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Indian Pediatr 2017;54: 647-651 |
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Consensus Statement of the Indian Academy of
Pediatrics on Newborn Hearing Screening
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Abraham Paul, #Chhaya
Prasad, $SS Kamath, *Samir
Dalwai, ‡MKC Nair and
@Waheeda Pagarkar;
for the National Consultation Meeting
for Developing IAP Guidelines on Neurodevelopmental Disorders under the
aegis of IAP Childhood Disability Group and the Committee on Child
Development and Neurodevelopmental Disorders
From Child Care Centre, Cochin Hospital; #Max Super
Speciality Hospital, Chandigarh; $Welcare Hospital, Vytilla; *New
Horizons Group, Mumbai; ‡Kerala University, Thrissur; India, and @Audiovestibular
Medicine, Hackney ARK and Royal National Throat Nose and Ear Hospital,
London.
Correspondence to: Dr Samir Dalwai, Director, New
Horizons Child Development Centre, Mumbai.
Email: [email protected]
Received: September 13, 2016;
Initial Review: September 19, 2016;
Accepted: May 15, 2017.
Published online: June 04, 2017.
PII:S097475591600067
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Justification: Hearing
impairment is one of the most critical sensory impairments with
significant social and psychological consequences. Evidence-based,
standardized national guidelines are needed for professionals to screen
for hearing impairment during the neonatal period.
Process: The meeting on
formulation of national consensus guidelines on developmental disorders
was organized by Indian Academy of Pediatrics in Mumbai, on 18th and
19th December, 2015. The invited experts included Pediatricians,
Developmental Pediatricians, Pediatric Neurologists and Clinical
Psychologists. The participants framed guidelines after extensive
discussions.
Objective: To provide
guidelines on newborn hearing screening in India.
Recommendations: The first
screening should be conducted before the neonate’s discharge from the
hospital – if it ‘fails’, then it should be repeated after four weeks,
or at first immunization visit. If it ‘fails’ again, then Auditory
Brainstem Response (ABR) audiometry should be conducted. All babies
admitted to intensive care unit should be screened via ABR. All
babies with abnormal ABR should undergo detailed evaluation, hearing aid
fitting and auditory rehabilitation, before six months of age. The goal
is to screen newborn babies before one month of age, diagnose hearing
loss before three months of age and start intervention before six months
of age.
Keywords: Assessment, Auditory brainstem
response audiometry, Deafness, Hearing loss, Otoacoustic emission,
Prevention.
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H
earing impairment is one of the most critical
sensory impairments with significant social and psychological
consequences. Failure to detect children with congenital or acquired
hearing loss may result in lifelong deficits in speech and language
acquisition, poor academic performance and personal-social and behavior
problems [1,2]. Deficits in speech and language lead to lack of
stimulation, which adversely affects the structure of the synaptic
junction. Lack of auditory stimulation leads to retrograde degeneration
in the cell body and axon [3].
Apart from the biological evidence, the data on
congenital disabilities indicate that hearing loss has a substantially
high incidence with congenital hearing loss affecting 30 per 10,000
children [4]. Significant hearing loss is the most common disorder,
occurring in 1 to 2 newborns per 1000 in the general population, and 24%
to 46% of newborns admitted to neonatal intensive care unit [5,6].
Vocabulary of a 3-year-old child with hearing impairment if remediated
at birth is 300-700 words; if re-mediated at 6 months is 150-300 words
and if remediated at 2 years is 0-50 words, respectively; as compared to
vocabulary of a 3-year-old child with typical hearing which is 500-900
words.
In view of the above, standard guidelines for
screening newborns for hearing loss are urgently needed. The meeting on
formulation of National consensus guidelines on developmental disorders
was organized by the Indian Academy of Pediatrics in Mumbai, on 18 th
and 19th December, 2015. The
invited experts included Pediatricians, Developmental Pediatricians,
Pediatric Neurologists and Clinical Psychologists. The participants
framed guidelines after extensive discussions and review of literature.
Thereafter, a committee was established to review and finalize the
points discussed in the meeting.
Subsequent sections include the points of consensus
on screening of newborn hearing.
Recommendations
Early Screening
Critical period for identification and remediation of
hearing loss is before the age of 6 months. Since the pediatrician is
the primary care provider for the child during the first few days of
life, it is the sole responsibility of the pediatrician (or the primary
physician) to evaluate the child for hearing loss (or ensure referral
for the same). It has been observed that practice of neonatal screening
has dramatically lowered the age of diagnosis of deafness from 1˝ - 3
years to less than 6 months of age. Screening should ideally be
‘universal’ i.e., everybody is screened and at a minimum, screening
should be ‘targeted’ i.e., ‘high risk’ babies are screened.
Causes of hearing loss are summarized in Box
1. These can be classified as: Conductive, Cochlear (i.e. Sensory:
defect in the cochlea and Neural: defect in the 8 th
cranial/ auditory nerve), Retrocochlear (i.e. defect at the level of
auditory nerve, brainstem auditory pathway or both) and Central (i.e.
defect in the auditory area in cerebral cortex).
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BOX 1 Causes of Hearing Loss
• Causes in ear canal/Conductive (e.g.,
congenital atresia, wax, foreign body, trauma, external otitis,
stenosis
• Causes in middle ear/Conductive (e.g.,
acute and chronic otitis media, perforation of tympanic
membrane, congenital defects, trauma, malformations either
hereditary or familial)
• Causes in the cochlea/Cochlear (e.g.,
ototoxic drugs, stay in neonatal intensive care unit due to
jaundice or other causes, neonatal infections, head injury,
noise); and
• Causes in auditory nerve/Retrocochlear (e.g.,
problems in cochlear nerve, auditory pathway or cortex like
tumors, trauma, de myelination).
• Intrauterine infections (tetanus,
toxoplasma, rubella, cytomegalovirus and herpes or TORCH group
of infections) can be classified as cochlear or retrocochlear
causes of Sensorineural hearing loss.
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With respect to current guidelines, sensorineural
hearing loss is most relevant and cochlear causes of sensorineural
hearing loss are more common. Many risk factors for hearing loss have
been identified and are listed in Box 2.
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BOX 2 Risk Factors for Hearing Loss [7]
• Family history of hereditary childhood
sensorineural hearing impairment
• Intrauterine infection (TORCH)
• Craniofacial anomalies
• Birth weight less than 1500 gram
• Hyperbilirubinemia at a serum level
requiring exchange transfusion
• Ototoxic medications used in multiple
courses, or in combination with loop diuretics.
• Bacterial meningitis
• APGAR scores 0-4 at 1 minute or 0-6 at 5
minute
• Mechanical ventilation for 5 days or longer
• Stigmata of other findings associated with
a syndrome known to include sensorineural and/or conductive
hearing loss.
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Congenital rubella syndrome, Usher syndrome and
Jervell and Lange-Nielsen (JLN) syndrome have been noted to be
associated with hearing loss; few other syndromes include Treacher-Collins
syndrome, Apert syndrome, Alport syndrome, Neurofibromatosis syndrome,
Achondroplasia, CHARGE syndrome, Brachio Oto Renal syndrome, Chudley
McCullough syndrome and Golden Har syndrome [8].
Screening for Newborn Hearing Loss
In India, majority of hospitals do not conduct
universal or high risk screening. In such a situation, a centralized
facility catering to all hospitals in a city is a practical option. A
two-stage screening protocol can be made, in which infants are screened
first with otoacoustic emissions (OAE). Infants who fail the OAE are
screened with auditory brainstem response (ABR). In this two tier
screening program, the second tier being ABR (which is more expensive)
is required only for a select few, making the program more practical and
viable.
The Child Health Screening and Early Intervention
Services Program (Rashtriya Bal Swasthya Karyakram) under National Rural
Health Mission initiated by the Ministry of Health and Family Welfare of
Government of India has included congenital deafness as one of the
conditions to be included for early identification and remediation. It
involves screening of infants and children under age 18 years by a
mobile team and provision of appropriate treatment at District Early
Intervention Centres (DEICs). This ambitious scheme is likely to
streamline the management of hearing disabilities [9].
Otoacoustic emissions (OAEs) are quicker methods (as
compared to electrophysiologic methods like ABR) for assessing hearing
in newborns via a simple set-up. Otoacoustic emissions (OAEs) are
sounds of cochlear origin recorded in the auditory meatus (ear canal),
produced by the action of healthy outer hair cells. The emissions
themselves serve no purpose and are simply a leakage of energy from the
ear. Hearing is facilitated by hair cell activity in the cochlea and
more specifically, the activity of outer hair cells. There are three
rows of outer hair cells (OHCs) and one row of inner hair cells that sit
on the basilar membrane, sandwiched by the tectorial membrane on top.
This forms the organ of Corti. There are around 12000 motile OHCs
working together to provide mechanical assistance to sound energy,
amplifying the travelling wave to overcome the viscous nature of the
cochlear fluid. As the ‘W’ shaped steriocilia are stimulated by fluid
moving over them, it causes the cells to alternately contract and
release, providing a pumping action. This mechanical system provides the
frequency tuning within the cochlea. The inner hair cells are also
stimulated and deflected by fluid flow; and at a specific threshold, the
inner cells release a neurotransmitter which causes the auditory nerve
to transmit a signal to the brain.
Cochlear damage is almost always apparent in the loss
of outer hair cells. This is true regardless of the etiology –
congential progressive hearing loss, ototoxic drugs, presbyacusis (Sensorineural
hearing loss with aging), as well as noise-induced hearing loss. With
damaged OHCs, there is no amplification or frequency tuning, thus the
child will not only suffer a threshold shift but also have problems with
frequency discrimination.
OAE test is performed via a small probe placed
in the child’s ear canal; click sounds are delivered and response is
detected (Web Appendix 1).
The child must be quiet [10].
Recommendations on Screening
• A two-stage screening protocol with OAE as the
first screen, followed by ABR for those who fail the OAE screen
[11].
• It is advisable that all hospitals with level-3
neonatal care have OAE and ABR facilities. If not feasible, a
centralized hearing screening with a portable OAE is suggested and
all abnormal cases can be referred for ABR to the nearest centre.
• The program is to be coordinated by an
audiologist and weekly assessment meeting is to be convened with the
staff to discuss and sort out the issues, if any (held by the
convenor). Usual issues could include non-compliance by parents to
bring the child for repeat OAE or ABR. This usually can be tackled
by phone calls made by screening personnel, coordinator, or in rare
instances by the convenor himself. A medical social worker can be
involved for problem-solving.
• Personnel with basic knowledge in computer and
good communication skills are chosen. They should be provided basic
training in hearing screening and also skills to gather information
on high-risk criteria, if any, from parents/hospital staff/hospital
records. This training is to be conducted over one day.
• The screening personnel should visit each
hospital daily/on alternate days/twice a week/weekly depending upon
the number of births in that particular hospital. Daily screening
may be carried out in hospitals which have more than 200 births,
alternate day screening in hospitals with 100-200 births and twice
weekly or weekly screening in hospitals with births less than 100
per month.
• All screeners should maintain a register of all
cases screened and those with abnormal results. Neonates with
abnormal screening results should be evaluated. It is the duty of
the screeners to call back all abnormal cases for follow up, with
the help of a coordinator. (Number of hospitals covered by a
screener depends on the number of cases in a particular hospital and
proximity of the hospitals)
• If abnormal OAE is detected, it is repeated at
6 weeks on the 1 st
immunization visit. If again abnormal, ABR is done for confirmation
followed by full audiological evaluation and remediation with
hearing aids (cochlear implant may be required in cases of profound
hearing loss or poor response to hearing aids).
• All NICU babies undergo ABR testing to rule out
auditory dyssynchrony/ auditory neuropathy.
• In babies with abnormal ABR, detailed enquiry
is made to identify and record any risk factors. Any baby missing
screening before hospital discharge is called for OAE test on the
first immunization visit.
• All babies with abnormal ABR should undergo
detailed ENT evaluation hearing- aid fitting and auditory
rehabilitation before 6 months of age. Systematic evaluation for
ruling out syndromic associations such as ophthalmic, paediatric and
cardiac assessments should be conducted.
• Children with neonatal meningitis should be
treated as a special category and need investigations including
imaging and intervention like cochlear implant (if needed) on a
semi-emergency basis. Delay can result in cochlear ossification
which may preclude subsequent intervention like a cochlear implant.
The goal is to screen newborn babies before 1 month
of age, diagnose hearing loss before 3 months of age and start
intervention before 6 months of age. Hurdles experienced in the
screening process include: less motivated pediatricians; lack of
awareness among parents/community; non-compliance by the family for
evaluation, and stigma attached to hearing aids.
Conclusions
As normal hearing is critical for speech and language
development, it is recommended that during first 6 months of life,
clinicians identify infants with hearing loss, preferably before 3
months of age. Other important issues are:
• Evaluate infants before discharge from nursery,
especially high risk babies
• Universal neonatal screening and not targeted
‘high risk’ screening is ideal since about 50% of infants with
hearing loss have no known risk factors for hearing loss and are
discharged from well-baby nursery
• Delayed onset hearing loss should be considered
and followed up (if presence of language delays, infections, head
trauma, stigmata of syndromes, ototoxic medications, recurrent
otitis media, intrauterine infections, neurofibromatosis type II)
• Prevalence of hearing loss is more than twice
that of the other newborn disorders combined, which can be screened
• Never delay hearing assessment in a suspected
case; no child is too young to be tested or too young to be
evaluated
• Never resort to rudimentary tests of
hearing (like clapping hands) as confirmatory tests, and reassure
parents that their child’s hearing is normal.
Universal Newborn Hearing Screening (UNHS) has become
a standard practice in most developed countries. The identification of
all newborns with hearing loss before six months has now become an
attainable and realistic goal. A concept of a centralized newborn
hearing screening model existing in Ernakulam District - Kerala to cater
to all hospitals in the district is worth replicating [12]. It takes
away the financial burden of each hospital investing for the screening
equipment. Follow up of positive cases and drop-outs are made easier
with the central reporting and monitoring system. With unified strength
of pediatricians, IAP city/ district branches could take initiative to
replicate this model in their respective towns or districts and by
collaborating with government agencies involved in implementation of
Rashtriya Bal Swasthya Karyakram.
Newborn hearing screening will help to identify
hearing loss at an earlier age and alleviate the double tragedy of
inability to hear and speak. Forming a consensus and national level
guidelines for hearing screening is very important to construct a
healthy independent society. Early intervention is mandatory for best
prognostic outcomes.
ANNEXURE I
Participants of the National Consultative Meet for
Development of IAP National Consensus Guidelines on Newborn Hearing
Screening
Convener: Dr Samir Dalwai, Mumbai.
Experts: (In alphabetical order) Abraham Paul,
Cochin; Anjan Bhattacharya, Mumbai; Anuradha Sovani, Mumbai; Bakul
Parekh, Mumbai; Chhaya Prasad, Chandigarh; Deepti Kanade, Mumbai; Kate
Currawalla, Mumbai; Kersi Chavda, Mumbai; Madhuri Kulkarni, Mumbai;
Monica Juneja, New Delhi; Monidipa Banerjee, Kolkata; Mamta Muranjan,
Mumbai; Nandini Mundkar, Bangalore; Neeta Naik, Mumbai; P Hanumantha
Rao, Telangana; Pravin J Mehta, Mumbai; SS Kamath,Cochin; Sandhya
Kulkarni, Mumbai; Shabina Ahmed, Assam; S Sitaraman, Jaipur; Sohini
Chatterjee, Mumbai; Uday Bodhankar, Nagpur; V Sivaprakasan, Tamil Nadu;
Veena Kalra, New Delhi; Vrajesh Udani, Mumbai; Zafar Meenai, Bhopal.
Rapporteur: Leena Deshpande, Mumbai; Leena
Shrivastava, Pune.
Invited but could not attend the meeting: MKC Nair, Thrissur;
Pratibha Singhi, Chandigarh; Jeeson Unni, Ernakulam, Cochin; Manoj
Bhatvadekar, Mumbai.
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Key Messages
• Hearing loss should be screened preferably
before 1 month of age.
• Universal neonatal screening rather than
targeted ‘high risk’ screening is ideal.
• If abnormal OAE detected, it is repeated at 6
weeks or on the first immunization visit. If again abnormal, ABR is
done for confirmation followed by full audiological evaluation and
remediation with hearing aids.
• All NICU babies should undergo ABR testing to
rule out auditory dys-synchrony/ auditory neuropathy.
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