Re: Auditory efferents and phase locking

[Matt Flax <flatmax@xxxxxxxx>]

I agree with your view John ...

The multi mode CA we developed suggests that whilst a finely tuned
system is very sensitive, if there is too much activity - i.e. if the
stereocilia are always 'on' or the reticular lamina is punctured - then
an abnormally strong SOAE occurs - which is peripheral tinnitus.

In order to hear at those frequencies, the tinnitus inducing SOAE must
first be suppressed, and most likely can't be ... the result appears to
be a broadening of the 'filters' but is really a dysfunctional region in
the ear. Due to coupled interactions, tinnitus is likely to be present
with hearing loss, but it may not be.

The other form of hearing loss is when the system gain is reduced ...
destruction of the hair cells, loss of Endocochlear Potential, neural
pathway degeneration, holes in the vestibular system, ossification of
the Scala Tympani, and other causes ... in this case, there really is a
broadening of the 'filters' and it isn't likely to be tinnitus inducing.

A different form of tinnitus is 'central' tinnitus, which is most likely
related to processes in the cortex, rather then the periphery.

Matt

On Thu, 2011-09-01 at 18:56 +0000, Beerends, J.G. (John) wrote:
> I presume an objective tinnitus can be recorded in the ear, which then in my view would be equivalent to an 
> oto acoustic emission which would imply correct OHC behavior??
> 
> Presumably the complement is a subjective tinnitus where there is only neural activity, would it be plausible 
> to say that not having a transduction leads to spontaneous activity=tinnitus, supported by the observation that
>  tinnitus has in most cases frequencies in the range where there is loss of sensitivity?
> 
> John Beerends
>  
> 
> -----Original Message-----
> From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxxxxxxxxx] On Behalf Of Richard F. Lyon
> Sent: donderdag 1 september 2011 17:03
> To: AUDITORY@xxxxxxxxxxxxxxx
> Subject: Re: Auditory efferents and phase locking
> 
> At 7:33 AM +0000 9/1/11, Beerends, J.G. (John) wrote:
> >Dick,
> >
> >Is in your view a dysfunctioning of the OHC's responsible for tinnitus 
> >(lack of efferent feedback)?
> 
> In cases of objective tinnitus, yes, sort of (the dysfunction may not be due to lack of efferent feedback); but in most tinnitus cases, probably no.
> 
> >And related, is in your view a correct functioning of the OHC's 
> >responsible for spontaneous otoacoustic emissions?
> 
> Certainly; and I think everyone agrees.
> 
> Dick
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