Transcript newborn hearing screening

 Definitions
 Importance of detection
 Methods of assessment
 Statewide Infant Screening ProgrammeHearing (SWISH)
A 3 frequency average hearing level of
40dB or worse in the better ear.*
* Australian Working Party Report, G. Birtles et al. July 1998
Because this loss:
 may lead to significant educational and
psychosocial delay
 can practically be detected in young children
 in the absence of an internationally agreed
standard, is commonly used in research
Frequency in Hz
125
250
500
1000
2000
4000
0
20
40
Hearing
level in dB
60
80
100
130
shaded region shows the level and
frequency of average speech
8000
Frequency in Hz
-10
0
10
Hearing Level in dB
20
30
40
50
60
70
80
90
100
125 250
500
1000 2000 4000 8000
Frequency in Hz
-10 125 250 500
0
10
20
30
40
50
60
70
80
90
100
1000 2000 4000 8000
Frequency in Hz
-10
0
10
20
30
40
50
60
70
80
90
100
125 250 500 1000 2000 4000 8000
Frequency in Hz
-10 125 250 500 1000 2000 4000 8000
0
10
20
30
40
50
60
70
80
90
100
Estimated incidence in Australia is
20/10,000 live births
Compare this with other currently screened disorders.
Disorder
Galactosaemia
PKU
Hypothyroidism
Cystic Fibrosis
Incidence/10,000
0.3
1.0
2.9
4.0
 cystic fibrosis
 hypothyroidism
 PKU
 all others
35
25
1
14
 deafness
174
 Risk factors for hearing impairment:
low birthweight/ preterm
positive family history
craniofacial anomaly
meningitis
ototoxic medication use
congenital infection
BUT, 50% of hearing impaired do not have
risk factors.
Language of Early and Later identified Children
with Hearing Loss
Christine Yoshinaga-Itano, Colorado
150 deaf infants
72
identified <6/12
78
identified>6/12
Aiding and early intervention within 2/12
Language &
cognition assessed
Total language quotient in early compared
to late treated groups*
100
90
94
93
91
91
90
84
77
80
MCDI total
language 70
quotient
60
73
72
68
<6/12
>6/12
50
40
mild
mod
mod-severe
severe
profound
level of hearing loss (normal cognition)
*Yoshinaga-Itano
Discrepancy between cognitive quotient and
language quotient by age of identification for
children with normal cognition*
Mean difference score
(CQ-LQ)
30
25
20
<6/12
>6/12
15
10
5
0
receptive
expressive
total
Language scale
*Yoshinaga-Itano
Mean total language scores at 31-36months by age
of identification of hearing loss*
earlier identification/
normal cognition
later identification/
normal cognition
earlier identification/
low cognition
later identification/
low cognition
20
30
40
50
60
70
80
90
100
110
mean language quotient
* Yoshinaga-Itano
Conclusion: from Yoshinaga-Itano
There appears to be a critical time at
around 6 months of age for
identification and remediation of
hearing impairment.
2nd C. Yoshinaga-Itano study J.Perinatol Dec2000
 By 1997 26/36 birthing U.S. hospitals screening
 25 matched pairs of children with hearing
impairment born in screening or nonscreening
hospitals
 Assessed language outcome (quotient>80 vs<70)
 If born in a screening hospital have 2½ x chance
of having the higher language score.
Other considerations
Improved hearing usually results in:
 Increased academic achievement
 Decreased costs of education and training
 Income proportional to language skills
and
 Parent-child relationships improved if parents know
about hearing impairment from the outset
 Distraction techniques
 Otoacoustic Emissions (OAE)
 Auditory Brainstem Response Audiometry
(ABR)
 combinations of the above
 VICS study child health nurses & distraction
 Marked increase in earlier detection(<12m)
 BUT still many late (3-4yrs) diagnoses
 Raised community awareness
 dearer than newborn screening(UK study)
 Tests pathway to the level of the cochlea
 Cochlear hair cells emit sounds spontaneously,
but usually tested in response to an input
signal
 Not of great value in the first 48 hours after
birth due to ear canal debris
 Probe containing an earphone and microphone
placed in the infant’s ear.
 Sounds measured in ear canal after click stimulus
 Quiet room necessary
 Quick and simple to perform
 Causes of hearing loss beyond the cochlea are missed
 Tests auditory pathways to brainstem
 Responses elicitable by about 34 weeks
gestation
 Can be done immediately after birth
Auditory
(end of wave V)
Pathways
in BAER
External
cochlear nerve
(Wave I)
(Wave IV-V)
(Wave III)
(Wave I I)
BAER waveform
 AABR (Automated ABR) is used
 False positive very low
 Neonatal high risk screens -sensitivity (100%)
-specificity (94-100%)
 AABR takes longer than OAE
AABR
screening
*Finitzo, Albright & O’Neal, 1998
1) Birth admission screen
2) Follow Up & diagnosis
3) Intervention services
Breakdown at any stage jeopardizes the entire
effort
 Expense
 Repeat tests require extra time & resources
from parents
 Parental anxiety
 Early discharge & rural births
 Resources for diagnosis and management
 Non-compliance with screening
 Cultural concerns
General Public
Antenatal education
Primary health providers
Audiologists
 Huge role for the family doctor
 Ongoing role once the diagnostic test has
proven hearing impairment
 Initial intensity of grieving may not be
related to degree or type of hearing loss
 Parents may experience depression, but
 report that the benefit of early-identification is
that they bond with their newborn as a child
with a hearing loss and don’t have to change
their mind about who their baby is.
All babies born in public hospitals in
NSW
In CSAHS all babies either at RPAH or
Canterbury
 Each area will have dedicated screeners (3 in
CSAHS)
 Each area will have a co-ordinator
 All hospitals with >400 births per year
Prior to discharge at the bedside
 Clinics on Monday morning at
Canterbury and Tuesday at RPA if
missed
Automated Auditory Brainstem Responses
(AABR)
Birth admission screen
pass
refer
2nd screen
refer
pass
pass (false
positive screen)
Diagnostic testing - Sydney
Children’s Hospital or Children’s at
Westmead
Counselling, aids, intervention
services, follow up and support