DEAR DR. PAUL:I have two questions: My 14 month
old niece seems not to be able to hear well Is it too early to
test her hearing? And the second question: can babies hear at
birth?
PEDIATRICIAN DR. PAUL Answers: Let me answer your
second question first: Yes, babies can hear at birth. As a matter
of fact they can hear even before they are born. It is a well
known fact that loud noises can be dangerous to adults, linked
to permanent hearing damage and even high blood pressure. Since
babies can hear at an early age and even before birth, the effect
of exposure to loud noises during pregnancy has been studied.
Alarmingly, several studies suggest that exposure to excessively
loud noises during pregnancy causes hearing loss, premature delivery
and growth retardation of the baby. Although more research is
needed, I think it is prudent to recommend that pregnant women
should avoid prolonged or regular exposure to excessively loud
noises(especially work environments such as factories and airports.)
Your other question brings up the important association between
hearing and speech development. We know that if a child cannot
hear, speech will not develop normally. So whenever a parent suspects
that their child or infant does not hear well, this concern should
be taken seriously. Can we perform hearing tests on babies? Yes.
During a usual hearing test or Audiogram, a sound is played into
the child's ear and the child is asked to signal that the sound
was heard. Obviously the younger a child, the more difficult this
is. In a babies, the technician looks for signs such as startling,
body or facial movements that indicate the sound was heard. However,
as one can imagine with babies, this can be quite difficult and
quite crude. Fortunately there exists a more sophisticated and
reliable test called the Auditory Evoked Response Test. Normally,
when sound is heard, it passes from the ear as an electrical signal
through the auditory(hearing) nerve to the back of the brain where
hearing is decoded and understood. By placing small electrodes
on the baby's head, the traveling electrical signal can be recorded
on a graph. During this test, a sound is played and the response
to the sound is then recorded on the graph. If the graph picks
up normal electrical activity of the auditory nerve in response
to the sound, this is considered normal. If there is a problem
with the nerve then the test can detect and actually quantify
the degree of the hearing loss, specifically referred to as neuro-sensory
hearing loss. Once a hearing loss(deafness) is confirmed, the
child is evaluated by an ENT doctor and other specialists aiming
to attempt to restore the hearing loss(through hearing aids or
in some cases, cochlear implants). In any case, the child will
also need to have special speech therapy to help talking and language
develop as normally as possible.
To conclude, hearing is a precious gift we are born with and should
be to protected by avoiding exposure to loud noises. Also any
suspicion of a hearing problem in children should be taken seriously
and checked out right away.
The information provided in this site is
designed to be an educational aid only. It is not intended to
replace the advice and care of your child's physician, nor is
it intended to be used for medical diagnosis or treatment. If
you suspect that your child has a medical condition, always
consult a physician.
