ABM .edf files after signal decontamination loading problem on Brainstorm

Discussions
1

290500000.290119.121738.Signals.Decon.edf (439.2 KB)
Hi Francois,

I have some problem about loading .edf EEG files produced with ABM B-Alert software. These .edf files contain the signals of a 9 channel EEG (ABM X10, with 9 EEG channels). I am interested only to the EEG channels. This .edf file is created after signal artifacts decontamination.

When I create the link to the .edf raw file, if I visualize the signal, the 9 EEG channels are visible, but the matching between these channels and the sensors positions on the default anatomy always fails, resulting in no matches between channels and sensors positions. This compromises the possibility to create brain maps and other topological data analysis.

So I think that there is some problem about how this .edf file has been written.

I would like to ask you: if I send you an .edf file of these as example, are there any chances to load these files directly on Brainstorm?

I attached an example of .edf file.

Thank you for your availability.

Best regards,
Marco

2

Hi Marco,

The EDF format cannot store 3D positions, so it is normal that you do not get them.
You need to import the positions of the electrodes separately (right-click on the channel file > Add EEG positions), and register them manually with the anatomy. You can refer to the EEG/Epilepsy tutorial for help with this step:
https://neuroimage.usc.edu/brainstorm/Tutorials/Epilepsy#Prepare_the_channel_file

If you don't have realistic 3D positions for your EEG cap, you can try using one of the templates available in Brainstorm.

Francois

3

Hi Francois,

thank you for the fast reply.

Yes I tried with several templates available in Brainstorm, since I have not realistic 3D positions for my EEG cap, but no one worked, giving always that no sensors matched.

This was the same approach I used for the EDF file of raw signal: initially it did not work, with the same problem I'm having now, then with your help and a Brainstorm update it worked. So I was thinking that the problem could be similar also in this case, with EDF files of decontaminated signal.

Thank you very much for your help,

Marco

4

You could try asking default 3D positions to the manufacturer or the reseller of your EEG cap.
Otherwise you could try position all the electrodes yourself on the head surface... it would help you open at least 2D topography views, even if it is not precise enough for source analysis.