Dealing with multiple subjects

[arnodelorme]

Import

The issue is that mffmatlabio does not provide any information that can be used to tell the subjects apart as it provides zero subject information.

EEGlab’s interface doesn’t need this information as it doesn’t really support combined subject averages in the first place.

Solution 1

So leaving aside the export support for now, would it be possible to add some additional information in the .hdr.org structure that would enable a user to determine which segment came from which subject?

Solution 2

I haven’t tried EEGlab out in this respect, but it sounds like for importing into .study structures, EEGlab just has you label each subject manually. In other words, multiple subject averages should be imported as studies.

Export

On the export side, I appear to be running into a difference between the EEGlab and EGI file format philosophies. If I understand your routines correctly, they are designed to export the equivalent of a .set file (which is to say, one cell from one subject). As I recall, EEGlab relies on the .study structure to handle multiple subjects and segments (with the Widmann variant handling the former and the .erp variant handling the latter). EGI files (such as mff), on the other hand, are designed for a single combined file that contains all the segments and subjects for a given dataset. Is it possible to output such a combined file with the current v3 code? Or do I need to just export each segment as a separate .mff file? If so, I would request support for a .study to .mff conversion procedure.

[arnodelorme]

Joe, my plan is to add the subject information in the time locking event. The alternative would be to import the data in an EEGLAB study, but STUDY work with single trials and these are trial averages. Would adding the subject information the time-locking event work for you.

[jdien07]

Yes, that would be a perfect solution!

Joe

[arnodelorme]

OK, I will let you know when it is done so you can have a look.

[jdien07]

although not necessary, it would be helpful to have the demographic information also provided (e.g., age and gender). Thanks! Joe

…

On Oct 11, 2019, at 22:50, Arnaud Delorme ***@***.***> wrote: OK, I will let you know when it is done so you can have a look. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#12?email_source=notifications&email_token=AE4T463THR5AQOVUBYMQTA3QOE3RBA5CNFSM4I76RWH2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEBBTVFY#issuecomment-541276823>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AE4T464NESTSLR75FC3AMULQOE3RBANCNFSM4I76RWHQ>.

-------------------------------------------------------------------------------- Joseph Dien, PhD Senior Research Scientist Department of Human Development and Quantitative Methodology University of Maryland, College Park E-mail: [email protected] Cell Phone: 202-297-8117 http://joedien.com

[arnodelorme]

I have implemented the changes for both grand average files and individual average files.