[Eeglablist] Problem importing .eeg -Files and rereferencing data

[Arnaud Delorme]

Dear Matthias,

we have recently worked on a plugin with Makoto to import Nihon Kohden data.
Try it out

ftp://sccn.ucsd.edu/pub/nihonkohden.tar.gz

(unzip in the plugins folder of eeglab and restart)
Note that it uses a compiled MEX file from the BIOSIG toolbox and so far I think it works best on Windows 64-bit.
Best,

Arno

On 7 Nov 2012, at 11:53, Stephen Politzer-Ahles wrote:

> Hi Matthias,
> 
> loadeeg() is actually for loading Neuroscan files, not Nihon; it's a little confusing because these and several other systems all use ".eeg" as their file extension. So your first error is probably because of this. I don't have experience working with your data format, but see http://sccn.ucsd.edu/pipermail/eeglablist/2008/002341.html .
> 
> As for your referencing issue, I'm not sure what could be causing the error (could you give a little more specific information about exactly what commands you have used?). If you're having trouble renaming channels, my guess is you will have better luck using pop_chanedit() (Edit > Channel Info in the graphical user interface) rather than pop_chanplot(). I just wanted to point out, though, that I calculating average reference is usually not recommended when you have only a small number of electrodes--see the discussions in http://sccn.ucsd.edu/wiki/Chapter_04:_Preprocessing_Tools#Re-referencing_the_data or in Luck (2005).
> 
> Best,
> Steve
> 
> On Wed, Nov 7, 2012 at 7:22 AM, Wittayer, Matthias <wittayer at students.uni-mainz.de> wrote:
> Dear experts,
> 
> 
> 
> we have several problems analyzing our Dataset acquired by our Nihon Kohden 2100- System with just very few channels recorded referenced to Fz. We normally use BESA for analysis of our data, but however it doesn't work for a dataset with just a few channels, so we switched to EEGLAB and are very contented with its different features.
> 
> The problems which occured are:
> 
> The data is saved as .eeg- files. Importing it to EEGLAB produces an error (EEGLAB error in function loadeeg() at line 237: Undefined function or variable "chan_names".) useing default settings. Since I am not able to reconstruct in which way the variable is declared in this routine, I am not able to troubleshoot. We already tried to modify settings of the import- dialogue but failed. So we converted .eeg - Data to .edf- files and it worked out quite well.
> 
> Now a new problem occured while rereferencing our data to linked mastoids (or at least trying to do so). The rereferencing routine works out fine for average reference but trying to rereference the data to any channel produces the error-message "Channel EEG not found".
> 
> I assume, that these problems (at least the second one) occur because of our channel's names (they are coded such as "EEG Fp1" with a space character in between to discriminate them from Triggerchannels). We already tried to rename the channels but did not succeed (pop_chanplot) because the "rename selected channel"- procedure was not available. So we tried to rename them manually but failed again.
> 
> In tutorials and troubleshooting- sites I was not able to find a problem similar to ours. All trying to solve it failed up to now.
> 
> Does anybody else have similar problems? How can we rename our channels properly so we can rereference our data to these channels? And does this work useing the imported edf- data as well? How can we import our .eeg- Data directly?
> 
> We would be grateful for some guidance or hints how to proceed.
> 
> 
> 
> Kind Regards
> 
> 
> 
> Matthias Wittayer,
> 
> 
> 
> Mainz, Germany
> 
> wittayer at students.uni-mainz.de<mailto:wittayer at students.uni-mainz.de>
> 
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> 
> -- 
> Stephen Politzer-Ahles
> University of Kansas
> Linguistics Department
> http://people.ku.edu/~sjpa/
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