for Kim

[Guest guest]

Hi Kim,

Nucleus can fire 20 electrodes at a time - However, studies done have

shown that people generally, do not prefer 20 maxima... When the Nucleus

24 was in

clinical trials they studied the number of maxima that people preferred

and only 1 person out of 50 preferred a large number of maxima.

I know when I was doing research at U Mich they tried various combination

of electrodes being fired. From 2 to 22, monopolar and bipolar. And

when they got to 11 or more, it became almost impossible to tell

anything. Interesting study though.

ACE doesn't only use 7 or 8 electrodes - it will use every electrode that

is active in the users MAP. ACE roves the implant looking for the

best electrodes to stimulate based on the incoming sound... In one sweep

of the cochlea (if a person has 8 maxima) it may pick electrodes

1,2.4,5,6,7,9,11... The next sound that is presented (with a 8 maxima)

it

may pick 12,14,15,16,17,18, 20... With CIS the same electrodes

are fired no matter what the incoming sound is.

The Original

Hi

Did Cochlear change to this when they introduced the Freedom? You

wrote : > Nucleus has 22 channels available in the electrode array,

all the time.

From what I understand - Cochlear uses only 7 or 8 electrodes

in their progamming. It is also my understanding that they utilize

a sampling. Gigabyte Mike shared once on this list an excellent

definition of ACE and mentioned :Specific to Cochlear this program

separates sound into a set number of Channels or Bands and fires the

electrode groups very rapidly. ACE is a " Variable rate " program

meaning it can be programmed to operate at different speeds for

example 720hz, 900hz, 1200 Hz, 1800hz

I do not think that Cochlear utilizes all 22 but then again I could

just need some help understanding this. But from what I have read

above is that Cochlear has 22 but limits the amount used in it's

programs design.

I hope that the recent emails on this list about Hi Res 120 have

helped clarify your previous description of the 120

Kim B

Advanced Bionics CI