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presence of otoacoustic emissions in profoundly deaf child (fwd)

David K. Brown dbrown at haircell.ear.ucalgary.ca
Fri Sep 15 15:52:09 EST 1995

In article <Pine.OSF.3.91.950914230418.6892C-100000 at curly.cc.utexas.edu>,
sirianni at UTS.CC.UTEXAS.EDU (Jeff Sirianni) wrote:

> ---------- Forwarded message ----------
>         I recently learned about a 16-month-old girl who was unresponsive 
> to sounds during behavioral testing and whose ABR only had a recordable 
> wave I at high intensity levels.  Even though she is profoundly deaf she 
> has recordable otoacoustic emissions.  This suggests that her cochlea is 
> normal and the problem lies within the central auditory system.  A 
> tactaid seems to be the only type of assistive device that may aid her in 
> developing an awareness of sounds.
>         Has anybody else heard of a similar case?  Are there any other 
> devices that may aid this girl in developing sound awareness?  Could a 
> cochlea with measurable OAEs be abnormal?

To date I have found three such cases, each one with different situations
and etiologoies.  The question they came with was why are they rejecting
their amplification and why does it not appear to help?  When emissions
were shown to be present we removed their amplification.  The Tactaid
sounds like an interesting way to go, let us know what happens.  It is
possible that a cochlea with measurable OAEs could be abnormal, Takeno et
al. (1994) using carboplatinum was able to destroy the IHC in chinchillas
but leave the OHC intact.  They found that AP thresholds were elevated
where there was IHC damage but that cochlear microphonic thresholds were
close to normal corresponding to the preservation of OHC.  This suggests
that OAEs may still be present but the cochlea would surely be damaged.
The OAE portion has not yet been proven but based on their findings it
might be possible. (Sounds like a possible thesis topic to me!).
David Brown

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