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The Veterinary Clinics of North... Nov 2012Cats have among the best hearing of all mammals in that they are extremely sensitive to a broad range of frequencies. The ear is a highly complex structure that is... (Review)
Review
Cats have among the best hearing of all mammals in that they are extremely sensitive to a broad range of frequencies. The ear is a highly complex structure that is delicately balanced in terms of its biochemistry, types of receptors, ion channels, mechanical properties, and cellular organization. Sensorineural deafness is caused by "flawed" genes that are inherited from one or both parents. Hearing loss can also be acquired as a result of noise trauma from industrialized environment, viral infection, or blunt trauma. To date, it is not practical to intervene and attempt to correct these forms of deafness in cats.
Topics: Animals; Cat Diseases; Cats; Deafness; Ear; Ear Diseases; Evoked Potentials, Auditory, Brain Stem; Hearing Loss, Sensorineural; Presbycusis
PubMed: 23122176
DOI: 10.1016/j.cvsm.2012.08.008 -
British Medical Journal Jan 1977
Topics: Deafness; Humans; Mental Disorders; Middle Aged; Paranoid Disorders
PubMed: 832070
DOI: No ID Found -
Human Genetics Apr 2022Sensorineural hearing loss (SNHL) is a major cause of functional disability in both the developed and developing world. While hearing aids and cochlear implants provide... (Review)
Review
Sensorineural hearing loss (SNHL) is a major cause of functional disability in both the developed and developing world. While hearing aids and cochlear implants provide significant benefit to many with SNHL, neither targets the cellular and molecular dysfunction that ultimately underlies SNHL. The successful development of more targeted approaches, such as growth factor, stem cell, and gene therapies, will require a yet deeper understanding of the underlying molecular mechanisms of human hearing and deafness. Unfortunately, the human inner ear cannot be biopsied without causing significant, irreversible damage to the hearing or balance organ. Thus, much of our current understanding of the cellular and molecular biology of human deafness, and of the human auditory system more broadly, has been inferred from observational and experimental studies in animal models, each of which has its own advantages and limitations. In 2013, researchers described a protocol for the generation of inner ear organoids from pluripotent stem cells (PSCs), which could serve as scalable, high-fidelity alternatives to animal models. Here, we discuss the advantages and limitations of conventional models of the human auditory system, describe the generation and characteristics of PSC-derived inner ear organoids, and discuss several strategies and recent attempts to model hereditary deafness in vitro. Finally, we suggest and discuss several focus areas for the further, intensive characterization of inner ear organoids and discuss the translational applications of these novel models of the human inner ear.
Topics: Deafness; Ear, Inner; Hearing Loss, Sensorineural; Hearing Tests; Humans; Organoids
PubMed: 34342719
DOI: 10.1007/s00439-021-02325-9 -
Annual Review of Genomics and Human... Aug 2022Current estimates suggest that nearly half a billion people worldwide are affected by hearing loss. Because of the major psychological, social, economic, and health... (Review)
Review
Current estimates suggest that nearly half a billion people worldwide are affected by hearing loss. Because of the major psychological, social, economic, and health ramifications, considerable efforts have been invested in identifying the genes and molecular pathways involved in hearing loss, whether genetic or environmental, to promote prevention, improve rehabilitation, and develop therapeutics. Genomic sequencing technologies have led to the discovery of genes associated with hearing loss. Studies of the transcriptome and epigenome of the inner ear have characterized key regulators and pathways involved in the development of the inner ear and have paved the way for their use in regenerative medicine. In parallel, the immense preclinical success of using viral vectors for gene delivery in animal models of hearing loss has motivated the industry to work on translating such approaches into the clinic. Here, we review the recent advances in the genomics of auditory function and dysfunction, from patient diagnostics to epigenetics and gene therapy.
Topics: Animals; Deafness; Ear, Inner; Genetic Therapy; Genomics; Hearing Loss; Humans
PubMed: 35667089
DOI: 10.1146/annurev-genom-121321-094136 -
Neural Plasticity 2016The effect of deafness on sensory abilities has been the topic of extensive investigation over the past decades. These investigations have mostly focused on visual... (Review)
Review
The effect of deafness on sensory abilities has been the topic of extensive investigation over the past decades. These investigations have mostly focused on visual capacities. We are only now starting to investigate how the deaf experience their own bodies and body-related abilities. Indeed, a growing corpus of research suggests that auditory input could play an important role in body-related processing. Deafness could therefore disturb such processes. It has also been suggested that many unexplained daily difficulties experienced by the deaf could be related to deficits in this underexplored field. In the present review, we propose an overview of the current state of knowledge on the effects of deafness on body-related processing.
Topics: Body Image; Deafness; Humans; Motor Activity; Neuronal Plasticity; Posture; Touch Perception
PubMed: 26881115
DOI: 10.1155/2016/5260671 -
Hearing Research Jan 2017This review explores cross-modal cortical plasticity as a result of auditory deprivation in populations with hearing loss across the age spectrum, from development to... (Review)
Review
This review explores cross-modal cortical plasticity as a result of auditory deprivation in populations with hearing loss across the age spectrum, from development to adulthood. Cross-modal plasticity refers to the phenomenon when deprivation in one sensory modality (e.g. the auditory modality as in deafness or hearing loss) results in the recruitment of cortical resources of the deprived modality by intact sensory modalities (e.g. visual or somatosensory systems). We discuss recruitment of auditory cortical resources for visual and somatosensory processing in deafness and in lesser degrees of hearing loss. We describe developmental cross-modal re-organization in the context of congenital or pre-lingual deafness in childhood and in the context of adult-onset, age-related hearing loss, with a focus on how cross-modal plasticity relates to clinical outcomes. We provide both single-subject and group-level evidence of cross-modal re-organization by the visual and somatosensory systems in bilateral, congenital deafness, single-sided deafness, adults with early-stage, mild-moderate hearing loss, and individual adult and pediatric patients exhibit excellent and average speech perception with hearing aids and cochlear implants. We discuss a framework in which changes in cortical resource allocation secondary to hearing loss results in decreased intra-modal plasticity in auditory cortex, accompanied by increased cross-modal recruitment of auditory cortices by the other sensory systems, and simultaneous compensatory activation of frontal cortices. The frontal cortices, as we will discuss, play an important role in mediating cognitive compensation in hearing loss. Given the wide range of variability in behavioral performance following audiological intervention, changes in cortical plasticity may play a valuable role in the prediction of clinical outcomes following intervention. Further, the development of new technologies and rehabilitation strategies that incorporate brain-based biomarkers may help better serve hearing impaired populations across the lifespan.
Topics: Adaptation, Psychological; Adolescent; Adult; Age Factors; Aging; Animals; Auditory Cortex; Auditory Perception; Child; Child Development; Child, Preschool; Cochlear Implantation; Cochlear Implants; Cognition; Cues; Deafness; Hearing; Hearing Aids; Humans; Neuronal Plasticity; Presbycusis; Visual Perception; Young Adult
PubMed: 27613397
DOI: 10.1016/j.heares.2016.08.012 -
Hearing Research Dec 2011Our understanding of hereditary hearing loss has greatly improved since the discovery of the first human deafness gene. These discoveries have only accelerated due to... (Review)
Review
Our understanding of hereditary hearing loss has greatly improved since the discovery of the first human deafness gene. These discoveries have only accelerated due to the great strides in DNA sequencing technology since the completion of the human genome project. Here, we review the immense impact that these developments have had in both deafness research and clinical arenas. We review commonly used genomic technologies as well as the application of these technologies to the genetic diagnosis of hereditary hearing loss and to the discovery of novel deafness genes.
Topics: Animals; DNA Mutational Analysis; Deafness; Genetic Association Studies; Genetic Predisposition to Disease; Genetic Testing; Genomics; Hearing; Heredity; Humans; Pedigree; Phenotype
PubMed: 22016077
DOI: 10.1016/j.heares.2011.10.001 -
Trends in Hearing 2021In children with congenital deafness, cochlear implantation (CI) prior to 12 months of age offers the opportunity to foster more typical auditory development during late... (Review)
Review
In children with congenital deafness, cochlear implantation (CI) prior to 12 months of age offers the opportunity to foster more typical auditory development during late infancy and early childhood. Recent studies have found a positive association between early implantation and expressive and receptive language outcomes, with some children able to achieve normal language skills by the time of school entry. Universal newborn hearing screening improved early detection and diagnosis of congenital hearing loss, allowing for earlier intervention, including decision-making regarding cochlear implant (CI) candidacy. It can be more challenging to confirm CI candidacy in infants; therefore, a multidisciplinary approach, including objective audiometric testing, is recommended to not only confirm the diagnosis but also to counsel families regarding expectations and long-term management. Surgeons performing CI surgery in young children should consider both the anesthetic risks of surgery in infancy and the ways in which mastoid anatomy may differ between infants and older children or adults. Multiple studies have found CI surgery in infants can be performed safely and effectively. This article reviews current evidence regarding indications for implantation in children younger than 12 months of age and discusses perioperative considerations and surgical technique.
Topics: Adolescent; Adult; Child; Child, Preschool; Cochlear Implantation; Cochlear Implants; Deafness; Hearing Loss, Sensorineural; Humans; Infant; Infant, Newborn
PubMed: 34281434
DOI: 10.1177/23312165211031751 -
Hearing Research Jan 2017The theory of predictive coding assumes that higher-order representations influence lower-order representations by generating predictions about sensory input. In... (Review)
Review
The theory of predictive coding assumes that higher-order representations influence lower-order representations by generating predictions about sensory input. In congenital deafness, one identified dysfunction is a reduced activation of deep layers in the auditory cortex. Since these layers play a central role for processing top-down influences, congenital deafness might interfere with the integration of top-down and bottom-up information flow. Studies in humans suggest more deficits in higher-order than in primary cortical areas in congenital deafness. That opens up the question how well neurons in higher-order areas can be activated by the input through the deprived auditory pathway after restoration of hearing with cochlear implants. Further it is unclear whether their interconnections to lower order areas are impaired by absence of hearing. Corticocortical anatomical fiber tracts and general auditory responsiveness in both primary and higher-order areas are generally preserved in absence of auditory experience. However, the existing data suggest a dichotomy between preservation of anatomical cortical connectivity in congenital deafness and functional deficits in corticocortical coupling. Further, cross-modal reorganization observed in congenital deafness in specific cortical areas appears to be established by functional synaptic changes and rests on anatomically preserved, genetically-predetermined and molecularly patterned circuitry connecting the sensory systems. Current data indicate a reduced corticocortical functional coupling between cortical auditory areas in congenital deafness, both in bottom-up and top-down information stream. Consequently, congenital deafness is likely to result in a deficit in predictive coding that affects learning ability after late cochlear implantation.
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Auditory Pathways; Auditory Perception; Cortical Synchronization; Deafness; Evoked Potentials, Auditory; Hearing; Humans; Learning; Neuronal Plasticity
PubMed: 27637669
DOI: 10.1016/j.heares.2016.08.017 -
Frontiers in Bioscience (Landmark... Jan 2014Maternally inherited diabetes and deafness (MIDD), a mitochondrial disease first described in 1992, results from the mitochondrial DNA mutation and affects up to 1% of... (Review)
Review
Maternally inherited diabetes and deafness (MIDD), a mitochondrial disease first described in 1992, results from the mitochondrial DNA mutation and affects up to 1% of the patients with diabetes. This review discusses the biomedical mechanisms of MIDD patients; summarizes the recent improvement of clinical and genetic diagnosis of MIDD; outlines the advances of the clinical management of these patients and their families.
Topics: DNA, Mitochondrial; Deafness; Diabetes Mellitus, Type 2; Female; Humans; Mitochondrial Diseases; Molecular Diagnostic Techniques; Mutation; Pregnancy
PubMed: 24389221
DOI: 10.2741/4244