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Current Protocols Mar 2021Congenital 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...
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.
Topics: Animals; Cochlear Implantation; Deafness; Hearing Aids; Hearing Loss; Hearing Loss, Sensorineural
PubMed: 33780161
DOI: 10.1002/cpz1.76 -
Brazilian Journal of Otorhinolaryngology 2022To present scientific evidence, based on a systematic review of the literature, on the benefit of brainstem implants in auditory rehabilitation and language development... (Review)
Review
OBJECTIVE
To present scientific evidence, based on a systematic review of the literature, on the benefit of brainstem implants in auditory rehabilitation and language development in children.
METHODS
A systematic search was used to identify studies that contain information about the benefit of brainstem implants in the auditory rehabilitation and language development of children. The review was conducted based on a structured literature search, following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist. The search was carried out in the PubMed, Web of Science and Scopus databases, using the combination "Auditory brainstem implants" AND "Pediatric", without restriction of language, period, and location. The quality assessment of the articles was performed using the Study Quality Assessment Tools.
RESULTS
Regarding hearing, children with brainstem implants showed sound detection, access to most speech sounds, basic auditory perception skills, recognition of ambient sounds, recognition of some frequently used words and phrases, in addition to some closed-set word discrimination capability. Expressive and comprehensive language were identified in children using auditory brainstem implants, increasing significantly in the short and long terms in most cases; however, in some of the children, such skills remained stable.
CONCLUSION
The auditory brainstem implant can be considered an effective alternative for children with cochlear malformation and/or auditory nerve deficiency and for those who cannot benefit from cochlear implant surgery.
Topics: Child; Humans; Deafness; Auditory Brain Stem Implants; Cochlear Implantation; Language Development; Cochlear Implants; Hearing; Brain Stem; Speech Perception
PubMed: 36088255
DOI: 10.1016/j.bjorl.2022.07.004 -
Medicine, Health Care, and Philosophy Mar 2020As reproductive genetic technologies advance, families have more options to choose what sort of child they want to have. Using preimplantation genetic diagnosis (PGD),...
As reproductive genetic technologies advance, families have more options to choose what sort of child they want to have. Using preimplantation genetic diagnosis (PGD), for example, allows parents to evaluate several existing embryos before selecting which to implant via in vitro fertilization (IVF). One of the traits PGD can identify is genetic deafness, and hearing embryos are now preferentially selected around the globe using this method. Importantly, some Deaf families desire a deaf child, and PGD-IVF is also an option for them. Selection for genetic deafness, however, encounters widespread disapproval in the hearing community, including mainstream philosophy and bioethics. In this paper I apply Elizabeth Barnes' value-neutral model of disability as mere-difference to the case of selecting for deafness. I draw on evidence from Deaf Studies and Disability Studies to build an understanding of deafness, the Deaf community, and the circumstances relevant to reproductive choices that may obtain for some Deaf families. Selection for deafness, with deafness understood as mere-difference and valued for its cultural identity, need not necessitate impermissible moral harms. I thus advocate that it is sometimes morally permissible to select for deafness in one's child.
Topics: Cultural Characteristics; Deafness; Humans; Morals; Parents; Philosophy, Medical; Preimplantation Diagnosis
PubMed: 31542873
DOI: 10.1007/s11019-019-09922-6 -
Brain : a Journal of Neurology Nov 2021Leukodystrophies are a heterogeneous group of rare inherited disorders that mostly involve the white matter of the CNS. These conditions are characterized by primary...
Leukodystrophies are a heterogeneous group of rare inherited disorders that mostly involve the white matter of the CNS. These conditions are characterized by primary glial cell and myelin sheath pathology of variable aetiology, which causes secondary axonal degeneration, generally emerging with disease progression. Whole exome sequencing performed in five large consanguineous nuclear families allowed us to identify homozygosity for two recurrent missense variants affecting highly conserved residues of RNF220 as the causative event underlying a novel form of leukodystrophy with ataxia and sensorineural deafness. We report these two homozygous missense variants (p.R363Q and p.R365Q) in the ubiquitin E3 ligase RNF220 as the underlying cause of this novel form of leukodystrophy with ataxia and sensorineural deafness that includes fibrotic cardiomyopathy and hepatopathy as associated features in seven consanguineous families. Mass spectrometry analysis identified lamin B1 as the RNF220 binding protein and co-immunoprecipitation experiments demonstrated reduced binding of both RNF220 mutants to lamin B1. We demonstrate that RNF220 silencing in Drosophila melanogaster specifically affects proper localization of lamin Dm0, the fly lamin B1 orthologue, promotes its aggregation and causes a neurodegenerative phenotype, strongly supporting the functional link between RNF220 and lamin B1. Finally, we demonstrate that RNF220 plays a crucial role in the maintenance of nuclear morphology; mutations in primary skin fibroblasts determine nuclear abnormalities such as blebs, herniations and invaginations, which are typically observed in cells of patients affected by laminopathies. Overall, our data identify RNF220 as a gene implicated in leukodystrophy with ataxia and sensorineural deafness and document a critical role of RNF220 in the regulation of nuclear lamina. Our findings provide further evidence on the direct link between nuclear lamina dysfunction and neurodegeneration.
Topics: Adolescent; Alleles; Amino Acid Sequence; Animals; Ataxia; COS Cells; Child; Chlorocebus aethiops; Deafness; Drosophila; Female; HEK293 Cells; Humans; Laminopathies; Male; Mutation; Pedigree; Ubiquitin-Protein Ligases; Young Adult
PubMed: 33964137
DOI: 10.1093/brain/awab185 -
The Journal of Neuroscience : the... Sep 2020Subjective tinnitus is the conscious perception of sound in the absence of any acoustic source. The literature suggests various tinnitus mechanisms, most of which invoke... (Review)
Review
Subjective tinnitus is the conscious perception of sound in the absence of any acoustic source. The literature suggests various tinnitus mechanisms, most of which invoke changes in spontaneous firing rates of central auditory neurons resulting from modification of neural gain. Here, we present an alternative model based on evidence that tinnitus is: (1) rare in people who are congenitally deaf, (2) common in people with acquired deafness, and (3) potentially suppressed by active cochlear implants used for hearing restoration. We propose that tinnitus can only develop after fast auditory fiber activity has stimulated the synapse formation between fast-spiking parvalbumin positive (PV) interneurons and projecting neurons in the ascending auditory path and coactivated frontostriatal networks after hearing onset. Thereafter, fast auditory fiber activity promotes feedforward and feedback inhibition mediated by PV interneuron activity in auditory-specific circuits. This inhibitory network enables enhanced stimulus resolution, attention-driven contrast improvement, and augmentation of auditory responses in central auditory pathways (neural gain) after damage of slow auditory fibers. When fast auditory fiber activity is lost, tonic PV interneuron activity is diminished, resulting in the prolonged response latencies, sudden hyperexcitability, enhanced cortical synchrony, elevated spontaneous γ oscillations, and impaired attention/stress-control that have been described in previous tinnitus models. Moreover, because fast processing is gained through sensory experience, tinnitus would not exist in congenital deafness. Electrical cochlear stimulation may have the potential to reestablish tonic inhibitory networks and thus suppress tinnitus. The proposed framework unites many ideas of tinnitus pathophysiology and may catalyze cooperative efforts to develop tinnitus therapies.
Topics: Animals; Auditory Pathways; Cochlear Implants; Deafness; Evoked Potentials, Auditory; Humans; Neurogenesis; Tinnitus
PubMed: 32938634
DOI: 10.1523/JNEUROSCI.1314-19.2020 -
The Journal of International Advanced... Nov 2021This study was planned (1) to evaluate long-term outcome after cochlear implantation in patients with post-meningitic deafness and (2) to compare the outcome measures...
BACKGROUND
This study was planned (1) to evaluate long-term outcome after cochlear implantation in patients with post-meningitic deafness and (2) to compare the outcome measures with patients implanted for deafness due to other causes.
METHODS
Records of 54 patients deafened as a sequel of bacterial meningitis and implanted at the largest university-based cochlear implant program in Turkey were retrospectively reviewed. Fifty-four age- and sex-matched patients with a similar interval of implant use were selected for controls. Surgical and long-term audiological outcome (in terms of categories of auditory performance-II scores) was assessed and compared.
RESULTS
Twenty-seven (52%) patients had some degree of labyrinthitis ossificans and 19 of them had full electrode insertion via basal turn cochleostomy. Patients with and without labyrinthitis ossificans in the post-meningitic group had no difference in final categories of auditory performance-II score (P=.559). Median categories of auditory performance-II scores were 6 for post-meningitic group and 7 for controls, with a significant statistical difference (P < .001). Partial or full insertions did not differ in outcome (P=.938). Mean time to implantation was not correlated with the final categories of auditory performance-II score for the post-meningitic group (P=.695).
CONCLUSION
Cochlear implant recipients deafened due to meningitis have a worse long-term hearing and speech performance as measured by categories of auditory performance-II than patients implanted for congenital deafness. The presence of labyrinthitis ossificans or the limited extent of electrode insertion produced overall results that were comparable with other cases.
Topics: Cochlear Implantation; Cochlear Implants; Deafness; Humans; Meningitis, Bacterial; Retrospective Studies; Speech Perception; Treatment Outcome
PubMed: 35177386
DOI: 10.5152/iao.2021.21105 -
Hearing Research Sep 2020Hearing impairment is a major health and economic concern worldwide. Currently, the cochlear implant (CI) is the standard of care for remediation of severe to profound... (Review)
Review
Hearing impairment is a major health and economic concern worldwide. Currently, the cochlear implant (CI) is the standard of care for remediation of severe to profound hearing loss, and in general, contemporary CIs are highly successful. But there is great variability in outcomes among individuals, especially in children, with many CI users deriving much less or even marginal benefit. Much of this variability is related to differences in auditory nerve survival, and there has been substantial interest in recent years in exploring potential therapies to improve survival of the cochlear spiral ganglion neurons (SGN) after deafness. Preclinical studies using osmotic pumps and other approaches in deafened animal models to deliver neurotrophic factors (NTs) directly to the cochlea have shown promising results, especially with Brain-Derived Neurotrophic Factor (BDNF). More recent studies have focused on the use of NT gene therapy to force expression of NTs by target cells within the cochlea. This could provide the means for a one-time treatment to promote long-term NT expression and improve neural survival after deafness. This review summarizes the evidence for the efficacy of exogenous NTs in preventing SGN degeneration after hearing loss and reviews the animal research to date suggesting that NT gene therapy can elicit long-term NT expression in the cochlea, resulting in significantly improved SGN and radial nerve fiber survival after deafness. In addition, we discuss NT gene therapy in other non-auditory applications and consider some of the remaining issues with regard to selecting optimal vectors, timing of treatment, and place/method of delivery, etc. that must be resolved prior to considering clinical application.
Topics: Animals; Brain-Derived Neurotrophic Factor; Deafness; Genetic Therapy; Humans; Neurons; Neurotrophin 3; Spiral Ganglion
PubMed: 32331858
DOI: 10.1016/j.heares.2020.107955 -
Developmental Medicine and Child... Apr 2022
Topics: Auditory Perception; Child; Cochlear Implantation; Cochlear Implants; Deafness; Humans; Infant, Newborn; Language
PubMed: 34693524
DOI: 10.1111/dmcn.15095 -
Archivos Argentinos de Pediatria Jun 2023Wildervanck syndrome (also known as cervico-oculo-acoustic dysplasia) is a very rare disease, characterized by the typical triad of cervical vertebral fusion or...
Wildervanck syndrome (also known as cervico-oculo-acoustic dysplasia) is a very rare disease, characterized by the typical triad of cervical vertebral fusion or Klippel-Feil anomaly, Duane syndrome (paresis of the sixth cranial nerve), and hearing loss. Other vascular, cardiac, and musculoskeletal conditions have also been described. In this case report, we describe a patient who met the cardinal triad and also presented additional clinical data that have not been previously reported, which contribute to broadening the disease phenotype. We have also reviewed the bibliography related to this syndrome.
Topics: Humans; Klippel-Feil Syndrome; Duane Retraction Syndrome; Deafness; Abnormalities, Multiple
PubMed: 36413195
DOI: 10.5546/aap.2022-02624.eng -
The Journal of International Advanced... Dec 2020
Topics: Cochlear Implantation; Cochlear Implants; Deafness; Hearing; Hearing Loss; Humans; Treatment Outcome
PubMed: 33136023
DOI: 10.5152/iao.2020.9024