False positives in universal neonatal screening for permanent childhood hearing impairment

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.

Protocol and programme factors associated with referral and loss to follow-up from newborn hearing screening: a systematic review

Background

An effective newborn hearing screening programme has low referral rate and low loss to follow-up (LTFU) rate after referral from initial screening. This systematic review identified studies evaluating the effect of protocol and programme factors on these two outcomes, including the screening method used and the infant group.

Methods

Five databases were searched (latest: April 2021). Included studies reported original data from newborn hearing screening and described the target outcomes against a protocol or programme level factor. Studies were excluded if results were only available for one risk condition, for each ear, or for < 100 infants, or if methodological bias was observed. Included studies were evaluated for quality across three domains: sample, screening and outcome, using modified criteria from the Ottawa-Newcastle and QUADAS-2 scales. Findings from the included studies were synthesised in tables, figures and text.

Results

Fifty-eight studies reported on referral rate, 8 on LTFU rate, and 35 on both. Only 15 studies defined LTFU. Substantial diversity in referral and LTFU rate was observed across studies. Twelve of fourteen studies that evaluated screening method showed lower referral rates with aABR compared to TEOAE for well babies (WB). Rescreening before hospital discharge and screening after 3 days of age reduced referral rates. Studies investigating LTFU reported lower rates for programmes that had audiologist involvement, did not require fees for step 2, were embedded in a larger regional or national programme, and scheduled follow-up in a location accessible to the families. In programmes with low overall LTFU, higher LTFU was observed for infants from the NICU compared to WB.

Conclusion

Although poor reporting and exclusion of non-English articles may limit the generalisability from this review, key influential factors for referral and LTFU rates were identified. Including aABR in WB screening can effectively reduce referral rates, but it is not the only solution. The reported referral and LTFU rates vary largely across studies, implying the contribution of several parameters identified in this review and the context in which the programme is performed. Extra attention should be paid to infants with higher risk for hearing impairment to ensure their return to follow-up.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03218-0.

A conceptual framework for rationalized and standardized Universal Newborn Hearing Screening (UNHS) programs

Congenital hearing loss is the most frequent birth defect. The American Academy of Pediatrics and the Joint Committee on Infant Hearing established quality of care process indicators for Universal Newborn Hearing Screening starting from 1999. In a previous systematic review of Universal Newborn Hearing Screening studies we highlighted substantial variability in program design and in reported performance data. In order to overcome these heterogeneous findings we think it is necessary to optimize the implementation of Universal Newborn Hearing Screening programs with an appropriate application of the planning, executing, and monitoring, verifications and reporting phases. For this reason we propose a conceptual framework that logically integrates these three phases and, consequently, a tool (a check-list) for their rationalization and standardization.Our paper intends to stimulate debate on how to ameliorate the routine application of high quality Universal Newborn Hearing Screening programs. The conceptual framework is proposed to optimize, rationalise and standardise their implementation. The checklist is intended to allow an inter-program comparison by removing heterogeneity in processes description and assessment.

Evaluating the Outcomes of a Hearing Screening Service for Grade One Learners in Urban Areas at Durban, South Africa

Early intervention through hearing screening can reduce the negative impact of hearing loss for children. Optimal outcomes are achieved when an appropriate screening protocol is selected, a pathway for follow up care is established, and when a hearing conservation component is included. This study aimed to describe the outcomes of a hearing screening service provided to grade one learners in urban areas at Durban. A cross-sectional design was employed. Learners (n=241) were conveniently sampled from six randomly selected schools. They were screened using otoscopy, tympanometry and pure tone audiometry. Fifty eight participants (24%) obtained a refer result, with 33% referred for diagnostic assessments, 29% for middle ear pathology and 38% for cerumen management. Findings further revealed that only 33% of referrals were followed up indicating poor compliance. Association between test results and income levels (P=0.38) as well as distance to the nearest health care facility (P=0.22) did not influence test outcomes. School aged children do present with common ear problems. Appropriate protocol selection, ensuring compliance to recommendations and education on hearing conservation are essential components of any health initiative.

Mitochondrial mutations associated with aminoglycoside ototoxicity and hearing loss susceptibility identified by meta-analysis

BACKGROUND

Genetic variations, including mitochondrial mutations, are important contributors to hearing loss, especially in children, and newborn genetic screens for hearing loss mutations are becoming increasingly common. Mitochondrial mutations have been linked with ototoxic responses to common antibiotics, therefore understanding the association of these mutations with hearing loss is of special importance. To address the usefulness of screening for these mutations in a clinical setting, we formed a collaboration of clinicians and geneticists to analyse the association of mitochondrial mutations with non-syndromic hearing loss, including the effect of ethnicity, audiological test methods and aminoglycoside exposure.

METHODS

This survey identified 122 variants in 43 studies that have been assessed for an association with hearing loss, and meta-analysis was performed on clinically relevant subsets. RNA folding and conservation analysis further explored possible relevance of these variants.

RESULTS

Among all studies, eight variants were found to have significant associations with hearing loss. A partially overlapping set of six variants had significant association with hearing loss when aminoglycoside exposure was assessed. Five of these variants predictive of sensitivity to aminoglycoside spatially co-localise in an RNA folding model. There was little effect of the audiological test method used to assess hearing loss on the association with the variants.

CONCLUSIONS

Our results found a small set of studied variants had reproducible association with hearing loss, which will help clarify mutations useful in genetic screens for hearing loss. Several of the aminoglycoside exposure-associated mutations may co-localise on folded 12S rRNA, suggesting a functional association between these loci and aminoglycoside-induced hearing loss.

Limitations of hearing screening in newborns with PDS mutations

OBJECTIVES

SLC26A4 (PDS) mutations are common cause of congenital hearing loss in East Asia. Hearing loss caused by PDS mutations tends to have delayed presentation; thus universal newborn hearing screening (UNHS) can be less effective in these patients. We examined the efficiency of newborn hearing screening test in patients with bi-allelic PDS mutations.

METHODS

Forty-three patients with sensorineural hearing loss were recruited. Patients had an enlarged vestibular aqueduct and biallelic PDS mutations. Among them, newborn hearing screening test had been performed on 14. The remaining 29 patients did not undergo newborn hearing screening test. Another 15 patients without a PDS mutation but who had sensorineural hearing loss were also recruited as a comparison group. We reviewed the hearing loss history of the children using medical records and parent interviews.

RESULTS

Among 14 patients with PDS mutation, four (28.6%) passed newborn hearing screening test in both ears and six (42.9%) passed in one ear. In contrast, only 2 of 15 (13.3%) children without a PDS mutation passed newborn hearing screening test bilaterally. The age at confirmation of bilateral hearing loss in bilateral "pass" patients with PDS mutation was 31.5 ± 17.9 months, which was significantly delayed compared to the age for bilateral "refer" children (1.75 ± 0.96 months) (p<0.05).

CONCLUSION

The UNHS is not an accurate tool for predicting long-term hearing loss in patients with PDS mutations. We recommend that genetic screening be combined with UNHS, particularly in communities with a high prevalence of PDS mutations, to better identify children in need of early habilitation.

Newborn genetic screening for hearing impairment: a preliminary study at a tertiary center

Universal newborn hearing screening (UNHS) is of paramount importance for early identification and management of hearing impairment in children. However, infants with slight/mild, progressive, or late-onset hearing impairment might be missed in conventional UNHS. To investigate whether genetic screening for common deafness-associated mutations could assist in identifying these infants, 1017 consecutive newborns in a tertiary hospital were subjected to both newborn hearing screening using a two-step distortion-product otoacoustic emissions (DPOAE) screening and newborn genetic screening (NGS) for deafness. The NGS targeted 4 deafness-associated mutations commonly found in the Taiwanese population, including p.V37I (c.109G>A) and c.235delC of the GJB2 gene, c.919-2A>G of the SLC26A4 gene, and mitochondrial m.1555A>G of the 12S rRNA gene. The results of the NGS were then correlated to the results of the NHS. Of the 1017 newborns, 16 (1.6%) had unilateral DPOAE screening failure, and 22 (2.2%) had bilateral DPOAE screening failure. A total of 199 (19.6%) babies were found to have at least 1 mutated allele on the NGS for deafness, 11 (1.1%) of whom were homozygous for GJB2 p.V37I, 6 (0.6%) compound heterozygous for GJB2 p.V37I and c.235delC, and 1 (0.1%) homoplasmic for m.1555A>G, who may potentially have hearing loss. Among them, 3 babies, 5 babies, and 1 baby, respectively, passed the NHS at birth. Comprehensive audiological assessments in the 9 babies at 3 months identified 1 with slight hearing loss and 2 with mild hearing loss. NGS for common deafness-associated mutations may identify infants with slight/mild or potentially progressive hearing impairment, thus compensating for the inherent limitations of the conventional UNHS.

Universal neonatal audiological screening: experience of the University Hospital of Pisa

The early identification of pre-lingual deafness is necessary to minimize the consequences of hearing impairment on the future communication skills of a baby. According to the most recent international guidelines the deafness diagnosis must occur before the age of three months and the prosthetic-rehabilitative treatment with a traditional hearing aid should start within the first six months. When a Cochlear implant becomes necessary, the treatment should start between the age of 12 months and 18 months. The only way to diagnose the problem early is the implementation of universal neonatal audiological screening programs. Transient evoked otoacoustic emissions (TEOAE) is the most adequate test because it's accurate, economic and of simple execution. Automatic auditory brainstem response (AABR) is necessary to identify patients with auditory neuropathy but it is also important to reduce the number of false-positives.The 20-30% of infant hearing impairment is represented by progressive or late-onset hearing loss (HL) so it's also necessary to establish an audiological follow up program, especially in infants at risk.From November 2005 all neonates born in the University hospital of Pisa undergo newborn hearing screening. From 2008 the screening program follows the guidelines for the execution of the audiological screening in Tuscany which have been formulated by our group according to the 2007 JCIH Position Statement and adaptated to our regional reality by a multidisciplinary effort. From November 2005 to April 2009 8113 neonates born in the Neonatal Unit of Santa Chiara Hospital (Pisa) have undergone newborn hearing screening. 7621 neonates (93.9%) without risk factors executed only the TEOAE test. 492 (6.1%) neonates had audiological risk factors and thus underwent TEOAE and AABR. 84 patients (1,04%) failed both TEOAE and AABR tests. 78 of them underwent further investigations. 44 patients resulted false positives (the 0,54% of the screened newborns). 34 neonates (4,2 ‰) had a final diagnosis of hearing impairment. 8 patients (0.99 ‰) had unilateral hearing loss (HL). 26 patients (3,2 ‰) had bilateral hearing impairment.In our screening program the percentage of false-positives was quite low (0.54%) while the incidence of bilateral HL (3.2 ‰) is a little higher than that found in literature reports. In most of our patients premature birth or neonatal suffering represent the main cause of HL.

[Newborn hearing screening test with multiple auditory steady-state responses]

INTRODUCTION

The techniques most frequently used within a screening context (otoacoustic emissions and click auditory brainstem response) have well-known limitations in hearing loss detection.

OBJECTIVE

This study examines the feasibility of a semi-automated multiple auditory steady-state responses (MSSR) system designed for neonatal hearing screening.

METHODS

A sample of 50 newborns without risk factors (well-babies) was tested within two weeks of birth. All had detectable auditory brainstem responses to clicks down to 40dB nHL in both ears. Two amplitude modulated carrier tones of 500 and 2,000Hz were mixed together and presented simultaneously. Each infant (and ear) was screened with the MSSR system; to simulate a hearing loss, a recording without stimulation was also obtained.

RESULTS

Mean auditory thresholds were 42.5±7dB HL at 500Hz and 35.5±6dB HL at 2,000Hz. The average duration of the MSSR recording was 2.6±1.6 minutes for each tested ear and the overall duration of the screening procedure (including electrode fitting and infant preparation) was 17.8±3.7 minutes. The diagnostic sensibility and the positive predictive values of the MSSR semi-automatic screening system was 100% and 96% respectively, with specificity of 96% and negative predictive values of 100%.

CONCLUSIONS

Although the diagnostic efficiency of the semi-automated MSSR system was found adequate, further technological improvements are still necessary to facilitate its use in the context of universal newborn hearing screening program.

Is discordance in TEOAE and AABR outcomes predictable in newborns?

OBJECTIVE

To determine the perinatal predictors of discordant screening outcomes based on a two-stage screening protocol with transient-evoked otoacoustic emissions (TEOAE) and automated auditory brainstem response (AABR).

METHODS

A cross-sectional study of infants tested with TEOAE and AABR under a hospital-based universal newborn hearing screening program in Lagos, Nigeria. Maternal and infant factors associated with discordant TEOAE and AABR outcomes were determined with multivariable logistic regression analyses adjusting for potential confounding factors.

RESULTS

Of the 4718 infants enrolled under the program 1745 (36.9%) completed both TEOAE and AABR. Of this group, 1060 (60.7%) passed both TEOAE and AABR ("true-negatives"); 92 (5.3%) failed both TEOAE and AABR ("true-positive"); 571 (32.7%) failed TEOAE but passed AABR ("false-positives") while 22 (1.3%) passed TEOAE but failed AABR ("false-negatives"). Infants with false-positives were likely to be admitted into well-baby nursery (p=0.001), belong to mothers who attended antenatal care (p=0.010) or who delivered vaginally (p<0.001) compared to infants with true-negatives while infants with true-positives were also more likely to be delivered vaginally (p=0.002) or admitted into well-baby nursery (p=0.035) compared to infants with false-negatives. Infants with true-positives were significantly more likely to be delivered vaginally (p<0.001) and have severe hyperbilirubinemia (p=0.045) compared with infants with true-negatives. No association was observed between false-negatives and true-negatives. Antenatal care status, mode of delivery and nursery type were useful predictors of discordant outcomes among all infants undergoing screening (c-statistic=0.73).

CONCLUSIONS

Given the available screening technologies, discordant TEOAE and AABR may be inevitable for some categories of hearing loss among apparently healthy newborns whose mothers received prenatal care. The potential limitations of perinatal morbidities as basis of targeted screening for such cases therefore merit further consideration.

Feasibility of neonatal hearing screening program with two-stage transient otoacoustic emissions in Turkey

BACKGROUND

The objective of this study was to investigate the incidence of hearing loss in neonates and evaluate the feasibility of a two-stage Transient Evoked Otoacoustic Emission (TEOAE) screening test. Maternal concerns about hearing screening were also studied.

METHODS

Neonatal intensive care patients and well babies were screened using a two-stage TEOAE test, which was followed by an Auditory Brainstem Response (ABR) test for those babies who failed the first test twice.

RESULTS

In total, 711 neonates were screened. At the end of the two TEOAE tests, the cumulative pass rate was 99.3% and false-positive rate was 0.3%. Five neonates (0.7%) were referred for the ABR test. Sensorineural hearing loss was found in three of them (0.4%). Of these three neonates, one was from the well baby nursery and two were from the NICU population. Families generally welcomed the screening program, with no refusals. Positive test results have not caused important maternal concerns.

CONCLUSIONS

Congenital hearing impairment is a prevalent disease in Turkey. The two-stage TEOAE program is suitable for the neonatal hearing screening program. In general, hearing screening tests do not cause notable maternal concerns.

Comparison of Auditory Steady-State Responses and Tone-Burst Auditory Brainstem Responses in Normal Babies

OBJECTIVE

To follow the development of tone-burst auditory brainstem response (TB-ABR) and auditory steady-state response (ASSR) thresholds in a group of normal babies through the first 6 wk of life.

DESIGN

This longitudinal study involved assessment at four data-collection points. TB-ABR and ASSR thresholds to 500-Hz and 4-kHz stimuli were established in 17 full-term subjects at 0, 2, 4, and 6 wk of age. Stimulus-modulation rates for ASSR assessment were 74 Hz (for 500-Hz tones) and 95 Hz (for 4-kHz tones). TB-ABR responses were recorded to stimuli presented at 39.1 Hz.

RESULTS

Mean ASSR thresholds (calibrated in dBHL) at 500 Hz ranged from 44.4 to 39.7 dB HL across the recording period, and at 4 kHz they ranged from 37.9 to 32.1 dB HL. TB-ABR thresholds (calibrated in dBnHL) were significantly lower, ranging from 36.8 to 36.2 dB nHL at 500 Hz and from 16.5 to 15.9 dB nHL at 4 kHz. However, when the stimuli used for each test were calibrated in the same units (peak equivalent dB SPL), the results were similar. That is, the differences between the two techniques were only an artifact of the calibration. ASSR thresholds were more variable than TB-ABR, particularly at the neonatal measurement point. Within-subject changes across the test period were observed for ASSR thresholds but not for TB-ABR.

CONCLUSIONS

The longitudinal findings presented in this study suggest that for normal neonates, the TB-ABR technique may offer a more reliable basis for prediction of hearing levels than ASSR assessment. This is not because TB-ABR thresholds (calibrated in dBnHL) are lower, but because the response is less affected by maturational development in the first weeks of life and is less variable across subjects.

Slight/mild sensorineural hearing loss in children

OBJECTIVE

The goal was to determine the prevalence and effects of slight/mild bilateral sensorineural hearing loss among children in elementary school.

METHODS

A cross-sectional, cluster-sample survey of 6581 children (response: 85%; grade 1: n = 3367; grade 5: n = 3214) in 89 schools in Melbourne, Australia, was performed. Slight/mild bilateral sensorineural hearing loss was defined as a low-frequency pure-tone average across 0.5, 1, and 2 kHz and/or a high-frequency pure-tone average across 3, 4, and 6 kHz of 16 to 40 dB hearing level in the better ear, with air/bone-conduction gaps of < 10 dB. Parents reported children's health-related quality of life and behavior. Each child with slight/mild bilateral sensorineural hearing loss, matched to 2 normally hearing children (low-frequency pure-tone average and high-frequency pure-tone average of < or = 15 dB hearing level in both ears), completed standardized assessments. Whole-sample comparisons were adjusted for type of school, grade level, and gender, and matched-sample comparisons were adjusted for nonverbal IQ scores.

RESULTS

Fifty-five children (0.88%) had slight/mild bilateral sensorineural hearing loss. Children with and without sensorineural hearing loss scored similarly in language (mean: 97.2 vs 99.7), reading (101.1 vs 102.8), behavior (8.4 vs 7.0), and parent- and child-reported child health-related quality of life (77.6 vs 80.0 and 76.1 vs 77.0, respectively), but phonologic short-term memory was poorer (91.0 vs 102.8) in the sensorineural hearing loss group.

CONCLUSIONS

The prevalence of slight/mild bilateral sensorineural hearing loss was lower than reported in previous studies. There was no strong evidence that slight/mild bilateral sensorineural hearing loss affects adversely language, reading, behavior, or health-related quality of life in children who are otherwise healthy and of normal intelligence.

How effectively can clinical examination pick up congenital heart disease at birth?

AIMS

To assess what proportion of all cardiac abnormality can be suspected at birth when all clinical examination before discharge is undertaken by a small stable team of clinicians.

METHODS

A prospective audit of all the 14 572 births in a maternity unit only staffed by nurse practitioners between 1996 and 2003.

RESULTS

1.2% of all babies born in the unit were found to have a structural defect (as confirmed by echocardiography) within a year of birth. The number not suspected before discharge declined over time, and only 6% were first suspected after discharge in the last four years of this eight year study. Four potentially life threatening conditions initially went unsuspected in 1996-8, but none after that. A policy of referring every term baby with a murmur at 1 day of age that was still present at 7-10 days resulted in 4.2% requiring cardiac referral; 54% of these babies still had a murmur when assessed one to two weeks later, and 33% had a structural defect. Parents said in independent, retrospectively conducted, interviews that they found it confidence building to have any possible heart defect identified early and the cause of any murmur clearly and authoritatively explained.

CONCLUSIONS

Effective screening requires experience and a clear, structured, referral pathway, but can work much better than most previous reports suggest. Whether staff bring a medical or nursing background to the task may well be of less importance.

Challenges in management of childhood sensorineural hearing loss in sub-Saharan Africa, Nigeria

The evaluation of a hearing-impaired child attempts to determine the aetiology, the degree of hearing loss and intervention to aid speech and language. This remains a challenge to practising otolaryngologists, especially in the developing countries as 85-90% of causes of hearing losses were never discovered leading to delayed intervention and irreversible effects. In a review of children presenting at the otolaryngology outpatient in the University College Hospital, Ibadan, Nigeria, sensorineural hearing loss was found in 103, giving a hospital prevalence rate of 14%, we still perceived this figure to be unrepresentatively and low, probably due to poor access to medicare, poverty and other factors. Genetic factor accounted for 25%, followed by measles infections 13% and meningitis 8%. About 60% of them had educationally significant hearing loss at presentation. Access to hearing aid was poor as only 12.5% of the patients could afford it and the rest were managed by deaf training. We conclude by suggesting an audiologic programme which has the comprehensive function of neonatal and infant hearing screening, subsidized hearing aid services and hearing rehabilitation surgery.

Universal newborn screening for permanent childhood hearing impairment: an 8-year follow-up of a controlled trial

An 8-year follow-up study of the birth cohort of babies enrolled in the Wessex controlled trial of universal newborn screening (UNS) for permanent childhood hearing impairment (PCHI) was undertaken to establish whether UNS would increase the proportion of all true cases of PCHI in children aged 7-9 years who are referred early. The proportion referred before 6 months of age increased from 11 of 35 (31%) children with true PCHI born during periods without UNS to 23 of 31 (74%) born during periods with UNS (difference 43%, 95% CI 19-60). UNS leads to early referral of PCHI.

Sequenzielles Neugeborenen-Hörscreening (TEOAE/AABR) reduziert Recall-Rate

BACKGROUND

1-2/1,000 newborns are affected by connatal permanent hearing impairment. Clinical diagnosis is often delayed. This demands newborn hearing screening (NHS). Some questions regarding the optimal method remain unsolved.

METHODS

The newborns in the obstetrical department (low-risk group) are tested by automated transitory evoked otoacustic emissions (TEOAE). TEOAE-fail is followed by automated auditory brainstem response (AABR) examination. All sick newborns admitted to the pediatric department (high-risk group) are primarily tested using AABR. Pathological AABR-testing leads to pedaudiological diagnostic work-up.

RESULTS

In the low-risk group, 82 out of 1,584 newborns failed TEOAE-testing (recall 5.18%). Only 5 of these patients failed consecutive AABR examination (recall 0.32%). Permanent hearing loss was finally confirmed in 3 children (0.13%). 10 out of 755 newborns in the high-risk group failed AABR-testing (1.32%). In 6 of these children, hearing loss was confirmed (0.79%).

CONCLUSION

A two-tier screening process as described is able to reduce recall rate, overall expenses and parental anxiety.

Sensorineural hearing loss in children

During the past three to four decades, the incidence of acquired sensorineural hearing loss (SNHL) in children living in more developed countries has fallen, as a result of improved neonatal care and the widespread implementation of immunisation programmes. The overall decrease has been accompanied by a relative increase in the proportion of inherited forms of SNHL. The contribution made by one gene in particular, GJB2, to the genetic load of SNHL has strongly affected the assessment and care of children with hearing loss. These changes in the incidence of SNHL have not been seen in children living in less developed countries, where the prevalence of consanguinity is high in many areas, and both genetic and acquired forms of SNHL are more common, particularly among children who live in poverty. Focused genetic counselling and health education might lead to a decrease in the prevalence of inherited SNHL in these countries. Establishment of vaccination programmes for several vaccine-preventable infectious diseases would reduce rates of acquired SNHL. Although the primary purpose of such programmes is the prevention of serious and in many cases fatal infections, a secondary benefit would be a reduction in disease-related complications such as SNHL that cause permanent disability in survivors.

[Universal hearing screening in newborns. Recommendations for organizing and conducting universal hearing screening for congenital hearing loss in Germany]

The Interdisciplinary Consensus Conference for Newborn Hearing Screening (IKKNHS) has worked out joint recommendations for universal hearing screening of newborns. In the consensus paper, 11 professional associations and scientific societies in the fields of gynecology and obstetrics, ENT, pediatrics, and phoniatrics and pedaudiology came to an agreement on how to implement newborn hearing screening in Germany. The paper deals with the following topics: goals of universal newborn hearing screening, target group of hearing screening, schedule for screening, personnel involved in the screening program, technologies and framework conditions of hearing screening, documentation, continuous quality control of screening, confirmation diagnostics for conspicuous test subjects, motivation to take part in screening, information on newborn hearing screening, tracking, various infrastructural situations in urban and rural regions, follow-up care, in-patient vs. out-patient screening, cost factors of screening, reporting children with permanent hearing loss to the German Central Registry for hearing loss in children.

Universal neonatal hearing screening moving from evidence to practice

Recent technological advances have made feasible universal newborn hearing screening and therefore early detection of permanent childhood hearing impairment. Over the past three years, new information has been published on whether early intervention is beneficial, the possibility of harm arising from newborn screening, and its cost. Dramatic progress has been made in the large scale implementation of universal screening in many parts of the western world.

Benefits and challenges of newborn hearing screening for developing countries

The late detection of permanent congenital and early-onset hearing loss (PCEHL) often has severe effects on linguistic, speech, cognitive and educational development in affected children. Since newborn hearing screening (NHS) allows most PCEHL to be detected early enough for optimal intervention, the prospects of its introduction in the developing world are reviewed in this paper. It is observed that a simple generalisation on the feasibility of NHS for the developing countries seems inappropriate in view of the diversities in the health and socio-economic status of these countries and the recent favourable reports of universal newborn hearing screening from the region. NHS empowers parents to make timely choices that will allow their hearing impaired children to be given a good start in life and be fully integrated into the wider community. It also compels attention towards the development of essential hearing healthcare services, besides the specific documented benefits. Existing child-healthcare structures such as the expanded programme on immunisation (EPI), baby friendly hospital initiatives (BFHI) and integrated management of childhood illness (IMCI) provide opportunities for the introduction of some form of NHS in many of these countries where routine or systematic childhood hearing screening does not exist. Limited funding, manpower shortages, inadequate support services, low public awareness and the uncertainty regarding the commitment from healthcare practitioners may present some challenges but these are not insurmountable. Pilot studies are necessary in each country to provide empirical data that will guide healthcare providers who wish to introduce such a programme at any level of healthcare delivery.

The newborn hearing screening programme in England

Following a systematic review of the role of neonatal hearing screening in the identification of hearing impaired and deaf children in 1997, the Department of Health in England commissioned a national programme of newborn hearing screening in 2001 and has linked a systematic evaluation to the first 23 sites in the implementation of that policy. It is anticipated that all areas of England will participate in the programme by 2004/2005. It is expected that other regions of the UK will also aim for implementation by this date. In addition to successful advocacy by the two major consumer organisations, there were three key elements linked to the decision to implement newborn hearing screening which were primarily evidence based and also driven by two significant service developments. The evidence base showed that newborn hearing screen was considerably more effective and efficient than the infant distraction test used in many areas and that there was a high probability that early intervention increased the potential for better language and communication. The concern over raised anxiety for those parents whose babies need differential assessment as a result of the screen is reduced by the low number of referrals and increased efficiency of assessment when national protocols are used for screening and assessment. The introduction of family friendly hearing services (FFHS) provides a context in which the health, education, voluntary and social services can work together to provide an equitable and seamless service throughout the year for hearing impaired and deaf children and their families. Currently, 22 areas with 110,000 births per annum, have been selected for implementation, some of whom use a pilot community-based model for screening. A major barrier to rapid progress has been a lack of evidence concerning elements of the screening process, e.g. equipment, IT systems, training at all levels. It is anticipated that a further 20-40 areas with an additional 150,000 birth per annum will be brought into the programme by end of 2002/2003. The aims, protocols, training programme and evaluation of the NHS Newborn Hearing Screening Programme are presented with a view to highlighting the research needed to improve specification of large scale screening programmes.

Methodological factors involved in neonatal screening using transient-evoked otoacoustic emissions and automated auditory brainstem response testing

The methodological factors involved in screening neonates for hearing loss, using transient-evoked otoacoustic emissions (TEOAEs) and automated auditory brainstem responses, have been evaluated from a large sample of neonates. The risk factors, commonly used to select babies for a targeted screen, have very little correlation with failing TEOAE testing. The parameters used to determine passing or failing the TEOAE test and the false alarm rate change markedly with age in the first few days of life as, of course, did the percentage of babies who failed the test. The stimulus level used was the default setting for the Otodynamics equipment but the stimulus level measured in the ear canal decreased over the first 140 h of life. It is thought that this reflects the impedance changes in outer and middle ears and possible changes in middle ear dynamics. The methodological variables investigated here can illuminate some of the differences in previous reports of neonatal screening, in particular the reported hit and false alarm rates.

Six month impact of false positives in an Australian infant hearing screening programme

AIMS

To assess short and longer term parent reported impacts of false positive referrals in the Victorian Infant Hearing Screening Program (VIHSP).

METHODS

Mailed retrospective case-control survey of infants consecutively referred to VIHSP between December 1998 and April 1999 for whom audiology did not confirm permanent hearing loss, comprising 137 infants screened with a neonatal risk factor questionnaire and 148 older infants screened with two consecutive behavioural (distraction) tests. The two control groups comprised non-referred screened infants matched by domicile, age, and gender. Main outcome measures were parent reported emotions experienced before and after child's audiology test, parent estimated impact of hearing loss, the Child Vulnerability Scale, audiology assessment satisfaction questionnaire, and questions relating to their child's hearing and language development.

RESULTS

Final sample: at risk cases (AR) 108 (79% response), at risk controls 64 (51%); distraction test cases (DT) 103 (70%), distraction test controls 53 (41%). Parents across all groups believed that hearing loss would have major effects on a child's language (91-96%), schooling (81-91%), and employment opportunities (67-75%). Before audiology, 71% (AR) and 72% (DT) of case parents were anxious/worried, falling to 4% and 15% afterwards. After the test 82% (AR) and 79% (DT) reported relief, but 19% and 18% continued to feel worried. Ongoing concerns about hearing, language, development, and general health were comparable for AR cases compared to controls, and for DT cases compared to controls.

CONCLUSIONS

Hearing screening tests are generally well received. Parents are realistic about the impact of childhood hearing loss and report a range of negative emotions when a false positive hearing screen requires referral. Although most are reassured by a normal test, a substantial number report continuing concern.

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.

Prevalence of permanent childhood hearing impairment in the United Kingdom and implications for universal neonatal hearing screening: questionnaire based ascertainment study

OBJECTIVE

To estimate the prevalence of confirmed permanent childhood hearing impairment and its profile across age and degree of impairment in the United Kingdom.

DESIGN

Retrospective total ascertainment through sources in the health and education sectors by postal questionnaire.

SETTING

Hospital based otology and audiology departments, community health clinics, education services for hearing impaired children.

PARTICIPANTS

Children born from 1980 to 1995, resident in United Kingdom in 1998, with severe permanent childhood hearing impairment (hearing level in the better ear >40 dB averaged over 0.5, 1, 2, and 4 kHz).

MAIN OUTCOME MEASURES

Numbers of cases with date of birth and severity of impairment converted to prevalences for each annual birth cohort (cases/1000 live births) and adjusted for under ascertainment.

RESULTS

26 000 notifications ascertained 17 160 individual children. Prevalence rose from 0.91 (95% confidence interval 0.85 to 0.98) for 3 year olds to 1.65 (1.62 to 1.68) for children aged 9-16 years. Adjustment for under ascertainment increased estimates to 1.07 (1.03 to 1.12) and 2.05 (2.02 to 2.08). Comparison with previous studies showed that prevalence increases with age, rather than declining with year of birth.

CONCLUSIONS

Prevalence of confirmed permanent childhood hearing impairment increases until the age of 9 years to a level higher than previously estimated. Relative to current yields of universal neonatal hearing screening in the United Kingdom, which are close to 1/1000 live births, 50-90% more children are diagnosed with permanent childhood hearing impairment by the age of 9 years. Paediatric audiology services must have the capacity to achieve early identification and confirmation of these additional cases.

Performance of neonatal and infant hearing screens: sensitivity and specificity

The terms 'sensitivity' and 'specificity' are defined and some of the factors that determine their values are discussed in the context of screening for permanent childhood hearing loss. There is a need to distinguish between the values observed in 'simple experiments' and those that may be obtained under more realistic 'field' conditions. It is not feasible to give a meta-analytic overview of published data because of the variety of methods and objectives used in those studies published in the literature. However, a qualitative synthesis of the data is possible. This suggests that most proposed neonatal hearing screening tests, when implemented in accordance with a programme of quality assurance, can be reasonably accurate at a modest cost. However, the optimal combination of tests and test parameters for given populations has not yet been fully researched. The infant distraction test screen has a lower sensitivity than neonatal hearing screening tests, particularly for moderate impairments, accompanied by a fairly low specificity.