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Hi, could one connect the EEG caps to the MEG machine through an extension cable, for impedance measurements only? If I'm not completely wrong, simple copper wires have resistances of <1Ohm/m, which shouldn't affect the impedance measurement too much. This would make impedance measurements at least a little bit easier and more comfortable for the subjects... Regards, Olaf >Date: Tue, 14 Aug 2007 12:31:26 +0100 >To: [log in to unmask] >From: Olaf Hauk <[log in to unmask]> >Subject: EEG impedance measurements > > >Hello, > >impedances of EEG electrodes can only be measured with the Neuromag >software while the subject is wired up to the MEG inside the MSR. This is >uncomfortable for the subject and can delay preparation time. One solution >would be to use a hand-held impedance meter to check impedances outside >the booth. > >Ideally, we would like to be able to see impedances for all electrodes >simultaneously on a screen while preparing the subject, as is usually the >case for standard EEG measurements. I was wondering whether there is a >commercial system for that purpose (independent of EEG amplifiers), or >whether anyone has already come up with a DIY solution. > > >Regards, > >Olaf > > >-------------------------------------------------------------------------------------------------------------------- > > Olaf Hauk > Medical Research Council > Cognition and Brain Sciences Unit > 15 Chaucer Road > Cambridge, CB2 7EF > England > tel.: +44 (0) 1223 273702 > fax: +44 (0) 1223 359062 > email: [log in to unmask] > > http://www.mrc-cbu.cam.ac.uk/ > http://www.mrc-cbu.cam.ac.uk/EEG/ > http://maia.mrc-cbu.cam.ac.uk/people/people-pages.php?id=57 -------------------------------------------------------------------------------------------------------------------- Olaf Hauk Medical Research Council Cognition and Brain Sciences Unit 15 Chaucer Road Cambridge, CB2 7EF England tel.: +44 (0) 1223 273702 fax: +44 (0) 1223 359062 email: [log in to unmask] http://www.mrc-cbu.cam.ac.uk/ http://www.mrc-cbu.cam.ac.uk/EEG/ http://maia.mrc-cbu.cam.ac.uk/people/people-pages.php?id=57