This document discusses hearing screening in newborns. It begins by defining different types and levels of hearing loss. It then discusses the importance of early identification of hearing loss in newborns through universal screening. Screening can be done using otoacoustic emissions testing or auditory brainstem response testing. Otoacoustic emissions testing evaluates the function of the outer hair cells in the cochlea by measuring sounds produced in response to sound stimuli. Early identification of hearing loss allows for early intervention, which research shows leads to better language development and academic outcomes for children.
2. Hearing, auditory perception, or audition is the ability to perceive
sound by detecting vibrations, changes in the pressure of the
surrounding medium through time, through an organ, i.e. the ear.
Hearing loss is one of the most common congenital anomalies,
occurring in approximately 2-4 infants per 1000 live births
3. DEFINITION
The extent of hearing loss is defined by measuring the hearing
threshold in decibels (dB) at various frequencies. Normal hearing has
a threshold of 0 to 20 dB. Hearing loss ranges from mild to
profound and is defined as follows:
Mild — 20 to 40 dB
Moderate — 41 to 60 dB
Severe — 61 to 90 dB
Profound — >90 dB
4. CLASSIFICATION
Conductive loss is generally caused by abnormalities of the outer or
middle ear, which 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), one type of SNHL, is
caused by absent or severely distorted auditory brainstem responses
with preservation of conductive and cochlear function.
Most neonatal hearing impairment is caused by SNHL. Approximately
one-half of these cases are due to genetic causes; the remaining
causes are acquired.
Mixed loss is a combination of conductive and SNHL.
5. INCIDENCE OF CONGENITAL CONDITIONS
(PER 10,000)
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
Source: http://www.infanthearing
6. PREVALENCE OF HEARING LOSS
Prevalence estimates vary across studies
Estimated that 1 to 3 per 1000 infants will have permanent
sensorineural hearing loss3, 4
1/1000 from the well baby nursery
10/1000 from the NICU
Rate increases to 6/1000 by school age4
Need for surveillance
7. WHY IS EARLY IDENTIFICATION
OF HEARING LOSS IMPORTANT?
Early identification and intervention can make a
difference
8. SCREENING FOR HEARING LOSS IN
NEWBORNS IS BASED ON TWO
CONCEPTS
1) A critical period exists for optimal language skills to develop, and
earlier intervention produces better outcomes.
2) Second, treatment of hearing defects has been shown to improve
communication.
Children with hearing loss typically experience significant delays in
language development and academic achievement.
10. READING COMPREHENSION IN
CHILDREN WITH MILD-MOD LOSS
0
20
40
60
80
100
120
140
Grade 1 Grade 4
Academic Grade
ReadingComprehensionStandardScore
Normal Hearing
Hearing Loss
11. Pediatrics. 2008 Sep;122(3):535-44. doi: 10.1542/peds.2007-2028.
Early language outcomes of early-identified infants with permanent
hearing loss at 12 to 16 months of age.
Vohr B, Jodoin-Krauzyk J, Tucker R, Johnson MJ, Topol D, Ahlgren M.
Prospective, longitudinal study of early-identified infants
30 children with mild-profound hearing loss (HL) compared to 96
normal hearing (NH) controls
Children identified < 3 months had stronger language development
at 12-16 months than those identified > 3 months
12. Pediatrics. 1998 Nov;102(5):1161-71.
Language of early- and later-identified children with hearing loss.
Yoshinaga-Itano C, Sedey AL, Coulter DK, Mehl AL.
Source
Department of Speech, Language, and Hearing Sciences, the University
of Colorado-Boulder, Boulder, Colorado, USA.
OBJECTIVE:
To compare the language abilities of earlier- and later-identified deaf
and hard-of-hearing children.
13. EFFECTS OF AGE OF
IDENTIFICATION ON LANGUAGE
DEVELOPMENT
Language Quotients at Three Years of Age
by Age of Identification Category
0
10
20
30
40
50
60
70
80
90
100
0-6 mos 7-12 mos 13-18 mos 19-24 mos 25-34 mos
Ages of Identification
LanguageQuotientScore
The participants' receptive and expressive language abilities were measured using
the Minnesota Child Development Inventory.
14. This study compared the receptive and expressive language abilities
of
72 deaf or hard-of- hearing children whose hearing losses were
identified before 6 months of age with
78 children whose hearing losses were identified after 6 months of
age.
Yoshinaga-Itano and her colleagues have shown that when children
are identified with hearing loss at birth and receive intervention
before 6 months of age, they ‘‘catch up’’ with their normal-hearing
peers and demonstrate essentially normal language development by 5
years of age
15. Pediatrics. 2000 Sep;106(3):E43.
Early intervention and language
development in children who are deaf
and hard of hearing.
Moeller MP.
Source
Center for Childhood Deafness, Boys Town National Research Hospital,
Omaha, Nebraska 68131, USA. moeller@boystown.org
OBJECTIVE:
The primary purpose of this study was to examine the relationship between
age of enrollment in intervention and language outcomes at 5 years of age in
a group of deaf and hard-of-hearing children.
16. VOCABULARY AT AGE FIVE BY AGE
OF INTERVENTION
This study completed at Boys Town
National Research Hospital on 112
children supported the Colorado findings.
Children identified earlier had stronger
receptive scores on the Peabody Picture
Vocabulary Test
17.
18.
19. CHECKLIST OF HIGH-RISK INDICATORS FOR
HEARING LOSS IN CHILDREN FROM BIRTH
TO 24 MO OF AGE.
Birth to 28 days
Family history of sensorineural hearing loss (SNHL), presumably
congenital
In utero infection associated with SNHL (eg, toxoplasmosis, rubella,
cytomegalovirus, herpes, syphilis)
Ear and other craniofacial anomalies
Hyperbilirubinemia at levels requiring exchange transfusion
Birth weight less than 1500 g
Bacterial meningitis
20. Low Apgar scores: 0–3 at 5 min; 0–6 at 10 min
Respiratory distress (eg, meconium aspiration)
Prolonged mechanical ventilation for more than 10 d
Ototoxic medication (eg, gentamicin) administered for more than 5 d
or used in combination with loop diuretics
Physical features or other stigmata associated with a syndrome
known to include SNHL (eg, Down syndrome, Waardenburg syndrome)
21. 29 days to 24 months
Parental or caregiver concern about hearing, speech or language,
and/or developmental delay
Any of the newborn risk factors listed above
Recurrent or persistent OME for at least 3 mo
Head trauma with fracture of temporal bone
Childhood infectious diseases associated with SNHL (eg, meningitis,
mumps, measles)
Neurodegenerative disorders (eg, Hunter syndrome) or demyelinating
diseases (eg, Friedreich ataxia, Charcot-Marie-Tooth syndrome)Joint Committee on Infant Hearing. Year 2000 position
statement: principles and guidelines for early hearing
26. EVIDENCE
The Joint Committee on Infant Hearing (JCIH) first published a set of risk
indicators for hearing loss in 1971, which were used primarily for screening
infants in the neonatal intensive care unit (NICU), because most infants with
risk factors were found in the NICU.
However, subsequent studies reported that
19 to 42 percent of profoundly hearing-
impaired children would be missed with targeted, risk
factor–based screening .
In 1999, Finitzio and Crumley reported that, according to the identification
rates currently reported from various screening programs, approximately
8,000-16,000 newborns are born with hearing loss each year. Of these, 50%
are discharged home from the well-baby nursery with no known risk factors
for hearing loss, according to the National Institutes of Health.
27. Although higher risk among NICU graduates should not be ignored, a
program in which only neonates meeting the high risk criteria are
screened was found to exclude as many as 50% of newborns with
significant congenital hearing loss.
This led to the initiation of the universal newborn hearing screening
program in USA, and in 1999, the American Academy of Pediatrics
estimated that 1 to 3 per 1000 infants born in well-baby nurseries
may have permanent hearing loss sufficient to interfere with normal
speech and language acquisition
28. RECOMMENDATIONS
All newborns should be screened, regardless of risk.
Highest on the high risk group is parental concern;
If universal screening is not feasible, the newborns in the high risk
category should definitely undergo hearing screening.
If a newborn passes the newborn hearing screening but has an
identified risk for sensorineural and/or conductive hearing loss, these
infants should be closely monitored for any changes in hearing
status.
29. The Healthy People 2010 goals include an objective to “increase the
proportion of newborns who are screened for hearing loss by one
month, have audiological evaluation by three months, and are
enrolled in appropriate intervention services by six months.”
These specific recommendations were expanded and articulated as
“principles” in the Joint Committee on Infant Hearing (JCIH) Year 2007
Position Statement.
30. 1-3-6 PLAN
All infants will access hearing screening using a
physiologic measure
no later than 1 month of age
All infants not passing initial screening and
subsequent rescreening should have confirmatory
audiological and medical evaluations
no later than 3 months of age
All infants with confirmed permanent hearing loss
should receive early intervention as soon as possible
no later than 6 months of age
31. WHAT ARE THE MODALITIES FOR
PERFORMING HEARING
SCREENING?
Auditory brainstem response (ABR),
otoacoustic emissions (OAEs), and
automated ABR (AABR) testing have been used in newborn hearing-
screening programs.
The discovery of OAEs by David Kemp in 1978 allowed the
development of an alternative screening technology that has become
common place in hospitals.
32. TIME-LINE IN NEWBORN HEARING
SCREENING
1965 - Babbidge Report : Recommended the development and nationwide
implementation of "universally applied procedures for early identification
and evaluation of hearing impairment."
1967 - Recommendations from the National Conference on Education of the
Deaf 2 High-risk register to facilitate identification. Public information
campaign. Testing of infants and children 5-12 months of age should be
investigated.
1988 - Commission on Education of the Deaf 3 Reported the average age of
identification for profoundly deaf children in the US was 2 1/2 years.
1988 - An advisory group of national experts convened
1988 - Former Surgeon General C. Everett Koop issued a challenge 5 That by
the year 2000, 90% of children with significant hearing loss be identified by
12 months of age.
33. 1990 - Joint Committee on Infant Hearing (JCIH) - Position Statement
6 Recommended that high-risk infants be screened prior to their
discharge from the hospital and no later than 3 months after their
birth.
1990 - Healthy People 20007. Goal: To reduce the average age at
which children with significant hearing impairment are identified to
no more than 12 months by year 2000.
1993 - National Institutes of Health (NIH) Consensus Development
Program 8 Recommended all newborns be screened for hearing loss
before leaving the hospital.
1994 - The JCIH Position statement 9 Recommended that "all infants
with hearing loss should be identified before 3 months of age and
receive intervention by 6 months of age."
34. 1999 - The American Academy of Pediatrics endorses:10 Universal
newborn hearing screening. Detection of hearing loss before three
months of age. Intervention services initiated by six months of age.
2000 - The JCIH Year 2000 Position Statement:11
2001 - Healthy People 2010: 12
Goal 28-11: Increase the proportion of newborns who are screened
for hearing loss by age 1 month, have audiologic evaluation by age 3
months, and are enrolled in appropriate intervention services by age
6 months.
36. OTOACOUSTIC EMISSIONS
Sounds are presented to the ear
canal and a small microphone
measures the response in the ear
canal
Average test time is 5 minutes/baby
38. 2-STAGE SCREENING PROTOCOL
All babies are screened using OAEs
Those babies who fail the OAE screening receive an ABR
screening prior to leaving the hospital
Average test time/baby (25-35 min)
Reduces refer rate; useful when follow up is likely to be
difficult or costly
Initial cost of equipment is higher than OAE or ABR screening
alone, but follow-up costs are less
41. BACKGROUND
The presence of cochlear emissions was hypothesized in the
1940’s on the basis of mathematical models of cochlear
nonlinearity.
However, OAEs could not be measured until the late 1970s,
when technology created the extremely sensitive low-noise
microphones needed to record these responses.
David Kemp first discovered Otoacoustic emissions in 1978.
42. Otoacoustic emissions (OAEs) are sounds measured in the external
ear canal that reflect movement of the outer hair cells in the cochlea.
Energy produced by outer hair cell motility serves as an amplifier
within the cochlea, contributing to better hearing.
Indeed, normal outer hair cells are essential for perfectly normal
auditory function.
43.
44. PURPOSE OF OAE’S
The primary purpose of otoacoustic emission (OAE) tests is to
determine cochlear status, specifically hair cell function. This
information can be used to
(1) screen hearing
(2) partially estimate hearing sensitivity within a limited range
(3) differentiate between the sensory and neural components of
sensorineural hearing loss
(4) test for functional hearing loss.
45. TYPES OF OAE’S
There are two types of otoacoustic emissions tests which are used
clinically.
These are:
1. Transient (TEOAEs): These are evoked responses from stimulating
the cochlea with a transient signal such as a click or tone burst
acoustic signal. TEOAEs are a wide frequency response in the 500 to
4,000 Hz range. They typically do not occur when hearing loss is
about 30 Dbhl or greater.
2. Distortion Product (DPOAEs): These are evoked response OAEs
from stimulating the cochlea with two simultaneously presented pure
tones of different frequency. This type of OAE may be recorded in
individuals with a greater degree of hearing loss at higher
frequencies. DPOAEs are typically measured in the frequency range of
750 to 6,000 Hz although many OAE devices are capable of
measuring at higher frequencies.
46. ANALYSIS AND INTERPRETATION
OF OAES
The first step is to verify adequate measurement conditions.
Specifically, noise levels must be sufficiently low (usually less than –
10 dB SPL) to permit confident detection of OAE activity and the
stimulus intensity levels in the ear canal should be close to the
desired (target) levels.
The next step in data analysis is to determine whether reliable
(repeatable) OAEs are recorded, that is, whether OAE amplitude
exceeds the noise level by 6 dB or more at the test frequency.
Finally, when the difference between OAE amplitude and noise floor ≥
6 dB SPL, findings are analyzed with respect to an appropriate normal
region for OAE amplitude.
47. Examples of the Pass and Refer outcomes for OAE screening are illustrated
in Figure
Amplitudes for distortion product otoacoustic emissions (see DP column) for
different stimulus frequencies (5000 to 2000 Hz) are displayed in tabular
form, along with the corresponding noise floor (NF) in the ear canal and the
signal-to-noise ratio (SNR), i.e., the difference between the distortion
product amplitude and the noise floor at that frequency region. As a rule, a
SNR of ≥ 6 dB indicates the presence of a DPOAE.
Just to the right of the table, in the figure, the bars depict the SNR for each
test frequency and, below, amplitude of the DP (at the frequency 2f1-f2) in
dB (SPL) plotted as a function of the f2 stimulus.
DP findings are automatically scored, with screening outcome (PASS or
REFER) displayed clearly. DPOAE screening over a limited high frequency
range (e.g., 5000 to 2000 Hz) is remarkably quick, often taking as little as
48. Pass” test results represent that OAEs are present, and one can
assume the individual's hearing is at least 30 dB or better.
If there is damage to the outer hair cells producing a mild hearing
loss, then OAEs may not present.
The test result is "Refer," and the patient may be at risk for possible
communication handicaps and can benefit from further diagnostic
assessment and possible rehabilitation.
52. WHAT IS EVOKED POTENTIAL?
Electrical potentials that occur in the group of neuron in
response to stimulation of a sense organ which can be recorded
by surface electrodes is known as Evoked Potential.
eg. SEP, ABR and VEP
53. INTRODUCTION
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
54. PHYSIOLOGY
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.
57. ORIGIN OF EACH WAVE
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 radiation(cortex
59. ELECTRODE PLACEMENT
(MONTAGE)
Cz (at vertex) (recording electrode)
Ipsilateral ear lobule or mastoid process (reference electrode).
Contra lateral ear lobule (act as a ground)
60. 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.
61. CONTD..
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.
62.
63.
64. 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.
Wave Latency
I <2mSec.
II <3 m.sec
III <4 m.sec
IV <5 m.sec
V <6 m.sec
VI <7 m.sec
65. IDENTIFICATION OF WAVES
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.
66.
67. CALCULATION & ANALYSIS
Write down the absolute peak latencies for the waves
Find out the interpeak latencies of I – III, III – V and I – V.
68. INTERPRETATION
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. Shortening of wave the interval with normal
latency of wave V indicate cochlear involvement.
69. APPLICATIONS
NEWBORN SCREENING
• Several clinical trials have shown auditory brainstem evoked
response (ABR) testing as an effective screening tool in the
evaluation of hearing in newborns, with a sensitivity of 100%
and specificity of 96-98%.
71. DEFINITION OF TARGETED
HEARING LOSS
Expanded from congenital bilateral and unilateral sensory or
permanent conductive HL to include neural hearing loss (auditory
neuropathy/dyssynchrony) in infants admitted to the NICU > 5 days.
72. HEARING SCREEN PROTOCOLS
Separate protocols are therefore recommended for NICU and well
baby nurseries.
NICU babies >5 days are to have ABR included as part of their screen
so that neural HL will not be missed
Screening results should be conveyed immediately to families so they
understand the outcome and the importance of follow-up when
indicated.
For rescreening, a complete evaluation of both ears is recommended,
even if only 1 ear failed the initial screen.
73. RE-ADMISSIONS
For readmissions of infants in the first month of life,
if there are conditions present which are associated with potential
hearing loss (e.g. hyperbilirubinemia req. exchange transfusion or
culture + sepsis), a repeat hearing screen is recommended prior to
discharge.
74. 2007 JCIH POSITION ON
SCREENING
NICU
>5 days in NICU
ABR should be included
to screen for neural loss
Rescreen BOTH ears, even
if only one ear fails
Non pass – refer to
Audiologist
Readmission – rescreen
before discharge
Well baby nursery
Screen with OAE or ABR
Repeat screen when
necessary before
discharge
When using 2 step
protocol test order
should be OAE then ABR
Rescreen BOTH ears,
even if only one ear fails
75. NNF CLINICAL PRACTICE
GUIDELINES
Recommendation:
NICU graduates should undergo first screening prior to discharge while
normal newborns, it may be delayed to a post discharge visit (usually at
6weeks when the child presents for immunization).
Infants who do not pass an initial hearing screening at birth should return
for follow-up testing within 1 month.
Diagnostic OAE and ABR testing is recommended for any infant who does
not pass the second screening session.
Both tests are necessary to differentially diagnose an infant's hearing
impairment.
In addition, children with risk factors for hearing loss who have a negative
hearing screen at birth should undergo audiologic testing every six months
until three years of age to look for any progressive hearing loss.
76.
77. In a recent survey, 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.
78. No dedicated national program has been carried out so far in India for
early detection of hearing loss in children.
NBHSP using oto acoustic emission was started at Kochi way back in
2000 by Abraham K Paul and now Kochi is the first city in India to
have a centralised hearing screening program.
NEWBORN HEARING SCREENING PROGRAM - T U
SUKUMARAN, INDIAN PEDIATRICS, VOLUME 48__MAY
17, 2011
79.
80. REFERENCES
1. Year 2007 Position Statement: Principles and Guidelines for Early
Hearing Detection and Intervention Programs- Pediatrics 2007
2. Joint Committee on Infant Hearing. Year 2000 position statement:
principles and guidelines for early hearing detection and
intervention. Pediatrics. 2000
3. Hearing Assessment in Infants and Children: Recommendations
Beyond Neonatal Screening- Pediatrics 2003
4. CDC - Historical Moments in Newborn Hearing Screening
5. Newborn Hearing Screening - National Center for Hearing
Assessment and Management (NCHAM) at Utah State University
6. Auditory Brainstem Evoked Response (ABR)- ksu.edu.sa
81. 7. Pediatricians Guide to Otoacoustic Emissions
8. NNF Clinical Practice Guidelines Hearing Screening
9. Update on Newborn Hearing Screening – NIDCD
10. Language of early- and later-identified children with hearing loss.
Yoshinaga Itano C, Pediatrics. 1998
11. Early intervention and language development in children who are deaf and
hard of hearing-Moeller MP. ,Pediatrics. 2000
12. Early language outcomes of early-identified infants with permanent
hearing loss at 12 to 16 months of age. Vohr B, Pediatrics 2008
13. Status of newborn hearing screening program in India. Kumar S,
Mohapatra B. Int J Pediatr Otorhinolaryngol. 2011