Re: Bite-induced pitch shift?

[Brad Ingrao <info@xxxxxxxxxxxxxx>]

Robert Levine at the Massachusetts Eye and Ear Infirmary has noticed
that some of his patients can change, cease or initiate tinnitus with
jaw or neck movements.  One theory on this may be that the Dorsal
Cochlear Nucleus is getting stimulated and is somehow communicating with
the Olivo-Cochlear Bundle and sending (or inteurrupting) effernet
signals to the cochlea via the outer hair cells.  If the theory holds
that part of our ability to hone in on frequency estimation, and
therefore pitch, is related to this Olivo-Cochlear feedback loop, then
pitch shifts with massiter muscle contraction doesn't seem that far
fetched.

____________________________________________
Best Regards,

Brad Ingrao, M.S.Ed. CCC-A, FAAA
Editor
EDEN - The Electronic Deaf Education Network
www.bradingrao.com
e-mail: info@bradingrao.com

-----Original Message-----
From: AUDITORY Research in Auditory Perception
[mailto:AUDITORY@LISTS.MCGILL.CA] On Behalf Of Bob Masta
Sent: Thursday, June 19, 2003 3:45 PM
To: AUDITORY@LISTS.MCGILL.CA
Subject: Bite-induced pitch shift?


Dear List:

In the June 9 issue of  Electronic Design <www.elecdesign.com> analog
electronics guru Bob Pease mentions that when he bites down hard "on
some tough nuts or a popcorn cake, the pitch seems to dip momentarily by
about half a note".

Has anyone heard of a phenomenon like this?  (The effect doesn't seem to
work for me, at least not when biting down on a plastic toothbrush
handle.)  He wonders what can cause this.  If this is truly a pitch
shift and not a resonance envelope (formant) shift due to distorting the
ear canal, could it be deforming the cochlea such that the stiffness of
the basilar membrane is changed? Seems pretty extreme!  Any ideas?


Robert Masta
tech@daqarta.com

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