In article <43s97f$1a9 at hollywood.cinenet.net> erc at cinenet.net (Eric Smith) writes:
>From: erc at cinenet.net (Eric Smith)
>Subject: Audiogram defects (was Re: Cochlea -- quality of filtering)
>Date: 21 Sep 1995 11:00:15 -0700
>Thanks for all the answers (and references) to my question about the
>quality of filtering in the cochlea, both here and by email. The
>general consensus seems to be that the quality of filtering is not very
>My next question is about the implications of this in cases where the
>hair cells are defective at some frequencies but not others. It seems
>like the person would still hear tones of those frequencies, but they
>would sound like other frequencies, and would have a higher threshold.
>But an audiogram does not ask what the tones sound like, just whether
>they can be heard at all. Thus, some people who are actually 100% deaf
>at some frequencies but have normal hearing at others, might have a
>very misleading audiogram.
My undersanding is that in ears with some impulse damage (e.g. gunshot
exposure), narrowband deep hearing loss shows up around 6 kHz +-
500 Hz. These 'channels' can be surrounded by 'islands' of residual hearing.
At higher frequencies, e.g. 8 kHz, hearing is somewhat better and so tests
in common audiograms of these folks.
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