Hi Kathryn,<br><br>I think you're right that the EOGs would show the same problem if they use the same reference as the scalp electrodes, but just because they're connected to the cap doesn't necessarily mean they do--for some setups the EOGs are bipolar montages (instead of being referenced to some electrode on the head, they are referenced to each other). I'm not sure what kind of setup you have so I'm not sure if that's the case.<br>
<br>Best,<br>Steve<br><br><div class="gmail_quote">On Wed, Feb 27, 2013 at 3:28 PM, Kathryn Campbell <span dir="ltr"><<a href="mailto:kacey.a.campbell@gmail.com" target="_blank">kacey.a.campbell@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Thanks for your reply. I thought that if the ground and
reference electrodes were not working properly, my eye electrodes would
show the same problem? My eye electrodes are connected to the cap. I will attempt to measure the impedance for these electrodes separately to see if there is a broken connection somewhere.<br><br>Thanks<br>Kathryn<br><br>
<div class="gmail_quote">On 27 February 2013 10:13, Michael Schubert <span dir="ltr"><<a href="mailto:mschuber@mail.upb.de" target="_blank">mschuber@mail.upb.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">Hi Kathryn,<div><br></div><div>from my experience I would suggest to check for broken reference/ground electrode(s). Usually the impedance is measured against a common ground electrode (which you described). To do this, try and see if you can set a different cap-electrode or even an extra-electrode placed somewhere else as ground/reference. If it works and the other electrodes show good impedances again, you probably would have to replace your ground/reference electrode in your cap.</div>
<div><br></div><div>Hope this helps,</div><div><br></div><div>Michael</div><div><div></div></div><div>
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<br><div><div>Am 26.02.2013 um 04:25 schrieb Kathryn Campbell <<a href="mailto:kacey.a.campbell@gmail.com" target="_blank">kacey.a.campbell@gmail.com</a>>:</div><br><blockquote type="cite"><div><div class="h5"><div>
<div>Hi,<br>
<br>I have a question regarding my impedance's when setting up for an EEG. I am using an EEG cap and I have had not problems getting my impedances down to an acceptable level until last week. My facial electrodes (eyes) seem to be fine but my cap electrodes will not reduce impedance at all. I have tried giving them a clean with ivory wash instead of what I was using previously and this seemed to help a bit- my impedances at least responded when I filled the electrodes with gel. However, in an effort to reduce my impedances further, I went back to try to improve the ground connection. After doing this, all impedances went back to terrible again and would not respond to gel/abrasion attempts. Any ideas what is going wrong? <br>
<br>Thanks<br>Kathryn<br></div></div></div></div><div>
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