Training for hearing care providers.

The lack of an appropriately trained global hearing-care workforce is recognized as a barrier to developing and implementing services to treat ear and hearing disorders. In this article we examine some of the published literature on the current global workforce for ear and hearing care. We outline the status of both the primary-care workforce, including community health workers, and specialist services, including audiologists, ear, nose and throat specialists, speech and language therapists, and teachers of the deaf. We discuss models of training health workers in ear and hearing care, including the role of task-sharing and the challenges of training in low and middle-income countries. We structure the article by the components of ear and hearing care that may be delivered in isolation or in integrated models of care: primary care assessment and intervention; screening; hearing tests; hearing rehabilitation; middle-ear surgery; deaf services; and cochlear implant programmes. We highlight important knowledge gaps and areas for future research and reporting.

Le manque de prestataires de soins auditifs adéquatement formés à l'échelle mondiale est considéré comme un obstacle au développement et à la mise en œuvre de services destinés à traiter les troubles de l'oreille et de l'audition. Dans cet article, nous examinons des documents publiés au sujet de la main-d'œuvre mondiale actuelle au service des soins de l'oreille et de l'audition. Nous présentons l'état de la main-d'œuvre au service des soins primaires, et notamment des agents de santé communautaires, ainsi que l'état des services de spécialistes, et notamment des audiologistes, des spécialistes ORL, des thérapeutes de la parole et du langage et des enseignants pour les personnes sourdes. Nous étudions des modèles de formation des agents de santé axés sur les soins de l'oreille et de l'audition, et en particulier sur le rôle du partage des tâches et les problèmes liés à la formation dans les pays à revenu faible et intermédiaire. Cet article s'articule autour des différents aspects des soins de l'oreille et de l'audition, qui peuvent être fournis isolément ou dans le cadre de modèles intégrés de soins: évaluation des soins primaires et intervention; dépistage; examens auditifs; réhabilitation auditive; chirurgie de l'oreille moyenne; services pour les personnes sourdes; et programmes d'implantation cochléaire. Nous attirons l'attention sur d'importantes lacunes et sur les domaines sur lesquels pourraient porter les recherches et les rapports à l'avenir.

Se reconoce que la falta de trabajadores especializados en el cuidado de la salud auditiva a nivel mundial constituye un obstáculo para el desarrollo y la implementación de servicios de tratamiento de los trastornos auditivos y del oído. En este artículo examinamos parte de la literatura publicada sobre los trabajadores que actualmente se dedican al cuidado de la salud auditiva y del oído en todo el mundo. Describimos la situación de los trabajadores de atención primaria, incluidos los trabajadores sanitarios de la comunidad, y de los servicios especializados, incluidos los audiólogos, los especialistas en oído, nariz y garganta, los terapeutas del habla y del lenguaje, y los profesores de las personas sordas. Discutimos los modelos de formación de los trabajadores sanitarios en el cuidado de la salud auditiva y del oído y de la, incluyendo la función de la asignación de tareas y los retos de la formación en los países de ingresos bajos y medios. Estructuramos el artículo por los componentes del cuidado de la salud auditiva y del oído que se pueden prestar de forma aislada o en modelos integrados de atención: evaluación e intervención de la atención primaria; exámenes; pruebas de audición; rehabilitación de la audición; cirugía de oído medio; servicios para las personas sordas; y programas de implantes cocleares. Destacamos importantes lagunas de conocimiento y áreas para la investigación y presentación de informes en el futuro.

Newborn and Infant Hearing Screening Facing Globally Growing Numbers of People Suffering from Disabling Hearing Loss.

Recent prevalence estimates indicate that in 2015 almost half a billion people-about 6.8% of the world's population-had disabling hearing loss and that prevalence numbers will further increase. The World Health Organization (WHO) currently estimates that at least 34 million children under the age of 15 have disabling hearing loss. Based on a 2012 WHO report, approximately 7.5 million of these children were under the age of 5 years. This review article focuses on the importance of high-quality newborn and infant hearing screening (NIHS) programs as one strategy to ameliorate disabling hearing loss as a global health problem. Two WHO resolutions regarding the prevention of deafness and hearing loss have been adopted urging member states to implement screening programs for early identification of ear diseases and hearing loss in babies and young children. The effectiveness of these programs depends on factors such as governmental mandates and guidance; presence of a national committee with involvement of professionals, industries, and stakeholders; central oversight of hearing screening; clear definition of target parameters; presence of tracking systems with bi-directional data transfer from screening devices to screening centers; accessibility of pediatric audiological services and rehabilitation programs; using telemedicine where connectivity is available; and the opportunity for case discussions in professional excellence circles with boards of experts. There is a lack of such programs in middle- and low-income countries, but even in high-income countries there is potential for improvement. Facing the still growing burden of disabling hearing loss around the world, there is a need to invest in national, high-quality NIHS programs.

Maternally transmitted aminoglycoside-induced and non-syndromic hearing loss caused by the 1494C > T mutation in the mitochondrial 12S rRNA gene in two Chinese families.

OBJECTIVE: To explore the molecular genetic characterization of two Chinese families with aminoglycoside-induced and non-syndromic hearing loss (NSHL). DESIGN: Clinical evaluations, sequence analysis of mitochondrial DNA (mtDNA) as well as two nuclear genes TRMU and MTO1 encoding mitochondrial proteins. STUDY SAMPLE: Two Chinese families with aminoglycoside-induced and NSHL. RESULTS: Clinical evaluations revealed incomplete penetrance (28.6% vs. 40.0%) and variable phenotype of hearing losses between two families. When the effect of aminoglycosides was excluded, the penetrances were both 0%. Sequence analysis of mitochondrial genomes showed a homoplasmic 1494C > T mutation in the12S rRNA gene (MT-RNR1) in all maternal relatives, as well as distinct sets of mtDNA polymorphism belonging to Eastern Asian haplogroups D4j and D5a2, respectively. However, none of these mtDNA variants was highly evolutionarily conserved and implicated to have functional significance. No mutations were identified in either TRMU or MTO1 gene. CONCLUSIONS: Mitochondrial 1494C> T mutation is the molecular basis responsible for the NSHL of two families, and the use of aminoglycoside antibiotics can worsen the hearing of the mutation carriers. Our results indicate the importance of a systematic screening for the mitochondrial 1494C > T mutation in Chinese subjects in the prevention of aminoglycoside-induced and non-syndromic hearing loss.

Unilateral auditory neuropathy caused by cochlear nerve deficiency.

Objective. To explore possible corelationship between the cochlear nerve deficiency (CND) and unilateral auditory neuropathy (AN). Methods. From a database of 85 patients with unilateral profound sensorineural hearing loss, eight who presented with evoked otoacoustic emissions (EOAEs) or cochlear microphonic (CM) in the affected ear were diagnosed with unilateral AN. Audiological and radiological records in eight patients with unilateral AN were retrospectively reviewed. Results. Eight cases were diagnosed as having unilateral AN caused by CND. Seven had type "A" tympanogram with normal EOAE in both ears. The other patient had unilateral type "B" tympanogram and absent OAE but CM recorded, consistent with middle ear effusion in the affected ear. For all the ears involved in the study, auditory brainstem responses (ABRs) were either absent or responded to the maximum output and the neural responses from the cochlea were not revealed when viewed by means of the oblique sagittal MRI on the internal auditory canal. Conclusion. Cochlear nerve deficiency can be seen by electrophysiological evidence and may be a significant cause of unilateral AN. Inclined sagittal MRI of the internal auditory canal is recommended for the diagnosis of this disorder.

An epidemiologic study of tinnitus in a population in Jiangsu Province, China.

BACKGROUND: Tinnitus is a common complaint and often of no clinical significance. There are a number of unresolved issues concerning the etiology, pathogenesis, and natural history of tinnitus. There are a few current population-based estimates of the prevalence of tinnitus done in representative large geographic areas, but there is little data from multi-area, large sample studies of tinnitus in China. PURPOSE: To investigate the prevalence of tinnitus and related factors in a Chinese population. These data would be used to plan and evaluate health-care services. RESEARCH DESIGN: We carried out an epidemiologic study of tinnitus as part of an epidemiologic study of ear and hearing disorders that was undertaken in Jiangsu Province, China. A question about tinnitus history was included in a comprehensive questionnaire about hearing. All participants also had both pure tone audiometry and an otological examination. STUDY SAMPLE: The sample consisted of 6333 people 10 yr of age or older, selected by the methods of probability proportional to size. DATA COLLECTION AND ANALYSIS: All participants answered a questionnaire concerning their tinnitus and had pure tone audiometry testing and an ear examination. All data were entered using EPIDATD 3.0 software and analyzed by a chi-squared test and test for trends. RESULTS: The overall prevalence of tinnitus was 14.5%, and the standardized rates were 11.4% in the whole country and 12.4% in Jiangsu province. Its prevalence increased with age. The prevalence of tinnitus was 11.9 and 15.6% in urban and rural residents, respectively There was no significant difference in prevalence between men and women. Hearing impairment, history of middle ear infections, and noise exposure were the main risk factors for tinnitus. CONCLUSION: Tinnitus is a common problem in the population. With the aging of the population, the prevalence of tinnitus will increase. The prevention of tinnitus should focus on hearing impairment screening, otitis media treatment, and noise exposure reduction. Health services in rural areas should emphasize prevention more.

Molecular screening of patients with nonsyndromic hearing loss from Nanjing city of China.

Hearing loss is the most frequent sensory disorder involving a multitude of factors, and at least 50% of cases are due to genetic etiology. To further characterize the molecular etiology of hearing loss in the Chinese population, we recruited a total of 135 unrelated patients with nonsyndromic sensorineural hearing loss (NSHL) for mutational screening of GJB2, GJB3, GJB6, SLC26A4, SLC26A5 IVS2-2A>G and mitochondrial 12SrRNA, tRNA(Ser(UCN)) by PCR amplification and direct DNA sequencing. The carrier frequencies of deafness-causing mutations in these patients were 35.55% in GJB2, 3.70% in GJB6, 15.56% in SLC26A4 and 8.14% in mitochondrial 12SrRNA, respectively. The results indicate the necessity of genetic screening for mutations of these causative genes in Chinese population with nonsyndromic hearing loss.

[The application of improved CHQS for mass epidemiology study on hearing impairment].

OBJECTIVE: To develop and evaluate the improved Chinese hearing questionnaire for school children (CHQS) for mass epidemiology study on hearing impairment in China. METHOD: Using the probability proportion to size (PPS) method, 8412 residents were investigated in 40 clusters in Jiangsu province with the WHO ear diseases and hearing disorders survey protocol. 87.9% of the residents aged 7 years and over answered the questionnaire and accepted the pure tone audiometry. RESULT: The prevalence of hearing impairment was 12.9% by the questionnaire. Compared with "golden standard" (pure tone audiometry), Sen = 58.5%, Spe = 96.7%, PV+ = 78.9%, PV- = 91.7%, overall accuracy = 90.0%. The sensitivity for women was higher than men. CONCLUSION: The questionnaire produced high efficiency and specificity values. It could be used in mass hearing screening, particularly in remote and rural area, although the sensitivity was as low as most questionnaires.

[Sequence analysis of DFNB59 gene in a Chinese family with dominantly inherited auditory neuropathy].

OBJECTIVE: To investigate if the DFNB59 gene contributes to the hearing loss of a Chinese pedigree with dominantly inherited auditory neuropathy (AN). METHOD: Nine members in four generations of the family were selected for this study. Genomic DNA was isolated from the peripheral leukocytes of the patients using the pure gene DNA isolation kits. Firstly, the subjects DNA fragment was PCR amplified using specific primers corresponding to exon 2 and 4 of the DFNB59 gene. Each fragment was purified and subsequently analyzed by direct sequencing in an applied biosystems 3730 automated DNA sequencer. The whole coding sequence of DFNB59 gene of one family patient were then PCR amplified and submitted for sequence analysis as described above. The resultant sequence data were compared with the standard sequence to identify deafness-associated mutations. RESULT: PCR amplifications were successfully conducted in all the subjects. We failed to detect the presence either of mutations T54I and R183W in the exon 2 and exon 4 that have been reported, or any other deafness-associated mutations in the whole DFNB59 gene, by sequence analysis. CONCLUSION: The DFNB59 gene seems not contribute to the pathogenesis of this Chinese AN family, which suggesting new gene(s) involvement.

[Sequence analysis of OTOF gene in a Chinese pedigree with autosomal dominant auditory neuropathy].

OBJECTIVE: To investigate if the OTOF gene contributes to the non-syndromic hearing loss of a Chinese pedigree with dominantly inherited auditory neuropathy (AN). METHOD: The subjects included were 9 live individuals in an autosomal dominant AN pedigree, 3 sporadic AN patients and 3 normal-hearing controls. Genomic DNA was isolated from the peripheral leukocytes of the subjects using the Pure gene DNA Isolation Kits. Firstly, the whole coding sequence of OTOF gene of one family patient were PCR amplified using specific primers. Each fragment was purified and subsequently analyzed by direct sequencing in an Applied Biosystems 3 730 automated DNA sequencer. The resultant sequence data were compared with the standard sequence to identify deafness-associated mutations. Other DNA samples were then screened for these mutations by PCR amplification and sequence analysis. RESULT: PCR amplifications were successfully conducted in all the subjects. Comparison of the resultant OTOF sequence in one family patient with the standard sequence identified 10 nucleotide variants which do not lead to amino acid change. These mutations were also detectable in other family individuals, 3 sporadic AN patients and 3 normal-hearing controls. CONCLUSION: The OTOF does not seem to contribute to the pathogenesis of this Chinese AN family, which suggest new gene(s) involvement.

[Auditory neuropathy in deaf school students].

OBJECTIVE: To investigate incidents and clinical features of auditory neuropathy in Nanjing deaf school students. METHOD: Three hundred and fifty-eight deaf students in the school accepted the first examination including otoscopic examination, tympanometry and transiently evoked otoacoustic emissions (TEOAE) screening. Detailed audiological and vestibular evaluations including pure-tone audiometry, immittance audiometry and acoustic reflex measures, transiently evoked otoacoustic emissions (TEOAE), distortion product otoacoustic emissions (DPOAE), auditory brain stem response (ABR), electronystagmography (ENG) and vestibular evoked myogenic potential (VEMP) were given to whom had positive TEOAE screening. RESULT: Three hundred and twenty-three students entered the program of screening for auditory neuropathy. One student had positive TEOAE in single ear while the other two had positive TEOAE in both ears. In the screening stage,there were strong evidences in these three students with auditory neuropathy in the detailed audiological procedures. CONCLUSION: Auditory neuropathy, which can also be found in deaf schools, is not as rare as we thought before. Early identification and intervention may help those children to avoid entering the deaf school and to return to normal society.

Clinical and genetic features in a Chinese pedigree with autosomal dominant auditory neuropathy.

BACKGROUND: A variety of processes and etiologies are thought to be involved in the pathophysiology of auditory neuropathy (AN). However, little is known about the clinical and molecular characteristics of hereditary AN. OBJECTIVE: To explore the clinical and genetic findings of a Chinese family with AN. METHODS: Seven patients in three consecutive generations of the pedigree were selected. Detailed history collection, physical examination, and audiological evaluations including pure-tone audiometry, acoustic immittance, auditory brainstem responses, cochlear microphonics, and evoked otoacoustic emissions, and mitochondrial DNA analysis were performed. RESULTS: All subjects involved are offspring of a female ancestor in the pedigree. In 6 of them, the hearing impairment started before the age of 9. Audiograms showed bilateral, symmetric, and profound deafness. Other audiological examinations revealed absent acoustic reflexes and auditory brainstem responses, and preserved evoked otoacoustic emissions and cochlear microphonics. One subject was characterized by normal audiological findings except high-frequency hearing loss with later onset. Hearing deterioration was found in 2 subjects who were followed for 26 months. Physical examination and mitochondrial DNA analysis yielded normal results. CONCLUSIONS: Clinical features in the pedigree are consistent with type II AN. Pedigree analysis and molecular findings indicate an autosomal dominant inheritance.

[Epidemiologic study on hearing impairment and ear diseases in old people].

OBJECTIVE: To investigate the prevalence of hearing impairment and ear diseases in old people and provide scientific data for drawing up the prevention and treatment strategies. METHODS: Using the probability proportion to size (PPS) method, 1261 people over 60 years were investigated in 40 clusters in Jiangsu Province with the WHO protocol. RESULTS: The prevalence of hearing impairment was 58.1% (the standardized rate: 59.5% in the whole country, 60.9% in Jiangsu province). Degrees of hearing impairment were mild (33.1%), moderate (17.8%), severe (5.9%) and profound (1.3%). The prevalence of hearing disability was 25.0% (the standardized rate: 26.6% in the whole country, 28.1% in Jiangsu province). There were significant difference of the prevalence between male and female, as well as urban and rural, and different ages. The prevalence of the ear diseases was auricle malformation (0.2%), wax (1.7%), otitis externa (0.1%), fungi (0.5%), serous otitis media (1.2%), chronic suppurative otitis media (1.6%), dry perforation of tympanic membrance (2.3%). The causes of hearing impairment were ear diseases (2.9%), non-infectious condition (92.6%), genetic condition (0.3%) and undetermined causes (4.2%). Of which, 31.1% of persons needed hearing aids while 2.3% of persons needed medicine treatment, but 0.9% of persons needed non-urgent surgery and 1.0% of persons needed other treatment. CONCLUSIONS: The prevalence of hearing impairment and disability in the old rised obviously than the last investigation in 1987. It was a heavy burden for social development in China. The government and the whole society should take more concern about the problem. The scientific strategies of prevention and treatment were urgently needed and implemented.

[Mitochondrial 12S rRNA gene A827G in two pedigrees with nonsyndromic deafness].

OBJECTIVE: To investigate the relationship of associating mitochondrial DNA 12S rRNA gene mutations with non-syndromic and aminoglycoside-induced hearing loss happening to Chinese families. METHODS: The diagnosis was validated by hearing tests. Blood samples were collected from 20 family members (13 subjects from pedigree A and 7 from pedigree B) and 32 sporadic deafness cases. DNA was extracted from the leukocytes in blood samples. The gene fragments of mitochondrial DNA 12S rRNA, tRNA(Ser(UCN)) and GJB(2) were amplified by polymerase chain reaction (PCR). PCR products were analyzed by sequencing. RESULTS: The target gene fragments of all individuals were successfully amplified by PCR. The mitochondrial DNA 12S rRNA 827 A to G transition was detected from all maternal members including 12 patients with hearing loss, which was the homoplasmic mutation. Non-maternal members in two pedigrees did not carry this mutation. However, the tRNA(Ser(UCN)) A7445G, 12SrRNA A1555G and GJB2 gene mutations were not found from both the family members of two pedigrees and sporadic patients. One sporadic individual (1/32) who was diagnosed as aminoglycoside-induced hearing impairment carried A827G mutation too. CONCLUSION: It is confirmed that the mitochondrial DNA 12S rRNA gene is a hot spot for mutations associated with non-syndromic inherited hearing loss. The 12S rRNA nt827 A to G mutation may play a pivotal role in the pathogenesis of hearing impairment in two Chinese pedigrees.

Mitochondrial 12S rRNA A827G mutation is involved in the genetic susceptibility to aminoglycoside ototoxicity.

We have analyzed the clinical and molecular characterization of a Chinese family with aminoglycoside-induced and non-syndromic hearing impairment. Clinical evaluations revealed that only those family members who had a history of exposure to aminoglycoside antibiotics subsequently developed hearing loss, suggesting mitochondrial genome involvement. Sequence analysis of the mitochondrial 12S rRNA and tRNA(Ser(UCN)) genes led to the identification of a homoplasmic A827G mutation in all maternal relatives, a mutation that was identified previously in a few sporadic patients and in another Chinese family with non-syndromic deafness. The pathogenicity of the A827G mutation is strongly supported by the occurrence of the same mutation in two independent families and several genetically unrelated subjects. The A827G mutation is located at the A-site of the mitochondrial 12S rRNA gene which is highly conserved in mammals. It is possible that the alteration of the tertiary or quaternary structure of this rRNA by the A827G mutation may lead to mitochondrial dysfunction, thereby playing a role in the pathogenesis of hearing loss and aminoglycoside hypersensitivity. However, incomplete penetrance of hearing impairment indicates that the A827G mutation itself is not sufficient to produce clinical phenotype but requires the involvement of modifier factors for the phenotypic expression. Indeed, aminoglycosides may contribute to the phenotypic manifestation of the A827G mutation in this family. In contrast with the congenital or early-onset hearing impairment in another Chinese family carrying the A827G mutation, three patients in this pedigree developed hearing loss only after use of aminoglycosides. This discrepancy likely reflects the difference of genetic backgrounds, either mitochondrial haplotypes or nuclear modifier genes, between two families.

Maternally inherited non-syndromic hearing loss associated with mitochondrial 12S rRNA A827G mutation in a Chinese family.

We explored the clinical and molecular characterization of a Chinese family with non-syndromic hearing impairment. Clinical evaluations revealed a possible maternal inheritance pattern, and showed an extremely similar phenotype of hearing loss including the age of onset, severity, and audiometric configuration. Sequence analysis of the mitochondrial 12S rRNA and tRNA(Ser(UCN)) genes led to the identification of a homoplasmic A827G mutation in all maternal relatives, which was absent in other family members and 40 Chinese controls. This mutation has previously been reported sporadically in a few individuals with aminoglycoside-induced and non-syndromic hearing loss. The A827G mutation is located at the A-site of the mitochondrial 12S rRNA gene which is highly evolutionarily conserved in mammals. The occurrence of the A827G mutation in these genetically unrelated subjects strongly suggests that this mutation is involved in the pathogenesis of hearing impairment. However, incomplete penetrance of hearing loss indicates that the A827G mutation alone is not sufficient to produce clinical phenotype but requires the involvement of modifier factors for the phenotypic expression, even though aminoglycosides and GJB2 gene may not contribute to the penetrance of the A827G mutation in this Chinese family. In contrast with the variable phenotype of hearing loss associated with other mitochondrial mutations, all of the patients in our family exhibited strikingly similar clinical features. This discrepancy likely reflects the difference of genetic backgrounds between this pedigree and others.

Tympanometric norms for Chinese schoolchildren.

Current tympanometric norms have acknowledged the relevance of age as an influencing factor. However, little attention has been afforded to other potentialities such as the non-pathological effects of gender, ear asymmetry, and racial heritage. This study aimed to examine normative tympanometric findings in a large sample of Chinese schoolchildren. Using a Madsen 901 Middle Ear Analyzer, data was collected from 269 children (538 ears), ranging in age from 6.2 12.7 years (mean = 9.4 years, SD = 1.7), in Jiangsu province. Descriptive statistics were calculated for the parameters of equivalent ear canal volume (chi = 1.03, SD = 0.25, 90% = 0.68 1.46), peak compensated static acoustic admittance (chi = 0.58, SD = 0.34, 90%=0.26 1.13), tympanometric width (chi = 112, SD = 36, 90% = 62-156), and peak pressure (chi = -25, SD = 30, 90% = -85 -/+ 10). Statistically significant ear asymmetry and grade/age effects were established, although differences found were minor. In comparison with past studies in Caucasian paediatric populations, the Chinese normative data displayed minimal disparities.

[Sequence analysis of the connexin 26 genes from a deafness family with A1555G mutation in Huaiyin].

OBJECTIVE: To ascertain whether connexin 26 (Cx26) gene was a nuclear modifier gene in an extensive family with matrilineal nonsyndromic deafness associated with A1555G mutation in Huaiyin, China. METHODS: Following PCR-restriction fragment length polymorphism (PCR-RFLP) with ApaI restriction enzyme, Cx26 genes from 26 cases, with A1555G mitochondrial mutations in this family, and 62 controls (including 2 patrilineal relatives, 10 spouse controls and 50 unrelated controls), were sequenced. RESULTS: Compared with the reference sequence of Cx26 gene, totally four kinds of nucleotide changes,79G -->A, 109G-->A, 341G-->A and 235delC, were detected in a heterozygous form. However, the former three were previously reported polymorphisms, and only the 235delC was a previously described recessive mutation associated with most autosomal nonsyndromic sensorineural hearing loss in Japan and China. Further study showed that the heterozygous 235delC mutation existed in both one individual with mild hearing loss and two individuals with normal hearing. Clinical characterization showed that 235delC mutation did not seem to modify the deafness phenotype due to the A1555G mutation. Moreover, this 235delC mutation was deduced to derive from a married-in control. Finally, there were no co-segregation between the phenotypes of hearing loss and the genotypes for Cx26 genes based on the four kinds of nucleotide changes. CONCLUSIONS: The heterozygous 235delC mutation of the Cx26 gene may not modulate the severity of hearing loss associated with A1555G mutation and Cx26 gene is unlikely to be a modifier gene for hearing loss due to A1555G mitochondrial mutation in this Chinese family.