Late-onset Deafness Research Articles

Newborn hearing screening program in China: a narrative review of the issues in screening and management.

Hearing loss is one of the most common sensory disorders in humans. The purpose of this review is to summarize the history and current status of newborn hearing screening in China and to investigate future developmental trends in newborn hearing screening with the intention of sharing experiences and providing a reference for other populations. In the 1980s, the research on hearing monitoring for high-risk infants led to the gradual development of newborn hearing screening in China. With the continuous improvement of screening technology, the newborn hearing screening program was gradually extended to the whole country and became a government-led multidisciplinary public health program. Genetic screening for deafness has been incorporated into newborn hearing screening in many regions of China to help screen for potential and late-onset deafness in newborns. In the future, it is necessary to further establish and improve whole life-cycle hearing screening and healthcare, conduct screening for congenital cytomegalovirus infection, and create a full-coverage, whole life course hearing screening and intervention system. Screening for deafness in China has been marked by 40 years of achievements, which have been a source of pride for entrepreneurs and comfort for patients and their families. Managing hearing screening data information more efficiently and establishing a quality control index system throughout the whole screening process are of paramount importance. The genetic screening for concurrent newborn hearing and deafness has a great clinical importance for the management of congenital deafness and prevention of ototoxicity. A hearing screening and intervention system across the whole life course should be developed.

The effect of risk factors on cognition in adult cochlear implant candidates with severe to profound hearing loss.

Hearing loss has been identified as a major modifiable risk factors for dementia. Adult candidates for cochlear implantation (CI) represent a population at risk of hearing loss-associated cognitive decline. This study investigated the effect of demographics, habits, and medical and psychological risk factors on cognition within such a cohort. Data from 34 consecutive adults with post-lingual deafness scheduled for CI were analyzed. Pure tone audiometry (PTA4) and Speech Discrimination Score (SDS) were recorded. The Repeatable Battery for Assessment of Neuropsychological Status for Hearing impaired individuals (RBANS-H) was used to measure cognition. Demographics (sex, age, years of education), habits (smoking, alcohol intake, physical inactivity), and medical factors (hypertension, diabetes, traumatic brain injury) were evaluated. Depression was measured using the Hospital Anxiety and Depression Scale (HADS), and social inhibition with the Type D questionnaire (DS14). All participants (mean age 62 ± 15 years) suffered from severe to profound hearing loss (PTA4:129 ± 60 dB; SDS:14 ± 24%). The mean RBANS-H total score was 83 ± 16. Participants reported a mean of years of formal education of 12 ± 5 years. The prevalence of habits and medical risk factors was: physical inactivity (29%), body mass index >30 (28%), traumatic brain injury (25%), hypertension (24%), heavy alcohol consumption (13%), smoking (13%), and diabetes (0%). Regarding psychological factors, the mean scores of social inhibition and depression were 10 ± 6 and 6 ± 5, respectively. The number of years of education was significantly correlated with the RBANS-H total score (p < 0.001), and with the domains “Immediate memory” (p = 0.003), “Visuospatial/constructional” (p < 0.001), and “Attention” (p < 0.001). The mean RBANS-H total score in participants who had university studies or higher level (12/34) was 97 ± 9, with the remaining participants reporting a mean score of 75 ± 15. Men performed better in the “Visuospatial/constructional” (p = 0.008). Physical inactivity was associated with lower scores in the “Delayed memory” (p = 0.031); hypertension correlated with lower RBANS-H total scores (p = 0.025) and “Attention” (p = 0.006). Depression and social inhibition were negatively correlated with RBANS-H total score and with the “Immediate memory,” “Visuospatial/constructional,” and “Attention” (all p < 0.05). In adults with late-onset deafness scheduled to CI, educational level has a significant effect. Additionally, sex, physical inactivity, hypertension, and psychological traits of social inhibition and depression may also influence cognitive status. Long-term studies with more participants would enable us better understand the effects different risk factors on cognitive status.

Cortical Auditory Evoked Potential in Adults With Cochlear Implants: A Comparison With Adults With Normal Hearing.

Background and ObjectivesTo examine the maturational status of the auditory cortex in adults with cochlear implants (CIs) using the latencies of the P1, N1, and P2 components of cortical auditory-evoked potentials (CAEPs).Subjects and MethodsA total of 25 adults with CIs and 25 age-matched, normal-hearing control subjects participated in this study. Specifically, patients with CIs were divided into three groups depending on their age of deafness onset: Group A comprised patients with prelingual deafness who had received CI during early childhood (n=7), Group B comprised patients with early childhood-onset, progressive deafness who had received CI during childhood (n=6), and Group C comprised patients with adult-onset deafness (n=12). The P1, N1, and P2 latencies of their CAEPs were then compared between CI patients and normal-hearing subjects.ResultsAll participants showed clear CAEP responses. P1 and N1 latencies in Group A and Group C patients were significantly longer than those in the control group. Meanwhile, Group B patients had significantly longer N1 and P2 latencies, as compared with those in the control group.ConclusionsPatients with prelingual deafness and those with early-childhood onset, progressive deafness who received CI developed primary and higher-order auditory areas postoperatively when they became adults. However, their auditory cortex maturational statuses seemed to be worse than that of normal-hearing individuals. Furthermore, adult patients with late-onset deafness might experience degenerative auditory cortex changes during the auditory deprivation period between deafness onset and cochlear implantation.

Reorganized Brain White Matter in Early- and Late-Onset Deafness With Diffusion Tensor Imaging.

Individuals with early- and late-onset deafness showed different functional and morphological brain changes, but white matter alterations in both deaf groups still need to be elucidated. This study aimed to investigate changes in white matter integrity and white matter anatomical connectivity in both early- and late-onset deaf groups compared with hearing group. Diffusion tensor imaging data from 7 early-onset deaf (50.7 ± 6.5 years), 11 late-onset deaf (50.9 ± 12.3 years), and 9 hearing adults (48.9 ± 9.5 years) were preprocessed using FSL software. To find changes in white matter integrity, tract-based spatial statistics was used, which implemented on FSL software. Fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) were calculated and compared among the groups with age as a nuisance variable. To find out the effect of onset age or duration of deafness to the white matter integrity, onset-age or duration of deafness was treated as a variable of interest in the general linear model implemented on tract-based spatial statistics. White matter connectivity was constructed by a deterministic tractography and compared among the groups. In comparison to the hearing group, the early-onset deaf group did not show any significant changes but the late-onset deaf group showed decreased FA and increased RD in the several white matter areas. AD in the late-onset deaf group was not significantly different compared with the hearing group. The regions included the corpus callosum, posterior and superior corona radiata, internal capsule, posterior thalamic radiation, superior longitudinal fasciculus, and tapetum of the right hemisphere. Increased RD was also additionally observed in the right external capsule, fornix, and cerebral peduncle. The onset age or duration of deafness was not significantly correlated with the white matter integrity in the early-onset deaf group. In contrast, the onset age showed a significantly positive correlation with the RD, and a negative correlation with the FA, in the late-onset deaf group. The correlated white matter areas were also similar to the findings of comparison with the hearing group. In comparison to the hearing group, the early-onset deaf group did not show altered white matter connectivity, while the late-onset deaf group showed decreased white matter connectivity in between the right lingual and hippocampal areas. The present results suggest that late-onset deaf adults showed decreased FA and increased RD, and early-onset deaf adults showed no difference compared with the hearing group. In the late-onset deaf adults, onset-age showed a significantly positive correlation with RD and negative correlation with FA. Duration of deafness was not significantly correlated with the changes. Increased RD indicating demyelination occurred in the brain, and the changes were not limited to the auditory cortex but expanded to almost whole brain areas, suggesting significant effect of auditory deprivation on the brain later in life. The altered white matter connectivity in between the right limbic-occipital areas observed in the late-onset deaf group might be caused by altered language functions after auditory deprivation. Future studies are necessary incorporating functional and anatomical aspects of the brain changes in deaf group.

A novel pathogenic variant in OSBPL2 linked to hereditary late-onset deafness in a Mongolian family

BackgroundTo investigate the clinical features and the underlying causal gene of a family with hereditary late-onset deafness in Inner Mongolia of China, and to provide evidence for the early genetic screening and diagnosis of this disease.MethodsFamily data were collected to draw a pedigree. Audiological testing and physical examination of the family members were conducted following questionnaire. Genomic DNA was extracted from peripheral blood of 5 family members (3 patients and 2 normal control) and subjected to whole genome sequencing for identifying deafness casual genes. The pathogenic variant in the deafness gene was further confirmed by Sanger sequencing.ResultsThe family is composed of a total of 6 generations, with 53 traceable individuals. In this family,19 of them were diagnosed with post lingual deafness with the age of onset between 10 and 40 years, displaying delayed and progressive hearing loss. Patients with hearing loss showed bilateral symmetry and mild to severe sensorineural deafness. The pattern of deafness inheritance in this family is autosomal dominant. Whole genome sequencing identified a novel pathogenic frameshift mutation, c.158_159delAA (p.Gln53Arg fs*100) in the gene OSBPL2 (Oxysterol-binding protein-related protein 2, NM_144498.2), which is absent from genomic data of 201 unrelated normal subjects. This pathogenic variant was further validated by Sanger sequencing, and was found to co-segregate in this family.ConclusionsWhole genome sequencing identified a two-nucleotide deletion in OSBPL2 (c.158_159delAA) as the pathogenic variant for deafness in the family. Our finding expands the mutational spectrum of OSBPL2 and contributes to the pathogenic variant list in genetic counseling for deafness screening.

Changes of metabolism and functional connectivity in late-onset deafness: Evidence from cerebral 18F-FDG-PET

Hearing loss is known to impact brain function. The aim of this study was to characterize cerebral metabolic Positron Emission Tomography (PET) changes in elderly patients fulfilling criteria for cochlear implant and investigate the impact of hearing loss on functional connectivity. Statistical Parametric Mapping-T-scores-maps comparisons of 18F-FDG-PET of 27 elderly patients fulfilling criteria for cochlear implant for hearing loss (best-aided speech intelligibility lower or equal to 50%) and 27 matched healthy subjects (p < 0.005, corrected for volume extent) were performed. Metabolic connectivity was evaluated through interregional correlation analysis. Patients were found to have decreased metabolism within the right associative auditory cortex, while increased metabolism was found in prefrontal areas, pre- and post-central areas, the cingulum and the left inferior parietal gyrus. The right associative auditory cortex was integrated into a network of increased metabolic connectivity that included pre- and post-central areas, the cingulum, the right inferior parietal gyrus, as well as the striatum on both sides. Metabolic values of the right associative auditory cortex and left inferior parietal gyrus were positively correlated with performance on neuropsychological test scores. These findings provide further insight into the reorganization of the connectome through sensory loss and compensatory mechanisms in elderly patients with severe hearing loss.

HMSN Lom in 12 Czech patients, with one unusual case due to uniparental isodisomy of chromosome 8.

Hereditary motor and sensory neuropathy-type Lom (HMSNL), also known as CMT4D, a demyelinating neuropathy with late-onset deafness is an autosomal recessive disorder threatening Roma population worldwide. The clinical phenotype was reported in several case reports before the gene discovery. HMSNL is caused by a homozygous founder mutation p.Arg148* in the N-Myc downstream-regulated gene 1. Here, we report findings from the Czech Republic, where HMSNL was found in 12 Czech patients from eight families. In these 12 patients, 11 of the causes were due to p.Arg148* mutation inherited from both parents by the autosomal recessive mechanism. But in one case, the recessive mutation was inherited only from one parent (father) and unmasked owing to an uniparental isodisomy of the entire chromosome eight. The inherited peripheral neuropathy owing to an isodisomy of the whole chromosome pointed to an interesting, less frequent possibility of recessive disease and complications with genetic counseling.

Quantifying and comparing the pattern of thalamic and cortical projections to the posterior auditory field in hearing and deaf cats.

Following sensory loss, compensatory crossmodal reorganization occurs such that the remaining modalities are functionally enhanced. For example, behavioral evidence suggests that peripheral visual localization is better in deaf than in normal hearing animals, and that this enhancement is mediated by recruitment of the posterior auditory field (PAF), an area that is typically involved in localization of sounds in normal hearing animals. To characterize the anatomical changes that underlie this phenomenon, we identified the thalamic and cortical projections to the PAF in hearing cats and those with early- and late-onset deafness. The retrograde tracer biotinylated dextran amine was deposited in the PAF unilaterally, to label cortical and thalamic afferents. Following early deafness, there was a significant decrease in callosal projections from the contralateral PAF. Late-deaf animals showed small-scale changes in projections from one visual cortical area, the posterior ectosylvian field (EPp), and the multisensory zone (MZ). With the exception of these minor differences, connectivity to the PAF was largely similar between groups, with the principle projections arising from the primary auditory cortex (A1) and the ventral division of the medial geniculate body (MGBv). This absence of large-scale connectional change suggests that the functional reorganization that follows sensory loss results from changes in synaptic strength and/or unmasking of subthreshold intermodal connections. J. Comp. Neurol. 524:3042-3063, 2016. © 2016 Wiley Periodicals, Inc.

Class III myosins shape the auditory hair bundles by limiting microvilli and stereocilia growth.

The precise architecture of hair bundles, the arrays of mechanosensitive microvilli-like stereocilia crowning the auditory hair cells, is essential to hearing. Myosin IIIa, defective in the late-onset deafness form DFNB30, has been proposed to transport espin-1 to the tips of stereocilia, thereby promoting their elongation. We show that Myo3a(-/-)Myo3b(-/-) mice lacking myosin IIIa and myosin IIIb are profoundly deaf, whereas Myo3a-cKO Myo3b(-/-) mice lacking myosin IIIb and losing myosin IIIa postnatally have normal hearing. Myo3a(-/-)Myo3b(-/-) cochlear hair bundles display robust mechanoelectrical transduction currents with normal kinetics but show severe embryonic abnormalities whose features rapidly change. These include abnormally tall and numerous microvilli or stereocilia, ungraded stereocilia bundles, and bundle rounding and closure. Surprisingly, espin-1 is properly targeted to Myo3a(-/-)Myo3b(-/-) stereocilia tips. Our results uncover the critical role that class III myosins play redundantly in hair-bundle morphogenesis; they unexpectedly limit the elongation of stereocilia and of subsequently regressing microvilli, thus contributing to the early hair bundle shaping.

Connectivity in Language Areas of the Brain in Cochlear Implant Users as Revealed by fNIRS.

Many studies, using a variety of imaging techniques, have shown that deafness induces functional plasticity in the brain of adults with late-onset deafness, and in children changes the way the auditory brain develops. Cross modal plasticity refers to evidence that stimuli of one modality (e.g. vision) activate neural regions devoted to a different modality (e.g. hearing) that are not normally activated by those stimuli. Other studies have shown that multimodal brain networks (such as those involved in language comprehension, and the default mode network) are altered by deafness, as evidenced by changes in patterns of activation or connectivity within the networks. In this paper, we summarise what is already known about brain plasticity due to deafness and propose that functional near-infra-red spectroscopy (fNIRS) is an imaging method that has potential to provide prognostic and diagnostic information for cochlear implant users. Currently, patient history factors account for only 10 % of the variation in post-implantation speech understanding, and very few post-implantation behavioural measures of hearing ability correlate with speech understanding. As a non-invasive, inexpensive and user-friendly imaging method, fNIRS provides an opportunity to study both pre- and post-implantation brain function. Here, we explain the principle of fNIRS measurements and illustrate its use in studying brain network connectivity and function with example data.

2014 CODEPEH Recommendations: Early Detection of Late Onset Deafness, Audiological Diagnosis, Hearing Aid Fitting and Early Intervention

The latest scientific literature considers early diagnosis of deafness as the key element to define the educational and inclusive prognosis of the deaf child, because it allows taking advantage of the critical period of development (0–4 years).Highly significant differences exist between deaf people who have been stimulated early and those who have received late or improper intervention.Early identification of late-onset disorders requires special attention and knowledge on the part of every childcare professional. Programmes and additional actions beyond neonatal screening should be designed and planned to ensure that every child with a significant hearing loss is detected early.For this purpose, the CODEPEH would like to highlight the need for continuous monitoring of children's auditory health. Consequently, CODEPEH has drafted the recommendations included in the present document.

Differential Modification of Cortical and Thalamic Projections to Cat Primary Auditory Cortex Following Early- and Late-Onset Deafness.

Following sensory deprivation, primary somatosensory and visual cortices undergo crossmodal plasticity, which subserves the remaining modalities. However, controversy remains regarding the neuroplastic potential of primary auditory cortex (A1). To examine this, we identified cortical and thalamic projections to A1 in hearing cats and those with early- and late-onset deafness. Following early deafness, inputs from second auditory cortex (A2) are amplified, whereas the number originating in the dorsal zone (DZ) decreases. In addition, inputs from the dorsal medial geniculate nucleus (dMGN) increase, whereas those from the ventral division (vMGN) are reduced. In late-deaf cats, projections from the anterior auditory field (AAF) are amplified, whereas those from the DZ decrease. Additionally, in a subset of early- and late-deaf cats, area 17 and the lateral posterior nucleus (LP) of the visual thalamus project concurrently to A1. These results demonstrate that patterns of projections to A1 are modified following deafness, with statistically significant changes occurring within the auditory thalamus and some cortical areas. Moreover, we provide anatomical evidence for small-scale crossmodal changes in projections to A1 that differ between early- and late-onset deaf animals, suggesting that potential crossmodal activation of primary auditory cortex differs depending on the age of deafness onset.

Amplified somatosensory and visual cortical projections to a core auditory area, the anterior auditory field, following early- and late-onset deafness.

Cross-modal reorganization following the loss of input from a sensory modality can recruit sensory-deprived cortical areas to process information from the remaining senses. Specifically, in early-deaf cats, the anterior auditory field (AAF) is unresponsive to auditory stimuli but can be activated by somatosensory and visual stimuli. Similarly, AAF neurons respond to tactile input in adult-deafened animals. To examine anatomical changes that may underlie this functional adaptation following early or late deafness, afferent projections to AAF were examined in hearing cats, and cats with early- or adult-onset deafness. Unilateral deposits of biotinylated dextran amine were made in AAF to retrogradely label cortical and thalamic afferents to AAF. In early-deaf cats, ipsilateral neuronal labeling in visual and somatosensory cortices increased by 329% and 101%, respectively. The largest increases arose from the anterior ectosylvian visual area and the anterolateral lateral suprasylvian visual area, as well as somatosensory areas S2 and S4. Consequently, labeling in auditory areas was reduced by 36%. The age of deafness onset appeared to influence afferent connectivity, with less marked differences observed in late-deaf cats. Profound changes to visual and somatosensory afferent connectivity following deafness may reflect corticocortical rewiring affording acoustically deprived AAF with cross-modal functionality.

高危新生儿听力和聋病易感基因联合筛查临床研究

目的：探讨在高危新生儿听力筛查基础上，联合聋病易感基因筛查的临床意义。方法：随机选择920例新生儿科住院具有听力损失高危因素的新生儿，于生后3~5天采集微量足跟血进行基因GJB2、SLC26A4及线粒体12SrRNA的聚合酶链扩增反应，通过基质辅助激光解吸附/电离飞行时间质谱方法检测GJB2基因35delG、176-191del16、235delC、299-300delAT；SLC26A4基因IVS7-2A > G、2168A > G；线粒体12SrRNA基因1494C > T、1555A > G等3个基因8个突变位点；听力筛查初筛采用自动判别听性脑干电位(auto-auditory brainstem response AABR)，复筛采用诊断型耳声反射(otoacoustic emission OAE) + AABR，仍不通过者于3月龄行听力学诊断；选取同期产后区938例健康新生儿为对照组。结果：高危新生儿组检出35例聋病基因携带，3个基因突变的总体携带率3.80%；检出听力障碍34例(3.70%)、其中重度以上听力障碍15例(1.63%)；30例(85.7%)聋病基因携带者通过了听力筛查。对照组检出21例聋病基因携带，3个基因突变的总体携带率2.23%；检出听力障碍4例(0.43%)、重度以上听力障碍1例(0.11%)；17例(68.0%)聋病基因携带者通过了听力筛查。两组聋病基因突变的总携带率、听力障碍及重度以上听力障碍检出率以及携带聋病基因者听力筛查通过率之间差异有统计学意义。结论：高危新生儿听力障碍的发生率和聋病基因突变携带率均高于正常新生儿应重点关注；采用听力和聋病易感基因联合筛查能及时发现常规通过听力筛查但具有耳聋高危因素和迟发性聋病遗传因素的新生儿，对早期干预、定期随访、减少聋病发生具有指导意义。 Objective: To investigate the mutation frequency and types of deafness susceptibility genes (GJB2, 12SrNA, SLC26A4) among high-risk neonates and to discuss the clinic signification of combining the original hearing screening with deafness susceptibility genes screening. Methods: 920 newborns with risk factors of hearing loss in the neonatology ward were chosen to collect films of heel blood for the study. Eight mutations of three genes (GJB2 35delG, 176-191del16, 235delC, 299-300delAT; SLC26A4 IVS7-2A > G, 2168 > G; MT 12SrRNA 1494C > T, 1555A > G) were detected by matrix assister laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Meanwhile, all these newborns received hearing screening. Auto-auditory brainstem response (AABR) was used for the first step screening and otoacoustic emission (OAE) combined with AABR was used for the second step screening. Audiology diagnosis would be applied for those who failed to pass the hearing screening when they were 3 months old. 938 healthy newborns in maternity ward as control group received same screening. Results: 35 infants with risk factors were deafness predisposing gene carriers. The overall carrier frequency of three genes was 3.8%, 34 were diag-nosed as hearing loss (3.7%) and 15 were diagnosed as severe hearing loss (1.63%). 30 (85.7%) carriers of deafness predisposing gene passed the hearing screening. 21 infants were deafness predisposing gene carriers in control group. The overall carrier frequency of three genes was 2.23%, 4 were diagnosed as hearing loss (0.43%) and 1 was diagnosed as severe hearing loss (0.11%). 17 (68%) carriers of deafness predisposing gene passed the hearing screening. Overall carrier frequency of three genes and detection rate of hearing loss or severe hearing loss were significant between the two groups. Conclusion: There were significant differences in carrier frequency of deafness predisposing gene and detection rate of hearing loss or severe hearing loss between the two groups. To combine newborns hearing screening with deafness susceptibility genes screening is able to find the newborns who will pass the regular hearing screening but with high deafness risks and late-onset deafness susceptibility genes. As a result, it is of guiding significance to early intervention, regular follow-up and deafness preventing.

Modified Areal Cartography in Auditory Cortex Following Early- and Late-Onset Deafness

Cross-modal plasticity following peripheral sensory loss enables deprived cortex to provide enhanced abilities in remaining sensory systems. These functional adaptations have been demonstrated in cat auditory cortex following early-onset deafness in electrophysiological and psychophysical studies. However, little information is available concerning any accompanying structural compensations. To examine the influence of sound experience on areal cartography, auditory cytoarchitecture was examined in hearing cats, early-deaf cats, and cats with late-onset deafness. Cats were deafened shortly after hearing onset or in adulthood. Cerebral cytoarchitecture was revealed immunohistochemically using SMI-32, a monoclonal antibody used to distinguish auditory areas in many species. Auditory areas were delineated in coronal sections and their volumes measured. Staining profiles observed in hearing cats were conserved in early- and late-deaf cats. In all deaf cats, dorsal auditory areas were the most mutable. Early-deaf cats showed further modifications, with significant expansions in second auditory cortex and ventral auditory field. Borders between dorsal auditory areas and adjacent visual and somatosensory areas were shifted ventrally, suggesting expanded visual and somatosensory cortical representation. Overall, this study shows the influence of acoustic experience in cortical development, and suggests that the age of auditory deprivation may significantly affect auditory areal cartography.

Amplified extrastriate visual cortical projections to the dorsal zone of auditory cortex following early- and late-onset deafness

Adaptive cross-modal plasticity refers to cortical reorganization that takes place across sensory modalities following the loss of a sensory system. This loss of one modality is often accompanied by a heightening of the remaining senses (Bavelier and Neville, 2002). Cat auditory cortex has been shown to undergo cross-modal reorganization following deafness, such that deaf animals are better able to detect visual motion than hearing controls, an advantage which can be localized to the dorsal zone (DZ) of auditory cortex (Lomber et al., 2010). However, because the structural adaptations that might subserve this plasticity remain largely unknown, the purpose of the present investigation was to examine modifications in anatomical connectivity following early- or late-onset deafness. We injected DZ of hearing, early- and late-deafened cats ( n = 5 per group) with biotinylated dextran amine (BDA). Immunohistochemistry was performed following perfusion to reveal the tracer. Overall, the pattern of cortical projections to DZ was similar in both early- and late-deafened cats and hearing controls. However, an increase in projection strength from visual areas involved in visual motion processing was observed in both early- and late-deafened animals compared to hearing controls. Our observations suggest that amplified cortical projections from visual motion processing regions to DZ may underlie the cross-modal reorganization that functionally manifests as superior visual motion detection abilities in the deaf animal. Furthermore, the degree to which this reorganization occurs is similar between early- and late-deafened animals, suggesting that structural compensations can occur regardless of duration of acoustic experience.

Identifying deafness in early childhood: requirements after the newborn hearing screen

BackgroundNewborn hearing screening has been nationally implemented, but longitudinal cohort follow-up is required to inform Children's Hearing Services of the requirements for postneonatal care pathways.MethodsA 10-year cohort of 35 668...

Investigation of the child with permanent hearing impairment

In England the birth prevalence of bilateral per manent childhood hearing impairment (PCHI) of >40 dB HL is approximately 1:1000 live births but almost doubles up to the age of...

Quiet as a mouse: dissecting the molecular and genetic basis of hearing

Mouse genetics has made crucial contributions to the understanding of the molecular mechanisms of hearing. With the help of a plethora of mouse mutants, many of the key genes that are involved in the development and functioning of the auditory system have been elucidated. Mouse mutants continue to shed light on the genetic and physiological bases of human hearing impairment, including both early- and late-onset deafness. A combination of genetic and physiological studies of mouse mutant lines, allied to investigations into the protein networks of the stereocilia bundle in the inner ear, are identifying key complexes that are crucial for auditory function and for providing profound insights into the underlying causes of hearing loss.

Novel syndrome of cataracts, retinitis pigmentosa, late onset deafness and sperm abnormalities: A new Usher syndrome subtype with X‐linked inheritance?

Tissues of the auditory, ocular and reproductive systems have some similarities in their protein families and structures. Consequently, syndromes comprising these systems are described. Hearing loss alone is a component of more than 400 known syndromes and is a common nonsyndromic congenital disorder. Here we describe a syndrome in five brothers with the distinctive presentation of late-onset progressive hearing loss, cataracts, retinitis pigmentosa, sperm motility and shape problems in a family from the Kurdish population in Iran. The clinical findings of these patients are presented in detail and compared to the classical Usher syndromes.