It
is important that babies are screened for hearing loss early.
Hearing is important for speech and language development.
A child with undetected hearing loss may be delayed in speech
and language. Children who receive early intervention services
by the time they are six months old normally do well with
language and other cognitive skills.
How
do they screen newborns hearing?
There
are two tests that are used to screen infants hearing. Both
tests record how your baby responds to sound. One test measures
brain activity and the other records how baby’s ears
respond to sound. The newborn hearing screening is painless
and can be done while baby is resting or sleeping.
Auditory
brainstem responses (ABR) – The ABR test
records how the brain responds to sound. Electrodes are placed
on baby’s head to record brain activity. Earphones will
be placed over baby’s ears and sounds will be played
for baby to hear. The electrodes record how your baby responds
to the sounds being played.
Otoacoustic
emissions (OAE)- In a normal ear, sound is sent
through the outer ear to the middle ear. The sound waves cause
the eardrum and three tiny bones to move. This movement sends
sound to the inner ear. In the inner ear, the cochlea is covered
with tiny hairs. These tiny hairs transmit signals to the
brain as they vibrate. The brain interprets these signals
so that it “hears” the sound. The way that the
OAE test works is that it records otoacoustic emissions (the
sounds that are produced by the tiny hairs on the cochlea
of the inner ear). These sounds can not be heard by people
but can be recorded by special instruments. During the screening,
a tiny probe will be placed inside your baby’s ear.
This probe will play sounds for your baby to hear. A microphone
inside the probe will record the emissions. Emissions are
not recorded in a baby who can not hear.
What
happens if my baby fails the newborn hearing screening?
The
newborn hearing screening is not a diagnostic test, but rather,
a screening to see if your baby might need further hearing
testing. If your baby fails her newborn hearing screening
she may be given a second screening to confirm the results.
Once the results are confirmed she will then be referred to
an audiologist for more comprehensive testing.
Up
to 5 percent of babies will fail the initial screening test.
If your baby fails her newborn hearing screening it does not
necessarily mean that she has hearing loss. A couple common
reasons babies do not pass the initial newborn hearing screening
are vernix in the ear or crying during testing. Most babies
go on to pass a second screening and do not have any problems
with their hearing.