Dear Martin,
> Do you have any information regarding how long it takes to
> digitize the locations of all electrodes (we are planing to use 64
> electrodes)? The time it takes is quite important for us as we are
> working with children and they don't like to sit still for too long
> ;-)
I don't think this depends on your digitizer and you can easily find
out without one. In any of the common digitizers the idea is that you
touch each of your electrodes with a pen and when you are ready press
some button. In addition you should measure at least 3 additional
points for fiducials. This is something you can try on a child without
a digitizer and see if it can be tolerated. I'd say it should take
10-15 min. Note that newer digitizers allow you to put some markers on
the head (for instance with special glasses) so the subject doesn't
have to keep still the whole time.
I have also seen somewhere that people take photos of their subject's
head from several angles and then use some software to reconstruct
electrode locations in 3D based on those photos. It might be something
that comes with the EGI system, but I'm not sure. That would be a good
solution for you since it's probably very fast. Here is a related link
I found with Google:
http://linkinghub.elsevier.com/retrieve/pii/S1388245705000076
Best,
Vladimir
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