Voice recordings were conducted in a soundproof room using a microphone, with the mouthpiece held at a distance of 10-15 cm from the patient. The patient was instructed to say "a" three times. Their voice was recorded and analyzed using Praat software (Version 6.1.15, developed by Paul Boersma and David Weenink, Phonetic Sciences, University of Amsterdam). Data were analyzed using IBM SPSS Statistics for Windows, Version 19 (Released 2010; IBM Corp., Armonk, New York) (Department of Biostatistics, Vanderbilt University, Nashville, Tennessee, USA), and the results were derived. Results The mean fundamental frequency for Group 1 (CI) was 266.03 ± 57.46 Hz, compared to 312.97 ± 22.15 Hz for Group 2 (NH). There was a statistically significant difference between the values of both groups, indicating that cochlear implantation positively impacted the fundamental frequency of speech. The study revealed a significant change in the fundamental frequency when children were implanted at an early age and received effective speech therapy post-implantation. This change was assessed after one year post-implant. Perturbation measures such as shimmer and jitter were lower in the cochlear implant group but were not statistically significant. Conclusion Children with congenital bilateral severe to profound sensorineural hearing loss tend to have higher values of the fundamental frequency of speech. However, when implanted at an early age, they showed a significant difference in the fundamental frequency of speech (p < 0.001). Speech perturbation was lower in the post-cochlear implant group, with a statistically significant difference in the values of shimmer alone. The study concludes that children with cochlear implants can achieve normal voice parameters with early intervention and training. However, the variability range is much higher than in typically hearing individuals.

Longitudinal Changes in BDNF and MMP-9 Protein Plasma Levels in Children after Cochlear Implantation

Congenitally deaf children who undergo cochlear implantation before 1 year of age develop their auditory skills faster than children who are implanted later. In this longitudinal study, a cohort of 59 implanted children were divided into two subgroups according to their ages at implantation-below or above 1 year old-and the plasma levels of matrix metalloproteinase-9 (MMP-9), brain-derived neurotrophic factor (BDNF), and pro-BDNF were measured at 0, 8, and 18 months after cochlear implant activation, while auditory development was simultaneously evaluated using the LittlEARs Questionnaire (LEAQ). A control group consisted of 49 age-matched healthy children. We identified statistically higher BDNF levels at 0 months and at the 18-month follow-ups in the younger subgroup compared to the older one and lower LEAQ scores at 0 months in the younger subgroup. Between the subgroups, there were significant differences in the changes in BDNF levels from 0 to 8 months and in LEAQ scores from 0 to 18 months. The MMP-9 levels significantly decreased from 0 to 18 months and from 0 to 8 months in both subgroups and from 8 to 18 months only in the older one. For all measured protein concentrations, significant differences were identified between the older study subgroup and the age-matched control group.

Inner Ear Malformations in Congenital Deafness Are Not Associated with Increased Risk of Breech Presentation

BackgroundThere is speculation that an immature vestibular system may be associated with breech presentation at delivery. Our aim was to determine whether syndromes with congenital inner ear malformations were accompanied by a higher frequency of breech presentation/malpresentations than in the general population (2%-3%). Methods: A review was conducted for published literature using PubMed/MEDLINE (1936-2016), to determine frequency of breech presentation and transverse lie in cases with congenital deafness (Michel aplasia, Wildervanck syndrome, Mondini-Alexander dysplasia, Waardenburg syndrome, CHARGE syndrome, Large vestibular aqueductal syndrome, Pendred syndrome, Oculo-aurico-vertebral spectrum, Jervel and Lange-Nielsen syndrome, Usher syndrome, and Scheibe dysplasia) and vestibular nerve aplasia. Results: Identified were total of 122 cases. The frequency of breech presentation was 1.64%, and of transverse lie 1.64%, giving a total of 3.28% malpresentations. Conclusion: The results of the study suggest that congenital malformations of the vestibular apparatus are not associated with the increased risk of breech presentation at delivery.

Universal newborn hearing screening in the Italian Region of Sicily in 2018

Objectives

We have clarified the role of Universal Neonatal Hearing Screening (UNHS) for both early diagnosis and rapid treatment in order to improve the prognosis of the deaf child and reduce patient management costs. Although in Sicily UNHS has been progressively implemented, there is scarce data in the literature on this matter. Therefore, the main objective was to collect in the year 2018 the following data: number of newborns screened for hearing loss, number of infants “referred” to transiently evoked otoacoustic emissions (TEOAE), number of infants with pathologic auditory brainstem response (ABR) and number of infants affected by permanent hearing loss.

Methods

UNHS monitoring was conducted through the collection of data through a questionnaire, which was analysed evaluating the effectiveness and adherence to the screening program prepared by the Department for Health Activities and the Epidemiological Observatory (DASOE).

Results

In 2018, there were 40,243 newborns in Sicily. A total of 37,562 newborns were screened (93.3%). There were 1,328 “referred” infants with TEOAE (3.5%). On the 2^nd level, “referred” newborns examined were 1,080 of 1,328 expected (missing 248 “refer” newborns, equal to 18.6%). The number of “referred” infants confirmed with TEOAE was 113 of 1,080, while “referred” infants confirmed with ABR were 71. On the 3^rd level, 67 of 71 were infants examined: 28 infants were suffering from monolateral hearing loss (13 slight/mild, 13 moderate, 1 severe and 1 profound) and 39 from bilateral hearing loss (1slight/mild, 19 moderate, 13 severe and 7 profound). Excluding 7 infants from the NICU, 60 of 37,562 infants had hearing loss (1.5%).

Conclusions

The monitoring of the UNHS in Sicily has allowed obtaining the data of individual centres, absent in the literature to date, to verify the effectiveness of the screening, according to JCIH criteria, to highlight some criticalities and, finally, to propose possible solutions.

Congenital Deafness and Recent Advances Towards Restoring Hearing Loss

Congenital hearing loss is the most common birth defect, estimated to affect 2-3 in every 1000 births. Currently there is no cure for hearing loss. Treatment options are limited to hearing aids for mild and moderate cases, and cochlear implants for severe and profound hearing loss. Here we provide a literature overview of the environmental and genetic causes of congenital hearing loss, common animal models and methods used for hearing research, as well as recent advances towards developing therapies to treat congenital deafness. © 2021 The Authors.

Functional Polymorphism of MMP9 and BDNF as Potential Biomarker of Auditory Neuroplasticity in Prelingual Deafness Treatment With Cochlear Implantation-A Retrospective Cohort Analysis

Genetic biomarkers of neuroplasticity in deaf children treated with cochlear implantation (CI) might facilitate their clinical management, especially giving them better chances of developing proficient spoken language. We investigated whether carrying certain variants of the genes encoding matrix metalloproteinase MMP9 and neurotrophin brain-derived neurotrophic factor (BDNF), involved in synaptic plasticity, can be taken as prognostic markers of how well auditory skills might be acquired. Association analysis of functional MMP9 rs3918242 and BDNF rs6265 variants and the child’s auditory development measured at CI activation and 1, 5, 9, 14, and 24 months post CI activation with LittlEARS Questionnaire (LEAQ) was conducted in a group of 100 children diagnosed with DFNB1-related deafness, unilaterally implanted before the age of 2 years. Statistical analysis in the subgroup implanted after 1 year of life (n = 53) showed significant association between MMP9 rs3918242 and LEAQ scores at 1 month (p = .01), at 5 months (p = .01), at 9 months (p = .01), and at 24 months (p = .01) after CI activation. No significant associations in the subgroup implanted before 1 year of life were observed. No significant associations between the BDNF rs6265 and LEAQ score were found. Multiple regression analysis (R² = .73) in the subgroup implanted after 1 year of life revealed that MMP9 rs3918242 was a significant predictor of treatment outcome. In conclusion, C/C rs3918242 MMP9 predisposes their deaf carriers to better CI outcomes, especially when implanted after the first birthday, than carriers of C/T rs3918242MMP9.

Numerical Magnitude Processing in Deaf Adolescents and Its Contribution to Arithmetical Ability

Although most deaf individuals could use sign language or sign/spoken language mix, hearing loss would still affect their language acquisition. Compensatory plasticity holds that the lack of auditory stimulation experienced by deaf individuals, such as congenital deafness, can be met by enhancements in visual cognition. And the studies of hearing individuals have showed that visual form perception is the cognitive mechanism that could explain the association between numerical magnitude processing and arithmetic computation. Therefore, we examined numerical magnitude processing and its contribution to arithmetical ability in deaf adolescents, and explored the differences between the congenital and acquired deafness. 112 deaf adolescents (58 congenital deafness) and 58 hearing adolescents performed a series of cognitive and mathematical tests, and it was found there was no significant differences between the congenital group and the hearing group, but congenital group outperformed acquired group in numerical magnitude processing (reaction time) and arithmetic computation. It was also found there was a close association between numerical magnitude processing and arithmetic computation in all deaf adolescents, and after controlling for the demographic variables (age, gender, onset of hearing loss) and general cognitive abilities (non-verbal IQ, processing speed, reading comprehension), numerical magnitude processing could predict arithmetic computation in all deaf adolescents but not in congenital group. The role of numerical magnitude processing (symbolic and non-symbolic) in deaf adolescents' mathematical performance should be paid attention in the training of arithmetical ability.

[The value of genetic diagnosis of deafness in evaluating the prognosis of cochlear implantation]

Congenital deafness is known as the most common birth defect, and most sufferers from it manifest sensorineural hearing loss （SNHL）, with hereditary factors responsible for approximately 60% of the cases of deafness. At present, cochlear implantation （CI） is regarded as the most mature and effective solution to treating severe and extremely severe SNHL. However, the outcome of implantation varies due to different genetic factors. With whole genome sequencing advancing, more deafness mutant genes and their types have been identified, which is conducive to clarifying the efficacy of CI in the patients with different mutations for clinical practice. This paper is aimed to summarize the different effects of CI on hereditary deafness and the potential mechanism discovered in recent years, and to clarify the role played by the genetic diagnosis of deafness in evaluating the efficacy of cochlear implantation.

Deafness Weakens Interareal Couplings in the Auditory Cortex

The function of the cerebral cortex essentially depends on the ability to form functional assemblies across different cortical areas serving different functions. Here we investigated how developmental hearing experience affects functional and effective interareal connectivity in the auditory cortex in an animal model with years-long and complete auditory deprivation (deafness) from birth, the congenitally deaf cat (CDC). Using intracortical multielectrode arrays, neuronal activity of adult hearing controls and CDCs was registered in the primary auditory cortex and the secondary posterior auditory field (PAF). Ongoing activity as well as responses to acoustic stimulation (in adult hearing controls) and electric stimulation applied via cochlear implants (in adult hearing controls and CDCs) were analyzed. As functional connectivity measures pairwise phase consistency and Granger causality were used. While the number of coupled sites was nearly identical between controls and CDCs, a reduced coupling strength between the primary and the higher order field was found in CDCs under auditory stimulation. Such stimulus-related decoupling was particularly pronounced in the alpha band and in top–down direction. Ongoing connectivity did not show such a decoupling. These findings suggest that developmental experience is essential for functional interareal interactions during sensory processing. The outcomes demonstrate that corticocortical couplings, particularly top-down connectivity, are compromised following congenital sensory deprivation.

Incidence of Mumps Deafness in Japan, 2005-2017: Analysis of Japanese Insurance Claims Database

Background

Mumps deafness causes serious problems, and incidence data are needed to identify its disease burden. However, such data are limited, and the reported incidence is highly variable. Nationwide studies in Japan with a large age range are lacking.

Methods

This was a retrospective observational investigation of the 2005–2017 mumps burden using employment-based health insurance claims data. Data were analyzed for 5,190,326 people aged 0–64 years to estimate the incidence of mumps deafness.

Results

Of 68,112 patients with mumps (36,423 males; 31,689 females), 102 (48 males; 54 females) developed mumps deafness—an incidence of 15.0 per 10,000 patients (1 in 668 patients). Fifty-four (52.9%) patients had mumps deafness in childhood (0–15 years), and 48 (47.1%) had mumps deafness in adolescence and adulthood (16–64 years); most cases occurred in childhood, the peak period for mumps onset. The incidence of mumps deafness per 10,000 patients was 73.6 in adolescence and adulthood, 8.4 times higher than the incidence of 8.8 in childhood (P < 0.001). In childhood, the incidence of mumps deafness was 7.2 times higher among 6–15-year-olds (13.8; 95% CI, 10.2–18.2) than among 0–5-year-olds (1.9; 95% CI, 0.6–4.5), and this difference was statistically significant (P < 0.001). No sex difference was observed.

Conclusions

The incidence of mumps deafness per 10,000 patients aged 0–64 years was 15.0 (1 in 668 patients). A secondary risk of deafness following mumps virus infection was identified not only for children, but also for adolescents and adults.

Endogenous α1-antitrypsin levels in the perilymphatic fluid correlates with severity of hearing loss

OBJECTIVES

To determine the levels of endogenous α1-antitrypsin in the perilymph of patients undergoing cochlear implant (CI), and its reverse association with the severity of hearing loss.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary care university hospital.

PARTICIPANTS

The study includes 38 patients undergoing CI surgery, 11 patients diagnosed with congenital deafness and 27 non-congenital deafness, eight patients diagnosed with moderate hearing loss (N = 8; PTA = 70 dB), severe hearing loss (N = 11; PTA 70-90 dB) and profound hearing loss (N = 19; PTA > 90 dB).

MAIN OUTCOME AND MEASURE

1 to 12 μL perilymphatic fluids were collected by micropipette. α1-antitrypsin levels were determined, and current and historic audiological parameters were obtained.

RESULTS

The congenital and non-congenital group exhibited AAT concentrations of 2.5 ± 1.9 × 10⁶ LFQ and 3.2 ± 1.2 × 10⁶ LFQ, respectively (mean ± SD; P = .38). Mean levels of α1-antitrypsin in the perilymph fluid within the moderate group was 3.64 × 10⁶  ± 2.1 × 10⁶ LFQ vs 3.5 × 10⁶  ± 1.2 × 10⁶ in severe hearing loss (P = .81) and 2.4 × 10⁶  ± 1.1 × 10⁶ LFQ in the profound hearings loss group (P = .06). The difference in levels of AAT in samples from the severe hearings loss group vs the profound hearings loss group reached statistical significance (P = .04).

CONCLUSION

Insufficiency in α1-antitrypsin levels in the perilymph fluid of the inner ear appears to display a relationship with the severity of hearing loss. The prospect of introducing clinical-grade plasma-purified α1-antitrypsin directly onto the site of cochlear injury deserves thorough investigation.

Research Insights on Neural Effects of Auditory Deprivation and Restoration in Unilateral Hearing Loss: A Systematic Review

Neuroplasticity following bilateral deafness and auditory restoration has been repeatedly investigated. In clinical practice, however, a significant number of patients present a severe-to-profound unilateral hearing loss (UHL). To date, less is known about the neuroplasticity following monaural hearing deprivation and auditory input restoration. This article provides an overview of the current research insights on the impact of UHL on the brain and the effect of auditory input restoration with a cochlear implant (CI). An exhaustive systematic review of the literature was performed selecting 38 studies that apply different neural analyses techniques. The main results show that the hearing ear becomes functionally dominant after monaural deprivation, reshaping the lateralization of the neural network for auditory processing, a process that can be considered to influence auditory restoration. Furthermore, animal models predict that the onset time of UHL impacts auditory restoration. Hence, the results seem to advocate for early restoration of UHL, although further research is required to disambiguate the effects of duration and onset of UHL on auditory restoration and on structural neuroplasticity following UHL deprivation and restoration. Ongoing developments on CI devices compatible with Magnetic Resonance Imaging (MRI) examinations will provide a unique opportunity to investigate structural and functional neuroplasticity following CI restoration more directly.

[Congenital deaf-mutism with pale complexion and anemia for 1 year in a school-aged girl]

An 11-year-old girl was found to have pale complexion and anemia with gradual aggravation for one year. She was weak in the past and developed pneumonia in the right middle lung 3-5 times per year, which was improved after anti-infective therapy. She and her mother had congenital deaf-mutism. Physical examination showed the appearance of anemia, without bleeding, jaundice, hepatosplenomegaly, or lymph node enlargement. Routine blood test results showed reductions in all three blood cell lines, normocytic anemia, and megaloblastoid change in granulocytic and erythroid cell lines in bone marrow, with no obvious increase in primitive cells or metastatic tumor cells. Whole exome sequencing indicated the presence of a known pathogenic mutation for Emberger syndrome (ES), c.1084C>T (p.Arg362*) in the GATA2 gene. The girl was finally diagnosed with ES, and myelodysplastic syndrome (MDS) progressed to acute myeloid leukemia during follow-up. ES is a rare type of MDS with autosomal dominant inheritance in clinical practice, and it is difficult to make a confirmed diagnosis. ES should be considered for children with unexplained lymphedema and congenital deafness, and gene detection should be performed to make a confirmed diagnosis.

A novel mutation in PRPS1 causes X-linked Charcot-Marie-Tooth disease-5

X-linked Charcot-Marie-Tooth disease-5 (CMTX5) is a rare hereditary disorder caused by mutations in the gene for phosphoribosyl pyrophosphate synthetase-1 (PRPS1). We investigated a boy with a novel PRPS1 mutation (c.334G>C, p.V112L) via genetic, neuropathological and enzymatic tests. The proband was a 13-year-old boy with congenital non-syndromic sensorineural deafness. At 3 year old, he developed progressive distal weakness of all limbs with muscle atrophy of both hands and shanks. Nerve conduction study revealed the loss of sensory nerve action potentials, and slowing down of motor nerve conduction velocities with a decrease of amplitudes of compound motor action potentials. Visual evoked potentials and brainstem auditory evoked potentials were not bilaterally evocable. Sural biopsy proved the loss of myelinated nerve fibers, with axonal degeneration, regenerating clusters and onion bulbs. Enzymatically, PRPS1 activity was close to zero in the proband and mildly reduced in his mother, compared with controls. To our knowledge, this is the first report of CMTX5 in a Chinese population. The genetic finding has expanded the genotypic spectrum of PRPS1 mutations.

Three New Mutations and Mild, Asymmetrical Phenotype in the Highly Distinctive LAMM Syndrome: A Report of Eight Further Cases

Labyrinthine aplasia, microtia, and microdontia (LAMM) is an autosomal recessive condition causing profound congenital deafness, complete absence of inner ear structures (usually Michel’s aplasia), microtia (usually type 1) and microdontia. To date, several families have been described with this condition and a number of mutations has been reported. We report on eight further cases of LAMM syndrome including three novel mutations, c. 173T>C p.L58P; c. 284G>A p.(Arg95Gln) and c.325_327delinsA p.(Glu109Thrfs*18). Congenital deafness was the primary presenting feature in all affected individuals and consanguinity in all but two families. We compare the features in our patients to those previously reported in LAMM, and describe a milder, asymmetrical phenotype associated with FGF3 mutations.

[The expression of P19ink4d in the pathogenesis and development of hearing loss]

Objective: This study aimed to investigate the P19ink4d expression in cochlea of mice model with noise induced hearing loss and the role of P19ink4d in the degeneration of inner ear cells. It also searched for P19ink4d gene alterations in patients with profound sensorineural deafness.Method: CBA/J mice were exposed to broad band noise at 101 dB SPL for 2 hours, auditory brainstem response (ABR) were examined to confirm noise lead to the permanent threshold shift. Immunohistochemical staining, Western blotting, and real-time polymerase chain reaction (PCR) were performed on cochlear tissues, to elucidate changes in P19ink4d expression in mice after noise exposure. For clinical evaluation, 400 children from unrelated families with severe or profound sensorineural hearing loss (SNHL) were recruited, genomic DNA was obtained from the patients and was subjected to DNA microarray to screen mutations in 4 most common genes. The sample that carried none of the common mutant alleles were subjected to PCR and sequenced to detect mutations in P19ink4d gene.Result: The ABR threshold shift of mice in the experimental group significantly increased after noise exposure and was higher than that in the null-noise group. The ABR of 1 day post noise was least among experimental groups and there is no statistical different between ABR of 7 days and 14 days post noise. The missing of outer hair cells occurred after noise exposure, while the inner hair cells hardly miss. It was found that the P19ink4d expression increased significantly in the inner ear cells 3 hours after noise exposure, then recovered in 24 hours. Western blot indicated that the amount of P19ink4d increased transitorily 3-6 h after the noise. However, no mutation existed within the coding exons of P19ink4d in the patients with profound sensorineural deafness.Conclusion: The results support the concept that P19ink4d may play an important role in the pathogenesis and development of noise induced hearing loss.

Gene Therapy in Mouse Models of Deafness and Balance Dysfunction

Therapeutic strategies to restore hearing and balance in mouse models of inner ear disease aim to rescue sensory function by gene replacement, augmentation, knock down or knock out. Modalities to achieve therapeutic effects have utilized virus-mediated transfer of wild type genes and small interfering ribonucleic acids; systemic and focal administration of antisense oligonucleotides (ASO) and designer small molecules; and lipid-mediated transfer of Cas 9 ribonucleoprotein (RNP) complexes. This work has established that gene or drug administration to the structurally and functionally immature, early neonatal mouse inner ear prior to hearing onset is a prerequisite for the most robust therapeutic responses. These observations may have significant implications for translating mouse inner ear gene therapies to patients. The human fetus hears by gestational week 19, suggesting that a corollary window of therapeutic efficacy closes early in the second trimester of pregnancy. We hypothesize that fetal therapeutics deployed prior to hearing onset may be the most effective approach to preemptively manage genetic mutations that cause deafness and vestibular dysfunction. We assert that gene therapy studies in higher vertebrate model systems with fetal hearing onset and a comparable acoustic range and sensitivity to that of humans are an essential step to safely and effectively translate murine gene therapies to the clinic.

Successful preimplantation genetic diagnosis by targeted next-generation sequencing on an ion torrent personal genome machine platform

Hearing loss may place a heavy burden on the patient and patient's family. Given the high incidence of hearing loss among newborns and the huge cost of treatment and care (including cochlear implantation), prenatal diagnosis is strongly recommended. Termination of the fetus may be considered as an extreme outcome to the discovery of a potential deaf fetus, and therefore preimplantation genetic diagnosis has become an important option for avoiding the birth of affected children without facing the risk of abortion following prenatal diagnosis. In one case, a couple had a 7-year-old daughter affected by non-syndromic sensorineural hearing loss. The affected fetus carried a causative compound heterozygous mutation c.919-2 A>G (IVS7-2 A>G) and c.1707+5 G>A (IVS15+5 G>A) of the solute carrier family 26 member 4 gene inherited from maternal and paternal sides, respectively. The present study applied multiple displacement amplification for whole genome amplification of biopsied trophectoderm cells and next-generation sequencing (NGS)-based single nucleotide polymorphism haplotyping on an Ion Torrent Personal Genome Machine. One unaffected embryo was transferred in a frozen-thawed embryo transfer cycle and the patient was impregnated. To conclude, to the best of our knowledge, this may be the first report of NGS-based preimplantation genetic diagnosis (PGD) for non-syndromic hearing loss caused by a compound heterozygous mutation using an Ion Torrent Personal Genome Machine. NGS provides unprecedented high-throughput, highly parallel and base-pair resolution data for genetic analysis. The method meets the requirements of medium-sized diagnostics laboratories. With decreased costs compared with previous techniques (such as Sanger sequencing), this technique may have potential widespread clinical application in PGD of other types of monogenic disease.

Induced cortical responses require developmental sensory experience

Sensory areas of the cerebral cortex integrate the sensory inputs with the ongoing activity. We studied how complete absence of auditory experience affects this process in a higher mammal model of complete sensory deprivation, the congenitally deaf cat. Cortical responses were elicited by intracochlear electric stimulation using cochlear implants in adult hearing controls and deaf cats. Additionally, in hearing controls, acoustic stimuli were used to assess the effect of stimulus mode (electric versus acoustic) on the cortical responses. We evaluated time-frequency representations of local field potential recorded simultaneously in the primary auditory cortex and a higher-order area, the posterior auditory field, known to be differentially involved in cross-modal (visual) reorganization in deaf cats. The results showed the appearance of evoked (phase-locked) responses at early latencies (<100 ms post-stimulus) and more abundant induced (non-phase-locked) responses at later latencies (>150 ms post-stimulus). In deaf cats, substantially reduced induced responses were observed in overall power as well as duration in both investigated fields. Additionally, a reduction of ongoing alpha band activity was found in the posterior auditory field (but not in primary auditory cortex) of deaf cats. The present study demonstrates that induced activity requires developmental experience and suggests that higher-order areas involved in the cross-modal reorganization show more auditory deficits than primary areas.

Familial clustering of congenital deafness, patent ductus arteriosus, Eisenmenger complex, and differential cyanosis: A case report

RATIONALE

Few studies had reported syndromes that include patent ductus arteriosus (PDA) with Eisenmenger syndrome and congenital deafness clustered in male siblings without facial, skeletal, or mental abnormalities.

PATIENT CONCERNS

Two brothers, who were deaf and had PDA with Eisenmenger complex, were first seen at our Cardiology clinic at the ages of 25 and 41, respectively. They presented with progressive dyspnea on exertion. Upon physical examination, both brothers had clubbing and/or cyanotic toes, normal fingers, and without facial, skeletal, ophthalmological, or mental abnormalities.

DIAGNOSES AND INTERVENTIONS

Echocardiography and multidetector computed tomography revealed large PDAs in both brothers. Cardiac catheterization showed bidirectional shunting via the PDA.

OUTCOMES AND LESSONS

Familial clustering of Eisenmenger PDA and congenital deafness is rare. Further studies are warranted to define possible genetic links.

Tietz/Waardenburg type 2A syndrome associated with posterior microphthalmos in two unrelated patients with novel MITF gene mutations

Tietz syndrome and Waardenburg syndrome type 2A are allelic conditions caused by MITF mutations. Tietz syndrome is inherited in an autosomal dominant pattern and is characterized by congenital deafness and generalized skin, hair, and eye hypopigmentation, while Waardenburg syndrome type 2A typically includes variable degrees of sensorineural hearing loss and patches of de-pigmented skin, hair, and irides. In this paper, we report two unrelated families with MITF mutations. The first family showed an autosomal dominant pattern and variable expressivity. The second patient was isolated. MITF gene analysis in the first family demonstrated a c.648A>C heterozygous mutation in exon 8 c.648A>C; p. (R216S), while in the isolated patient, an apparently de novo heterozygous c.1183_1184insG truncating mutation was demonstrated in exon 10. All patients except one had bilateral reduced ocular anteroposterior axial length and a high hyperopic refractive error corresponding to posterior microphthalmos, features that have not been described as part of the disease. Our results suggest that posterior microphthalmos might be part of the clinical characteristics of Tietz/Waardenburg syndrome type 2A and expand both the clinical and molecular spectrum of the disease. © 2016 Wiley Periodicals, Inc.

Decoding Visual Location From Neural Patterns in the Auditory Cortex of the Congenitally Deaf

Sensory cortices of individuals who are congenitally deprived of a sense can exhibit considerable plasticity and be recruited to process information from the senses that remain intact. Here, we explored whether the auditory cortex of congenitally deaf individuals represents visual field location of a stimulus-a dimension that is represented in early visual areas. We used functional MRI to measure neural activity in auditory and visual cortices of congenitally deaf and hearing humans while they observed stimuli typically used for mapping visual field preferences in visual cortex. We found that the location of a visual stimulus can be successfully decoded from the patterns of neural activity in auditory cortex of congenitally deaf but not hearing individuals. This is particularly true for locations within the horizontal plane and within peripheral vision. These data show that the representations stored within neuroplastically changed auditory cortex can align with dimensions that are typically represented in visual cortex.

Retrospective analysis of 12,472 samples of amniotic fluid

OBJECTIVE

to determinate the role of heterozygosis of M34T mutation of GJB2 gene in non syndromic congenital deafness.

METHODS

retrospective study between March 2010 and June 2013. Molecular screening for 35delG and M34T mutations of the GJB2 gene was offered to all women undergoing to second trimester genetic amniocentesis. Patients were excluded from the study group if one of the following conditions were present: infections, fetal abnormalities, family history for congenital deafness, diagnosis of chromosomal abnormalities, and consanguinity between parents.

RESULTS

a total of 12.472 Caucasian women gave informed consent for this test. Seventy-seven cases were excluded. From the 12.395 amniotic fluid analysis remained, the following was found: 2 cases of 35delG homozygosis and 352 cases of heterozygous carriers (42 M34T mutation, 298 35delG mutation, 12 double heterozygosis M34T/35delG). The follow up in first year of life in the 42 newborns with heterozygosis for M34T mutation showed a mild deafness in 23 cases.

CONCLUSIONS

in our series, presence of heterozygosis M34T mutation is associated in more than 50% of cases to mild congenital deafness.

The petrous portion of the temporal bone as shown on sonography between 14 and 40 weeks' gestation

OBJECTIVES

The purpose of this study was to examine the feasibility of sonographically identifying, measuring, and constructing nomograms of the fetal petrous bone, the part of the temporal bone that houses the auditory apparatus.

METHODS

A total of 248 consecutive pregnant women between 14 and 40 weeks' gestation were included. During a routine scan using transvaginal or transabdominal sonography, the fetal head was assessed in transverse sections. First, the parotid gland or external ear was identified, followed by the petrous bone. This annular echogenic structure, located medially and superior to the parotid gland or external ear, was measured at its largest anteroposterior diameter. The petrous bone on at least one side was measured; if both sides were visualized easily, both petrous bones were measured.

RESULTS

In 247 fetuses, at least one petrous bone was measured. The petrous bone measurement correlated well with the gestational age (R = 0.908; P < .001), biparietal diameter (R = 0.983; P < .001), and femur length (R = 0.913; P < .001).

CONCLUSIONS

Depiction of the petrous bone is feasible at all gestational ages and correlates well with the gestational age, biparietal diameter, and femur length. The usefulness of the ability to depict this bone in prenatal diagnosis of congenital malformations of the inner ear should be tested in prospective studies.

Congenital and prolonged adult-onset deafness cause distinct degradations in neural ITD coding with bilateral cochlear implants

Bilateral cochlear implant (CI) users perform poorly on tasks involving interaural time differences (ITD), which are critical for sound localization and speech reception in noise by normal-hearing listeners. ITD perception with bilateral CI is influenced by age at onset of deafness and duration of deafness. We previously showed that ITD coding in the auditory midbrain is degraded in congenitally deaf white cats (DWC) compared to acutely deafened cats (ADC) with normal auditory development (Hancock et al., J. Neurosci, 30:14068). To determine the relative importance of early onset of deafness and prolonged duration of deafness for abnormal ITD coding in DWC, we recorded from single units in the inferior colliculus of cats deafened as adults 6 months prior to experimentation (long-term deafened cats, LTDC) and compared neural ITD coding between the three deafness models. The incidence of ITD-sensitive neurons was similar in both groups with normal auditory development (LTDC and ADC), but significantly diminished in DWC. In contrast, both groups that experienced prolonged deafness (LTDC and DWC) had broad distributions of best ITDs around the midline, unlike the more focused distributions biased toward contralateral-leading ITDs present in both ADC and normal-hearing animals. The lack of contralateral bias in LTDC and DWC results in reduced sensitivity to changes in ITD within the natural range. The finding that early onset of deafness more severely degrades neural ITD coding than prolonged duration of deafness argues for the importance of fitting deaf children with sound processors that provide reliable ITD cues at an early age.

c-Ret-mediated hearing losses

About 120 million people worldwide suffer from congenital (early-onset) hearing loss. Thirty percent of them have syndromic hearing loss and the remaining 70% have non-syndromic hearing loss. In addition, a large number of elderly people worldwide suffer from age-related (late-onset) hearing loss. c-Ret and c-RET have been shown to be essential for the development and maintenance of neurons including the enteric nervous system (ENS) in mice and humans. Impairments of endothelin receptor B (EDNRB) and SOX10 have been shown to cause a significantly increased risk of dominant sensorineural deafness in Hirschsprung disease (HSCR) patients. We have recently shown that impairments of tyrosine 1062 (Y1062) phosphorylation in c-Ret causes syndromic congenital deafness in mice and humans and non-syndromic age-related hearing loss with neurodegeneration of spiral ganglion neurons (SGNs) in mice. This review focuses on the pathogenesis of hearing loss caused by impairments of c-Ret.