Re: Cochlear implants and pitch.

[Matthew Flax <flatmax@xxxxxxxxxxxxxxx>]

On 27 November 2001, Bob Masta wrote:
> Al:
>
> I'm no particular expert on implants, but I do know that there is a
> substantial amount of current spread.  There are two basic ways
> that stimulation is given, either between (typically adjacent) implant
> electrodes or between an implant electrode and a reference (usually on the
> mastoid, I think).  Your experiment seems to require this latter type,
> but either way I think that the current spread would stimulate such
> a wide region that you won't get a satisfying answer.

I have heard this too - about the current spread.
Perhaps it would be possible however to stimulate adjacent electrodes in
quick succession ? Neural response/firing might still be active in the
first bassilar section when the second bassilar section begins to fire ?

> And you can't
> just use electrodes that are farther apart, since they tend to be rather
> big steps in terms of the frequency span of the cochlea.  (Note also
> that even though there may be a lot of electrodes on the implant, they
> are rarely all in proper position to stimulate... maybe 8 or so if you are
> lucky, as I recall.  And they tend to be at the high-frequency basal end,
> since that's where the implant is inserted... the rest don't make it in.)

I'm sure this depends on the implant and the skill of the surgeon, but I
am no expert either !

> Robert Masta
> tech@daqarta.com
>
>          D A Q A R T A
> Data AcQuisition And Real-Time Analysis
>  Shareware from Interstellar Research
>         www.daqarta.com

--
Matt

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