Hearing screening program

1. Newborn- Hearing
Screening

2. Wilson's criteria for screening tests
• the condition should be an important health problem
• the natural history of the condition should be understood
• there should be a recognisable latent or early symptomatic stage
• there should be a test that is easy to perform and interpret, acceptable,
accurate, reliable, sensitive and specific
• there should be an accepted treatment recognised for the disease
• treatment should be more effective if started early
• there should be a policy on who should be treated
• diagnosis and treatment should be cost-effective
• case-finding should be a continuous process

3. Introduction:
• Hearing loss is the MC disorder at birth ,leading
to
- delayed language development,
- difficulties with behaviour and psychosocial
interactions.
- poor academic achievement.
0
5
10
15
20
25
30
35
Hearing loss Cleft lip or
palate
Down
syndrome
Limb defects Spina bifida Sickle cell
anemia
PKU
Congenital Condition Type
Numberper10,000

4. Definition:
 Normal hearing has a threshold of 0 to 20 dB.
 The extent of hearing loss is defined by measuring the
hearing threshold in decibels (dB) at various frequencies.
 WHO classifies:
• Mild — 20 to 40 dB
• Moderate — 41 to 60 dB
• Severe — 61 to 90 dB
• Profound — >90 dB
 Severity –based on better functioning ear

5. Classification:
 Conductive loss
-abnormalities of the outer or middle ear,
-limits the amount of external sound that gains access to
the inner ear.
 Sensorineural hearing loss (SNHL) involves the
cochlea or auditory neural pathway.
- Auditory neuropathy (AN):absent or severely distorted
ABR with preservation of conductive and cochlear
function.
- Most neonatal hearing impairment is caused by SNHL.
 Mixed loss is a combination of conductive and SNHL.

6. Prevalence:
• Prevalence estimates vary across studies .
• Estimated that 1 -3 /1000 infants will have
permanent sensorineural hearing loss
– 1/1000 from the well baby nursery
– 10/1000 from the NICU
• Rate increases to 6/1000 by school age
– Need for surveillance
• 4 out of every 1000 children born in India were
found to have severe to profound hearing loss .’
‘Rehabilitation Council of India. Status of Disability in India-2000: New Delhi;
2000. p. 172-185).

7. Rationale for Newborn Hearing
screening:
1. Earlier detection and intervention .
2. Early intervention can improve
speech and language development,
and educational achievement in
affected patients.

8. Earlier detection:
• Controlled trial of 53,781 neonates born in
four English hospitals from 1993 to 1996.
• Infants with hearing loss born during periods
of screening likely to be detected at an
earlier age (OR= 5) and to receive earlier
intervention (OR= 8).
Controlled trial of universal neonatal screening for early identification of permanent childhood
hearing impairment. Wessex Universal Neonatal Hearing Screening Trial Group. Lancet
1998; 352:1957

9. Earlier diagnosis improves
outcome:
• Netherlands –Detected by newborn
screening vs screening at 9 months.
• Newborn screening group -higher scores
for developmental, social development,
gross motor development, and quality of
life testing when evaluated at three to five
years of age.
Korver AM, Konings S, Dekker FW, et al. Newborn hearing screening vs later hearing
screening and developmental outcomes in children with permanent childhood hearing
impairment. JAMA 2010; 304:1701.

10. Earlier diagnosis improves
outcome:
• Study from Australia reported better scores –
receptive,expressive language, receptive
vocabulary who were diagnosed earlier due to
UNHS ,than patients selectively screened based
on identifying risk factors or based on
opportunistic detection for hearing loss.
Wake M, Ching TY, Wirth K, et al. Population Outcomes of Three Approaches
to Detection of Congenital Hearing Loss. Pediatrics 2016; 137.

11. Screening tests for Hearing:
• The American Academy of Pediatrics
(AAP) Task Force on Newborn and Infant
Hearing ,defined a
effective neonatal hearing screening test
- as one that detects hearing loss of ≥35
decibels (dB) in the better ear and is
reliable in infants ≤3 months of age .

12. • Two electrophysiologic techniques meet
these criteria:
1. Automated auditory brainstem
responses (AABR)
2. Otoacoustic emissions (OAE)

13. Screening tests for Hearing:
• Both - inexpensive, portable, reproducible,
and automated.
• They evaluate the peripheral auditory
system and the cochlea.
• Cannot assess activity in the highest
levels of the central auditory system.
• These tests alone are not sufficient to
diagnose hearing loss.
• Any child who fails one of these screening
tests requires further audiologic
evaluation.

14. Automated auditory brainstem
response
(AABR):
• AABR measures the summation of action
potentials from the VIII N to the inferior
colliculus of the midbrain in response to a click
stimulus.
• Difference between AABR and ABR(BERA).
- AABR is a screening tool
automated pass/fail response
- ABR diagnostic test provides quantitative data
(eg, waveforms) interpreted by a trained

15. Technique:
• The AABR utilizes click stimuli presented at 35 dB.
• Three surface electrodes
• - forehead, nape, and mastoid .
-detect waveform recordings generated by the auditory
brainstem response to the click stimuli.
• The morphology and latency of the waveforms are compared
with normal, and a pass or fail reading is generated, and the
examiner does not see the waveforms.
• AABR typically requires 4 to 15 minutes for testing,

16. Otoacoustic emissions:
• OAE testing measures the presence or absence of
sound waves (ie, OAEs) generated by the cochlear outer
hair cells of the inner ear in response to sound stimuli.
• A microphone at the external ear canal detects these
low-intensity OAEs.
• Since OAE evaluates hearing from the middle ear to the
outer hair cells of the inner ear, it cannot detect AN.
Technique — The apparatus for OAE screening consists of a miniature
microphone placed into the infant's outer ear canal.
• The microphone produces a stimulus (clicks or tones) and detects
sound waves as they arise from the cochlea.
• OAE testing generally requires approximately four to eight minutes.

17. AABR VS OAE:
• Test time − OAE require less patient preparation
time and a shorter test time,
- can be performed when the infant is awake,
feeding, or sucking on a pacifier
• Interference − OAE is sensitive to background
noise and noise generated by the baby
• False positve: Increased false-positive rate with
OAE, caused by vernix occluding the external
ear canal

18. • Tympanic membrane mobility − OAE requires , normal middle ear.
decreased tympanic membrane mobility can reduce screening pass
rates with this technique
• Auditory Neuropathy:
AABR will detect the hearing loss in infants with AN, but OAE will
not.
-AABR should always be used to screen hearing in infants who are
at risk for AN (eg, infants with hypoxia, prematurity,
hyperbilirubinemia, or neurologic impairment).
-All NICU graduates should also be screened using AABR.
• Relative costs − Actual screening cost is lower for OAE ( US$32.23
vs US$33.68)
-the overall cost of screening and audiologic evaluation lower with
AABR because the lower referral rate for audiologic assessment.
US$58.07 for OAE and US$45.85 for AABR.

19. Universal screening vs selective
screening:
• Development of rapid, low-cost screening
tests made it feasible for universal
screening.
• Adoption of UNHS, the age at
identification of hearing loss has
decreased from a range of 24 to 30
months to 2 to 3 months of age

20. Universal screening vs selective
screening:
• Targeted screening program - risk factors ,identify 50 to
75 percent of infants with moderate to profound bilateral
hearing loss.
• Australian population-based study, the mean age for
diagnosis older for programs using selective screening
compared with universal screening (16.2 versus 8.1
months)
• Health care organizations, professional societies, and
the United States Preventive Services Task Force
(USPSTF) recommend universal screening for all
newborn infants .

21. Risk factors:
• Caregiver concern for hearing, speech,
language, or developmental delay
• Family history of permanent childhood
hearing loss
• Infants requiring neonatal intensive care
for more than 5 days, including
administration of
o Extracorporeal membrane oxygenation (ECMO),
o Assisted ventilation,
o Ototoxic medications,

22. Risk factors:
• Postnatal infections such as Meningitis, Encephalitis,
Sepsis, and Herpes
• In utero infections, including cytomegalovirus, herpes,
rubella, syphilis, and toxoplasmosis
• Craniofacial anomalies including cleft palate or lip,
anomalies of the pinna or ear canal,ear tags, ear pits,
or temporal bone anomalies
• Head trauma (especially involving basal skull or
temporal bone)

23. Risk factors:
• Syndromes associated with hearing loss (or a
family history of same)
o Neurofibromatosis
o Osteopetrosis
o Waardenburg syndrome
o Pendred syndrome
o Jervell syndrome
o Lange-Nielsen syndrome
o Alport syndrome
o Usher syndrome
o Treacher-Collins syndrome

24. JCIH and USPSTF recommendations:
1-3-6 RULE
• All newborns should be screened before they
reach
1 month of age.
• Audiologic assessment of all infants who fail
their screening test by 3 months of age.
• Intervention for those infants with significant
hearing impairment by 6 months of age .

25. UNHS-Single stage:
• Single stage - One screening test, OAE
or AABR, detects 80-95% hearing
impairment.
• Referral for audiologic evaluation .
- 4 %of infants screened with AABR
- 5 -21%of infants screened with OAE
• High false-positive rate in OAE resulting
in -number of infants with normal hearing
referred for audiologic assessment .

26. UNHS-Two stage:
• Two stage - second test is given to patients who
fail the initial study.
-and only patients who fail both tests are referred
for audiologic assessment
• Two-stage compared decreases the referral rate
for audiologic assessment
• Two-stage screening may miss infants with
hearing loss,
- it inaccurately assumes that all infants who fail
the initial screen but pass the second have normal

27. Well baby nursery:Screening
• Two-stage UNHS decrease the number of
infants with normal hearing who would be
referred for further audiologic assessment .
• OAE test is used as the initial test rather
than AABR.
• Infants who fail the OAE are then screened
using AABR.
• If utilizing only a one-stage UNHS
-AABR, which results in a lower false-positive
rate and lower referral rate for audiologic

28. NICU & Hearing screening:
• Infants admitted to the NICU have a 2 %risk for hearing
loss, including auditory neuropathy (AN).
• Increased risk for SNHL and AN in patients admitted to
the NICU, Joint Committee on Infant Hearing (JCIH),
recommends AABR screening for these patients, OAE
screening will fail to detect AN
• One audiologic reassessment between 24 -30 months of
age for any infant requiring more than five days of NICU
care or with one or more of the following risk factors
regardless of length of stay-ECMO,DVET etc.

29. • Case-control Norwegian study - children with
BW less than 1500 g had a 6 greater risk for
hearing loss compared with children with BW
between 3.5-4kg.
• VLBW preterm infants (BW < 1500 g) are at risk
of experiencing progressive or delayed-onset
hearing loss.
- These infants should have follow-up monitoring
with a diagnostic hearing test by 12 months
adjusted chronologic age.

30. Summary
• Significant hearing loss-1-3/1000 live
births
• Newborn screening detects hearing loss at
an earlier age, resulting in earlier
intervention .
• AABR and OAE-screening tests-portable,
automated, and inexpensive.
• UNHS preferred over selective screening.
• UNHS-Two stage is recommended,if one
stage –AABR.
• 1-3-6 formula.

31. NNF India Recommendations:
• Ideally, efforts should be made to organize UNHS -
42% of profoundly hearing impaired children may be
missed risk-based screening .
• Short of universal screening, high risk screening
should be mandatory.
• Screening modalities include OAE and ABR.
• OAE alone not a sufficient screening tool in high risk
infant.
• Positive screening tests -referred for definitive
testing and intervention services.
• Early intervention -improves language &
communication skills.
• Identification and intervention -should occur before
6 months of age.

32. Auditory Brainstem
Response(BERA):
• Auditory brainstem response (ABR) is a
neurologic test of auditory brainstem
function in response to auditory (click)
stimuli.
• It’s a set of seven positive waves recorded
during the first 10 seconds after a click
stimuli. They are labeled as I - VII

33. • Auditory brainstem response (ABR) typically uses a click
stimulus that generates a response from the hair cells of
the cochlea, the signal travels along the auditory
pathway from the cochlear nuclear complex to the
inferior colliculus in mid brain generates wave I to wave
V

34. Auditory
pathway:

35. • Wave I - Cochlear nerve
• Wave II - Dorsal &
Ventral cochlear nucleus
• Wave III - Superior
olivary complex
• Wave IV - Nucleus of
lateral lemniscus
• Wave V - Inferior
colliculus
• Wave VI - Medial
geniculate body
• Wave VII - Auditory

36. Electrode placement:
• Cz (at vertex) (recording electrode)
• Ipsilateral ear lobule or mastoid process
(reference electrode).
• Contra lateral ear lobule (act as a ground)

37. Procedure:
• Subject lying supine with a pillow under his
head.
• Room should be quite.
• Clean the scalp & apply electrode.
• Check the impedance.
• Apply the ear phone (red for the right ear & blue
for the left ear)
• Select the ear in the stimulator & apply masking
to the opposite ear.

38. Procedur
e:
• Stimulation rate : 11/sec.
• Repetition : 2000
• Find out the threshold of hearing.
• ABR should be done at around 80dB.
• Start averaging process & continue until the
required repetition accomplished.
• Calculate the peak – interpeak latencies for the
ABR waves.

39. Waves Identification:
• Identify wave V which is the most persitent
wave. It comes as IV-V complex, and
wave V comes to the base line.
• Go in reverse order, wave IV, III, II, & I.
• Also observe their latencies, eg. latency of
wave I will be less than 2mSec.

40. Normal
values
• Peak latency of a wave =
less than the next higher no.
wave
• Or just add 1 to that wave,
latency will be less than
that.
eg. Latency of wave 1 is less
than 2.
• Absolute peak latencies for
the waves noted
• Interpeak latencies of I – III,
III – V and I – V measured.
Wave Latency
I <2mSec.
II <3 m.sec
III <4 m.sec
IV <5 m.sec
V <6 m.sec
VI <7 m.sec

41. Interpretatio
n:
• Wave I : small amplitude, delayed or absent
may indicate cochlear lesion
• Wave V : small amplitude, delayed or absent
may indicate upper brainstem lesion
• I – III inter-peak latency: prolongation may
indicate lower brainstem lesion.
• III – V inter-peak latency: prolongation may
indicate upper brainstem lesion.
• I – V inter-peak latency: prolongation may
indicate whole brainstem lesion.

44. References:
• Screening the newborn for hearing
loss,Uptodate.December 2016
• Controlled trial of universal neonatal screening for early
identification of permanent childhood hearing
impairment. Wessex Universal Neonatal Hearing
Screening Trial Group. Lancet 1998; 352:1957.
• US Preventive Services Task Force. Universal
screening for hearing loss in newborns: US
Preventive Services Task Force recommendation
statement. Pediatrics 2008; 122:143.
• American Academy of Pediatrics, Joint Committee
on Infant Hearing. Year 2007 position statement:
Principles and guidelines for early hearing detection and

45. THANK YOU