5. Newborn hearing screening
Chapter editors: Gwen Carr, Inger Uhlén
a. Context and introduction
Newborn hearing screening aims to enable identification of hearing loss in the earliest weeks and months of life so that babies, and their families, can receive the intervention and support they need for optimal linguistic, communicative and socio-emotional development. Hearing screening for newborns is the first step in the care pathway which importantly includes diagnosis and intervention. There is now compelling evidence that newborn hearing screening, when followed up by appropriate assessment, audiological management and family-centred support for communication development, can radically improve outcomes and life opportunities for children born with hearing loss1 2.
There is little value or benefit in screening without the other essential parts of the care pathway. Therefore, planning for implementation of a newborn hearing screening programme needs to be undertaken in conjunction with steps to ensure that:
- babies who are referred by the screening test can receive timely audiological asssessment and, if necessary, treatment
- babies can be provided with appropriately fitted hearing aids and where possible, referred for cochlear implants when meeting audiological criteria
- there is skilled support for families and for the assessment and promotion of speech, language and communication development in young children, following confirmation of hearing loss
Research has also shown that “success is achieved when early identification is paired with early interventions that actively involve families”3. Therefore all parts of the care pathway should ideally be delivered in a family-centred way, responsive to the needs of individual families. Enabling families to meet other families of deaf and hard of hearing children, and adults with hearing loss, can be an important part of providing this support.
Screening can use one of two approaches:
- opportunistic: meaning that the screening is implemented as part of some existing routine care
- proactive: meaning that the population targeted for screening is actively identified to participate in the programme
In the case of newborn hearing screening, there are a number of natural opportunities to integrate into existing care provision: either around the time of birth or during the days following, alongside other elements of routine medical care.
b. Pre-implementation considerations and preparations
Consideration of the political, cultural, geographic, economic and demographic elements in preparation for implementation are covered in chapter 4 of this manual. In addition, from both strategic and practical perspectives to help design the programme delivery, it is essential to determine:
- whether the proposed programme is local, regional, or national
- whether to implement a targeted programme (screening only babies who are considered higher risk) or a universal programme (screening all babies born in the chosen area). Since targeted screening identifies only about half of the children with hearing loss at birth, a universal programme is recommended
- how the programme will be funded – both for initial implementation and for sustainability
- whether screening will be offered free to families or at a cost
- the number of live births each year in the chosen implementation area
- what kind of maternity care expectant mothers receive
- where babies are born (% hospital, home, elsewhere)
- how many babies, on average, are well babies and how many typically require time or treatment in special care such as neonatal intensive care units (NICU)
- what proportion of babies are full term births and what proportion are premature
- how long mothers of well babies stay in the hospital after the birth, before being discharged
- whether babies receive other routine medical checks (for example hips, eyes, heart), or other screening tests before being discharged from hospital and how and by whom are these done
- if any hospital-born baby were to go home without being screened, whether parents could easily return to the hospital or another location for screening within the first few weeks, or whether babies could be screened at home
- what typical healthcare mothers and babies receive in the period after birth, after they have left hospital or have given birth at home, and when and where that takes place and by whom
- whether there is a childhood vaccination programme, and if so, what is included and how the programme is organised, to assess the possibility of combining hearing screening with vaccinations
- what requirements exist for consent for medical procedures
- whether IT support is available in potential screening locations
- how the newborn hearing screening programme will be administered and managed and how data will be collected and used
- how the screening process itself will be conducted and how it will be reported on, evaluated and quality assured
- who will do the screening: dedicated hearing screening personnel or other professionals (such as maternity nurses) as part of their routine involvement in newborn care/examinations or other existing screening activity
- how screening personnel will be trained and how their performance can be assessed and standards maintained (both at time of completing training and in an ongoing way)
- what equipment and protocols to use, considering the possibilities and limitations of the settings in which screening is to be implemented
- how current hearing care is provided and whether there are audiologists or other hearing professionals (such as ENT physicians or paediatricians with additional training in audiology) able to undertake diagnostic testing and to fit and manage amplification
- whether the necessary follow-up diagnostic testing facilities exist in terms of appropriate venues and equipment and if so, how these are accessed
- what provision exists or could be developed to provide the necessary skilled and trained support to families for developing their child’s language and communication
- whether and what routes exist for raising awareness of hearing screening and informing parents about the screen before the programme is implemented, taking into consideration:
- how information about healthcare initiatives are typically shared with the public (see also chapter 10)
- what contacts with expectant mothers are routinely made during pregnancy
- what opportunities are there to educate them about the screen and the importance of early identification of hearing loss
- the attitude of the public / community towards identifying disability in babies and young children, and any barriers that exist
c. Planning a screening programme
The programme requires:
a) Leadership and governance:
- to provide strategic direction and oversight (including data, finance and equipment) to ensure the whole screening pathway is safe, functional and sustainable
- to agree the objectives of the programme, to set quality standards and to monitor programme performance against agreed benchmarks or Key Performance Indicators (KPIs)
- to agree on the screening protocols to be used
- to ensure clear communication about the programme at all levels: to policy makers, health departments, healthcare providers, the general public and parents
- to produce clear information for parents pre-screening and throughout the screening pathway to the point of discharge for those babies passing the test and referral to audiology for those babies who need further assessment
- to quality assure and audit the programme
- to ensure effective risk and incident management
- to ensure effective training and competency assessments for all personnel involved
The setting up of a multi-disciplinary board with representatives from all stakeholders (audiology, neonatal care, ENT, maternity ward, early intervention programme) can support coordination and effective clinical governance.
b) Management and administration:
- to co-ordinate and run the programme at national / regional / local level in accordance with agreed policy, procedures and protocols
- to ensure babies to be screened are identified
- to ensure that all eligible babies are screened according to protocol and receive a recorded screen outcome
- to ensure effective data capture and handling to support the screening and referral processes
- to oversee screener training and to continuously monitor screener performance
- to report on the performance of the screening programme, including risks and incidents
- to manage all aspects of screening equipment, to ensure that QA checks are undertaken, and that the equipment is serviced and calibrated at required intervals
c) Screening personnel:
- to ensure all babies identified for screening are offered the screening test
- to communicate with parents about the purpose of the screen, and gain their consent
- to carry out the hearing screening and to accurately record clinical and test data
- to sensitively and accurately communicate the screening test results to parents and inform them about next steps
- to ensure the safety of the screening equipment
- to ensure screening follows all agreed protocols and best practice
ii. Operational elements of the programme
Operational steps in delivering the programme include:
- identifying the target population
- inviting the target population
- informing and gaining consent
- administering the test(s) and recording the results
- communicating the test results and taking appropriate action without delay
- enabling / ensuring fit-for-purpose assessment, diagnosis, treatment and support for those babies referred
a) The target population
In a universal programme, all eligible babies born in the agreed area (national, regional or local) within the first month of life. The test can be done for babies up to three months of age (corrected age for premature babies). In some circumstances, this may be extended to six months of age.
In a targeted programme, only those babies at higher risk for hearing loss, for example babies with an illness or condition that requires admission to special care for 48 hours or longer, findings associated with a syndrome known to include hearing loss or a family history of hearing loss. A full list can be found in this paper4
For some babies routine screening is not appropriate, and they should be referred directly for audiological assessment. These include babies who have:
- atresia (no obvious ear canal in one or both ears)
- suspected or confirmed meningitis
- confirmed congenital cytomegalovirus
- a ventriculoperitoneal shunt inserted to drain extra cerebrospinal fluid from the brain in cases of hydrocephalus
Babies who have tested positive for Zika virus, or whose mothers have tested positive for Zika virus, may also be referred directly for audiological assessment without screening. In some programmes however they may be included in the screening, in which case they should receive automated Auditory Brainstem Response (aABR) testing rather than Otoacoustic AEmissions testing (OAE). See section Screening tests and equipment below.
b) The target condition
Permanent (sensorineural) hearing loss of 35dB or 40dB or greater, depending on policy choice.
The programme should define the target condition(s). These may be: permanent (sensorineural) hearing loss of 35 or 40dB, depending on policy choice: unilateral loss; permanent conductive hearing loss; and auditory neuropathy spectrum disorder (ANSD).
c) The programme objective
To enable early identification of babies with the agreed target condition(s) and to ensure the provision of safe and effective assessment and support. The desired health outcome is the optimal development of language and communication skills (whether spoken or signed) for children born with hearing loss.
d) Communication and information
A universal programme needs a high level of coverage in order to be successful, with high uptake from the population. Therefore it is important to ensure a good degree of awareness amongst healthcare providers and in the general public. Wide communication is required and needs to cover:
- what the programme aims to achieve and why (the early detection of hearing loss so that children can develop speech language and communication skills, whether spoken or signed, and have better life chances)
- how, when and where the programme will be implemented
- how the programme will operate and what is involved
- how the programme fits in to existing healthcare
In addition, there should be specific more detailed information aimed at expectant parents. This should be available to them as a leaflet or other appropriate format during the antenatal period so that they know that the screen will be offered for their newborn baby. It needs to be accessible both in terms of language and readability. The leaflet should be given to them again before the screening process begins. It should cover:
- what newborn hearing screening is, its risks and limitations
- an explanation of hearing loss, and its impact on development if it is undiagnosed
- the benefits of early identification
- an explanation of the screening test(s) and the potential outcomes / results
- what the next steps will be, depending on outcome
- details of further contacts for any questions they may have after the screen
The leaflet should be used alongside the verbal explanation by the screener during the consent process and then given to the parent to keep. Programmes may have a second leaflet for babies referred from the screen to Audiology for further assessment, explaining in accessible language what a ‘refer’ result means and what they may expect at that appointment.
Many existing screening programmes have leaflets which could be used as basic templates. These should be adapted in a culturally appropriate way for different national, regional or local circumstances, in keeping with the specific needs of the programme.
e) Screening tests and equipment
High quality screening requires tests with high sensitivity and high specificity.
‘Sensitivity’ means the screening test’s ability to accurately identify babies who do have the target condition. ‘Specificity’ means the screening test’s ability not to refer babies who do not have the condition.
Major reputable manufacturers of screening equipment ensure their products go through rigorous scientific evaluation to make sure the technical specification is fit-for-purpose and has high specificity and sensitivity. However, a number of other issues can affect specificity and sensitivity, including the skills of individual screeners, the conditions in which screening is undertaken and the age of the infant at the time of the screen. Attendance rates and coverage (ie. the proportion of eligible babies receiving a test and having a recorded result) also affect the sensitivity and specificity of the overall screening programme.
There are two screening methods that may be used:
- Otoacoustic Emissions (OAE): this test measures soundwaves produced in the inner ear. A small soft-tipped probe is placed in the baby’s ear canal and tones or clicks are played. If the cochlea (the organ of hearing) and middle ear are functioning normally, an otoacoustic emission is detected
- Automated Auditory Brainstem Response (aABR): this test measures how the hearing nerve and brain stem respond to sound. Three electrodes are placed on the baby’s head and neck / shoulder and clicks or tones are played through soft earphones into the baby’s ears
In both tests, the responses are automatically analysed by the equipment, which then displays the results as ‘pass’ or ‘refer’ (fail). No specialist interpretation of results is required by the screener. Both screening tests are quick and painless and are done when the baby is asleep or awake and quiet. Depending on the protocol chosen, one or both methods may be used.
OAE and aABR technology can be separate pieces of equipment or combined in one screening device which can perform both tests. A combined OAE / aABR device is typically more expensive than separate OAE only and aABR only devices, although pricing will vary according to local circumstances and also the amount of equipment purchased. OAE and most aABR technology requires the use of disposables (such as ear probe tips, electrodes, earmuffs, adhesive sensors, and wipes). These come at extra cost. In addition, the equipment needs regular (annual) calibration to make sure it continues to function optimally. Although annual calibration involves a cost, and means that the machine is unavailable for use during the time taken to calibrate, the process is essential to ensure accurate functioning. Choice of technology should be guided by the needs and circumstances of individual programmes, and individual manufacturers provide detailed information on the relative benefits and performance of different equipment. Further detailed information and guidance can be found in the NCHAM e-book A resource guide for early hearing detection and intervention, chapter 2.
Screening needs to take place in an environment which is quiet. If there is too much noise, or a baby is too unsettled, the test results can be affected. It is possible to test babies at the bedside if the room is not noisy, but otherwise it may be better to have a separate quiet room where the mother can be with her baby for the test. A fully sound treated room is not a necessity.
f) Test protocols
‘Screening protocol’ refers to the choice and sequence of tests. There are many factors to take into account when choosing a protocol, such as how long mothers stay in hospital after giving birth, and how easy it is for them to return if re-tests are required, as well as financial considerations.
Most existing screening programmes use a combination two-step protocol of OAEs followed by aABR. Some screening programmes use aABR as the preferred method due to its higher specificity and sensitivity to. aABR has higher sensitivity and specificity than OAE and aABR testing can detect auditory neuropathy spectrum disorder (ANSD). However, aABR testing is more costly and takes longer to perform. OAE is a quick and straightforward test but if babies are screened too soon after birth, they may refer (‘fail’) on the test due to having birth fluid in the ear canal or middle ear. For this reason, although babies can be screened within the first 24 hours of birth, and as early as 6 hours of age, it is advisable to wait as long as possible and to perform screening close to the time of discharge home from hospital. Alternatively, babies can be screened later in the following days in a special clinic or community setting or at home, depending on the design of the programme.
Various protocols or test combinations are possible:
For well babies the most common protocol are the two-step OAE+OAE and the three-step OAE + OAE + aABR, at least in countries with high health expenditure (countries with lower health expenditure tend to use OAE-only protocols). If the baby passes on both ears on the first OAE, he or she is discharged from the programme. If not, a second OAE is undertaken. If the result is a pass on both ears, the baby is discharged from the programme. If clear responses are not recorded, then aABR is undertaken. If the baby has clear responses on aABR testing, he/she is discharged from the programme. If not, the baby is referred to audiology for further testing. The length of time between each stage is dependent on local factors. Depending on the length of time mother and baby are in hospital, it is possible to complete screening before they leave to go home. For babies who are discharged from hospital, the second OAE and aABR if needed may be done on one or more return visits or in a community setting. The crucial aim is for screening to be completed in proper time and a result recorded, and for babies not to be ‘lost to follow up’ before screen completion. An OAE + aABR protocol may be appropriate and useful for well babies where families may have difficulty returning for a second OAE if they do not receive a pass result on the first OAE. Where local factors mean that it may be the best protocol to ensure good coverage and screen completion, aABR + aABR is also a possible protocol.
An alternative protocol is commonly used for babies who have spent considerable time (more than between 48 and 120 hours) in special care, such as a neonatal intensive care unit (NICU). Because these infants are presumed to be at higher risk for neural hearing loss, they must always be screened with aABR (because OAE identifies cochlear or conductive hearing loss but will miss neural hearing loss, unlike aABR).5 Optionally, OAE can also be used for special care babies in addition to aABR.
Programmes should select protocols which suit their chosen target conditions and also take into account the circumstances of their operational implementation so as to achieve the objective of the programme. The EUSCREEN cost-effectiveness model can simulate different protocols to provide insight into the consequences of changes in protocol.
g) Communicating results to parents
It is important that communication of the screening test results to parents is both clear and sensitive, taking into account both cultural and individual family circumstances. Screener communication should be consistent with the information in the screening leaflets.
When well babies receive a ‘pass’ result on both ears on the initial screening test, it should be explained that this means that the baby appears to have normal hearing and no further testing is needed. It is important for the screener to explain that some babies can develop hearing loss later and so parents should always be alert to their babies’ responses to sound and seek advice if they feel worried or concerned at any time about their child’s hearing or speech and language development.
If a baby does not receive a pass result on the initial test and further testing is required, the possible reasons for not getting clear results should be explained:
- there could have been too much noise for the test to complete successfully
- the baby may have been too unsettled
- the baby may still have birth fluid in the ear canal
- the baby may have a hearing loss and further testing is required
Screeners need to avoid creating over-anxiety in the parents, but at the same time, ensure that they understand the importance of further testing by not unduly minimising the possibility of hearing loss.
If, following screening, results indicate that a baby requires referral to audiology, screeners should explain that this does not necessarily mean the baby has a hearing loss, but that it is a possibility and that it is very important that the family attends the appointment.
For babies who have been in special care such as a neonatal intensive care unit (NICU), screeners need to be aware that the baby may have other health needs or disabilities which may affect how parents feel about hearing screening. It may not be seen by them as a priority, and the possibility of hearing loss could be seen as unimportant. Alternatively, it may be seen as a major issue, and be significantly upsetting to the family. It is important that screeners work as a team with the medical staff in special care to properly understand the baby’s and the family’s circumstances.
In a screening programme, there should be consistency between screeners when it comes to communication. For this reason, ‘scripts’ have been developed by programmes which screeners can follow, whilst personalising the experience to individual parents. Existing scripts could be used as templates for adaptation for particular programmes’ cultural styles and needs.
iii. Quality Standards, benchmarks and Key Performance Indicators (KPIs)
Internationally, as specified in the 2007 Joint Committee on Infant Hearing’s ’Position Statement: Principles and Guidelines for Early Hearing Detection and Intervention Programs’, the recommended goals for the pathway are to:
- complete screening within 1 month (4 weeks) from birth *
- undertake audiological assessment within the first 3 months from birth *
- fit amplification and begin early language and communication intervention and family support within 6 months from birth *
* For premature babies, the age would be a corrected age (chronological age minus the number of weeks / months premature).
Mature established programmes are now moving from 1-3-6 month goals to 1-2-3 month goals (screening before 1 month, assessment before 2 months, treatment before 3 months), informed by the evidence that earlier intervention can further improve outcomes6.
Coverage and minimising ‘loss to follow-up’ are key aspects of any programme. For this reason, Key Performance Indicators also need to focus on:
- maximising the proportion of babies receiving a completed screen and receiving a documented screen outcome
- minimising unnecessary referrals to follow up by ensuring effective screening
The Joint Committee on Infant Hearing recommends a benchmark of more than 95% of infants completing screening by one month of age, and a target of less than 4% referrals from screening to audiology. It is important however to recognise that benchmarks should be set at an achievable level, with a commitment to regularly review them as measures of performance, and increase them as programmes develop and mature.
Other quality standards may be set according to the needs of a programme. They may relate to data, or screener training, or other aspects of programme delivery which are felt to be really important.
Good data and good data management are essential to the success of a programme. A data management system (whether electronic or paper-based) should assure:
- the ability to document the instance and result of screening
- the ability to track whether or not the infants who are referred follow up to further screen and audiological assessment/evaluation
- the ability to track results of diagnostic audiological evaluation and age at identification
- if the child is deaf or hard of hearing, the ability to fit and report age at amplification fit
- the ability to record referral to early intervention services and age at commencement of early intervention services
- the ability to report the proportion and number of children who meet the 1-3-6 (or 1-2-3) goals
- the completeness of inclusion of the to-be-screened group, e.g access to the birth registries
Screener training and assessment
High quality training and assessment is essential and should ensure that screeners:
- understand the principles of screening and the difference between screening and diagnostics
- recognise and understand the potential risks and harms, limitations and benefits of screening
- fully understand the workings of the chosen equipment, its use and care
- have extensive hands on experience with the equipment and a period of supervised practice before independently screening babies
- are knowledgeable about the policies and procedures of the hospital or clinic in which they are screening and how the screening programme fits in to routine practice
- are knowledgeable about and confident with the screening protocols
- are knowledgeable about the full screening pathway
- understand and can accurately document results and use the data management system
- can communicate sensitively and clearly with parents
- understand about childhood hearing loss, its impact on development, and the interventions and services which exist to support deaf and hard of hearing children and their families
- are confident and calm dealing with babies and new parents
- understand the importance of working as part of a team with both other members of the screening programme and other professionals
On completion of training screeners should be assessed for competency, in both knowledge and skills. Many established programmes have produced guides to training and competency checklists for screenings. Some typical examples of these can be found here and here. The New Zealand UNHS and Early Intervention programme also produces a National Policy and Quality Standards (2016) document which has a detailed section (Section 2) on screening competency, performance and operation. This can be found here.
The quality assurance of a programme, regularly monitoring its coverage, uptake, attendance, referrals, and meeting of its benchmarks and Key Performance Indicators are crucial to the success and effectiveness of a programme. Good data capture and use is central to this, as is a skilled and competent workforce. For detailed information on monitoring, see chapter 11. Data should be used to support the ongoing quality of the screening programme delivery as well as for audit purposes. Regular and documented equipment checks and maintenance, including the consumables, are also key elements of assuring quality.
Programme personnel should have ongoing supervision and mentoring. Training should be refreshed and competency checks undertaken at regular intervals. Competency checks should include both assessment of knowledge and understanding and also observation of practical skills, in all the areas covered in the screeners’ initial training. In addition, the checks should include monitoring of screener performance in terms of their use of the data management system, the numbers of declines of the screen and the numbers of referrals made by individual screeners.
Failsafe procedures (systems which can prevent errors or a plan that comes into action when things do go wrong) should be put in place as a core element of the programme and regularly reviewed. All incidents should be investigated and the learning from them used to address any weaknesses in the programme and to strengthen policies and practice. The performance of the programme, and all its elements, should be subject to periodical, preferably annual, review with an accompanying report produced.
- Yoshinaga-Itano C, Coulter D, Thomson V (2001): Developmental outcomes of children with hearing loss born in Colorado hospitals with and without universal newborn hearing screening programs. Semin Neonatol 6(6):521-9.
- Korver AM, Konings S, Dekker FW et al. (2010): Newborn hearing screening vs later hearing screening and developmental outcomes in children with permanent childhood hearing impairment. JAMA 304(15):1701-8.
- Moeller MP (2000): Early intervention and language development in children who are deaf and hard of hearing. Pediatrics 106(3):E43.
- Kerschner JE (2004): Neonatal hearing screening: to do or not to do. Pediatr Clin North Am 51(3):725-36.
- Joint Committee on Infant Hearing (2007): Year 2007 Position Statement: Principles and Guidelines for Early Hearing Detection and Intervention Programs. Pediatrics 120(4):898-921.
- Ching TYC, Dillon H, Button L, Seeto M, Van Buynder P, Marnane V, Cupples L, Leigh G (2017): Age at Intervention for Permanent Hearing Loss and 5-Year Language Outcomes. Pediatrics 140(3):e20164274.