[Eeglablist] Question Regarding Impedance Problem

[Makoto Miyakoshi]

Dear Kathryn,

I had same experience. I tried MANY solutions but nothing worked perfectly.
It was completely unscientific.

Sorry I just wanted to share resentment with you and I have no good
solution.

Makoto

2013/2/27 Stephen Politzer-Ahles <politzerahless at gmail.com>

> Hi Kathryn,
>
> 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.
>
> Best,
> Steve
>
>
> On Wed, Feb 27, 2013 at 3:28 PM, Kathryn Campbell <
> kacey.a.campbell at gmail.com> wrote:
>
>> 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.
>>
>> Thanks
>> Kathryn
>>
>> On 27 February 2013 10:13, Michael Schubert <mschuber at mail.upb.de> wrote:
>>
>>> Hi Kathryn,
>>>
>>> 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.
>>>
>>> Hope this helps,
>>>
>>> Michael
>>>
>>>
>>> Am 26.02.2013 um 04:25 schrieb Kathryn Campbell <
>>> kacey.a.campbell at gmail.com>:
>>>
>>> Hi,
>>>
>>> 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?
>>>
>>> Thanks
>>> Kathryn
>>> _______________________________________________
>>> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
>>> To unsubscribe, send an empty email to
>>> eeglablist-unsubscribe at sccn.ucsd.edu
>>> For digest mode, send an email with the subject "set digest mime" to
>>> eeglablist-request at sccn.ucsd.edu
>>>
>>>
>>>
>>
>> _______________________________________________
>> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
>> To unsubscribe, send an empty email to
>> eeglablist-unsubscribe at sccn.ucsd.edu
>> For digest mode, send an email with the subject "set digest mime" to
>> eeglablist-request at sccn.ucsd.edu
>>
>
>
>
> --
> Stephen Politzer-Ahles
> University of Kansas
> Linguistics Department
> http://people.ku.edu/~sjpa/
> _______________________________________________
> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> To unsubscribe, send an empty email to
> eeglablist-unsubscribe at sccn.ucsd.edu
> For digest mode, send an email with the subject "set digest mime" to
> eeglablist-request at sccn.ucsd.edu
>



-- 
Makoto Miyakoshi
JSPS Postdoctral Fellow for Research Abroad
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20130228/1b025f5b/attachment.html>