(Automated) transitory-evoked otoacoustic emissions testing
Automated auditory brainstem response testing
Advantages
Simple testing technique (relatively minimal training needed to perform OAE testing)
Superior evaluation of the auditory system (vs assessment of outer hair cell function alone as in OAE)
Cheaper than AABR screening
Likely provides better detection of infants with auditory neuropathy
Fast
Disadvantages
Limited assessment of the auditory system
Requires more operator knowledge than OAE testing
Impacted by middle ear fluid issues
Potential for electrical and noise artefact yielding poor screening
Potentially impacted by vernix or wax in the ear canal
Requires sleeping or quiet infant
Optimal to perform in a quiet environment
Optimally performed in a quiet environment
Requires longer times than OAE screening
Typically more costly than OAE screening
In order to reduce the false-positive rate because of middle ear fluid or vernix, the combination of OAE and AABR with the measurement of wideband reflectance had been recommended.
17.1.4 Limitations of the UNHS and Dealing with Screening Failures
As long as there is no governmental regulation of UNHS, it is hard to cover a large percentage of newborns (Kaye 2006).
The test failure rate ranges from 2 to 4% and is dependent on the training of the personnel conducting the UNHS (Morton and Nance 2006). Thus the extraordinarily low failure rates of metabolic screening procedures cannot be met.
Permanent hearing loss is defined as hearing loss of more than 40 dB in the UK and of more than 35 dB in the USA (Morton and Nance 2006). Consequently, in many countries, UNHS is limited to hearing loss of more than 35 or 40 dB. For this reason mild hearing loss is not taken into consideration although its negative implications are well known. Although more than 90% of the newborns are screened in the USA, mild bilateral hearing loss and unilateral hearing loss (UHL) are still a problem because they seem to be under-identified (Ross et al. 2008). The authors concluded that the newborn prevalence of UHL was 0.35/1000 newborns and 0.16/1000 for mild bilateral hearing loss. In contrast Choo and Meinzen-Derr (2010) advanced the opinion that the sensitivity and specificity of OAE and AABR are effective enough.
Some cases of early-onset hearing loss are not apparent at birth. There is no alternative to UNHS performed with otoacoustic emissions and AABR, but improvement is necessary in order to identify prelingual hearing loss, which is not apparent shortly after birth because many of the parents trust in the results of UNHS and do not react adequately when language acquisition is delayed. Morton and Nance (2006) recommend combining the UNHS with tests on blood samples which had been collected on Guthrie cards. GJB2 deafness, the mitochondrial A1555G mutation (showing aminoglycoside-induced hearing loss) and SLC26A4 (associated with Pendred syndrome), as well as a test for the presence of Cytomegalovirus infection, should additionally be performed, in order to identify delayed-onset prelingual hearing loss (Morton and Nance 2006). Choo and Meinzen-Derr (2010) also argue that almost 1% of the newborns are infected with Cytomegalovirus. Tranebaerg (2008) recommends an early aetiological examination for persons without known aetiology, including the examination of the parents, a three-generation pedigree, a temporal bone imaging, a physical examination from top to toe and a genetic screening for a GJB2 mutation.
Ear probe blocked
Outer ear canal blocked by debris, amniotic fluid or cerumen
Ear probe positioned against the outer ear canal
Ear probe too small
Child is not quiet
Too loud an environment
Is full and sleeping (very tired)
Has no cream applied to its face
Does not sweat
Environment or the child is too loud
Myogenic artefacts (child is fretful)
Impedance at the electrodes is too high
External electronic emission
Position of the headphone (out of place)
Another problem of the newborn hearing screening protocols is the under-identification of auditory neuropathy/dyssynchrony disorders (ANDD). Usually newborns with ANDD pass the OAE screening because the OAE signals are robust. In order to diagnose ANDD reliably, a newborn hearing screening protocol that includes both OAE and AABR is needed. However, most of the protocols implement a two-step protocol starting with the cheaper and faster OAE, followed by AABR when the newborn does not pass the OAE examination (Choo and Meinzen-Derr 2010).
From the high frequency of viral and genetic aetiologies, it may be foreseen that future hearing screening protocols will develop in this direction.
17.1.5 Setting Up a Screening Programme
To motivate the birthing centres to perform UNHS.
To build up a tracking centre. The aim of a tracking centre is to follow every newborn until normal hearing is proved or until the hearing-impaired baby has started a specific phoniatric-(ped)audiologic therapy.
To motivate ENT specialists to perform a second screening test in those babies who failed the first one or who did not participate in a screening test in the birthing centre.
To motivate specialists in phoniatrics and pedaudiology to perform confirmatory diagnostics.
To monitor and audit the screening programme.
17.1.6 Early Hearing Detection and Intervention Programmes
It is reasonable to combine early hearing detection with an intervention programme (e.g. ASHA: Early Hearing Detection and Intervention (EHDI) 2016) and early aetiological investigations because there are some aetiologies that are characterised by progressive hearing loss or crucial associated anomalies.
17.1.7 Management of Control Intervals/Screenings for Late-Onset Hearing Loss
Control intervals should be kept as short as possible. In general diagnostics of hearing loss and hearing aid fitting should be completed within the first 3–6 months of age. It is the main activity of the tracking centres to motivate the parents to attend the screening tests even when the parents are convinced that their child is able to hear correctly.
Barreira-Nielsen et al. (2016) found in 47.9% of 330 hearing-impaired children (251 exposed to NHS) progression of hearing loss and recommend close audiological monitoring after early hearing loss detection.
Holzinger et al. (2016) collected data from a complete sample of hearing-impaired school-aged children born in 1997–2001 in the Austrian federal state Carinthia. 85.2% of them had undergone NHS and 50% of those had passed this early screening. The observed rate of hearing impairment was twice the rate detected in newborns.
Skarżyński and Piotrowska (2012) presented the European Consensus Statement on Hearing Screening of Pre-School and School-Age Children to develop hearing screening programmes for these age groups.
Louw et al. (2017) successfully tested smartphone-based hearing screening at primary healthcare clinics in South Africa even in 3-year-old children.
17.1.8 Early Aetiological Investigations
To know the aetiology of permanent childhood hearing loss will disburden many mothers who are threatened by self-doubt because they fear to have caused the hearing loss by some misconduct during pregnancy. It is also important to know the aetiology in the context of family planning, the prognosis of the hearing loss as well as the prognosis of associated anomalies in syndromic hearing loss. Principally the aetiology of hearing loss is divided into pre-, peri- and post-natally acquired and into syndromic and non-syndromic genetic hearing loss. The most important pre- and peri-natal aetiologies are listed according to their frequency in the “year 2000 position statement: principles and guidelines for early hearing detection and intervention programs” (Joint Committee on Infant Hearing 2000). CMV infections have gained importance during recent years, and new therapy programmes promise to reduce CMV-related hearing loss (Gandhi et al. 2010; de Vries et al. 2011). Because we find ourselves in a phase of extremely fast developments in genetic diagnostics, it is foreseeable that in the coming years we can expect an increasingly complete genetic diagnosis and, derived from that, new therapy options. Until then it is recommended to repeat aetiological investigations at the age of 3–6 years, at the age of 9–12 years and in early adulthood because, especially in syndromic hearing loss, many signs and symptoms that had not been present before become obvious with increasing age (e.g. retinitis pigmentosa in Usher’s syndrome).
17.1.9 Role of Immunisation
T = Toxoplasmosis
O = Others
R = Rubella
C = Cytomegalovirus
H = Herpes
For some authors the acronym is extended to STORCH where S stands for syphilis. The prevalence of this sexually transmissible disease is growing again mainly in eastern European countries after many years of reduced morbidity. In most of the European nations, comprehensive vaccination programmes have been introduced, and prenatal care is an essential healthcare issue as well. However, in some countries without compulsory vaccination, it has become fashionable to forgo vaccinations. There are also significant differences in the prevalence of these diseases. For example, toxoplasmosis, which appears much more frequently in Belgium, is a matter of prenatal care. Reviewing five studies about toxoplasmosis and hearing loss, Brown et al. (2009) pointed out a prevalence of toxoplasmosis-associated hearing loss from 0 to 26%. In utero toxoplasmosis infection may lead to delayed-onset or progressive hearing loss and therefore can be overlooked in UNHS. When an antiparasitic therapy was started before 2.5 months of age and continued for 12 months, no children (0%) developed hearing loss. The authors stressed that it seemed to be important that the compliance with the treatment needs to be monitored.
Without any doubt Cytomegalovirus infections are underdiagnosed dramatically in childhood hearing loss. Cytomegalovirus infections are the most common infections in newborns (Gandhi et al. 2010). According to de Vries et al. (2011), 7 out of 1000 newborns are infected, and 85–90% of these are without any symptoms.
17.1.10 How to Communicate the Results of UNHS
It is important to communicate the test results to the parents in adequate terms. It is not helpful to use terms such as fail, suspicious, etc. These terms may induce adverse reactions because in such a situation many of the parents are highly irritated, depressed and agitated. Often they do not accept having to wait a few days for a further examination. Parental anxiety is natural and can be expected when their children fail hearing screening, but may be reduced if counselling is done by skilled and empathetic professionals (Low et al. 2005) using terms indicating that the results are insecure as long as there are no distinct results that exclude a hearing loss or that confirm it in detail. In the Anglo-Saxon language area, the euphemism “refer” has been adopted to indicate a failed screening test.
17.2 Programmes for Enhancing Parental Communication Skills
17.2.1 Introduction
Newborn hearing screening is now the accepted standard of care in many countries and is being increasingly adopted in others. The advantages of early identification and advances in technology enable children with hearing loss to develop language and communication at a similar rate to that of hearing peers. The meaningful and effective involvement of parents and family, however, has been shown to be the single most effective predictor of a newly identified child’s success (Yoshinaga-Itano 2000), and late engagement and limited family involvement have been shown to be associated with significant developmental delay in children’s language skills (Moeller 2000; DesJardin 2006).
For this reason, much attention has been directed towards the development of family-centred service delivery in early intervention for children with hearing loss. An international consensus statement on Best Practices in Family-Centred Early Intervention with Deaf and Hard of Hearing Children (Moeller et al. 2013) detailed ten research and evidence-based key principles supporting positive outcomes for children with hearing loss. In addition to principles relating to the broader context of early support, specific early intervention provider behaviours are highlighted in relation to parent-infant interaction and progress monitoring that underpin all approaches to promoting language and communication development.
Promote their child’s language and communication.
Partner effectively with professionals and develop self-advocacy skills.
17.2.2 Examples of Enabling Parents to Promote Their Child’s Language
Following diagnosis, the teacher of the deaf or speech and language pathologist will support the parents in understanding their child’s communication and language needs and how these may be met. Ongoing assessment and monitoring of the child’s developing communication skills is undertaken in partnership with parents/caregivers. The practitioner and parent then agree on short-term goals for the deaf child, and the professional coaches the parent on how to build maximum opportunities for language growth within typical daily routines.
Establishing eye contact and eye gaze
Promoting turn taking
Following the child’s lead in conversation
Enabling language rather than correcting
Being emotionally attuned in terms of facial expression (see Fig. 17.2)
Providing pauses to enable the child to process
Positive interaction between parent and child demonstrating the essential eye contact. The child is wearing a cochlear implant. Photo with kind permission of the parents
Emotionally attuned facial expressions in parent and child. The child is wearing a cochlear implant. Photo provided with kind permission of the parents
The Hanen Parent Education Programme, in which:
the parent is encouraged to enhance the quality of interaction in spontaneously occurring events using a number of techniques (Baxendale and Hesketh 2003)
and which focuses on empowering parents to foster both early language and social communication development.
Auditory-verbal therapy, an approach to early habilitation, in which:
caregivers and therapists provide the children with maximal acoustic stimulation to develop listening, speech, and language skills. (Easterbrooks et al. 2000)
17.2.3 Example of Enabling Parents to Partner Effectively with Professionals
A five-session training course has been developed at the authors’ centre (Wandsworth Hearing Support Service) to train parents in communicating effectively with professionals. Parents develop skills in assertiveness, understanding models of disability, effective listening and preparing for meetings. One hundred per cent of parents who attend report a significant shift in their ability to advocate for their child. Information on the parent training course can be obtained from info@wandsworthhis.org.uk.
17.3 Stimulation of Language Development
See Part III Sect. 12.2.
17.4 Family Audiometry
Family audiometry may be helpful in some cases of a hearing disorder in a child.
If a child has been diagnosed with a hearing disorder, family members (at the minimum siblings and parents) should undergo audiometric examination. As the risk for a sibling to have a hearing disorder is high, i.e. 25% in an autosomal recessive disorder, younger siblings especially may benefit from an early diagnosis to prevent or minimise speech development impairment (White 2004). The aim is to demonstrate any hearing loss that may be present. Additionally, patients with bilateral hearing loss of unknown aetiology more frequently have relatives with undiagnosed mild or unilateral hearing loss, hinting at a genetic background (Tharpe and Sladen 2008).
Audiogram shape | Rate of progression | Age of onset | Severity |
|---|---|---|---|
Downsloping (high-frequency) | Stable | Congenital | Mild |
U-shaped (mid-frequency) | Progressive | Early | Moderate |
Upsloping (low-frequency) | Late onset | Severe | |
Residual hearing (measurable frequencies only in low frequencies) | Profound |
(a–f) Examples of audiograms showing non-syndromic hearing losses. (a) Sharply downsloping, (b) gently downsloping, (c) residual, (d) flat, (e) U-shaped and (f) upsloping. All hearing losses shown are sensorineural, but bone-conduction thresholds have been omitted for clarity of presentation. Audiograms adapted from Liu and Xu (1994), copyright © 1994 by SAGE Publications, Inc. Reprinted by Permission of SAGE Publications, Inc.
Furthermore, the results of audiometric evaluation of several family members may provide useful hints of a genetic disorder (non-syndromic/syndromic hearing disorder) and permit establishment of a family pedigree that will improve the quality of genetic counselling (Kochhar et al. 2007) (see Sect. 17.5). In family members with a hearing disorder, special attention should be paid to morphological changes, i.e. craniofacial abnormalities that might be related to syndromic hearing disorders. On the other hand, if an individual is diagnosed with syndromic hearing loss, family members should be examined for symptoms related to the respective syndrome. Syndromic hearing disorders are described in Sect. 14.11.
17.5 Genetic Counselling
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