> Date: Mon, 10 Sep 2012 10:03:24
-0500
> From:
flatmax@xxxxxxxxxxx
> Subject: Re: [AUDITORY] Tinnitus
and a dip in the audiogram
> To:
AUDITORY@xxxxxxxxxxxxxxx
>
> Your second point here is one I
like. However it may also be the same as
> your first point :)
>
> Our mixed-mode Cochlear amplifier
supports your hypothesis.
>
http://adsabs.harvard.edu/abs/2011AIPC.1403..611F
>
> The general idea is that certain
types of Cochlea damage enhance the
> peripheral hearing circuit.
>
> For example, consider this thought
experiment based on our mixed-mode
> Cochlear amplifier model :
>
> Imagine that your stereocillia are
lopped off in a small region of inner
> hair cells - the same can be said
for outer hair cells. This may happen
> due to ageing or damage.
> In this case assume that the
stereocillia resistance is reduced - due
to
> gaping open ion channels - and
ionic currents into the cell (potassium)
> and our from the cell (sodium) are
enhanced ... the hair cell now
> experience a depolarisation. This
depolarisation generates more
> spontaneous neurotransmitter
release.
> The neurotransmitters generate more
synaptic transmission in the
> cochlear nerve.
> The cochlear nerve excites the
superior olive and this not only
> generates perception of the tone,
but sends signals back to the Cochlear
> over the lateral and medial
efferents.
> The medial efferents stimulate the
motors in the outer hair cells and
> they in turn generate movement at
the inner hair cells which start the
> process again ... over and over
again ... the end result is a
> mecho-neural standing wave ... or
'tinnitus'.
> This type of tinnitus masks low
level sound heard through the ear ...
> however if the external sound gets
loud enough, then it masks the tinnitus
!
>
> What do you think ?
>
> Matt
>
> On 09/10/2012 08:22 AM, Matt Winn
wrote:
> >
> > Mark and everyone,
> >
> > Although I am not a tinnitus
researcher, I have had lots of
experience
> > with patients with tinnitus in
the audiology clinic. Generally, we try
> > to avoid the confusion of
tinnitus with testing tones by using
pulsed
> > and/or warbled tones. As you
point out, this doesn’t always work out
> > perfectly.
> >
> > It has been my experience that
dips in the audiogram are indeed
> > frequently accompanied by
tinnitus. having measuring hearing at
the
> > VA, this connection might be
limited to hearing loss that is
> > noise-induced. The two most
common explanations I have heard for
this
> > are 1) damage to the auditory
system at the site of the hearing loss
> > underlies both the threshold
elevation and improper firing by damaged
> > nerves, and 2) tinnitus that
exists in the region of the dip is not
> > masked out by external
stimulation because the external sounds
are
> > less audible; thus rendering
tinnitus more noticeable. This latter
> > explanation accounts for the
relief from tinnitus experienced by many
> > people who use hearing aids.
Specifically, tinnitus isn’t “cured,”
but
> > it is masked out by the
amplified input, and then the tinnitus
returns
> > after the hearing aid is
removed.
> >
> > Returning to the point of
tinnitus without apparent hearing loss,
I
> > have found that salt intake
and stress level are two (among many)
> > contributing factors to and my
own tinnitus, and I don’t have hearing
> > loss. The dependence of OHCs
on metabolic factors underscores this
> > connection, which seems
anecdotally to be exacerbated in
patients with
> > Ménière’s.
> >
> > Matt
> >
> >