Fwd: AUDITORY On cochlear implants (CI) and hearing


Subject: Fwd: AUDITORY On cochlear implants (CI) and hearing
From: Kevin Austin (kevin.austin@videotron.ca)
Date: Wed Mar 09 2005 - 08:10:58 EST


Some background: http://www.nidcd.nih.gov/health/hearing/coch.asp

>>A cochlear implant is a small, complex electronic device that can
>>help to provide a sense of sound to a person who is profoundly deaf
>>or severely hard of hearing. The implant is surgically placed under
>>the skin behind the ear.

Date: Wed, 09 Mar 2005 00:01:27 -0500
From: Automatic digest processor <LISTSERV@LISTS.MCGILL.CA>

Date: Tue, 8 Mar 2005 12:20:13 -0500
From: Ray Goldsworthy <raygold@SENS.COM>
Subject: CI Music Perception

Dear list,

Hello, I am a new member. A colleague pointed out this list to me since
I am a CI user as well as a research scientist interested in CI
psychoacoustics. I thoroughly enjoy listening to and playing music. I
play drums and keyboard. I lost my hearing suddenly to meningitis at 12
and was implanted at 13. As a child, I did not have a good sense of
harmony, nor could I sing in tune, but I began playing drums around the
age of 11. I am now in an amateur band and listen to several hours of
music every day. Preferences tend towards rhythmic pieces such as Indian
music (I also play tablas) and bluegrass (love the finger-picking), but
I my interests vary.

The greatest deficit that I have noticed is that I don't feel a strong
percept associated with chords. I do experience a weak percept allowing
me to classify a strong harmonic diad such as tonic and fifth, or tonic
and octave, versus tonic and major 7th. But in a controlled study, I
think I would fail to classify majors versus minors.

A couple comments related to previous threads. First, I think I know a
CI user who can sing in tune. I've always felt that I was one of the
stars of the implant world, but this guy is phenomenal and is more of a
professional musician than me (i.e. he gets paid gigs). He is a
keyboardist, but is trained so well, that I wouldn't be surprised if he
can match his voice.

Second, and this is huge. Please do not think that the CI simulations
currently used are accurate is transmitting the percept of sound. At
best, they are accurate indicators of the information content
transmitted by a generic CI sound processing strategy. The moment you
use either a noise carrier or sinusoids or even band-limited impulse
trains, you are producing a percept that is fundamentally different from
what music sounds like to me. As a musician dances upwards in a scale,
the individual notes produce distinct electrode amplitude patterns that
in turn produce a percept (hopefully pitch matched). But for a NH
listening to a CI simulation, two adjacent bands being bombarded with
band-limited noise carriers is not going to produce the same percept at
all. To begin with, using noise carriers will introduce temporal
fluctuations in the envelope signal that is distinctly interpreted as
noise. I could go on, but I feel I am going to fast to make a cohesive
statement, so will stop.

I hope these comments prove interesting since they are my introduction
to the list....
Ray

Sensimetrics Corporation
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    Tel: 617-625-0600 x240
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