> Date: Mon, 10 Sep 2012 10:03:24 -0500
> From: flatmax@xxxxxxxxxxx
> Subject: Re: [AUDITORY] Tinnitus and a dip in the
> 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
> 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
> 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 ?
> 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