Onset Of Deafness Research Articles

Angular Electrode Insertion Depth and Speech Perception in Adults With a Cochlear Implant: A Systematic Review.

Objective:By discussing the design, findings, strengths, and weaknesses of available studies investigating the influence of angular insertion depth on speech perception, we intend to summarize the current status of evidence; and using evidence based conclusions, possibly contribute to the determination of the optimal cochlear implant (CI) electrode position.Data Sources:Our search strategy yielded 10,877 papers. PubMed, Ovid EMBASE, Web of Science, and the Cochrane Library were searched up to June 1, 2018. Both keywords and free-text terms, related to patient population, predictive factor, and outcome measurements were used. There were no restrictions in languages or year of publication.Study Selection:Seven articles were included in this systematic review. Articles eligible for inclusion: (a) investigated cochlear implantation of any CI system in adults with post-lingual onset of deafness and normal cochlear anatomy; (b) investigated the relationship between angular insertion depth and speech perception; (c) measured angular insertion depth on imaging; and (d) measured speech perception at, or beyond 1-year post-activation.Data Extraction and Synthesis:In included studies; quality was judged low-to-moderate and risk of bias, evaluated using a Quality-in-Prognostic-Studies-tool (QUIPS), was high. Included studies were too heterogeneous to perform meta-analyses, therefore, effect estimates of the individual studies are presented. Six out of seven included studies found no effect of angular insertion depth on speech perception.Conclusion:All included studies are characterized by methodological flaws, and therefore, evidence-based conclusions regarding the influence of angular insertion depth cannot be drawn to date.

Novel Usher syndrome pathogenic variants identified in cases with hearing and vision loss

BackgroundUsher syndrome, the most common form of inherited deaf-blindness, is unlike many other forms of syndromic hereditary hearing loss in that the extra aural clinical manifestations are also detrimental to communication. Usher syndrome patients with early onset deafness also experience vision loss due to progressive retinitis pigmentosa that can lead to legal blindness in their third or fourth decade.MethodsUsing a multi-omic approach, we identified three novel pathogenic variants in two Usher syndrome genes (USH2A and ADGRV1) in cases initially referred for isolated vision or hearing loss.ResultsIn a multiplex hearing loss family, two affected sisters, the product of a second cousin union, are homozygous for a novel nonsense pathogenic variant in ADGRV1 (c.17062C > T, p.Arg5688*), predicted to create a premature stop codon near the N-terminus of ADGRV1. Ophthalmological examination of the sisters confirmed typical retinitis pigmentosa and prompted a corrected Usher syndrome diagnosis. In an unrelated clinical case, a child with hearing loss tested positive for two novel USH2A splicing variants (c.5777-1G > A, p. Glu1926_Ala1952del and c.10388-2A > G, p.Asp3463Alafs*6) and RNA studies confirmed that both pathogenic variants cause splicing errors. Interestingly, these same USH2A variants are also identified in another family with vision loss where subsequent clinical follow-up confirmed pre-existing hearing loss since early childhood, eventually resulting in a reassigned diagnosis of Usher syndrome.ConclusionThese findings provide empirical evidence to increase Usher syndrome surveillance of at-risk children. Given that novel antisense oligonucleotide therapies have been shown to rescue retinal degeneration caused by USH2A splicing pathogenic variants, these solved USH2A patients may now be eligible to be enrolled in therapeutic trials.

Brain Plasticity Can Predict the Cochlear Implant Outcome in Adult-Onset Deafness.

Sensory plasticity, which is associated with deafness, has not been as thoroughly investigated in the adult brain as it has in the developing brain. In this study, we examined the brain reorganization induced by auditory deprivation in people with adult-onset deafness and its clinical relevance by measuring glucose metabolism before cochlear implant (CI) surgery. F-18 fluorodeoxyglucose positron emission tomography (18F-FDG-PET) scans were performed in 37 postlingually deafened patients during the preoperative workup period, and in 39 normal-hearing (NH) controls. Behavioral CI outcomes were measured at 1 year after implantation using a phoneme identification test with auditory cueing only. In the deaf individuals, areas involved in the auditory pathway such as the inferior colliculus and bilateral superior temporal gyri were hypometabolic compared to the NH controls. The hypometabolism observed in the deaf auditory cortices gradually returned to levels similar to the controls as the duration of deafness increased. However, contrary to our previous findings in congenitally deaf children, this metabolic recovery failed to have a significant prognostic value for the recovery of the speech perception ability in adult CI patients. In a broad occipital area centered on the primary visual cortices, glucose metabolism was higher in the deaf patients than the controls, suggesting that the area had become visually hyperactive for sensory compensation immediately after the onset of deafness. In addition, a negative correlation between the metabolic activity and behavioral speech perception outcomes was observed in the visual association areas. In the medial frontal cortices, cortical metabolism in most patients decreased, but patients who had preserved metabolic activities showed better speech performance. These results suggest that the auditory cortex in people with adult-onset deafness is relatively resistant to cross-modal plasticity, and instead, individual traits in late-stage visual processing and cognitive control seem to be more reliable prognostic markers for adult-onset deafness.

ВЕЛИКИЕ ЛЮДИ, СТРАДАЮЩИЕ ЗАБОЛЕВАНИЯМИ УХА. ПРИОБРЕТЕННАЯ АКУСТИЧЕСКАЯ СЕНСОРНАЯ ДЕПРИВАЦИЯ И СПОСОБНОСТИ ЛЮДЕЙ ЧАСТЬ 1.Б. ВЕЛИКИЕ КОМПОЗИТОРЫ

Auditory sensory deprivation is a phenomenon characterized by a significant decrease or complete subsidence in sending external sound information through the organ of hearing to the human brain. Various infectious diseases, vascular pathology, genetic abnormalities, and intoxication conditions may lead to various diseases of the ear and, as a consequence, to hearing loss or deafness. The second part of the paper covers the biographical data of such composers as Agathe Backer Grøndahl, Aleksandr A. Kasyanov, Evelyn Elizabeth Ann Glennie. The paper assesses the development of auditory sensory deprivation with the onset of deafness and shows the influence of auditory sensory deprivation and the psychological state of composers on the results of their creative activity. The author compares the internal crisis, mental destabilization, and the lack of sound perception with the effective implementation of musical experience, which allowed the composers to create great musical works, despite their pathological condition. In addition, the paper points out the possibility to continue effective creative activity and give live musical performances due to the sense of ‘feeling’ the vibrations and the ability to develop and use it in a proper way (Evelyn Glennie). Synesthetic perception is revealed through the given work.

Masking in pure tone audiometry

Hearing testing is particularly important both as a me­thod of prevention (auditory screening) and as a me­thod of diag­nosing hearing loss and monitoring it. Determining the type of hearing loss, conductive, sen­so­ri­neu­ral or mixed is es­sen­tial in recommending the ap­pro­pria­te treatment for each patient. In addition, the sudden hearing loss must be au­dio­lo­gi­cal­ly diagnosed within the first 72 hours, given the me­di­cal urgency of the sudden onset of deafness. Masking is an audiometric me­thod essential in differentiating these types of hearing loss. It is a difficult to perform technique, which requires in­tense practice of the audiologist or audiometrist, un­der­stan­ding of the physiology of the auditory system and permanent observation of the tested patient.

Cochlear implantation in patients with ossified cochleas.

The timing of CI for postmeningitic deafness is controversial and differential outcomes have been reported. To review and share our surgical and auditory outcomes. 17 patients with ossified cochleas who received CI were enrolled. Clinical data including the cause of cochlear ossification, preoperative examination, onset of deafness, age at implantation, surgical findings, and relevant auditory outcomes was analysed. Cochlear ossification was observed in 53% of patients with HRCT, whereas the corresponding value for MRI was 59%. Patients in both stage I and II received complete insertion of the electrode array, however, stage III patients only received partial insertion. 1 patient in stage II received bilateral CI. Hearing tests showed increased average hearing threshold for stage III patients than those in stage I and II (P < 0.05). CAP scores were much lower for stage III patients than those in stage I and II (P < 0.05). Postlingual deafness patients showed higher SIR scores than prelingual deafness children (P < 0.05). HRCT and MRI have comparable value in predicting the occurrence of ossification in cochleas. We recommend fast surgical intervention in the patients with bilateral profound postmeningitic deafness. If possible, bilateral cochlear implantation is recommended.

Irrefutable arguments: Teresa de Cartagena defends her right to authorship

Teresa de Cartagena wrote a masterful text of consolation for all who suffer illness or impairment entitled Arboleda de los enfermos [Grove of the Infirm] in which she recounts her spiritual response to the onset of deafness. The work was maligned, not for its content, but rather because detractors refused to believe that Arboleda could have been penned by a woman, especially one who suffered from a physical impairment. Teresa responded to those who doubted her authorship by writing a second text, Admiraçión operum Dey [Wonder at the Works of God]. She felt compelled to respond to her critics in order to assert a single, and irrefutable, truth: God gave her the ability to write Arboleda, and, since anything is possible for God, to deny her authorship is tantamount to denying the omnipotence of God. She declares that any reader who doubts her authorship does not believe that God is capable of miraculous deeds. She argues that it is rare for a woman to write but certainly not impossible if God so wills it. This article explores how Teresa constructs and builds what, on the surface, appears to be a simple, in not outright indisputable, tenet of Christian doctrine, i.e., God’s unlimited and inscrutable power.

The Relationship Between Spectral Modulation Detection and Speech Recognition: Adult Versus Pediatric Cochlear Implant Recipients.

Adult cochlear implant (CI) recipients demonstrate a reliable relationship between spectral modulation detection and speech understanding. Prior studies documenting this relationship have focused on postlingually deafened adult CI recipients—leaving an open question regarding the relationship between spectral resolution and speech understanding for adults and children with prelingual onset of deafness. Here, we report CI performance on the measures of speech recognition and spectral modulation detection for 578 CI recipients including 477 postlingual adults, 65 prelingual adults, and 36 prelingual pediatric CI users. The results demonstrated a significant correlation between spectral modulation detection and various measures of speech understanding for 542 adult CI recipients. For 36 pediatric CI recipients, however, there was no significant correlation between spectral modulation detection and speech understanding in quiet or in noise nor was spectral modulation detection significantly correlated with listener age or age at implantation. These findings suggest that pediatric CI recipients might not depend upon spectral resolution for speech understanding in the same manner as adult CI recipients. It is possible that pediatric CI users are making use of different cues, such as those contained within the temporal envelope, to achieve high levels of speech understanding. Further investigation is warranted to investigate the relationship between spectral and temporal resolution and speech recognition to describe the underlying mechanisms driving peripheral auditory processing in pediatric CI users.

Contralateral Interference Caused by Binaurally Presented Competing Speech in Adult Bilateral Cochlear-Implant Users

Bilateral cochlear implants (BI-CIs) are intended to improve sound localization and speech understanding in the presence of interfering sounds. For normal-hearing listeners, improved speech understanding in the presence of interfering sounds can be achieved with monaural head shadow and binaural unmasking. While some BI-CI listeners experience binaural unmasking under certain testing conditions, others appear to not. This study tested a group of BI-CI users with hearing histories that have been linked to poor binaural processing-early onset of deafness or long duration of deafness in just one ear. We predicted that these listeners would experience the opposite of binaural unmasking (i.e., contralateral interference) when trying to understand speech in the presence of a competing talker. Nine adult BI-CI users who were deafened early in life or had an asymmetric hearing history (e.g., a much longer duration of deafness in one ear) participated in this study. The coordinate response measure corpus was used to assess speech understanding for a male target talker in quiet or in the presence of one male competing talker. Experiment 1 measured binaural unmasking in a paradigm that provided no head-shadow component. The target was always presented monaurally, while the interferer was presented either monaurally or diotically. Experiment 2 measured spatial release from masking in a paradigm that included both a head-shadow component and possible binaural-unmasking component. Nonindividualized head-related transfer functions were used to simulate talker locations in the front or 90° to the left or right. In experiment 1, all nine listeners experienced contralateral interference (9 dB on average). Four listeners demonstrated roughly symmetric contralateral interference; five listeners experienced asymmetrical contralateral interference. In experiment 2, the listeners experienced only 1 dB of spatial release from masking on average; this small amount was possibly a result of the contralateral interference observed in experiment 1. The results were best explained by individual differences in speech understanding in quiet, which significantly correlated with the duration of deafness in the ipsilateral ear. Specifically, instances of asymmetrical contralateral interference could correspond to asymmetrical hearing histories. Bilateral cochlear implantation should provide a hearing benefit to the recipient. For the BI-CI listeners specifically recruited for this study, there seems to be a conflict with processing the auditory information across the two ears, which produced the opposite of the desired hearing benefit. This suggests that there may be a subset of potential BI-CI users for whom contralateral interference offsets much of the potential head-shadow benefit. If so, earlier implantation in the second implanted ear might have produced larger binaural benefits, which is important information for clinicians advising patients considering bilateral implantation.

Cortical and thalamic connectivity to the second auditory cortex of the cat is resilient to the onset of deafness.

It has been well established that following sensory loss, cortical areas that would normally be involved in perceiving stimuli in the absent modality are recruited to subserve the remaining senses. Despite this compensatory functional reorganization, there is little evidence to date for any substantial change in the patterns of anatomical connectivity between sensory cortices. However, while many auditory areas are contracted in the deaf, the second auditory cortex (A2) of the cat undergoes a volumetric expansion following hearing loss, suggesting this cortical area may demonstrate a region-specific pattern of structural reorganization. To address this hypothesis, and to complement existing literature on connectivity within auditory cortex, we injected a retrograde neuronal tracer across the breadth and cortical thickness of A2 to provide the first comprehensive quantification of projections from cortical and thalamic auditory and non-auditory regions to the second auditory cortex, and to determine how these patterns are affected by the onset of deafness. Neural projections arising from auditory, visual, somatomotor, and limbic cortices, as well as thalamic nuclei, were compared across normal hearing, early-deaf, and late-deaf animals. The results demonstrate that, despite previously identified changes in A2 volume, the pattern of projections into this cortical region are unaffected by the onset of hearing loss. These results fail to support the idea that crossmodal plasticity reflects changes in the pattern of projections between cortical regions and provides evidence that the pattern of connectivity that supports normal hearing is retained in the deaf brain.

Congenital deafness is associated with specific somatosensory deficits in adolescents

Hearing and touch represent two distinct sensory systems that both rely on the transformation of mechanical force into electrical signals. Here we used a battery of quantitative sensory tests to probe touch, thermal and pain sensitivity in a young control population (14–20 years old) compared to age-matched individuals with congenital hearing loss. Sensory testing was performed on the dominant hand of 111 individuals with normal hearing and 36 with congenital hearing loss. Subjects with congenital deafness were characterized by significantly higher vibration detection thresholds at 10 Hz (2-fold increase, P < 0.001) and 125 Hz (P < 0.05) compared to controls. These sensory changes were not accompanied by any major change in measures of pain perception. We also observed a highly significant reduction (30% compared to controls p < 0.001) in the ability of hearing impaired individual’s ability to detect cooling which was not accompanied by changes in warm detection. At least 60% of children with non-syndromic hearing loss showed very significant loss of vibration detection ability (at 10 Hz) compared to age-matched controls. We thus propose that many pathogenic mutations that cause childhood onset deafness may also play a role in the development or functional maintenance of somatic mechanoreceptors.

The Change in Electrical Stimulation Levels During 24 Months Postimplantation for a Large Cohort of Adults Using the Nucleus® Cochlear Implant.

To examine electrical stimulation data over 24 months postimplantation in adult implant users. The first aim was to calculate mean T and C levels for seven time points, for four cochlear segments, and two array types. The second aim was to (a) analyze the degree of change in each of the T and C levels as a function of dynamic range for six consecutive time point comparisons, for the four segments, and (b) to determine the proportion of participants with an acceptable degree of change. The third aim was to examine relationships between demographic factors and degree of change. T levels, C levels, and dynamic ranges were extracted for 680 adults using Nucleus implants for the following postimplant time points: 2-, 3-, 6-, 9-, 12-, 18-, and 24-month. For each time point, mean levels were calculated for the four segments. The degree of change in each of the levels was analyzed for six consecutive time point comparisons. The criterion for an acceptable degree of change was ≤20% of DR. Mean T level was significantly lower for the 2-month time point compared with all time points after the 3-month time point. Mean C level was significantly lower for the 2- and 3-month time points compared with all other time points. Mean T level was significantly lower for the apical compared with all other segments and for the lower-basal compared with the upper-basal segment. Mean C level was significantly different across all four segments. Mean C level for the basal segments was 4 CLs higher for the perimodiolar array compared with the straight array. No significant differences were evident for the mean degree of change between consecutive time point comparisons. For all segments, approximately 65 to 75% of the participants showed an average acceptable degree of change in levels from the 3- to 6-month comparison. The mean degree of change in T levels was significantly greater for the basal segments compared with all other segments. The mean degree of change in levels was significantly greater for the otosclerosis group compared with all other groups, and for the prelingual onset of deafness group compared with the postlingual group. Given the very large cohort, this study provides evidence for the mean levels and the degree of change in these levels that should be expected for four segments in the first 24 months postimplantation for adults using Nucleus implants. The mean T and C levels were consistent after the 3- and 6-month time points postimplant, respectively. The degree of change was variable between individuals. For each segment, however, a large percentage of participants showed an average change of ≤20% in each of the T and C levels from the 3- to 6-month comparison. Given the large degree of change in levels for some groups, the results provide strong evidence in favor of frequent monitoring of levels in the first 24 months postimplantation for patients with otosclerosis, prelingual onset of deafness, and those who exhibit >20% change in levels after 3 months postimplantation.

Speechreading in Deaf Adults with Cochlear Implants: Evidence for Perceptual Compensation.

Previous research has provided evidence for a speechreading advantage in congenitally deaf adults compared to hearing adults. A ‘perceptual compensation’ account of this finding proposes that prolonged early onset deafness leads to a greater reliance on visual, as opposed to auditory, information when perceiving speech which in turn results in superior visual speech perception skills in deaf adults. In the current study we tested whether previous demonstrations of a speechreading advantage for profoundly congenitally deaf adults with hearing aids, or no amplificiation, were also apparent in adults with the same deafness profile but who have experienced greater access to the auditory elements of speech via a cochlear implant (CI). We also tested the prediction that, in line with the perceptual compensation account, receiving a CI at a later age is associated with superior speechreading skills due to later implanted individuals having experienced greater dependence on visual speech information. We designed a speechreading task in which participants viewed silent videos of 123 single words spoken by a model and were required to indicate which word they thought had been said via a free text response. We compared congenitally deaf adults who had received CIs in childhood or adolescence (N = 15) with a comparison group of hearing adults (N = 15) matched on age and education level. The adults with CI showed significantly better scores on the speechreading task than the hearing comparison group. Furthermore, within the group of adults with CI, there was a significant positive correlation between age at implantation and speechreading performance; earlier implantation was associated with lower speechreading scores. These results are both consistent with the hypothesis of perceptual compensation in the domain of speech perception, indicating that more prolonged dependence on visual speech information in speech perception may lead to improvements in the perception of visual speech. In addition our study provides metrics of the ‘speechreadability’ of 123 words produced in British English: one derived from hearing adults (N = 61) and one from deaf adults with CI (N = 15). Evidence for the validity of these ‘speechreadability’ metrics come from correlations with visual lexical competition data.

Results of Speech Audiometry Testing in Case of Transcranial CROS Depend on Duration of Deafness

In single sided deafness, treatment with transcranial CROS makes pseudo stereophonic listening possible. This leads to improved speech understanding in noise. However, several reports show large variations between the individual results of the benefit by speech audiometry in noise. One possible factor is the duration and changes in the auditory pathway between the onset of deafness to CROS supply. 18 patients with single sided deafness have tested a transcranial CROS supply. The speech intelligibility thresholds were evaluated in 2 spatial hearing situations each with CROS and unaided. When speech was arriving at 45° from the deaf ear and noise at 45° from the hearing ear, a significant improvement of speech reception threshold for 50% intelligibility was detected by CROS supply compared the medians. Patients with longer duration of deafness showed higher benefit by an average of -4.0 dB, in contrast to patients with short duration of deafness. In the reversed situation, that speech on the hearing ear and noise on the deaf ear was a significant deterioration observed, an average of 3.1 dB at longer deafened patients. In addition, a highly significant correlation was found with the individual changes in the speech recognition threshold between the two situations. The duration of deafness is an essential factor in the individual benefit estimate for treatment with transcranial CROS supply. The time frame for audimetrically proven changes in the auditory pathway as a result of unilateral auditory deprivation can be estimated to about 1-3 years. Patients with short duration of deafness have low or no benefit from transcranial CROS supply.

For some bilateral cochlear implantees, a second implant can cause interference rather than improved speech understanding in the presence of competing speech

The goal of bilateral cochlear implantation is to provide binaural-processing benefits, such as improved sound localization and speech understanding in background noise. A recent study [Bernstein et al., Ear Hear. 37, 282-288] showed that bilateral cochlear-implant (BICI) listeners could receive up to 5 dB of binaural speech-understanding benefit when listening with two ears compared to one. However, one outlier demonstrated interference rather than improvement from the second ear, which warranted further investigation. We recruited nine BICI listeners with pre- or peri-lingual onset of deafness and/or a long duration of deafness in at least one ear. We hypothesized these listeners might also demonstrate interference in binaural speech understanding. They listened to a male target and a male interferer, both taken from the Coordinate Response Measure corpus, in monaural (target and interferer in one ear) and binaural (monaural target, diotic interferer) listening configurations. On average, listeners received 9 dB of interference from their second ear. For listeners with a much longer duration of deafness in one ear, interference patterns were asymmetrical (little interference in the first implanted ear, extreme interference in the second). These data demonstrate that certain spatial listening configurations may hinder the advantages of bilateral implants for some users.

Attitudes toward carrier screening and prenatal diagnosis for recessive hereditary deafness among the educated population in urban China.

Approximately 80% of hereditary deafness is recessive, in which case most mutation carriers were unaware of their carrier status. Though parental attitudes toward genetic testing and prenatal diagnosis are overall positive in those with deaf children, there is little information about that in the general population. To this end, we designed a self-completed questionnaire and distributed it in two colleges in Shanghai, China. A total of 975 completed surveys were returned in print or online forms. Our results showed that 98.7% of the respondents without family history of early onset deafness did not know or underestimated their likelihood to carry a recessive mutation in common deafness genes. After brief written information was given using GJB2, the most common recessive deafness gene as the example, 67.7% of the respondents expressed interest in knowing if they are carriers of GJB2 mutations through genetic testing. In hypothetical circumstance of carrying a recessive GJB2 mutation, 86.9% would suggest their partners to also take the test. In case that both were carriers, 88.7% would consider prenatal diagnosis and 80.7% would consider terminating an affected pregnancy. On the basis of these results, it was concluded that despite the poor awareness to the risk of recessive hereditary deafness, the majority of the educated population in urban China likely hold a positive view toward carrier screening and prenatal diagnosis of recessive deafness genes. © 2016 Wiley Periodicals, Inc.

A Case of Wolfram Syndrome Presenting with Restlessness

Wolfram Syndrome ( DIDMOAD) is a rare genetic disorder presenting with Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, Deafness and some other neurological , reproductive , hormonal, urological and psychic problems. About 200 cases have been reported so far. Here we present a 25 years old Bangladeshi male having early onset Diabetes Mellitus, optic atrophy, deafness and many other features consistent with Wolfram Syndrome. We examined the patient thoroughly and did necessary investigations to confirm our diagnosis. As there is no cure of this disorder, we gave symptomatic and supportive treatment to the patient to make his life easier. Although the outcome is unrewarding , such patients will be kept in regular follow up for early detection of new complications and possible solutions.J Bangladesh Coll Phys Surg 2016; 34(1): 42-44

Identification of a novel WFS1 homozygous nonsense mutation in Jordanian children with Wolfram syndrome

Wolfram syndrome (WS) is a rare autosomal recessive neurodegenerative disorder characterized by the presentation of early onset type I diabetes mellitus and optic atrophy with later onset diabetes insipidus and deafness. WFS1 gene was identified on chromosome 4p16.1 as the gene responsible for WS disease given that most of the WS patients were found to carry mutations in this gene. This study was carried out to investigate the molecular spectrum of WFS1 gene in Jordanian families. Molecular and clinical characterization was performed on five WS patients from two unrelated Jordanian families. Our data indicated that WS patients of the first family harbored two deletion mutations (V415del and F247fs) located in exon 8 and exon 7 respectively, with a compound heterozygous pattern of inheritance; while in the second family, we identified a novel nonsense mutation (W185X) located in exon 5 in the N-terminal cytoplasmic domain with a homozygous pattern of inheritance. This mutation can be considered as loss of function mutation since the resulting truncated protein lost both the transmembrane domain and the C-terminal domain. Additionally, the W185X mutation lies within the CaM binding domain in wolframin protein which is thought to have a role in the regulation of wolframin function in response to calcium levels.

Genetic and clinical analysis of nonsyndromic hearing impairment in pediatric and adult cases

Previous studies have linked GJB2 gene and mitochondrial DNA (mtDNA) mutations to nonsyndromic hearing impairment (NSHI), but no study in China has yet investigated these mutations across all age groups. To fill the gap, this study ascertained 263 patients with NSHI between ages 2 months and 60 years and analyzed the presence of GJB2 gene and mtDNA A1555G/C1494T mutations by polymerase chain reaction (PCR) and DNA sequencing. A total of 20 types of mutations were detected for the GJB2 gene. The GJB2 gene and mtDNA A1555G/C1494T mutations were detected in 18.63 and 11.41% cases, respectively. At the first hospital visit, GJB2 gene mutations were detected in 5.97% of adult patients (>18 years) and 22.96% pediatric patients (<18 years) (χ2 =9.506, p = 0.002), and mtDNA A1555G/C1494T mutations were detected in 31.34% of adult patients and 4.59% of pediatric patients (χ2 = 35.359, p <0.001). When patients were classified by age at onset of deafness, significantly more (20.68%) pediatric patients had GJB2 gene mutations than did adult patients (0.0%) (χ2 = 4.685; p = 0.006). Mitochondrial DNA A1555G/C1494T mutations were detected in 15.38% of adult-onset and 8.86% pediatric-onset patients, respectively. Interestingly, most GJB2 gene mutation carriers experienced NSHI onset within the first year of life (65.31%), while mtDNA A1555G/C1494T mutation carriers experienced onset at any age. Therefore, GJB2 gene mutations appear to contribute to congenital deafness, while mtDNAA1555G/C1494T mutations contribute mainly to acquired deafness in Chinese individuals. Both newborn hearing screening and genetic testing are important to diagnose and treat deafness.

The HI HOPES data set of deaf children under the age of 6 in South Africa: maternal suspicion, age of identification and newborn hearing screening.

BackgroundIdentification of deafness before 3 months of age substantially improves the socio-linguistic and cognitive development of deaf children. Existing studies demonstrating the feasibility of newborn hearing screening in South Africa have used small samples unrepresentative of general population characteristics. This study establishes the characteristics of the largest data set of deaf infants and their families in South Africa on which there is baseline and longitudinal data (n = 532); explores its representativeness in terms of socio-demographic features and reports on access to and quality of newborn hearing screening within the sample. It examines specifically the relationship between age of maternal suspicion of childhood deafness and age of identification of deafness by cohort characteristics.MethodsSecondary analysis, using descriptive and inferential statistics, of a pre-existing longitudinal data set (n = 532) of deaf infants under 6 years of age, and their families, collected as routine monitoring of the HI HOPES (HH) early intervention programme.ResultsThe HH cohort is representative in terms of racial profile and private/public health care use but displays slightly higher level of maternal education and slightly lower socio-economic status than national comparators. 102 out of 532 infants had undergone newborn hearing screening, resulting in 29 true positives, 15 of whom would have met the criteria for targeted screening. Later onset deafness does not account for the 73 false negatives. The median age of maternal suspicion (n = 247) of infant deafness was 18 months; the median age of identification of 28 months. Age of identification was unrelated to private/public health care status. The median delay between age of suspicion and age of identification was significantly longer in the public sector (7 m; IQR 0–15 m) compared to the private sector (2 m; IQR 0–8.5 m) (p = 0.035). Age of suspicion was unrelated to level of maternal education. Earlier age of suspicion did not predict earlier identification.ConclusionTargeted screening as timely response to maternal suspicion offers a viable means to reduce substantially the age of identification of deafness in South Africa until implementation of newborn hearing screening on a population-wide basis can be justified.