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INFANT HEARING
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What are the milestones of hearing as infants develop?
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Birth to three
months of age:
- Begins to localize or turn towards interesting
environmental sounds.
- Seems to "listen" to speech or sounds, pays
attention.
- Awakens more easily to loud environmental
sounds.
Three to six months of age:
- Localizes to
environmental sounds.
- Smiles when you speak to them.
- Starts to
understand a few words such as "no",
"bye-bye", or "so
big".
- Starts to imitate some sounds.
Six to nine months of
age:
- Says first meaningful word such as mama or dada.
- Responds
to his or her name.
- Babbles and makes lots of different sounds.
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Responds to "No".
Nine to twelve months of age:
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Turns to look when name is called.
- Responds to simple commands " give
me", "come here"
- Understands
"bye-bye"
Twelve to eighteen months of age:
- Points
to objects or familiar people by name.
- Imitate simple sounds or
words.
- Follows simple directions.
- Says 2-3 words by age One and 8-10
words by 18 months.
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What pre-natal or birth conditions can put a newborn at risk for a hearing loss? |
There are several high-risk factors
that suggest a newborn to 28 day old may have either a conductive or a
sensorineural hearing loss:
- A family history of hereditary childhood
sensorineural hearing loss.
- An in-utero infection, such as
cytomegalovirus, rubella, syphilis, herpes, or toxoplasmosis.
- Craniofacial
anomalies, including those with morphological abnormalities of the pinna and
ear canal.
- Birth weight less than 1500 grams (3.3 lbs).
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Hyperbilirubinemia at a level requiring exchange transfusion.
- The use of
prolonged or multiple courses of ototoxic medications, including but not
limited to aminoglycosides.
- Mechanical ventilation lasting five days or
longer.
- Stigmata or other findings known to be associated with a syndrome
that is associated with a sensorineural or conductive hearing loss.
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What conditions are associated with hearing loss for infants from 29 days through two years of age?
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For the older infant, the following conditions warrant
hearing testing:
- Parent or caregiver concern about hearing,
speech, or language development or developmental delay.
- Bacterial
meningitis and other infections associated with sensorineural hearing
loss.
- Head trauma associated with loss of consciousness or skull
fracture.
- Stigmata or other findings associated with a syndrome known to
include a sensorineural or conductive hearing loss.
- Ototoxic medications,
including but not limited to chemotherapeutic agents or aminoglycosides, used
in multiple courses or in combination with loop diuretics.
- Recurrent of
persistent otitis media with effusion for at least three months.
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At what age can an infant's hearing be tested?
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At any age!
In 1994, a Joint Committee on Infant Hearing Screening issued a
position statement recommending universal detection of infants with hearing
loss as early as possible and before three months of age. They also recommended
that intervention and rehabilitation occur before six months of age. For this
to occur effectively infants should be tested in the newborn nursery or they
may never be tested until specific symptoms of hearing loss are observed by
parents or caregivers.
Please remember that all babies, even
pre-mature newborns, can be given a hearing test. It is never too early to test
a baby's hearing.
Prior to a few years ago, newborns in the nursery
were chosen for hearing screening based on their inclusion in a high-risk
registry for hearing loss (see above). The literature has shown, however, that
approximately 50% of infants with significant hearing loss will not be
identified by sole use of the high-risk registry. Therefore, a number of
states, North Carolina included, are starting to mandate that all infants be
screened while they still are in the newborn nursery.
In the nursery,
infants can be tested either with the brainstem auditory evoked response (BAER)
or with Otoacoustic Emissions (OAEs). The BAER involves placing several
electrodes on the baby's head. The change in electrical activity (EEG) of the
brain in response to sound is computer processed while the child is asleep.
These procedures are non-invasive and do not hurt even a pre-mature/medically
fragile newborn. It is best to perform either procedure just before discharge
from the nursery so as to take advantage of infant maturation.
Please
remember that all babies, even pre-mature newborns, can be given a hearing
test.
It is never too early to test a baby's
hearing
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