Outcomes of neonatal screening for hearing loss by otoacoustic emission

National Infant Screening for Hearing Program in India: Necessity, Significance and Justification

Hearing impairment is one of the most prevalent disorder in children and adults worldwide, which not only interferes with the acquisition, development and maintenance of speech and language skills but also adversely deprive the auditory nervous system for future learning. It can have long term harmful effect on educational, social, emotional and cognitive skills in young children; restrict the vocational options and employment opportunities in adults; and can cause isolation, loneliness and depression in older adults, if remain undetected and intervened at the earliest. However, early identification and intervention is known to greatly reverse the ill effects and improve the quality of life of children and adults with hearing impairment. Current clinical means and methods to identify and intervene hearing loss are convenient, cost effective, reasonably accurate beneficial and evidenced based, can be easily employed nation-wide for early identification and intervention of hearing loss. This paper attempts to convince medical colleagues, public health care experts and policy makers by justifying the hearing, as public health issue and relevance of medical screening criteria for hearing. It also discusses the preferred model of hearing screening and intervention strategies in India.

Prevalence of permanent childhood hearing loss detected at the universal newborn hearing screen: Systematic review and meta-analysis

CONTEXT

Permanent childhood hearing loss (PCHL) can affect speech, language, and wider outcomes. Adverse effects are mitigated through universal newborn hearing screening (UNHS) and early intervention.

OBJECTIVE

We undertook a systematic review and meta-analysis to estimate prevalence of UNHS-detected PCHL (bilateral loss ≥26 dB HL) and its variation by admission to neonatal intensive care unit (NICU). A secondary objective was to report UNHS programme performance (PROSPERO: CRD42016051267).

DATA SOURCES

Multiple electronic databases were interrogated in January 2017, with further reports identified from article citations and unpublished literature (November 2017).

STUDY SELECTION

UNHS reports from very highly-developed (VHD) countries with relevant prevalence and performance data; no language or date restrictions.

DATA EXTRACTION

Three reviewers independently extracted data and assessed quality.

RESULTS

We identified 41 eligible reports from 32 study populations (1799863 screened infants) in 6195 non-duplicate references. Pooled UNHS-detected PCHL prevalence was 1.1 per 1000 screened children (95% confidence interval [CI]: 0.9, 1.3; I2 = 89.2%). This was 6.9 times (95% CI: 3.8, 12.5) higher among those admitted to NICU. Smaller studies were significantly associated with higher prevalences (Egger's test: p = 0.02). Sensitivity and specificity ranged from 89-100% and 92-100% respectively, positive predictive values from 2-84%, with all negative predictive values 100%.

LIMITATIONS

Results are generalisable to VHD countries only. Estimates and inferences were limited by available data.

CONCLUSIONS

In VHD countries, 1 per 1000 screened newborns require referral to clinical services for PCHL. Prevalence is higher in those admitted to NICU. Improved reporting would support further examination of screen performance and child demographics.

Detection of Deafness in Puppies Using a Hand-Held Otoacoustic Emission Screener

The purpose of this study was to evaluate the use of a hand-held otoacoustic emissions screener to detect deafness in puppies. Specifically, distortion product otoacoustic emissions were recorded from 34 puppies (both sexes) of a variety of breeds, from 6-10 wk of age, and the results were compared to brainstem auditory evoked responses (BAER) recorded from the same puppies. Recordings were obtained from both ears in awake or lightly anesthetized puppies, and the results from each ear were compared. In all 62 ears that had normal BAERs, the distortion product otoacoustic emissions screener gave a response of "Pass." The three puppies that had flat BAER recordings in one or both ears provided a screener result of "Refer." In two ears with unusual BAERs (waveforms with reduced amplitudes and prolonged latencies) and a "Refer" response from the screener, there was compacted debris in one external ear canal, and the other ear canal was normal. The screener technology has proven application in human infants and is an attractive alternative to BAER testing in puppies because of expense and ease of use.

Language ability in children with permanent hearing impairment: the influence of early management and family participation

OBJECTIVE

The goal was to examine the relationships between management after confirmation, family participation, and speech and language outcomes in the same group of children with permanent childhood hearing impairment.

METHODS

Speech, oral language, and nonverbal abilities, expressed as z scores and adjusted in a regression model, and Family Participation Rating Scale scores were assessed at a mean age of 7.9 years for 120 children with bilateral permanent childhood hearing impairment from a 1992-1997 United Kingdom birth cohort. Ages at institution of management and hearing aid fitting were obtained retrospectively from case notes.

RESULTS

Compared with children managed later (> 9 months), those managed early (< or = 9 months) had higher adjusted mean z scores for both receptive and expressive language, relative to nonverbal ability, but not for speech. Compared with children aided later, a smaller group of more-impaired children aided early did not have significantly higher scores for these outcomes. Family Participation Rating Scale scores showed significant positive correlations with language and speech intelligibility scores only for those with confirmation after 9 months and were highest for those with late confirmed, severe/profound, permanent childhood hearing impairment.

CONCLUSIONS

Early management of permanent childhood hearing impairment results in improved language. Family participation is also an important factor in cases that are confirmed late, especially for children with severe or profound permanent childhood hearing impairment.

Success rate of newborn and follow-up screening of hearing using otoacoustic emissions

OBJECTIVE

During the last 6 years, and after a long period of pilot study, a universal newborn hearing screening program based on otoacoustic emissions is implemented in Iaso Maternity Hospital. Our purpose is to present the success rate of otoacoustic emission testing on discharge from the hospital and 1 month later.

METHODS

All full-term newborns who were screened during a period of 2 years and failed testing after one or more sessions of transiently evoked otoacoustic emissions, on discharge from the hospital, were included in the study. These newborns were retested approximately 1 month after discharge.

RESULTS

Twenty-five thousand and thirty-two newborns were examined in total. We found 534 (2.1%) 'refer' cases. Only 223 of them (41.8%) returned to retest in follow-up after 1 month. From the rescreening, 59 (2.3 per thousand) newborns failed in the test again and were referred for diagnostic audiological evaluation.

CONCLUSIONS

The rate of referrals was small, but efforts should be made to decrease it further. The final number of 'failures' found, approaches the expected rate of definitely diagnosed deafness reported from other settings. The main problem we have still to confront is the high missed to-follow-up rate.

Making universal newborn hearing screening a success

OBJECTIVE

Following a long period of pilot study, Iaso maternity hospital established a universal newborn hearing screening program based on transiently evoked otoacoustic emissions (TEOAEs). The aim of this study is to present the improvement of outcome measures of this program, comparing the results of two groups of newborns screened successively.

METHODS

We analyzed data from two groups of full-term newborns screened at our setting. The first group included all newborns born and screened during the initial 3 years of application of the program and the second group included all newborns born and screened during the next 2 years. TEOAEs were performed during the first days after birth. All newborns who failed the initial test underwent repeat testing with TEOAEs before hospital discharge. Newborns with absence of otoacoustic emissions were referred to follow-up test after 1 month. Results were compared between the two groups.

RESULTS

The first group included 22,195 newborns-examined during 3 years and the second group included 25,032 newborns-examined during 2 years, due to reduction of the rate of newborns who missed screening. Refer rate was 3.1% for the first group and 2.1% for the second group. "Missed to follow-up" rate was reduced from 72.2% in the first group to 58.2% in the second group.

CONCLUSIONS

The rate of newborns who did not undergo screening and the rate of "missed to follow-up" newborns were reduced in time, due to various modifications of the protocol. Universal newborn hearing screening may be, thus, a feasible and cost effective method of identifying congenital hearing loss.

A two-step scenario for hearing assessment with otoacoustic emissions at compensated middle ear pressure (in children 1-7 years old)

OBJECTIVE

Otoacoustic emissions (OAEs) are widely used for assessing congenital and early-acquired sensorineural hearing loss in young children. Middle ear pathology has a negative effect on the presence of OAEs. In this study we investigated whether measuring OAEs at compensated middle ear pressure (CMEP) resulted in a higher pass rate than at ambient pressure. Secondly, we analysed the influence of 12 different pass definitions on the pass rates.

METHODS

One hundred and eleven children (age 1-7 years, mean 4 years and 5 months) were measured twice in one session: first at ambient pressure and then at CMEP.

RESULTS

The study showed a higher pass rate of OAEs at CMEP than at ambient pressure. A two-step scenario reduced the number of fails by 18-26%, depending on the pass/fail definition used.

CONCLUSION

Measuring OAEs at CMEP results in higher pass rates. Secondly, pass/fail definitions have a large influence on pass rates and this issue deserves further attention. Further studies must be done, before this method is readily applicable to universal neonatal screening.

Decreasing test time in newborn hearing screening

This study examined the effect of reducing the number of accepted responses in transiently evoked otoacoustic emissions based on the results of a universal neonatal hearing screening program. Our intention was to decrease the test time of newborns. A total of 464 ears were examined by using a universal newborn hearing-screening program implemented in a private maternity hospital. ILO88 Otodynamics Analyzer Quickscreen program was used for all testing and a two-stage procedure was adopted. In the first stage, the results were continuously evaluated for the 'pass' criteria, during the test, after at least 20 low-noise sweeps had been presented. As soon as the criteria were met, the test was interrupted and the results were recorded. In the second stage of the procedure, the test was continued and finally terminated after 260 quiet samples had been recorded. The results of each stage of this procedure were compared and evaluated. A total of 402 ears had normal otoacoustic emissions and only 62 ears had absent emissions. It was concluded that after a minimum of 20 averaged quiet responses, which we consider necessary in order to record reliable emissions and as soon as the 'pass' criteria were fulfilled the test could be terminated without affecting the 'pass-fail' rates which were similar in both stages. However, we believe that for diagnostic and clinical purposes, all 260 quiet samples must be used, because the results after the second stage indicated statistically better scores in response and reproducibility measures.

Qualitative analysis of parents' experience with early detection of hearing loss

AIMS

To determine key themes from parents' comments on paths to diagnosis and intervention for their children with hearing loss, following introduction of at-risk neonatal hearing screening and modification of distraction test screening for infants not at-risk.

METHODS

Parents of children born in 1993 in Victoria, Australia, who were eligible for screening via the Victorian Infant Hearing Screening Program and who were subsequently diagnosed with a permanent congenital hearing loss and fitted with hearing aids prior to the year 2000 were asked to complete a semi-structured questionnaire shortly after aid fitting. Two researchers independently analysed parent comments using the constant comparative method.

RESULTS

Parents of 82 children (61%) replied to the questionnaire. Themes analysis revealed a generally positive response to neonatal ABR screening, with a mixed response to the distraction test; powerful emotions experienced by parents at diagnosis including denial and shock; frustration arising from delays in diagnosis, and communication difficulties with providers. Special difficulties testing children with other medical and developmental problems, confusion about tympanostomy tube insertion, and difficulty with wearing hearing aids were also reported. Some children had experienced problems in the school setting. Experience of post-diagnostic services was generally positive.

CONCLUSIONS

Parents need greater support both during the testing of screen failures and at the time of diagnosis. Providers need more training in how to communicate findings to parents, particularly at times when parents are experiencing strong emotions. Parents need more strategies to enable hearing aid wearing in very young children. Some children with additional medical, developmental, and behavioural problems need specialised approaches to testing.

Projected cost-effectiveness of statewide universal newborn hearing screening

OBJECTIVES

Early identification of hearing impairment may improve language outcomes and subsequent school and occupational performance of the deaf. Universal newborn hearing screening (UNHS), currently mandated by 32 states, can reduce the median age of identification of hearing impairment from 12 to 18 months to 6 months or less. However, because false-negative tests must be minimized, the prevalence of congenital deafness is low, and screening tests are imperfect, UNHS results in many false-positive results and has a low positive predictive value (PPV). The objective of this study was to evaluate UNHS and selective screening in terms of both short- and long-term benefits, harms, and financial costs and to identify steps in the screening process that could be improved to increase cost-effectiveness.

METHODS

The cost-effectiveness analysis, conducted from the societal perspective, compared the projected outcomes of 1) no newborn hearing screening, 2) selective newborn hearing screening, and 3) UNHS for a hypothetical state birth cohort of 80 000 infants. Probability and cost estimates for the decision model were obtained from published studies, expert opinion, and national and state sources. The main outcomes were incremental cost per infant whose deafness was diagnosed by 6 months, which included only the cost of screening and diagnostic evaluation; and incremental cost per deaf child with normal language, which also included the costs of medical care, education and assistive devices, and lost productivity over the lifetime of the deaf individual.

RESULTS

Selective screening identified 62 of the 128 deaf infants in the birth cohort, referred 0.18% of all infants for diagnostic evaluation, and had a PPV of 43%. UNHS identified 116 of the 128 deaf infants, referred 1.6% of all infants, and had a PPV of 8.8%. Our model simulated real-world conditions in which some infants whose deafness is identified at screening do not receive a definitive diagnosis of being deaf before 6 months; and a portion of deaf and hard-of-hearing infants who 1) have false-negative screening test results, 2) are not screened, or 3) fail the hearing screen but are not immediately followed up with diagnostic evaluation nonetheless receive a diagnosis by 6 months of age. In the absence of newborn hearing screening, approximately 30 deaf infants were identified by 6 months of age by passive detection alone at a cost of $69 000. The selective screening protocol, when compared with no newborn hearing screening, resulted in an additional 36 infants whose deafness was diagnosed by 6 months at an additional cost of approximately $600 000, yielding an incremental cost-effectiveness of approximately $16 000 per additional infant whose deafness was diagnosed by 6 months. Compared with selective screening, the UNHS protocol resulted in 33 additional infants whose deafness was diagnosed by 6 months of age at an additional cost of approximately $1.5 million, yielding an incremental cost-effectiveness of approximately $44 000 per additional infant whose deafness was diagnosed by 6 months of age. Increasing the rate of follow-up to diagnostic evaluation from the base-case estimate of 77% to 100% decreased the incremental cost of UNHS to $38 000 per additional infant whose deafness was diagnosed by 6 months. Under the base-case assumptions about lifetime savings that result from normal language with early intervention, UNHS resulted in normal language achievement for more deaf children and was cost saving in the long term compared with both selective screening and no screening.

CONCLUSIONS

The short-term cost-effectiveness of UNHS is comparable to the cost per case diagnosed of other newborn screening programs and could be improved by increasing the rate of follow-up to diagnostic evaluation after positive screening test results. If early identification results in improved language abilities, lower educational and vocational costs, and increased lifetime productivity, then UNHS has the potential for long-term cost savings compared with selective hearing screening and no screening. To understand the actual long-term economic effects of UNHS, better evidence is needed regarding the impact of early intervention on language outcomes and subsequent changes in educational costs and lifetime productivity.

Emissão otoacústica evocada transitória: instrumento para detecção precoce de alterações auditivas em recém-nascidos a termo e pré-termo

Introdução: O diagnóstico e a intervenção precoces nas alterações auditivas são de fundamental importância no desenvolvimento infantil. O registro das emissões otoacústicas tem sido largamente indicado, por ser um exame rápido, de fácil aplicação. Objetivo: Os objetivos do presente estudo foram avaliar a função auditiva periférica de recém-nascidos a termo e pré-termo adequados e pequenos para a idade gestacional, por meio da pesquisa das emissões otoacústicas transitórias, identificando a prevalência de alterações auditivas nesta população; verificar a influência das variáveis idade gestacional e peso ao nascimento, assim como de tipos de tratamento, ventilação mecânica, administração de medicamentos ototóxicos e permanência em incubadora e analisar os fatores que interferem nos programas de triagem auditiva neonatal. Forma de estudo: Clínico prospectivo. Material e método: Foram avaliadas 157 crianças, sendo 43 nascidas a termo, 79 pré-termo adequadas à idade gestacional e 35 pré-termo pequenas à idade gestacional. Resultado: Observou-se que recém-nascidos prematuros falham mais nas respostas das emissões otoacústicas. A prevalência de perda auditiva condutiva na população estudada foi de 29 orelhas para 1000 e para perda auditiva neurossensorial de 16 orelhas para 1000. As crianças de peso baixo ao nascimento foram as mais difíceis de serem avaliadas. As emissões otoacústicas transitórias foram observadas a partir de 27 semanas de idade gestacional. Os tipos de tratamentos utilizados foram fatores que influenciaram negativamente nas respostas das emissões otoacústicas nos grupos de prematuros. Conclusão: O trabalho de diagnóstico precoce da perda auditiva deve ser objetivo de equipe interdisciplinar -- neonatologista, pediatra, otorrinolaringologista, fonoaudiólogo, enfermeiro e familiares -- e deve ser seguido, imediatamente, por programas de intervenção precoce.

The feasibility of hospital-based universal newborn hearing screening in the United Kingdom

Current hearing screening programmes in the United Kingdom are performing unacceptably poorly. Davies et al. (1997) suggested that universal newborn hearing screening (UNHS) would be more effective and cheaper to run. However, there is concern that hospital-based UNHS would not be feasible because of early postnatal discharge, and thus babies not staying in hospital long enough to be screened. Two studies were designed to determine the viability of hospital-based UNHS in a district general hospital in the United Kingdom. Study 1 retrospectively determined the discharge age and time of discharge of all 3021 well babies born at St Helier hospital, Carshalton, and the number of babies born at home in the area, from 19 October 1997-18 October 1998. Most well babies were found to pass through hospital at a convenient time for predischarge hearing screening, and the optimal protocol was screening from 9 am-2 pm, 7 days a week. The predicted maximal screening coverage was 92.68%. Study 2 tested the calculated optimal protocol over 1 week. It was found that UNHS with otoacoustic emissions on the maternity ward from 9 am-2 pm, 7 days a week, achieved a coverage of 89.06%, with an acceptable false positive rate of 6.2%. It is likely that a similar protocol with slight modifications could be implemented successfully in other hospitals in the United Kingdom.

Neonatal screening for hearing impairment

Over the last 25 years, technological developments have facilitated the implementation of neonatal screens for hearing impairment. Restricting tests to 10% of the cohort with risk factors enables detection of around 40% of congenital impairments. Critical review has therefore recommended universal screening targeting for identification all neonates with moderate or worse impairment. Both oto-acoustic emission and auditory brainstem response (ABR) recording make this possible. The emission test is very sensitive to mild impairments. Specificity critically depends upon the age of maternity testing, but a false positive rate of 8% at discharge is typical. This is reduced to <1% by implementing a second outpatient test, or an ABR before discharge. Both tests are required to identify auditory neuropathies. Widespread implementation will follow pilot trials that are currently being undertaken. The accurate assessment of screen positives, and appropriate habilitation for those identified, is also required. These needs are complex, and require further study if universal screening is to become routine.

[Implantation of a program for the early detection of neonatal hearing loss]

Permanent childhood hearing impairment is a serious public health problem. Identification by screening in the first few months of life has the potential to improve affected children development. Neonatal hearing screening programs endorse the WHO requirement for a cost efficient screening. This paper shows the implementation of a medium-size hospital-based universal newborn hearing screening program using transient evoked otoacoustic emissions. Operational procedures and requirements are discussed. Quality control and results are showed.

Universal neonatal hearing screening: past, present, and future

After a brief review of the history of newborn hearing screening including the Downs behavioral testing procedure, the Crib-o-gram and similar devices, and the use of auropalpebral reflex and otoacoustic emissions, there is a discussion of key issues that need to be resolved before universal hearing screening is introduced. Included are questions regarding the target population(s) of screening programs, well baby versus NICU screening, dealing with false-positives and the effects on parent-child relationships, and finally, the availability of resources for screening and follow-up. The results of a recent study in the United Kingdom that assessed the current state of audiology services and found there is a difference between existing standards and what is actually being done in practice, are presented and considered in terms of current trends in the United States to move ahead with universal screening without a solid database of information regarding the preparedness of clinical centers to deal with the need for services that will result from the initiation of universal programs. Caution is urged.

Improvement in early detection of congenital hearing impairment due to universal newborn hearing screening

OBJECTIVE

The aim of this study was to determine whether universal newborn hearing screening (UNHS) is effective in increasing the number of children whose hearing impairment is detected early, i.e. within the first 6 months of life. It also investigated whether UNHS contributes most to the early detection of moderately and severely hearing-impaired newborns, as suggested by a recently published report.

METHODS

The study consisted of a retrospective analysis of the data of all children born in Tyrol between 1980 and 1999 and having an at least moderate permanent hearing loss in the better ear.

RESULTS

The findings are that since UNHS was introduced in some newborn nurseries in 1995, a substantially higher number of hearing-impaired children has been detected early. For the whole sample, the increase of the early detection rate is 39.9%, with a 95% confidence interval of 33.2-46.8% (P<0.0001). For moderate hearing loss the increase is 49.2 with a 95% confidence intervall of 39.6-58.8% (P=0.000).

CONCLUSIONS

On the whole, our findings lend support to the view that UNHS is effective in early detection of congenital hearing impairment. We conclude that UNHS provides the greatest benefit for moderately hearing-impaired children who, otherwise, would have been detected last.

Identification of neonatal hearing impairment: hearing status at 8 to 12 months corrected age using a visual reinforcement audiometry protocol

OBJECTIVES

1) To describe the hearing status of the at-risk infants in the National Institutes of Health-Identification of Neonatal Hearing Impairment study sample at 8 to 12 mo corrected age (chronologic age adjusted for prematurity). 2) To describe the visual reinforcement audiometry (VRA) protocol that was used to obtain monaural behavioral data for the sample.

DESIGN

All neonatal intensive care unit infants and well babies with risk factors (including well babies who failed neonatal tests) were targeted for follow-up behavioral evaluation once they had reached 8 mo corrected age. Three thousand one hundred and thirty-four (64.4%) of the 4868 surviving infants returned for at least one behavioral hearing evaluation, which employed a well-defined VRA protocol. VRA thresholds or minimum response levels (MRLs) were determined for speech and pure tones of 1.0, 2.0, and 4.0 kHz for each ear using insert earphones.

RESULTS

More than 95% of the infants were reliably tested with the VRA protocol; 90% provided complete tests (four MRLs for both ears). Ninety-four percent of the at-risk infants were found to have normal hearing sensitivity (MRLs of 20 dB HL) at 1.0, 2.0, and 4.0 kHz in both ears. Of the infants, 2.2% had bilateral hearing impairment, and 3.4% had impairment in one ear only. More than 80% of the impaired ears had losses of mild-to-moderate degree.

CONCLUSIONS

This may be the largest study to attempt to follow all at-risk infants with behavioral audiometric testing, regardless of screening outcome, in an effort to validate the results of auditory brain stem response, distortion product otoacoustic emission, and transient evoked otoacoustic emission testing in the newborn period. It is one of only a few studies to report hearing status of infants at 1 yr of age, using VRA on a clinical population. Successful testing of more than 95% of the infants who returned for the VRA follow-up documents the feasibility of obtaining monaural behavioral data in this population.

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.

Neonatal hearing screening using the auditory brainstem response

A targeted screen of babies at risk of having a sensorineural hearing loss (SNHL) using the auditory brainstem response has been in place since 1987 in Bradford and Airedale. The aims of this paper were to ascertain what proportion of a 4-year cohort of children with SNHL should have been identified by the programme; was identified by the programme; and the reasons for failing when children were missed. The cohort of 49 children had moderate to profound SNHL (> 50 dB) and were born between 1 April 1991 and 31 March 1995. Although 92% had at risk factors (higher than in other series), 80% was the maximum that could have been prospectively detected by the programme and only 37% were actually diagnosed as a result of the screening programme. Apart from a generalised under-recruitment, children with risk factors arising because of in utero, perinatal and postnatal events (as opposed to family history, craniofacial abnormalities and syndromes) tended to be missed (P < 0.01). The overall yield of the screening programme was 0.5/1000/year. While the yield of a universal neonatal screening programme based on otoacoustic emissions should be double this, a targeted infant distraction test later in infancy will be an essential backup. Improved liaison with paediatricians in particular as well as simplification of the referral criteria should improve targeting children at risk.

Confirmation of deafness in infancy

AIM

To assess delay in confirming hearing impairment in infants identified by universal neonatal screening and to investigate the causes.

PATIENTS

Infants identified from 25 199 babies screened from January 1992 to December 1997.

METHODS

A two stage transient evoked oto-acoustic emission test (TEOAE), with a threshold auditory brainstem response (ABR) recording undertaken on those who failed. The screen identified infants with a permanent congenital hearing impairment (PCHI) averaging 40 dBnHL or worse in the best ear. Those with less impairment were also ascertained. The positive predictive value (PPV) of the ABR test and measures of delay between identification and eventual diagnosis were analysed.

RESULTS

A targeted PCHI was found in 1.18/1000 neonates. The PPV of the ABR for confirming a targeted PCHI was 100% when the ABR threshold was >/= 80 dBnHL. Nine of 11 infants with this threshold had severe or profound permanent deafness. The delay from ABR to audiological certainty was about 1 month-diagnosis was confirmed around 3 months. There was uncertainty when the ABR was 40-80 dBnHL. The PPV was 60% and 8% when the ABR thresholds were 70 dBnHL and 50 dBnHL, respectively. 85 of 111 infants with ABR thresholds in this range had a temporary conductive impairment. Their early diagnosis depended upon the type and degree of hearing impairment and diagnosis was delayed to about 8 months in these infants.

CONCLUSIONS

Hearing impairments identified by universal screening are delayed in all but those with severe or profound bilateral PCHI. This delay can be reduced by applying in early infancy a battery of audiological tests and requires further exploration.

Otological evaluation of newborns who failed otoacoustic emission screening

Early identification of congenital hearing loss and early rehabilitation is extremely important. Otoacoustic emissions (OAE) are an efficient tool for hearing screening. Previous studies using click evoked otoacoustic emissions (CEOAEs) for newborn hearing screening resulted in approximately 70% pass rate, reflecting intact hearing. The aim of our study was to perform a detailed otological evaluation of newborns who failed OAE screening, using otoscopy, tympanometry and ABR. CEOAEs were recorded from 257 newborns prior to their release from the hospital. Those babies who did not pass the CEOAE were examined by DPOAE, otoscopy, tympanometry and ABR, if needed. 73% of all the newborns had CEOAE in both ears. 20% had CEOAE in only one ear. When the test was administered again three days postpartum, the CEOAE pass rate increased; 98% passed in at least one ear. Most of the newborns (84%) who failed had an obstruction of the external ear canal (collapsed ear canal or debris). There was a good correlation between the otoscopy and the tympanometry. Based on the above results, a newborn hearing screening protocol was introduced.

Identification of permanent hearing loss in children: are the targets for outcome measures attainable?

A collaborative nine-centre study was designed to follow the routes to identification of all children up to the age of seven years newly diagnosed with permanent hearing impairment (> or = 50 dB HL) during the period 1993-1994. Ages of identification were compared with the standards set by the National Deaf Children's Society (NDCS), ascertaining whether these targets could be achieved with current service provision. Of the 126 children identified, 104 had congenital sensorineural hearing loss: 19% were identified by the age of six months and 39% by their first year. These results fall short of the NDCS targets of 40% and 80%, respectively, and point to the need for modifications of current practice, such as the introduction of universal neonatal screening.

Newborn and infant hearing loss: detection and intervention.American Academy of Pediatrics. Task Force on Newborn and Infant Hearing, 1998- 1999

This statement endorses the implementation of universal newborn hearing screening. In addition, the statement reviews the primary objectives, important components, and recommended screening parameters that characterize an effective universal newborn hearing screening program.

Bilateral otoacoustic emissions pass in a baby with Mondini deformity and subsequently confirmed profound bilateral hearing loss

Evoked otoacoustic emissions are well established as a hearing screening technique and are used extensively in paediatric audiology. They are believed to originate from the outer hair cells and can be detected in almost 100% of normally hearing ears; even a mild hearing loss has been shown to abolish otoacoustic emissions. Results are presented of a baby boy born at 29 weeks' gestation requiring 77 days of neonatal care, but experiencing no complications following discharge from the neonatal unit. This child had clear bilateral evoked otoacoustic emissions at almost four months of age, but was subsequently found to have a profound bilateral hearing impairment and absent otoacoustic emissions. Radiological investigations revealed bilateral Mondini dysplasia, and this child has now been implanted with a multi-channel MXM Digisonic cochlear implant. He is progressing well and shows awareness of sound. Approximately 10 previous cases of otoacoustic emissions occurring in profoundly deaf ears have been reported in the literature. Although it is likely that this child's hearing loss was progressive in nature, the authors believe that this is the first reported case of otoacoustic emissions being recorded in the presence of Mondini dysplasia. This raises concerns about the use of neonatal screening in isolation without adequate mechanisms for later identification of hearing impairment, although it is acknowledged that it represents a rare situation.

Click evoked otoacoustic emissions: inter-aural and gender differences in newborns

Click evoked otoacoustic emissions (CEOAEs) are an objective and reliable method of assessing cochlear status, particularly suitable for newborns. This study aimed to assess CEOAE inter-aural and gender differences. Other non-auditory factors, such as infant's head size and weight, were considered. Band averaged CEOAEs were analyzed for 120 healthy, full term newborns, 61 females and 59 males. The babies were randomly selected from the nursery and tested in a quiet room away from the ward, using an Otodynamic ILO 92 system. The CEOAEs of the females were significantly larger than those of the males. For the frequency bands 2, 3, and 4 kHz and for the overall response, the emissions were larger in the right ear, for both males and females. These inter-aural differences were more pronounced in male subjects than in female subjects. These findings may reflect the accumulating evidence that differences exist in efferent cochlear inhibition.