A Reader asks why, during ear impression taking, they
can still hear conversationReader inquiries can be
directed to "contact us" or faxed to 719-676-6882.
Replies are for educational purposes only, and are not
to be construed as medical advice or opinion.
Q: When ear impressions were being made on me at my
dispenser’s office I could still hear him and my husband
in conversion as if my ears were not even plugged. I was
surprised, because both ears were filled with material
all the way to the eardrums. How is that possible?
---Mrs. E.S.
Dear Mrs. E.S.: I’m glad you asked that, for it provides
a lesson in ear physiology that I think will be
interesting to our readers.
There are actually four avenues of hearing to our ears.
The first two everyone knows about: sound traveling from
the external ear to the middle ear ossicles to the inner
ear on up the central auditory process (CAP) and
auditory cortex in the higher brain region. Since these
two pathways (right and left) were closed off with
impression material, the only other routes would have
been:
§ Through bone conduction, in which the body’s skeletal
frame can act as a conduit of sound, to the inner ear.
§ But most likely you were hearing through the nose and
mouth through a patent (open) Eustachian tube directly
into the middle ear cavity and from there through the
oval and/or round windows leading into the cochlea
(inner ear).
It is surprising how much sound travels these two
routes, without which one could not monitor the sound of
their own voice properly.
Once, when I was a visiting consultant at an audiology
clinic, a staff audiologist came in just as we were
making ear impressions on a new hearing aid patient. He
proceeded to give me some sensitive health information
about another patient in front of this patient, to which
I suggested we talk later about it.
His comment was, “He can’t hear what I’m saying. His
ears are plugged up” to which the patient said, “Oh yes
I can!” Shock to all, the patient was hearing through
his open mouth, up an otherwise normally closed
Eustachian tube into the middle ear cavity.
Moral to the story is, yes, there is more than one road
leading to Rome…er, the brain, where hearing actually
occurs.
Questions may be directed to
www.digicare.org or faxed
to at (719) 676-6882. Due to space limitations,
questions may be edited. |
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