Congenital hearing disability--epidemiology and identification: a comparison between two health authority districts

Assessing Loss to Follow-up After Newborn Hearing Screening in the Neonatal Intensive Care Unit: Sociodemographic Factors That Affect Completion of Initial Audiological Evaluation

OBJECTIVES

Neonatal intensive care unit (NICU) patients are at high risk for congenital hearing loss. Previous studies have found sociodemographic factors associated with loss to follow-up for newborn hearing screening, but none have specifically studied the NICU population. Our objective is to determine if demographics and socioeconomic status is associated with loss to follow-up in a newborn population with extended NICU stay.

DESIGN

A retrospective cohort study was conducted on 443 NICU infants with extended NICU stay utilizing data extracted from infant and maternal medical records at an urban safety-net hospital.

RESULTS

Younger maternal age (adjusted odds ratio [OR] 0.95, confidence interval [CI] 0.91 to 0.99), higher gravidity (adjusted OR 1.39, CI 1.12 to 1.72), and former smoking status (adjusted OR 2.57, CI 1.07-6.18) were identified as independent predictors of loss to follow-up for NHS after conducting a multivariable logistic regression. Demographic and socioeconomic variables, such as sex, parity, birth weight, mode of birth, highest level of maternal education, maternal race/ethnicity, zip code metrics, and maternal language were not found to be associated with loss to follow-up.

CONCLUSIONS

Maternal age, gravidity, and smoking status are risk factors for loss to follow-up for NHS in newborns with extended NICU stay, a group at high risk for hearing loss. Our findings demonstrate that socioeconomic and demographic factors for loss to follow-up in the extended-stay NICU population are distinct from the well-baby population. Further investigation of these patients will allow prioritization of limited resources to subgroups within the extended-stay NICU population at risk for loss to follow-up for newborn hearing screening.

The Effect of Age at Cochlear Implantation on Speech and Auditory Performances in Prelingually Deaf Children

To understand the effect of age at implantation on speech and auditory performances of 74 prelingually deaf Indian children after using cochlear implants for 3, 6 and 12 months. We also evaluate the causes of late implantation in this population. Seventy four children who underwent cochlear implantation from December 2013 to December 2015 in the Department of Otorhinolaryngology and Head Neck Cancer in SMS Medical College, Jaipur were participated in this study. To compare the efficacy of cochlear implant, candidates are classified into 2 groups according to the age at the time of implantation: 1-4 years and 4.1-7 years. The sample size is 37 in both age groups. Their auditory performance and speech intelligibility were rated using the Revised Categories of Auditory Perception scales, Speech Intelligibility Rating scales and Meaningful Auditory Integration Scale. The evaluations were made before implantation and 3, 6 and 12 months after implantation. The scores when compared in both the groups revealed that the results were comparable and significant after 12 months of follow up while the scores were not significant after 3 and 6 months. The results were statistically significant when baseline is compared with different postoperative stages. The children implanted before the age of 4 years had significantly better auditory and linguistic performances. At least 12 months of audio-verbal rehabilitation and speech and language therapy are required to compare the effects of cochlear implant in any set of children. Our study shows that hearing impaired children who receive cochlear implantation below 4 years of age acquires better auditory ability for developing language skills.

Screening of Newborn Hearing at a Tertiary Care Hospital in South India

Hearing loss can have a devastating impact on the cognitive development and psychological well-being of children and their families. Newborn hearing screening should be given special attention especially in a country like ours where the burden of this disability is heavy. Screening all newborns irrespective of risk factors helps in better detection, and hence further management can be initiated at appropriate time. To implement newborn hearing screening at Vanivilas hospital and to estimate the incidence of hearing loss among the high risk groups. To create awareness about the need for detecting childhood deafness among parents and general population. To develop a centre of excellence for evaluation, intervention and rehabilitation for hearing impaired in a tertiary care hospital. Prospective study. All neonates born in Vanivilas Hospital attached to Bangalore Medical College and Research Institute underwent hearing screening using four stage protocols with otoacoustic emission (OAE) tests and final confirmation with Brainstem evoked response audiometry (BERA) tests. May 2015-May 2017. Number of newborns screened were 26,487, and 19 (0.717/1000) newborns were detected to have hearing impairment. The incidence of hearing loss among high risk group was 0.188/1000, and among the non risk group was 0.528/1000. Newborn hearing screening must be made mandatory and multi-staged protocol based screening for hearing loss should be implemented. This will make newborn screening programme more efficient and also will help in initiating treatment at an early stage so that further damage can be prevented.

Outcomes of Newborn Hearing Screening Program: A Hospital Based Study

Hearing loss is hidden disability and second most common congenital pathology. Prevention, early identification and early intervention of hearing loss can prevent further disability in development of speech, language, cognition and other developmental domains. The prevalence of congenital hearing loss has been estimated to be 1.2-5.7 per thousand in neonates. In these contexts, the aim of study was to determine outcomes of neonates hearing screening program in Hospital. It is a clinical cross-sectional study which was conducted in tertiary care centre from 8th July, 2015 to 31th May, 2016. Total no of 2254 cases were screened. Details case history including high risk register, Pediatric Audiometry, Otoacoustic Emission tests were performed followed brainstem evoked response audiometry. The Prevalence of hearing loss among high risk babies confirmation by BERA was 8.8% per 1000 babies and 16 cases were recommended for Cochlear Implant. The screening protocol with objective test i.e. Distortion Product Otoacoustic Emission and confirmation by Brainstem Evoked Response Audiometry is very useful tool in early identification of congenital hearing loss in neonates. Hence, the results of this study will be used to initiate universal newborn hearing screening in other hospitals. Moreover, this study highlights the relevance of neonatal hearing screening in other states of India and country where this screening is not performed routinely in all hospitals and creating awareness to identify neonatal risk factors associated with hearing loss and understand the importance of early identification and early intervention and among health care professionals.

Fetal Central Auditory System Metabolic Response to Cochlear Implant Stimulation

OBJECTIVES: The purpose of this study was to examine the effects of profound auditory deprivation and its treatment by cochlear implantation and stimulation on the metabolic activity of the central auditory system in fetal sheep.

METHODS: Six ovine fetuses at 85% to 90% gestation were bilaterally deafened by kanamycin perfusion and unilaterally implanted with cochlear electrode arrays. Half of the implanted animals were stimulated with an extrauterine sound processor, and half were not. Four animals served as hearing controls. One week postoperatively, central nervous system metabolic activity was evaluated in ambient laboratory noise by quantitative autoradiography using 14C-deoxyglucose.

RESULTS: Kanamycin perfusion deafened all treated animals as verified by auditory brainstem response and scanning electron microscopy. Glucose utilization in the inferior colliculus was markedly lower in deafened and unstimulated animals relative to hearing controls. Glucose utilization in implanted-stimulated animals was similar to normal controls.

CONCLUSIONS: Changes in central auditory system metabolic activity associated with congenital deafness may be minimized by prompt auditory habilitation.

Effects of policy changes to universal newborn hearing screening follow-up in a university clinic

PURPOSE

The purpose of this study was to evaluate the effects of policy changes on loss to follow-up rates and the ability to achieve the goals of the American Academy of Pediatrics Joint Committee on Infant Hearing Screening (2007) for diagnosis of hearing loss by 3 months, amplification within 1 month of diagnosis, and start of intervention by 6 months.

METHOD

From the files of 111 infants, data were extracted on the following: date of birth, birth hospital, hometown, parents' ages, ethnicity, nursery status, medical history, age at initial evaluation and diagnosis, results of evaluation(s), and age at hearing aid fitting and start of early intervention. Data were compared with previously published data from the clinic (Krishnan, 2009).

RESULTS

Policy changes led to a decrease in loss to follow-up and a younger age at diagnosis of hearing loss. Infants identified with hearing loss were fit with amplification at younger ages but not within 1 month of diagnosis of hearing loss. Policy changes had positive outcomes on loss to follow-up and age of diagnosis and amplification.

CONCLUSIONS

Challenges remain in meeting the goals of amplification within 1 month of diagnosis and documenting the start of early intervention. Improved communication between and education of all parties involved in the care of infants is needed.

Universal Newborn Hearing Screening Follow-Up: A University Clinic Perspective

Purpose

To evaluate the referral and follow-up procedures at a university clinic to determine whether the early intervention program is achieving the goals of diagnosis of hearing loss by 3 months, amplification within 1 month of diagnosis, and intervention services by 6 months, as outlined in the Joint Committee on Infant Hearing (JCIH; 2007) position statement.

Method

Files for 142 infants were examined, and the following data were collected from each file: date of birth, birth hospital, hometown, parents' ages, ethnicity, nursery status (well baby or neonatal intensive care unit), medical history, age at initial evaluation and at diagnosis, results of evaluation(s), and age at hearing aid fitting and start of early intervention services.

Results

Results revealed that 17% of infants were older than 3 months at the initial evaluation, and 18% of infants who needed further evaluation were lost to follow-up. None of the infants identified with hearing loss received amplification within 1 month of diagnosis or early intervention services by the age of 6 months.

Conclusions

The findings provide further evidence of the challenges of early intervention programs as stated by the JCIH (2007), and they emphasize the importance of communication between practitioners and implementation of monitoring systems and checks and balances to improve the efficacy of early intervention programs.

Neonatal hearing screening in Albania: Results from an ongoing universal screening program

The paper describes the outcomes of an ongoing universal hearing screening program in Tirana, Albania. The main objectives of the project were the evaluation of the feasibility of a neonatal hearing screening program in Albania, and an evaluation of the prevalence of risk factors in the NICU environment. One thousand five hundred and sixty-one (1561) infants from both the WB and NICU were screened with transient evoked otoacoustic emissions (TEOAE). A detailed history of risk factors was collected in each case, thus it was possible to evaluate the main factors influencing the output of the screening program. It was concluded that the program had the capacity to identify infants with congenital hearing loss provided that an informative component is well-structured and delivered. Also, although the prevalence of risk factors appeared high, the reduction of 'case leakage' would allow the precise estimation of the incidence of hearing loss in the Albanian population.

Neonatal screening for hearing loss: pilot study from a tertiary care centre

Many developed countries have well established universal neonatal hearing screening programs. In India, the viability of such a program, in an already overburdened health system is indeed a challenge. This cross sectional study was undertaken to evaluate the possible burden of hearing loss among neonates born at a tertiary care hospital in Southern India. Five hundred neonates were screened with automated distortion product otoacoustic emission (aDPOAE) for hearing loss, 9.2% of whom had one or more high risk factors. Although 6.4% had hearing loss at initial assessment, only 1.6% had hearing loss on retesting with aDPOAE. Retesting with OAE before an automated Auditory brainstem response (aABR) helped to exclude patients without hearing loss. The frequency of moderate to moderately severe hearing loss in this study was 0.6%. This pilot study underscores the importance of the introduction of screening for congenital deafness in specialized centers in India, despite its challenges.

Hearing Impairment in the Neonate of Preeclamptic Women

Objective

Preeclampsia is a critical condition that puts both pregnant women and their offspring at risk for multiorgan failure, including inner ear, due to systemic toxemia and vascular events. This study was done to determine the probable prevalence of hearing impairment in children whose mothers had pregnancy-induced hypertension, compared to those born to healthy mothers.

Methods and Materials

A cohort study was performed on two groups; the first group was made up of the offspring of preeclamptic women (n = 36) and the second was made up of offspring born to healthy mothers (n = 114). They were matched for sex and age. Other confounding variables that could have influenced the hearing were excluded. Transient evoked otoacoustic emission (TEOAE) and auditory brain response (ABR) tests were performed to screen hearing loss in each group.

Results

Failure rates in the first step for cases and controls were 33.33 percent and 12.76%, respectively, which showed a significant difference statistically ( P = 0.001). However, the final results of the second TEOAE and ABR between the two groups were not statistically significant ( P > 0.05).

Conclusion

Although it does not seem that pregnancy toxemia plays a role in permanent hearing loss in neonates of affected mothers, it might have a transient effect on hearing.

Toward a systems biology of mouse inner ear organogenesis: gene expression pathways, patterns and network analysis

We describe the most comprehensive study to date on gene expression during mouse inner ear (IE) organogenesis. Samples were microdissected from mouse embryos at E9-E15 in half-day intervals, a period that spans all of IE organogenesis. These included separate dissections of all discernible IE substructures such as the cochlea, utricle, and saccule. All samples were analyzed on high density expression microarrays under strict statistical filters. Extensive confirmatory tests were performed, including RNA in situ hybridizations. More than 5000 genes significantly varied in expression according to developmental stage, tissue, or both and defined 28 distinct expression patterns. For example, upregulation of 315 genes provided a clear-cut "signature" of early events in IE specification. Additional, clear-cut, gene expression signatures marked specific structures such as the cochlea, utricle, or saccule throughout late IE development. Pathway analysis identified 53 signaling cascades enriched within the 28 patterns. Many novel pathways, not previously implicated in IE development, including beta-adrenergic, amyloid, estrogen receptor, circadian rhythm, and immune system pathways, were identified. Finally, we identified positional candidate genes in 54 uncloned nonsyndromic human deafness intervals. This detailed analysis provides many new insights into the spatial and temporal genetic specification of this complex organ system.

Meeting the challenge: using policy to improve children's health

We reflect on the proceedings of a symposium at a conference of the Centers for Disease Control and Prevention National Center on Birth Defects and Developmental Disabilities. We present examples of bridging the gap between science and policy to achieve improvements in children's health through case studies in early hearing detection and intervention, folic acid fortification to prevent birth defects, sleep positioning recommendations to reduce infant mortality, and workplace lactation support programs. We discuss case studies that present different policy strategies (public health law and voluntary practices) for improving public health. These case studies demonstrate both the power of policy as a tool for improving children's health and the challenges of communicating public health research to policy decisionmakers.

Normal hearing and language development in a deaf-born child

BACKGROUND

Congenital deafness leads to major problems in speech, language, education, and social integration. Neonatal hearing screening and cochlear implantation now allow early hearing restoration. This article reports on a prospective longitudinal study of the first infant ever who received two cochlear implants in the prelexical period of her life.

METHODS

The first deaf-born girl ever who received two implants at the ages of 5 and 15 months, respectively, was followed-up with repeated and detailed quantitative assessments from birth to 4 years of age. This consisted of 1) audiologic evaluation (audiometry, speech audiometry, and Categories of Auditory Performance score), 2) linguistic evaluation (monthly video analyses and tests of vocabulary, language skills, grammar, and intelligibility of the child's speech), and 3) descriptive assessment of the educational setting.

RESULTS

All results lie within the 95% confidence interval of hearing peers. The audiologic performance lies at or above average from age 2 years onward. The child started babbling at the normal age of 8 months. Her linguistic skills increased from low percentiles before age 2 to above average from age 2 for comprehension and from age 3 for production. The grammar and intelligibility of the child's speech increased from low percentiles to average at age 4. The girl entered preschool at the normal age of 2.5 years, and this with only very limited special assistance.

CONCLUSION

This case illustrates the fact that congenital deafness no longer has to lead to abnormal hearing and abnormal speech development. It opens the debate of the ethics of not implanting a deaf child in the first few months of life.

[Program of hearing loss early detection in newborn infants in Cantabria. Results of the first year of activities]

AIMS

To report the findings in the first year of follow-up of the Cantabrian Program to screen newborn babies for congenital permanent hearing loss.

METHODS

The study population consisted of infants born during a year period in Cantabria (Spain). Universal hearing screening by transient evoked otoacoustic emissions (TEOAE) in 2 stage protocol was performed. Infants with failure scores in these 2 stages and those with risk factors for hearing loss were referred for diagnostic evaluation with auditory brainstem response. Hearing aids were recommended for those infants who had bilateral hearing loss and referrals to infant speech and language rehabilitation.

RESULTS

Out of the 4117 eligible babies, 3987 were studied. One hundred and ten (2.6) had risk factors for hearing loss, 3.5% were referred for audiological assessment and 1.2/1000 were diagnosed as having a permanent hearing loss. The false-positive rate was 0.72% after the two-stage screening procedure was performed. Positive predictive value for permanent hearing loss was 10%.

CONCLUSIONS

During the first year working with the Cantabrian Screening Program for congenital permanent hearing loss in newborn babies, the most part of the proposed aims have been achieved.

Newborn hearing screening in Western Australia

AIM

To report the preliminary findings of a pilot program to screen newborn babies for congenital bilateral permanent hearing loss.

SETTING

The five largest maternity hospitals in Perth, Western Australia. Screening was gradually introduced over seven months from February to August 2000.

PARTICIPANTS

All babies born at these hospitals after the introduction of hearing screening until 30 June 2001.

METHODS

One or both of two automated screening devices were used: one measuring transient evoked otoacoustic emissions (TEOAE) and the other automated auditory brainstem responses (AABR). If a "pass" was not obtained in both ears, screening was repeated. All babies who did not obtain a pass in either ear at follow-up were referred for audiological assessment.

MAIN OUTCOME MEASURES

Prevalence of permanent bilateral hearing loss.

RESULTS

Of 13 214 eligible babies, 12 708 (96.2%) received screening. The main reason for missing screening was early hospital discharge (309; 2.3%). Of the screened babies, 99% had a pass response in both ears at either the initial or follow-up screen. Twenty-three babies were referred for audiological assessment, and nine were diagnosed with bilateral permanent hearing loss (0.68/1000; 95% CI, 0.31-1.28).

CONCLUSIONS

Despite our program meeting process quality indicators, our detection rate was low. Before extending the program to smaller hospitals, we need to validate our screening instruments and put in place a system to monitor false negative results.

The expanding role of the otolaryngologist in managing infants and children with hearing loss

Universal newborn hearing screening will increase the number of very young children requiring care from an otolaryngologist. Although the otolaryngologist is the perceived expert in managing hearing loss, he or she must collaborate with a team of specialists to provide comprehensive treatment for the newly diagnosed child and its family. Working within a team that includes a pediatrician, audiologist, otolaryngologist, speech pathologist, teachers, and care coordinators allows each professional to contribute significantly to the well-being of the child and parents. Group cooperation and parental support can increase the chances of normal speech and language development in an infant with hearing loss. By identifying related or syndromal associations, the otolaryngologist can prevent complications related to other organ systems such as the heart and eyes. Most importantly, parents and patients look up to the validation of the care plan by the ear physician.

Epidemiology of permanent childhood hearing impairment in the Tyrol, 1980-94

In recent years the need for reliable data on permanent childhood hearing impairment (PCHI) has increased, owing to both scientific interest and practical aspects such as implementation of neonatal hearing screening. In order to obtain data about the epidemiology of PCHI in the Austrian state of Tyrol, the medical records of all hearing-impaired Tyrolean children born between 1980 and 1994 were researched. A total of 165 children with at least moderate hearing impairment in the better ear were registered, of whom 52.7% were found to be moderately hearing-impaired, 24.2% severely hearing-impaired and 23.0% profoundly hearing-impaired. Sensorineural hearing loss was observed in 87.3%, conductive hearing loss in 6.7% and mixed hearing loss in 6.1%. As for aetiology, non-syndromic hereditary hearing loss was diagnosed in 22% of the children and syndromic hearing loss in 8%. Congenital malformation of the ear was found in 3%. In 19% of the children, perinatal risk factors were seen, and in 10% a pre-, peri- or postnatal infection had occurred. Aetiology remained unknown in 36% of the children. The prevalence rate of newborn hearing impairment was 1.27/1000 newborns. The results are considered to fit well to the PCHI findings reported from other European regions.

Towards a universal newborn hearing screening

Hearing loss is a common problem which, if remaining undetected during early childhood, could affect the patient's linguistic and mental abilities permanently. Although recommended, mass hearing screening has so far been problematic or even impossible due to several reasons. The available otoacoustic emission devices appear to be effective tools for universal hearing screening. The aim of this study is to evaluate the reliability and practicability of a new device for recording click-evoked otoacoustic emissions (cEOEs) on a pediatric population. Sixty children aged between 6 days and 14 years were evaluated audiologically both by auditory brainstem responses (ABR) and otoacoustic emissions. The latter were obtained by using the well-known ILO88v3.92 otoacoustic analyser and a new, portable device ('Echocheck', Otodynamics Ltd, UK). Sensitivity and specificity of cEOEs recorded by 'Echocheck'was found to be 93% and 91%, respectively, when compared to ABR results. Additionally, 'Echocheck' recordings were proved to be much easier to perform, needing considerably less time in comparison with those of the ILO88 system. In our opinion, 'Echocheck' as well as all similar portable devices--screeners--may represent a much-desired solution for implementing universal hearing screening programmes.

A hospital based universal neonatal hearing screening programme using click-evoked otoacoustic emissions

Since 1997 a hospital-based universal hearing screening programme (Milan Programme) has been carried out at the Neurophysiopathology Unit of the Mangiagalli Clinic in Milan, for the early identification of hearing loss in neonates (5650 well babies, 749 newborns from the Neonatal Pathology Unit (NPU) without risk for hearing loss and 118 newborns at risk for hearing loss). As a result, considering the well baby population, three pathological neonates (one profound bilateral and two unilateral hearing loss) were identified. Three additional cases were found among the NPU newborns, whereas 16 cases with bilateral and 11 with unilateral hearing loss were found among the at-risk babies.

The New York State universal newborn hearing screening demonstration project: ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention

OBJECTIVE

To determine the ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention through a multi-center, state-wide universal newborn hearing screening project.

DESIGN

Universal newborn hearing screening was conducted at eight hospitals across New York State. All infants who did not bilaterally pass hearing screening before discharge were recalled for outpatient retesting. Inpatient screening and outpatient rescreening were done with transient evoked otoacoustic emissions and/or auditory brain stem response testing. Diagnostic testing was performed with age appropriate tests, auditory brain stem response and/or visual reinforcement audiometry. Infants diagnosed with permanent hearing loss were considered for hearing aids and early intervention. Ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention were investigated regarding nursery type, risk status, unilateral versus bilateral hearing loss, loss type, loss severity, and state regions.

RESULTS

The prevalence of infants diagnosed with permanent hearing loss was 2.0/1000 (85 of 43,311). Of the 85 infants with hearing loss, 61% were from neonatal intensive care units (NICUs) and 67% were at risk for hearing loss. Of the 36 infants fitted with hearing aids, 58% were from NICUs and 78% were at risk for hearing loss. The median age at identification and enrollment in early intervention was 3 mo. Median age at hearing aid fitting was 7.5 mo. Median ages at identification were less for infants from the well-baby nurseries (WBNs) than for the NICU infants and for infants with severe/profound than for infants with mild/moderate hearing loss, but were similar for not-at-risk and at-risk infants. Median ages at hearing aid fitting were less for well babies than for NICU infants, for not-at-risk infants than for at-risk infants, and for infants with severe/ profound hearing loss than for infants with mild/ moderate hearing loss. However, median ages at early intervention enrollment were similar for nursery types, risk status, and severity of hearing loss.

CONCLUSIONS

Early ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention can be achieved for infants from NICUs and WBNs and for infants at risk and not at risk for hearing loss in a large multi-center universal newborn hearing screening program.

Non-syndromic autosomal dominant progressive non-specific mid-frequency sensorineural hearing impairment with childhood to late adolescence onset (DFNA21)

An autosomal dominant trait of progressive, non-syndromic, non-specific mid-frequency sensorineural hearing impairment was identified in a Dutch family. Many affected family members (n = 21) were identified, among whom seven out of nine relatives aged < 30 years do not show pure mid-frequency hearing impairment, which suggests variable expression. Regression analysis was used to evaluate the age-related hearing threshold data in a cross-sectional analysis in 24 affected patients and in a longitudinal analysis in five of these. At all frequencies, progression in hearing impairment (i.e. the regression coefficient) was significant and fairly similar: the pooled value was about 1.0 dB/y. There was no significant (i.e. not =0 dB) offset threshold (i.e. Y intercept at age 0) found at any frequency. The regression lines could be pooled for the low frequencies (0.25-0.5 kHz) and the mid/high frequencies (1-8 kHz) and this produced apparent onset ages of about 3 and 4 years and annual threshold increases of 0.75 and 1.1 dB/y, respectively. In most patients there is a relatively late onset age (maximum in the range of at least 25-45 years). However, based on the longitudinal analysis of a patient from the age of 4 years onwards in some patients sensorineural hearing impairment might be congenital/prelingual. Oculo-vestibular function was found to be normal. Results from linkage studies tentatively position the underlying gene defect telomeric to the repositioned DFNA13 locus at chromosome 6p21-22.

The need for universal neonatal hearing screening--some aspects of epidemiology and identification

The devastating consequences of a congenital/early-acquired hearing disability on the speech language and social development of a child and the estimated prevalence rates of at least 1-1.5/1000 live births of congenital permanent hearing impairment are important health problems. Universal neonatal hearing screening programs have provided the opportunity to detect neonates with permanent congenital hearing loss, and thus initiate auditory rehabilitation before the age of 3 mo. Universal neonatal hearing screening represents secondary prevention of hearing impairment/deafness, and the world-wide documented delayed identification of children with congenital/early-acquired hearing impairment will no doubt be improved with the implementation of universal neonatal hearing screening programs.

Neonatal hearing screening with transient evoked otoacoustic emissions: a learning curve

The present paper reports on the implementation of a neonatal hearing screening programme in a private hospital in Belgium. A maternity-based neonatal hearing screening project with transient evoked otoacoustic emissions (TEOAEs) was started in 1993. The cost of the test was not covered by the public health insurance, so the parents had to pay the full cost for screening their child (approximately 30 Euro). Since 1993 the programme strategies have been changed on several occasions to improve the quality and efficacy. A retrospective analysis was performed on: (1) the test pass rate; (2) the coverage; and (3) the number of children who become 'Lost to follow-up' after failing the initial test. The data show a steady learning curve with a time course of several years. They also demonstrate that it is worthwhile and feasible to run a high-quality screening programme in a private establishment.

Hearing screening--aspects of epidemiology and identification of hearing impaired children

Mass screening of hearing in children is based on the concept of secondary prevention. In recognition of the importance of an early identification and intervention in children with congenital or early-acquired (i.e. neonatal period) hearing disability, numerous hearing screening programs have been introduced throughout the world. The devastating consequences of a congenital/early acquired hearing disability upon the speech, language, and social development of a child, and the estimated prevalence rates of at least 1-1.5/1000 live births of congenital permanent hearing impairment, represent an important health problem. The increase in the estimated prevalence of permanent hearing impairment in childhood, reaching at least 3.6-8.2% of live births at 5-9 years of age further emphasizes the importance of the problem. The delayed identification of children with congenital/early acquired hearing disability should result in the implementation of universal neonatal hearing screening, and the negative impact on the learning processes during school age from hearing impairment acquired throughout childhood seems to justify the introduction or maintenance of a hearing screening at school entrance. Implementation of efficient hearing screening programs throughout the neonatal period, infancy, or childhood should result in secondary prevention of this important health problem.

Non-syndromal autosomal dominant hearing impairment: ongoing phenotypical characterization of genotypes

This review is concerned with the present state of phenotypical characterization of known genotypes of non-syndromal autosomal dominant hearing impairment. A brief outline of history and context of phenotyping and genotyping of hearing impairment is given with particular reference to the most recent developments in this field, followed by descriptions of DFNA1, DFNA2, DFNA5, DFNA6/14, DFNA8/12, DFNA9, DFNA 13, DFNA17 and DFNA21. Phenotyping those known genotypes may support the ongoing search for mutations in the corresponding gene and enhance genetic counselling. It is recommended that sufficient attention is given to a detailed description of the phenotype in each (newly) described hereditary hearing impairment disorder.

Progressive cochleovestibular impairment caused by a point mutation in the COCH gene at DFNA9

OBJECTIVES

Analysis of phenotype-genotype correlation.

STUDY DESIGN

Family study.

METHODS

Auditory and vestibulo-ocular functions were examined in a Dutch family with autosomal dominantly inherited sensorineural hearing impairment caused by a 208C > T mutation in the COCH gene, located in chromosome 14q12-q13 (DFNA9). Linear regression analysis of individual longitudinal hearing threshold data (n = 11) on age was performed.

RESULTS

Fifteen of the 16 genetically affected persons could be evaluated. They all developed hearing and vestibular impairment symptoms--and in many cases also cardiovascular disease--in the fourth to fifth decade. At the low frequencies (0.25-2 kHz), hearing loss started at the age of about 40 years and showed an average annual progression of approximately 3 dB, finally resulting in profound hearing losses. In two exceptional cases, annual progression attained levels of up to 24 dB. At the high frequencies (4-8 kHz), the average threshold increased from about 50 dB at the age of 35 years to about 120 dB at the age of 75 years (which amounts to 1.8 dB annual threshold increase). All affected individuals tested showed normal ocular motor functions. The patients older than 46 years generally showed absence of the vestibulo-ocular reflex, but their cervico-ocular reflex was enhanced compared with normal subjects, whereas those aged 40 to 46 years showed either severe vestibular hyporeflexia or unilateral caloric areflexia.

CONCLUSION

These findings suggest a gradual development of cochleovestibular impairment caused by the new mutation found.

Prevalence and characteristics of children with serious hearing impairment in metropolitan Atlanta, 1991-1993

OBJECTIVES

There is a paucity of data describing the epidemiology of serious hearing impairment among children in the United States. This report provides information on the prevalence of serious hearing impairment among children born in the 1980s and living in the metropolitan Atlanta area in 1991-1993 and on the characteristics of children with serious hearing impairment.

METHODS

Data for this report are drawn from the Metropolitan Atlanta Developmental Disabilities Surveillance Program, an ongoing, active case-ascertainment system for mental retardation, cerebral palsy, hearing impairment, and vision impairment among children 3 to 10 years of age. Hearing impairment was defined as a bilateral, pure-tone hearing loss at frequencies of 500, 1000, and 2000 Hz averaging 40 decibels or more, unaided, in the better ear. Both severity and type of hearing loss were examined. Cross-sectional as well as birth cohort prevalence rates of serious hearing impairment were computed by sex and by race. The presence of mental retardation, cerebral palsy, vision impairment, or a seizure disorder was also assessed. An attempt was made to determine the probable etiology of a subset of the cases.

RESULTS

The average, annual prevalence rate for moderate to profound hearing loss was 1.1 per 1000. The prevalence rate increased steadily with age. Ninety percent of all cases for which the type of loss was recorded were sensorineural. The highest rate was seen among black male children (1.4 per 1000). Thirty percent of case children had another neurodevelopmental condition, most frequently mental retardation. Black male children also experienced the highest rate of presumed congenital hearing impairment. The mean age at which children with presumed congenital hearing impairment first met the surveillance case definition was 2. 9 years. A probable etiology could only be found for 22% of cases born in the study area.

CONCLUSIONS

The data presented here provide information on the descriptive epidemiology of serious hearing impairment among United States children. The reasons for the higher rates among black children, especially males, may be a fruitful direction for further research.

Language of early- and later-identified children with hearing loss

OBJECTIVE

To compare the language abilities of earlier- and later-identified deaf and hard-of-hearing children.

METHOD

We compared the receptive and expressive language abilities of 72 deaf or hard-of-hearing children whose hearing losses were identified by 6 months of age with 78 children whose hearing losses were identified after the age of 6 months. All of the children received early intervention services within an average of 2 months after identification. The participants' receptive and expressive language abilities were measured using the Minnesota Child Development Inventory.

RESULTS

Children whose hearing losses were identified by 6 months of age demonstrated significantly better language scores than children identified after 6 months of age. For children with normal cognitive abilities, this language advantage was found across all test ages, communication modes, degrees of hearing loss, and socioeconomic strata. It also was independent of gender, minority status, and the presence or absence of additional disabilities.

CONCLUSIONS

Significantly better language development was associated with early identification of hearing loss and early intervention. There was no significant difference between the earlier- and later-identified groups on several variables frequently associated with language ability in deaf and hard-of-hearing children. Thus, the variable on which the two groups differed (age of identification and intervention) must be considered a potential explanation for the language advantage documented in the earlier-identified group.

State of the States

This study reports the results of a comprehensive survey of 16 states regarding the coordination and characteristics of universal newborn hearing screening, audiologic assessment, and intervention programs. The survey establishes a baseline assessment that was conducted by states as part of their first year of participation in a Maternal and Child Health Bureau grant on state systems for universal newborn hearing screening, assessment, and intervention. States are making progress toward achieving universal newborn hearing screening. However, several issues continue to impede the establishment of statewide systems for linking screening programs to diagnosis and intervention.

Epidemiology of moderate to profound childhood hearing impairments in northern Finland. Any changes in ten years?

The epidemiology of childhood hearing impairments was studied in a clinical series of the birth cohorts for 1973-82 and 1983-92 from a geographically well-defined area. The overall prevalence of hearing impairments with PTA0.5-4 kHz > or = 40 dB was 1.2/1000 live births. Even in the later cohort, the median age ascertainment was 2.6 years for the congenital or early acquired group and 3.0 years for all impairments. Risk indicators for hearing impairment were present in half of the children, and those referred for the risk were ascertained at the median age of 1.1 years. The delay from suspicion to ascertainment was over a year in about one fifth of cases, while the median time from referral to ascertainment was only 1.8 months. The planning and implementation of neonatal hearing screening are suggested, and general information is given on paedoaudiology for both parents and professionals. A database could be beneficial in increasing the systemacy of the diagnostic process.

Infant hearing screening: a comparison of two techniques

Hearing screening programs for Australian children are known to have poor coverage in many areas. In addition, only a minority of children are screened for hearing loss before 2 years of age. However, early detection of hearing loss and early treatment are generally considered very important to successful rehabilitation outcomes. Traditional methods of screening infants have limitations with their accuracy in detecting children with hearing loss. This study compared the results obtained with a traditional questionnaire approach to screening and a newer objective technique involving otoacoustic emission measures. Poor correlation was found between pass rates for the two techniques, suggesting that the questionnaire approach is not an accurate screening method for detecting infant hearing loss. With further development, otoacoustic emission testing holds promise as an objective alternative hearing screening procedure.

Conditions for paediatric hearing screening: a survey in 28 Finnish child welfare clinics

The present Finnish paediatric hearing screening programme was assessed by interviewing nurses and doctors in 28 child welfare clinics responsible for the hearing screening of 18,500 preschool children. Practical issues which might have effects on both performing the screenings and referring the children with abnormal screening results were emphasised. This survey brought out a great variety of deficiencies, which may contribute to the existing delayed diagnosis of hearing impairments. Hearing screening was routinely done 4-12 times per child before school age, instead of the 3 times recommended. Methods with a nonspecific frequency range and sound pressure level were often used. Audiometers were only used in 22 of the 28 clinics, and in only 9 clinics were the audiometers calibrated yearly. The median time of working in the child health care field at that particular health centre was 7 y for the nurses and 6 y for the doctors. Both the nurses and the doctors had numerous responsibilities other than paediatric hearing screening. Implementation of an updating training programme in paediatric audiology for the personnel is recommended.

Prevalence and etiology of bilateral sensorineural hearing impairment in a Finnish childhood population

A retrospective study was performed on the prevalence and etiology of bilateral sensorineural hearing impairment (> 25 dB at 0.5-4 kHz in the better ear) among children born 1974-1987 in a province of eastern Finland. A total of 98 children with hearing impairment were identified, which gave a prevalence of 2.1 per 1000 live births. This prevalence was higher than reported form most of other developed countries but slightly lower than reported from Sweden. A slight decline from the prevalence of 2.3 per 1000 in the 1970s to the prevalence of 1.9 per 1000 in the 1980s was observed. Contrary to several earlier studies, no male predominance was noted, there were even slightly more females than males (52 vs. 46). Etiology of the hearing loss was estimated to be genetic in 41%, congenital nongenetic in 13%, delayed-onset nongenetic in 16% and remained unknown in 30%. On average, children with a congenital disorder had more severe hearing impairment than those with delayed-onset hearing loss, e.g. 31% of the former patients had profound (> 95 dB) hearing loss compared to 6% of the latter. A very gratifying finding was that no case of congenital hearing impairment caused by maternal rubella was identified after 1982, obviously due to general vaccinations. Also, a decline in cases of hearing loss attributed to perinatal and neonatal complications was observed.

Universal newborn hearing screenings: a three-year experience

OBJECTIVE

To perform hearing screenings on all newborns before hospital discharge, using auditory brainstem evoked responses with analysis of time, cost, and failure rates to evaluate and determine the screening practicality.

METHOD

Over a 3-year period from January 1, 1993 to December 31, 1995, auditory brainstem evoked response screenings were performed on 15 749 infants born at Saint Barnabas Medical Center, Livingston, New Jersey, before their hospital discharge by certified/licensed audiologists. The auditory brainstem evoked response screenings were conducted using the Nicolet Compass Evoked Potential System.

RESULTS

A 3-year experience of testing 15 749 infants proved to be a cost-effective program with costs less than $30.00/baby. To date, 46 babies have been identified with bilateral sensorineural hearing loss and 6 babies with unilateral sensorineural hearing loss.

CONCLUSIONS

The universal newborn hearing screening program at Saint Barnabas Medical Center has proved to be effective, beneficial, and necessary for an institution with more than 5000 births, annually. Early identification of hearing loss has resulted in infants receiving early intervention, and the screening program has provided education and follow-up services to both parents and physicians.

Profound permanent hearing impairment in childhood: causative factors in two European countries

A collaboration between Denmark and Wales was established in order to evaluate any differences between countries in factors causing permanent childhood hearing impairment (PCHI). Two identical 6-year birth-cohorts from 1975-1980 suffering from a permanent hearing loss > or = 90 dB HL in the better hearing ear, averaged across 0.5-4 kHz (BEHL), were included in the analysis. The overall estimated prevalence of children with this loss was 0.41/live births in Wales (n = 59). In Denmark the overall prevalence was 0.45/1,000 live births (n = 34), there being no significant differences in prevalence between the two countries. Both cohorts were subjected to a multidisciplinary investigation protocol. No significant differences were found between countries in the proportion of hearing impairment caused by the various factors, when based on uniform criteria and identical birth-cohorts. The proportion of inherited hearing loss is 47-50% in the two countries. Within inheritance the proportion of non-syndromal/syndromal inheritance differs slightly, as non-syndromal inheritance comprises 50% in Wales, and 76% in Denmark. The reported proportion of 16-34% of unknown factors causing profound PCHI emphasises the need for appropriate protocols for aetiological evaluation.

Identification and diagnostic evaluation of hearing impairments in early childhood in German-speaking infants

The present study was devised to gather epidemiological information to aid in understanding the etiology, identification, and management of children with permanent hearing losses in Lower Saxony as a defined geographical area of Germany. All infants and preschool children were identified in the Department of Phoniatrics and Pediatric Audiology during a 1-year period (October 1994 until October 1995). Forty-four hearing-impaired children were identified, of whom 41 (93%) had sensorineural losses and 3 had pure conductive losses. Thirty-two children (73%) had bilateral hearing impairments. The causes of hearing loss were unknown in 17 children (39%). The median age of identification for the study group was 32 months, with a median age of 35.5 months when fitting hearing aids. Severity of hearing loss was inversely associated with age of identification. Prelingually deaf children had the worst comprehension levels of all children tested psychologically. Results were tabulated and special references to other studies were discussed. Our findings show again that the successful out-come of speech and language development depends on early identification and management of the hearing loss, and on continued assessment of the progress of habilitation. These require a basic assessment of the stage of language development (in perception and expression) as relevant rehabilitation measures. The next step is the treatment of existing linguistic deficits followed by retests at regular intervals.

The effect of neonatal universal hearing screening in a health surveillance perspective--a controlled study of two health authority districts

The contribution describes the effect of a neonatal hearing screening program in terms of estimated prevalence rate of congenital hearing impairment and age at identification in two five-year cohorts born between 1990 and 1994 as a function of health authority districts (HADs). In addition, identically defined five-year birth cohorts from 1970 to 1974 and 1980 to 1984 living in the same HADs evaluated previously are used in the analysis, offering longitudinal data. In 1990 a non-targetted neonatal hearing screening program based on EOAE was introduced in the County-HAD, whereas the City-HAD continued its child hearing health surveillance program unchanged. Assuming an unchanged prevalence estimate of 1.5 per 1000 of congenital or early acquired (i.e. neonatal period) hearing disability, i.e. > or = 25 dB HL for the better ear at 0.5-4 kHz in both HADs, an underestimate of 68 per cent in the City and of 20 per cent in the County, respectively, was found at the time of data collection (January 1995). Significant longitudinal improvements in the early identification from the 1970-1974 cohort compared to the 1980-1984 cohort has been demonstrated, but the improvement in the proportion of children identified as a function of both 6 and 12 months of age in the 1990-1994 cohort is significantly greater, showing a median age at identification of 11 months in the County-HAD. The cross-sectional and longitudinal comparisons between the HADs imply that a neonatal universal hearing screening program with a 20 per cent coverage may add significantly to the early identification of children with early-onset hearing impairment.

Epidemiology of permanent hearing impairment in children in relation to costs of a hearing health surveillance program

The objective of this investigation was to estimate the prevalence of any permanent hearing impairment (PHI) in the right and or left ear based on children included into a surveillance program in the local pediatric hearing health services (PHHS), and to analyze the costs, generated by the children. The study is a cross-sectional study, which is part of a major prospective study directed towards delineation of all aspects of pediatric audiology. The present sample comprises 228 children, 115 males and 113 females, at a median age of 13 years, range 0-24, and involves all children living in the health district of the City of Copenhagen, who are or have been included in a local surveillance program with one (school children) or two (pre-school children) annual visits for children with PHI > 20 dB HL at any frequency in either the left or the right ear. The prevalence of PHI increases with increasing age, reaching its peak in the age band 10-14 years exhibiting a rate of 5.32 1000 (95% confidence intervals: 4.27 to 6.64 per 1000). The estimated incidence of PHI in a ten year cohort born 1977-1986 is 325 100 000 children born (95% confidence intervals: 277 to 382 per 100 000). The most frequent factor causing PHI is inheritance, showing an increase from 20% in 1977-1981 cohorts, to 37% in 1982-1986 cohorts. The costs involved in the PHHS concerning PHI varies considerably from approximately 345 000 to 990 000 DKr.. depending on the model used for the economical analysis. No data on cost-benefit or cost-effectiveness can be given in this context, and it is concluded that the documented changes in the prevalence and causes of PHI in children emphasize the need for a continuous monitoring and evaluation of the epidemiological figures.

Rehabilitation of hearing-impaired children: intervention and outcome

A cohort of 72 hearing-impaired children of a median age of 9.7 years, range 4.3-13.9, born during 1980-1990 and living in the health district of Copenhagen City was examined cross-sectionally in order to evaluate the interval from identification to the initial fitting of hearing aids (HAs) and children's use of HAs. As measures of outcome, the use of HAs at 1, 6, 12 months after fitting, and at the time of data collection was assessed along with the primary language of each child. One month after the fitting, 53% of the total sample used the HAs > 8 h/day, and no significant longitudinal changes in the proportion of time-related use were found. 56% of the children stayed in the same user category during the years, while the rest either increased (25%) or decreased (19%) the use of amplification from 1 month after fitting to the time of data collection. Children with better ear hearing level (BEHL) 0.5-4 kHz between 60 and 89 dB used the HAs significantly more than those with mild or profound hearing impairments, whereas age at onset (congenital, acquired, age at onset unknown) and age at intervention were unrelated to use of amplification. 72% of the children were oral, while 25% were manual (unknown 3%), and no differences in the use of HAs were found between these two groups. A subdivision of congenitally hearing-impaired children according to BEHL 0.5-4 kHz below/above 75 dB demonstrated a significantly larger proportion of manual children in the poorer hearing group despite a significantly younger amplification age. It is concluded that age at intervention is unrelated to primary language, although the number of children precludes dependable conclusions.

Prevalence of childhood hearing impairment in southern Finland

The Department of Audiology in Helsinki University Central Hospital provides paedoaudiological services for the Province of Uusimaa, including Helsinki. Our purpose was to study the prevalences of hearing threshold loss in children born in the period 1973 to 1990. The material consisted of 353 hearing-disabled children. The pure-tone average (0.5, 1 and 2 kHz) of the better ear was the parameter for hearing threshold. In 36 subjects the hearing acuity was determined with the behavioural observation test or the brainstem electric response measurement. The number of hearing-impaired per birth year (hearing level > or = 35 dB) ranged from 6 to 30 and the prevalence rate from 0.3 to 1.9 in 1000, totalling 1.1. After matching the hearing-impairment criteria with those of the previous reports from northern Sweden, Denmark and the European Community, we were able to compare the prevalences.

The causes of profound hearing impairment in a school for the deaf--a longitudinal study

The study was aimed towards an evaluation of the causes of hearing loss in children attending the School for the 'Deaf' in Copenhagen in 1993-4 in comparison to causes evaluated 10 and 40 years previously (Arnvig, 1953; Holten and Parving, 1985). The 124 children attending the school in 1993 represent 0.04% of the age-matched target population of 312,715. A more detailed evaluation of two comparable cohorts born in 1969-77 and 1979-87 demonstrates a significant increase of children attending this type of school from 0.03% to 0.05% within a 10-year period, while a comparison between 1953 and 1993 demonstrates a reduction from 0.07% to 0.04%. The longitudinal evaluation of the causes of hearing loss showed a significant increase in the frequency of congenital inherited hearing impairment from 29% (1953) through 33% (1983) to 43% (1993), whereas a significant reduction of about 17% in the frequency of acquired deafness due to chronic otitis media was found. Between 1953 and 1993 a minor reduction (2%) in post-meningitic acquired hearing impairment was found, between 1953 and 1983 there was a significant increase in prenatal infections, compared with a decrease of 6% between 1983 and 1993. It is concluded that significant changes are found both in the prevalence of children referred to the school and in the factors causing severe to profound hearing impairment in children. Continuous recording of, and improvement in, diagnostic classification is necessary to obtain preventive measures.