Bilateral sensorineural hearing disorders in children: etiology of deafness and evaluation of hearing tests

Ti3 C2 Tx MXene Composite 3D Hydrogel Potentiates mTOR Signaling to Promote the Generation of Functional Hair Cells in Cochlea Organoids

Organoids have certain cellular composition and physiological features in common with real organs, making them promising models of organ formation, function, and diseases. However, Matrigel, the commonly used animal-derived matrices in which they are developed, has limitations in mechanical adjustability and providing complex physicochemical signals. Here, the incorporation of Ti₃ C₂ T_x MXene nanomaterial into Matrigel regulates the properties of Matrigel and exhibits satisfactory biocompatibility. The Ti₃ C₂ T_x MXene Matrigel composites (MXene-Matrigel) regulate the development of Cochlear Organoids (Cochlea-Orgs), particularly in promoting the formation and maturation of organoid hair cells. Additionally, regenerated hair cells in MXene-Matrigel are functional and exhibit better electrophysiological properties compared to hair cells in Matrigel. MXene-Matrigel potentiates the amycin (mTOR) signaling pathway to promote hair cell differentiation, and mTOR signaling inhibition restrains hair cell differentiation. Moreover, MXene-Matrigel facilitates innervation establishment between regenerated hair cells and spiral ganglion neurons (SGNs) growing from the Cochlea modiolus in a co-culture system, as well as promotes synapse formation efficiency. The approach overcomes some limitations of the Matrigel-dependent culture system and greatly accelerates the application of nanomaterials in organoid development and research on therapies for hearing loss.

A novel MPZL2 c. 68delC variant is associated with progressive hearing loss in Chinese population and literature review

Objective

Methods

Results

Conclusion

Etiology of early hearing loss in Brazilian children

INTRODUCTION

Hearing loss etiology depends on the population studied as well as on the ethnicity and the socio-economic condition of the analyzed region. Etiological diagnosis contributes to the improvement of preventive measures and to the early identification of this deficiency.

OBJECTIVE

To identify the etiological factors of hearing loss and its prevalence in a tertiary hospital in southern Brazil, to verify the frequency of mutations in GJB2 and GJB6 genes, and to correlate the degree of hearing loss with the etiological factors of deafness.

METHODS

This prevalence study involved 140 children with bilateral sensorineural or mixed hearing loss. Medical history, physical examination, audiometry, and evoked auditory brainstem response were conducted. Imaging and genetic examinations were also performed.

RESULTS

Etiologies and their prevalence were as follows: (a) indeterminate causes, 31.4%; (b) conditions related to neonatal period, 22.1%; (c) genetic, 22.1%; (d) auditory neuropathy, 10%; (e) other factors (cortical malformation, intracranial hemorrhage, and internal ear malformations), 7.9% and (f) congenital infections, 6.4%. Within the genetic cases, ten homozygous and seven heterozygotes of the 35delG mutation were identified, besides two cases of rare variants of GJB2: p.Try172* and p.Arg184Pro. One case with homozygosis of del(GJB6-D13S1830) was found. Regarding severity of hearing loss, in 78.6% of the cases the degree of hearing loss was profound and there were no significant differences when comparing between etiologies.

CONCLUSION

The number of indeterminate etiologies is still high and congenital CMV infection may be a possible cause of undiagnosed etiology for hearing loss. The predominance of etiologies related to neonatal conditions and infectious causes are characteristic of developing countries. The most prevalent mutation was 35delG, the main GJB2 gene, probably because of the European influence in the genotype of our population.

Etiology of Childhood Bilateral Sensorineural Hearing Loss in Shandong Province, China

Objectives The purpose of this study is to ascertain the etiology of bilateral sensorineural hearing loss (SNHL) in children aged ≤ 18 years living in Shandong province. Method Data were taken from a cross-sectional study, which was conducted between 2015 and 2017. The study included children aged ≤ 18 years, recruited from special schools for children with hearing loss and from hearing rehabilitation centers in Shandong province of China. Children were screened for bilateral SNHL through audiological testing. Clinical examination, genetic testing, and structured interviews were conducted for those children who were identified as having hearing loss to identify the potential cause. Results The etiology of bilateral SNHL in our sample was genetic in 874 (39.3%), acquired in 650 (29.3%), and unknown in 697 (31.4%) children. Among children with acquired SNHL, the cause was maternal viral infection in 75 (11.5%); perinatal factors in 238 (36.6%); meningitis, measles, and mumps in 146 (22.5%); and ototoxic exposure in 117 (18%) children. Among the children with genetic SNHL, only 44 (4.9%) were identified as having syndromic hearing loss, and the remainder (95.1%) were classified as nonsyndromic hearing loss. Conclusion The findings indicated that nearly 30% of bilateral SNHL in Shandong province could be preventable through immunization, early prenatal diagnosis, proper treatment of infections, and avoidance of prescription of ototoxic drugs. This finding emphasizes the need for programs aimed at improving the health services at primary and secondary levels of health care, which will in turn prevent childhood hearing loss.

Long-term functional outcomes of hearing and speech rehabilitation efficacy among paediatric cochlear implant recipients in Shandong, China

Purpose: To evaluate the auditory performance and speech intelligibility of 100 children with bilateral profound sensorineural hearing loss up to 3 years after cochlear implantation.Methods: A cohort study was established consisting of 100 children who received cochlear implantation at Shandong Ear Nose and Throat Hospital from 2012 to 2015. Children were examined after 1 month, 1, 2, and 3 years of implantation to assess auditory performance and speech intelligibility using standard tools. The paired Wilcoxon signed-rank test was used to assess whether the scores obtained at different testing points differed significantly. The Mann-Whitney test was utilized to examine the between-group differences (e.g., age at implantation).Results: Three years after implantation, 60% out of 100 children reached the maximal category (7) of categorical auditory performance and 37% achieved the highest category (5) of speech intelligibility rating. Significant improvements were found over time in categorical auditory performance category and speech intelligibility rating (from month 1 to year 1, p < 0.001; from year 1 to year 2, p < 0.001; and from year 2 to year 3, p < 0.001). Larger improvements in auditory outcomes and speech intelligibility were observed in children with a younger age at implantation and those who received speech therapy.Conclusions: Cochlear implantation appears to make a significant, positive contribution to the development of communication skills of young congenital and prelingually deaf children in China. These improvements continue for up to 3 years after implantation. Positive outcomes appear to be associated with earlier age at implantation and receipt of speech therapy.Implications for rehabilitationBilateral sensorineural hearing loss.Bilateral sensorineural hearing loss in children can cause delay in speech development, poor language skills and potentially disorders in psychological behaviour and social isolation.Cochlear implantation (CI) is an effective strategy that helps children with bilateral sensorineural hearing loss gain the ability to hear and continue to develop language.This study shows that the auditory performance and speech intelligibility of deaf children who speak Mandarin continued to improve up to 3 years of implantation, when follow-up ceased.

Impaired frequency selectivity and sensitivity to temporal fine structure, but not envelope cues, in children with mild-to-moderate sensorineural hearing loss

Psychophysical thresholds were measured for 8-16 year-old children with mild-to-moderate sensorineural hearing loss (MMHL; N = 46) on a battery of auditory processing tasks that included measures designed to be dependent upon frequency selectivity and sensitivity to temporal fine structure (TFS) or envelope cues. Children with MMHL who wore hearing aids were tested in both unaided and aided conditions, and all were compared to a group of normally hearing (NH) age-matched controls. Children with MMHL performed more poorly than NH controls on tasks considered to be dependent upon frequency selectivity, sensitivity to TFS, and speech discrimination (/bɑ/-/dɑ/), but not on tasks measuring sensitivity to envelope cues. Auditory processing deficits remained regardless of age, were observed in both unaided and aided conditions, and could not be attributed to differences in nonverbal IQ or attention between groups. However, better auditory processing in children with MMHL was predicted by better audiometric thresholds and, for aided tasks only, higher levels of maternal education. These results suggest that, as for adults with MMHL, children with MMHL may show deficits in frequency selectivity and sensitivity to TFS, but sensitivity to the envelope may remain intact.

Effects of vaginal birth versus caesarean section on hearing screening results in a large series from the Aegean region

Objective: To evaluate the effects of caesarian section (CS) versus vaginal birth (VB) delivery techniques on results from neonatal hearing screening tests (NHSTs).Design: Retrospective analysis.Study sample: A total of 10,767 neonates divided into two groups according to delivery technique underwent NHSTs. Those who failed TEOAE or AABR were sent for diagnostic ABR examination.Results: A total of 5620 of 6044 (92.9%) of the neonates in the CS group passed the TEOAE test bilaterally and 424 (7.1%) failed either unilaterally or bilaterally. In the VB group, 4496 of 4723 (95.1%) neonates passed the TEOAE test bilaterally, while the remaining 227 (4.9%) failed the test either unilaterally or bilaterally. Bilateral passing rate of TEOAE test results was significantly higher in the VB group than the CS group (p < 0.05). The AABR failure rate (unilaterally or bilaterally) was 1% in the CS group, which was significantly higher than that in the VB group (0.6%). Diagnostic ABR bilateral pass rate was not statistically different between the groups.Conclusions: Delivery method was shown to affect the results of NHSTs. We found that the rates of failing the TEOAE and screening AABR examinations were higher among neonates born by CS compared to VB.

Behavioral and Electrophysiological Assessment of Adults Who Underwent Cochlear Implantation After Hearing Aid Experience

Introduction  Cochlear implantation has been considered a viable option to restore hearing perception in adults with severe to profound postlingual hearing loss. Objectives  To analyze behavioral hearing responses and P300 latency and amplitude measurements in adults with bilateral sensorineural hearing loss at two phases, first when they were using hearing aids (HAs) and, then, after 12 months of cochlear implant (CI) use. The association between behavioral and electrophysiological evaluations was explored, as it is believed that the study of auditory processing with different hearing devices can contribute to future CI adjustments and fittings, especially for patients who cannot give subjective feedback (such as small children and individuals with multiple disabilities). Methods  Prospective comparative study (Ethical approval 11489/2014). Twelve adults were assessed, 7 males and 5 females, in the 22 to 76 years old age range, who had undergone CI surgery after HA experience. Results  The analyses showed an improvement of hearing thresholds when patients started using CIs. Comparing data from P300 latency measurements, there was an increase of the P300 wave post-CI at Cz and Fz. Regarding the amplitude, P300 mean values decreased at Cz, but increased at Fz. There was no significant correlation between behavioral and electrophysiological assessment and the variables age, gender, auditory deprivation, and electronic device used. Conclusion  There was a significant improvement of hearing thresholds after twelve months of CI experience. The mean latency values of P300 after 12 months of CI use increased at Cz and Fz, while mean amplitude values decreased at Cz and increased at Fz.

An epidemiological study on children with syndromic hearing loss

OBJECTIVES

To study the epidemiological factors in children with syndromic hearing loss.

STUDY DESIGN

Interview based prospective study.

SETTINGS

Govt. ENT Hospital, AYJNIHH, NIMH-SEC, and Schools for the Deaf-in Hyderabad and SecunderabadPatients: Children aged below 14 years, with hearing loss, their parents/guardians.

INTERVENTION(S)

The study revealed type and degree of hearing impairment. In high risk groups genetic counseling was offered.

RESULTS

Epidemiological studies were carried out in 743 children below 14 years with hearing impairment and 138 (18.57%) were found to have syndromic deafness. Majority of the children with hearing loss have an association of ocular abnormality (22.46%, n=31) followed by skeletal anomalies 14.49% (n=20) and dental anomalies (10.86%). We observed 24 cases (3.21%) with genetically well recognized syndromes.

CONCLUSION

Data is generated on epidemiological and etiology of Hearing Impairment. Hearing Impairment is due to both environmental and genetic causes. Environmental factors in 17 (13.77%), genetically inherited 21 cases (15.22%) and the cause is not known in the remaining cases. Such a data is required in order to offer genetic counseling to reduce the genetic burden.

Characteristics of children and adolescents in the Dutch national in- and outpatient mental health service for deaf and hard of hearing youth over a period of 15 years

In this study socio-demographic, deafness-related and diagnostic characteristics of hearing impaired children and adolescents referred to a national mental health service for deaf and hard of hearing children and adolescents were examined. Socio-demographic and diagnostic characteristics were compared to corresponding characteristics of hearing referred peers with identified mental health problems. The difference in characteristics between them and hearing referred peers with identified mental health problems was analyzed. A total of 389 deaf and hard of hearing and 3361 hearing children and adolescents was extracted from a database, all first referrals of patients of a center for child and adolescent psychiatry over a 15-year period. With deaf and hard of hearing patients we found higher rates of environmental stress, as indicated by conditions such as more one parent families (38.6% versus 25.8%), and more parents with a low educational level (44.2% versus 31.1%). Moreover, deaf and hard of hearing patients were older at their first referral (10.8 versus 9.4 years) and had higher rates of pervasive developmental disorders (23.7% versus 12.3%) and mental retardation (20.3% versus 3.9%). Within the target group of deaf and hard of hearing patients, most patients were deaf (68.9%; 22.3% was severely hard of hearing), relatively few (13.7%) had a non-syndromal hereditary hearing impairment, and more (21.3%) had a disabling physical health condition, especially those with a pervasive developmental disorder (42.6%). These findings illustrate both the complexity of the problems of deaf and hard of hearing children and adolescents referred to specialist mental health services, and the need for preventive interventions aimed at early recognition.

Postural control in children with typical development and children with profound hearing loss

Purpose

To describe the behavior of the postural control in children with profound sensorineural hearing loss and compare the results of experimental tests with hearing children aged 7 to 10 years.

Patients and methods

This is a cross-sectional study where 100 children were divided into experimental and control groups. We used a force platform, AccuSway Plus, where the tests were conducted under the experimental conditions: open base, eyes open (OBEO); open base, eyes closed (OBEC); closed base, eyes open (CBEO); closed base, eyes closed (CBEC). The body sway velocity (V) of the center of pressure, the displacement in the anteroposterior direction (COPap) and mediolateral (COPml) of the center of pressure were the parameters to evaluate the postural control. For statistical analysis we used the nonparametric Mann–Whitney U test, with a significance level of 5%.

Results

In comparisons of variables between the groups, the experimental group outperformed by at least 75% of the control group values. In terms of global trends, the experimental group shows higher values of body oscillations in all experimental conditions and variables evaluated. Children with hearing loss had poorer balance performance compared to the group of hearing. The inferential analysis revealed a statistically significant difference in the balance between deaf and hearing children in the OBEC experimental condition in relation to the COPml parameter (P = 0.04). There were no statistically significant differences in comparisons between the sexes when the groups were analyzed separately. The prevalence of unknown etiology showed 58% of cases and congenital rubella in 16%. The discovery of deafness occurred in 70% of children before the age of 3 years.

Conclusion

In this study, children with hearing loss had poorer balance performance compared to the group of hearing children. This finding confirms the need to investigate postural control through longitudinal studies to identify the area of sensory deficit causing poor balance performance and promote more specific early interventions.

[Progressive or delayed early-onset pediatric sensorineural hearing loss]

The introduction of newborn-hearing screening has enabled early childhood hearing loss to be diagnosed and increased the number of children undergoing early care. Bilateral hearing loss is found in 0.08% of newborns and children whose hearing loss progresses or onset is delayed account for 4 to 30% of all pediatric hearing impairment. Children with perinatal risk factors tend to have deteriorated hearing or delayed-onset hearing loss in early childhood, necessitating audiometric follow-up. We also are aware of some children without risk factors who develop hearing impairment during infancy or early childhood. Hearing deterioration may be difficult to diagnose objectively, especially in young children, the presence of risk factors must be determines as soon as possible, especially given the lack of hearing management and close examination of children without apparent risk factors. We retrospectively studied children born from April 1998 to March 2007 and undergoing cochlear implantation as of April 2008. Among cases, we focused on 10 whose hearing impairment advanced during infancy -4 with risk factors known before hearing deterioration progressed, and 6 cases thought not to have any risk factors. We detected enlarged vestibular acquaduct in 3 of these 6 cases, and 3 more of whom had no risk factors -2 passing newborn-hearing screening and 1 in whom such screening detected hemilateral hearing loss. Our results underscore the need for early temporal computed tomography for detecting enlarged vestibular aquaduct. Even children with mild or hemilateral hearing loss should undergo audiometric and developmental testing at least every 6 months up to going to elementary school. Children suspected of impaired hearing should undergo thorough hearing tests regardless of newborn hearing-screening results to catch any problems early. Appropriate regular hearing and language development check-up tests must also be developed.

Hearing loss in congenital toxoplasmosis detected by newborn screening

Congenital toxoplasmosis may cause sensorineural deficit in up to 20% of the patients and proper treatment in the first year improves prognosis. In Brazil, this infections impact on hearing impairment is unknown.

AIM

To evaluate hearing of newborns with congenital toxoplasmosis identified by the newborn screening service.

METHOD

This prospective study analyzed children with congenital toxoplasmosis identified by newborn screening (IgM anti-T.gondii) in Belo Horizonte during 2003/2004. The presence of IgM and/or IgA in the first 6 months or IgG at 12 months-of age in serology was used as case definition. Hearing tests were carried out at the time of diagnosis and 12 months later, including behavioral audiometry, evoked otoacoustic emission and brainstem evoked responses audiometry.

RESULTS

Among 30.808 screened children (97% of live births), 20 had congenital toxoplasmosis, 15 (75%) were asymptomatic at birth. Nineteen children were evaluated by hearing tests. Four had sensorineural impairment (21.1%). One child had other risk factors for hearing impairment; the other three had no other risk factors but toxoplasmosis. Two properly children treated still had hearing loss, in disagreement with current literature.

CONCLUSION

Results suggest that congenital toxoplasmosis, common in Brazil, is a risk factor for hearing impairment and its impact on hearing loss deserves further studies.

Estudo retrospectivo de crianças e jovens com deficiência auditiva: caracterização das etiologias e quadro audiológico

OBJETIVO: conhecer os fatores de risco para deficiência auditiva e obter informações sobre o tempo transcorrido entre suspeita, diagnóstico e intervenção em crianças e jovens deficientes auditivos atendidos no Serviço de Audiologia Educacional, DERDIC-PUC-SP. MÉTODOS: estudo retrospectivo de 162 prontuários de deficientes auditivos com idade entre um e 17 anos e 6 meses, atendidos de 1999 a 2002. Para registro dos dados utilizou-se a adaptação do protocolo elaborado no Fórum de Reabilitação Aural do Encontro Internacional de Audiologia, no Brasil. RESULTADOS: 54% dos sujeitos eram do sexo masculino e 46% do feminino; 60% tinham idade entre três e oito anos e 11 meses; 43% tiveram a suspeita da deficiência auditiva no primeiro ano de vida. Em 25% dos casos, o diagnóstico ocorreu logo após a suspeita, em 34% ocorreu um intervalo de até um ano; 11% iniciaram atendimento fonoaudiológico após diagnóstico, 54% demoraram até um ano e 27% demoraram mais de um ano. Trinta e dois por cento apresentaram etiologia desconhecida, 18% genética, 17% presumida multifatorial, 15% meningite, 9% rubéola congênita. CONCLUSÃO: a prevalência da etiologia desconhecida aponta para a necessidade do aprofundamento no diagnóstico etiopatológico (estudos genéticos, de imagens e laboratoriais) como rotina para se obter as causas da deficiência auditiva. Observou-se que mesmo após as campanhas de vacinação, a rubéola ainda foi a maior causa de deficiência auditiva congênita e a meningite a maior causa das deficiências auditivas adquiridas após o nascimento. Constatou-se um longo intervalo de tempo entre suspeita, confirmação e início da intervenção fonoaudiológica.

Post-natal hearing loss in universal neonatal hearing screening communities: current limitations and future directions

Universal hearing screening has dramatically improved outcomes for babies born with detectable hearing abnormalities; yet there are some infants who develop significant hearing problems after passing a neonatal screen. There is much conjecture as to the number and the characteristics of infants with post-natal hearing losses; yet evidence suggests that many children may be affected, and that a large proportion have no discoverable cause. Currently, screening programmes use lists of risk factors to enroll babies into surveillance programmes. This practice is problematic because audiological follow-ups are expensive and under-utilised, and parental disclosure is often inaccurate. The large databases from universal neonatal programmes could inform the development of effective, evidence-based practice and policy for the detection and intervention of children who develop post-natal hearing losses.

Deficiência auditiva na toxoplasmose congênita detectada pela triagem neonatal

A toxoplasmose congênita pode causar déficit neurossensorial em até 20% dos casos e o tratamento no primeiro ano de vida melhora o prognóstico. No Brasil, desconhece-se o impacto da infecção na hipoacusia. OBJETIVO: Avaliar a audição de crianças com toxoplasmose congênita identificadas pela triagem neonatal. MATERIAL E MÉTODO: Estudo prospectivo de crianças com toxoplasmose congênita identificadas pela triagem neonatal (IgM anti-T. gondii) em Belo Horizonte, durante 2003/2004. Realizada sorologia confirmatória (mãe/filho) e consideradas positivas as crianças apresentando IgM e/ou IgA nos primeiros seis meses ou IgG aos 12 meses de vida. Avaliações auditivas ao diagnóstico e após 12 meses incluíram Audiometria Comportamental, Emissões Otoacústicas, Imitanciometria, Audiometria de Tronco Encefálico. RESULTADOS: Dentre 30.808 crianças triadas (97% dos nascidos vivos), 20 apresentavam toxoplasmose congênita, 15 (75%) com infecção subclínica. Dezenove crianças realizaram avaliação auditiva. Quatro apresentaram déficit neurossensorial (21,1%). Uma criança apresentou outros fatores de risco para hipoacusia; nas outras três, a toxoplasmose foi o único fator observado. Duas crianças, tratadas adequadamente com antiparasitários, apresentaram déficit auditivo, em desacordo com a literatura. CONCLUSÃO: Os achados sugerem que a toxoplasmose congênita, prevalente no Brasil, é um fator de risco para hipoacusia e o impacto dessa infecção nas perdas auditivas deve ser estudado.

Etiology of hearing impairment in children and adolescents of a reference center APADA in the city of Salvador, state of Bahia

Hearing represents the main source for acquisition of language and speaking skills in childhood. In the first months of life, the hearing impaired child is deprived of sound stimulation in the most important period of development, and consequently, might present emotional, social and linguistic disorders. Therefore, it is of utmost relevance to learn about the main etiological factors that cause the auditory damage to trace a reliable nosological profile, and to take the appropriate measures to prevent and guide the family on the repercussions of hearing impairment in childhood.

Aim

To characterize the etiology profile of hearing impairment in a reference center for hearing impaired children and adolescents.

Methodology

We performed interviews, speech and hearing screening and analyses of medical charts of 87 hearing impaired children that were part of Associação de Pais e Amigos dos Deficientes Auditivos do Estado da Bahia (APADA-BA), trying to define etiology, gender distribution, age at diagnosis, level of hearing loss, age at hearing aid fitting, and rehabilitation.

Results

Among the 87 children and adolescents who had undergone speech and hearing screening, we select a sample of 53 subjects, whose parents had come for three sessions of anamnesis and assessment. The main responsible etiological factor for hearing loss in the evaluated population was maternal rubella, amounting to 32% of the cases of deafness, followed by pyogenic meningitis with 20%, idiopathic cause with 15%, prematurity with 9%, heredity (deaf father or mother) and neonatal jaundice, which also presented 6% incidence; chronic otitis media represented 4%, use of misoprostol in the gestation, measles, ototoxicity and mumps, each factor with 2%.

Conclusion

The present study demonstrated the heterogeneity of factors that cause hearing impairment, and the two main causes (rubella and pyogenic meningitis) still present high incidence in the studied population. We believe that preventive measures must be taken, especially in the prophylaxis of maternal rubella and extended vaccination of neonates and infants against bacterial meningitis.

[Sonar System- digital sounds of instruments for behavior hearing tests with infants]

BACKGROUND

The use of musical instruments, in the clinical practice, for the behavioral assessment of hearing has a limited possibility to control loudness, and does not restrict the test situation to a determined frequency. A new method of testing infants is through the Sonar System. This program can be used for the behavioral hearing assessment of infants, with the possibility of choosing the frequency range and loudness in which the test will be carried out. The Sonar System is different from other behavioral assessment methods once it offers instruments with standardized sounds and is limited to certain frequency ranges; all controlled by the examiner. With this method, one can offer more precise assessments and researches with better methodological control, once the presented sound will not suffer interferences of the examiner.

AIM

To use the Sonar System--digital band--to follow up the development of hearing in infants, born at term, from one to six months of age.

METHOD

An average of 30 infants was monthly evaluated. For the assessment the following recordings of instruments were presented: clapper, ganzá, coco and drum. These recordings were respectively set at the frequencies of 3000, 1500, 700 and 500 Hz. All infants went through evoked otoacoustic emissions screening.

RESULTS

Statistical analysis revealed significant responses in all of the tested frequencies. Results indicated statistically significant differences in all of the tested frequencies for the second trimester, but not for the first one.

CONCLUSION

The use of the Sonar System (digital band) is recommended for the behavioral hearing assessment of this age group. Since this is a new technique to assess behavioral hearing, the use of the Sonar System should be expanded to other populations and in other social contexts in order to allow and facilitate the assessment, diagnosis and intervention of infants and small children.

Fatores etiológicos da deficiência auditiva em crianças e adolescentes de um centro de referência APADA em Salvador-BA

A audição representa a principal fonte para aquisição das habilidades de linguagem e fala da criança. A criança portadora de deficiência auditiva nos primeiros meses de vida é privada de estimulação sonora no período mais importante de seu desenvolvimento, e conseqüentemente, poderá apresentar alterações emocionais, sociais, e lingüísticas. Neste contexto é de suma relevância conhecer os principais fatores etiológicos que ocasionam a lesão auditiva para se traçar um perfil nosológico fidedigno, e serem tomadas as medidas cabíveis de prevenção e orientação as famílias sobre as repercussões da deficiência auditiva na infância. OBJETIVOS: Caracterizar o perfil etiológico da deficiência auditiva em um centro de referência para atendimento a crianças e adolescentes deficientes auditivos. METODOLOGIA: Foram realizadas entrevistas, triagem fonoaudiológica e avaliação de prontuários de 87 crianças deficientes auditivas cadastradas na Associação de Pais e Amigos dos Deficientes Auditivos do Estado da Bahia(APADA-BA), buscando-se determinar a etiologia, distribuição por sexo, idade do diagnóstico, grau de deficiência, idade de protetização e da reabilitação fonoaudiológica. RESULTADOS: Dentre as 87 crianças e adolescentes que passaram pela triagem fonoaudiológica, selecionamos uma amostra de 53 sujeitos, cujos pais compareceram as três sessões de anamnese e avaliação. O principal fator etiológico responsável pela deficiência auditiva na população avaliada foi a rubéola materna responsável por 32% dos casos de surdez, seguida pela meningite piogênica com 20%, causa idiopática com 15%, prematuridade com 9%, hereditariedade (pai ou mãe surdo) e icterícia neonatal também apresentaram incidência de 6%; otite média crônica representou 4%, uso de misoprostol na gestação, sarampo, ototoxicidade e caxumba apareceram na amostra, cada fator, com 2%. CONCLUSÃO: O presente estudo demonstrou a heterogeneidade de fatores que ocasionam o comprometimento auditivo, e como as duas principais causas (rubéola e meningite piogênica) ainda apresentam uma incidência alta na população em estudo. Acreditamos que medidas de prevenção devem ser tomadas, principalmente na profilaxia da rubéola materna e na vacinação ampliada de neonatos e lactentes contra a meningite bacteriana.

The results of newborn hearing screening by means of transient evoked otoacoustic emissions

OBJECTIVE

The incidence of sensorineural hearing loss is between 1 and 3 per 1000 in healthy neonates and 2-4 per 100 in high-risk children. Transient evoked otoacoustic emissions (TEOAEs) represent a method which can be applied to all newborns prior to hospital discharge, enabling early identification of hearing loss. The aim of the study was to evaluate the results of newborn hearing screening by means of TEOAEs.

METHODS

Between 01.10.2002 and 30.09.2003, 5601 newborns born in the University Hospital in Poznan, Poland were screened with ERO SCAN (MAICO). Healthy neonates were screened in the second or third day of life and children treated in pathology unit--when their general condition was stable. The risk factors of hearing loss were recorded in a questionnaire. Children who failed the screening test or had risk factors of hearing impairment were referred to the outpatient clinic for further evaluation.

RESULTS

Risk factors were identified in 739 newborns. The most often risk factors were: use of ototoxic drugs, low Apgar score and prematurity. Positive test result was obtained in 219 (3.91%) children unilaterally and in 137 (2.45%) bilaterally. In healthy children the prevalence of positive results was 3.56% and in high-risk infants 24.9%. The relative risk of positive test results was the highest in infants with positive family history (RR=7.5), congenital malformations (RR=6.7) and low Apgar score (RR=5). Of the group of 912 children, who were referred to the specialist, only 218 turned up to be assessed during the observation period and had the additional otoacoustic emission test performed. There was not any significant difference in the percentage of children with and without risk factors who turned up for the second test and in whom the result was positive (39.7% versus 40.3%). In 41.9% children with risk factors whose screening test was negative, the second exam gave positive result.

CONCLUSIONS

The incidence of positive results in newborn hearing screening is much higher than the prevalence of hearing loss in general population and these results need verification by more precise methods. However, TEOAEs enable to select children who should be referred for audiological evaluation.

Study of the hearing loss in children and adolescents, comparing the periods of 1990-1994 and 1994-2000

INTRODUCTION

In 1994, a study was performed with 200 children and adolescents suffering from hearing loss. It concluded that the diagnostic confirmation of hearing loss within 2 years of age occurred in just 13% of the cases, although 56% were suspected in that phase. The loss of time of over 2 years between suspicion and confirmation of hearing loss occurred in 42% of the cases.

OBJECTIVES

The comparison of the main hearing loss etiologies-genetic cause, consanguinity, congenital rubella, meningitis, perinatal events and unknown causes-in children and adolescents in the periods of 1990-1994 and 1994-2000; comparison of incidence, in males and females, for each etiology and among the others; comparison of age at the first consultation, for each and among them; and the investigation as to whether the time between suspicion and diagnosis of hearing loss was different for each etiology and among the others.

METHODS

During the period of 1990-2000, of the 519 children and adolescents with hearing loss, 442 individuals were selected, in the two moments of the study: 1990-1994 and 1994-2000. The variables used were: sex, age at first consultation, suspected etiology and time between suspicion and confirmation of hearing loss.

RESULTS

Congenital rubella, genetic and perinatal causes, meningitis, consanguinity and unknown causes were responsible for over 80% of all etiologies, in both periods. There were no differences between the sexes in the periods studied. There was no relation among age, sex and etiology. Among the etiologies studied, there were no differences in the lengths of times between suspicion and confirmation of hearing loss, in each period separately. The comparative study showed that congenital rubella, genetic and unknown causes took longer times between suspicion and confirmation of hearing loss, for the period of 1990-1994, as compared with 1994-2000.

CONCLUSIONS

Congenital rubella remains as an important etiology, as well post-meningitis deafness. Age at first consultation did not show relationship to the hearing loss etiology nor to sex. Independently of whether the etiology being pre-natal, perinatal or post-natal, congenital or acquired, the length of time between suspicion and confirmation of hearing loss did not differ between the periods studied, separately.

Etiological diagnosis of bilateral, sensorineural hearing impairment in a pediatric Greek population

Early diagnosis, evaluation and treatment of childhood deafness are essential for a child's normal growth. Etiological diagnosis of hearing loss makes prevention, family scheduling and more effective therapy feasible goals. Etiological assessment of sensorineural deafness still remains difficult although recently with the progress of genetics it has become more efficient. In this retrospective study, the etiology of bilateral, sensorineural hearing loss with indication for hearing aids has been studied in 153 hearing impaired children. Etiological diagnosis was based on family and patient record, physical, audiological and laboratory examinations. Among the 94 children who completed the diagnostic protocol etiological groups revealed the following distribution: non-hereditary acquired hearing impairment was present in 36 children (38%) and hereditary was present in 44 (47%) children. The etiology remained unknown in 14 (15%) children. Non-syndromic autosomal dominant type accounted for 13 (29% of hereditary hearing loss) children, non-syndromic autosomal recessive type for 21 (48%) children and syndromic deafness for 10 (23%) children. Modern diagnostic methods, such as genetic testing, help diminish the number of cases with hearing impairment of unknown etiology, for the benefit of children who receive early and appropriate medical, audiologic, genetic and educational counseling based on the etiology of their hearing loss.

Prevalence of the GJB2 mutations and the del(GJB6-D13S1830) mutation in Brazilian patients with deafness

Mutations in the GJB2 gene are the most common cause of sensorineural non-syndromic deafness in different populations. One specific mutation, 35delG, has accounted for the majority of the mutations detected in the GJB2 gene in many countries. The aim of this study was to determine the prevalence of GJB2 mutations and the del(GJB6-D13S1830) mutation in non-syndromic deaf Brazilians. The 33 unrelated probands were examined by clinical evaluation to exclude syndromic forms of deafness. Mutation analysis in the GJB2 gene and the testing for the del(GJB6-D13S1830) were performed in both the patients and their family members. The 35delG mutation was found in nine of the probands or in 14 of the mutated alleles. The V37I mutation and the del(GJB6-D13S1830) mutation were also found in two patients, both are compound heterozygote with 35delG mutation. These findings strengthen the importance of genetic diagnosis, providing early treatment, and genetic counseling of deaf patients.

Syndromic etiology in children at schools for the deaf in Turkey

OBJECTIVE

The aim of this study was to determine the syndromic etiology of bilateral severe sensorineural hearing disorders in children and current etiological causes to reduce the cases in the unknown group.

METHODS

This study was conducted on 550 students of five schools for the deaf in Istanbul and Zonguldak, Turkey. Otologic, audiologic, dysmorphologic, ophthalmologic and dental examinations were performed in all children. Familial and medical histories were obtained.

RESULTS

The etiology of hearing loss was genetic in 346 (62.90%), acquired in 107 (19.45%) and unknown in 97 (%17.63) cases. A total of 619 malformations were defined in 550 children and 99 of them belonged to a syndrome. We identified 33 different syndromes for these 99 syndromic children. Syndromic etiology was found in 18.0% of the total and 28.61% of the subjects with genetic etiology. Most common syndrome was Waardenburg syndrome which occurred in 33 children.

CONCLUSION

The incidence of hereditary hearing impairment is very high in developing countries compared to developed countries. Prevention is essential to reduce the incidence, multidisciplinary approach and genetic counselling are necessary in this regard.

Systematic review of the etiology of bilateral sensorineural hearing loss in children

OBJECTIVE

Identification of the etiology of sensorineural hearing loss (SNHL) in children facilitates management and provides important prognostic information. In recent years, the etiology of bilateral SNHL in children has changed due to advances in genetic testing and treatment of perinatal infections. The objective of this study was to determine the frequency of etiologies of moderate-profound bilateral sensorineural hearing loss (SNHL) in children.

METHODS

The English literature was searched in Medline for articles published between 1966 and 2002. The inclusion criteria were studies involving bilateral SNHL >/=40dB in children less than 18 years of age. The studies were required to account for all patients, and provide a breakdown of etiologic factors. Etiologies investigated included genetic and non-genetic (prenatal, perinatal, postnatal). To compare differences between the frequencies of etiologies a two-sample t-test was performed assuming unequal variance. Studies were stratified according to perceived confounders: start date of study, study design, and degree of hearing loss.

RESULTS

Seven hundred and eighty abstracts were screened for relevancy. Forty-three studies satisfied the inclusion criteria. The common etiologies of bilateral SNHL were unknown (41.5%), genetic non-syndromic (27.2%), prenatal (11.5%), perinatal (9.7%), postnatal (6.6%), and genetic syndromic (3.5%). Unknown and Rubella were significantly less frequent etiologies in the more recent studies, while genetic non-syndromic, asphyxia and prematurity were more common. Genetic non-syndromic hearing loss was more frequent in the prospective studies compared to the population and retrospective studies, but this difference was not significant. Genetic non-syndromic hearing loss was more common among patients with profound hearing loss.

CONCLUSION

Accounting for the recent decline in infectious etiologies, the most common causes of bilateral SNHL are unknown (37.7%), genetic non-syndromic (29.2%), prenatal (12%), perinatal (9.6%), postnatal (8.2%), and genetic syndromic (3.2%).

Análise das principais etiologias de deficiência auditiva em Escola Especial "Anne Sullivan"

OBJETIVO: Determinar as principais etiologias de deficiência auditiva em estudantes da Escola de Ensino Especial para surdos "Anne Sullivan" em São Caetano do Sul e comparar com os dados da literatura mundial. FORMA DE ESTUDO: Estudo retrospectivo. MATERIAL E MÉTODO: Cento e trinta e um alunos da escola no ano de 2001 foram avaliados através de análise de seus prontuários, levando-se em conta dados de anamnese com a família, exame físico otorrinolaringológico, avaliação fonoaudiológica e psicológica. RESULTADOS: Dos 131 pacientes, 67 (51%) eram do sexo masculino e 64 (49%) do sexo feminino. A perda auditiva sensorioneural foi a mais encontrada, representando 99% dos casos. Quanto ao grau de disacusia, 65% foi classificado como profundo. Quanto à etiologia, 24% foi classificada como desconhecida e das causas identificáveis a rubéola congênita foi a mais encontrada (22%). Na maioria dos pacientes a suspeita e o diagnóstico foram feitos com 12 meses de idade. CONCLUSÕES: A etiologia não definida foi a mais representativa, seguida pela rubéola, e a idade de diagnóstico predominou entre 12 e 30 meses.