Cochlear implants and pitch.

[Al Bregman <al.bregman@xxxxxxxxx>]

Dear list members,

I don't know very much about the experiences of people wearing
cochlear implants.  So this question may just be silly.

I assume that at least in some cases, when you apply a signal to
an electrode, A, a pitch is heard.  If you stimulate an
electrode, B, that is separated from A by one step in the
electrode array, with the same signal, another pitch is heard.
So here's the question:  What is heard when both A and B are
stimulated at the same time, with the same signal: (1) a pitch
intermediate between the pitches of A and B? (2) the pitches of A
and B both heard at the same time? (3) something else?

What got me thinking about this was diplacusis.  Even though the
left and right ear hear different pitches when stimulated
individually by the same signal, usually when both are stimulated
by the same signal, only one pitch is heard, falling between the
two.  Somehow a compromise pitch is heard.  Considering separate
electrodes to be the analog of the separate ears in diplacusis,
is the result of joint stimulation a compromise or a duality?

Thanks,

Al

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Albert S. Bregman, Emeritus Professor
Dept of Psychology, McGill University
1205 Docteur Penfield Avenue
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