Hi,
I am using brainstorm for my EEG analysis and I noticed an update on the Band-Pass filter. The issue is that I did half of my subjects on February 21, 2019 and I applied a Band-pass filter without paying attention to which filter version I was using. Yesterday I ran the other half and applied the Band-pass filter once again to my new set of files and noticed the option of choosing between the versions 2019 or previous ones.
My question is: Is there a way to know which version of filter I used in my files on Feb 21, 2019 ? and Is there too much of a difference between 2019 and previous versions of the Band-pass filter: 0.1Hz-30Hz
Thank you!
Gloria
Dear Gloria,
This is indeed right when we updated the bandpass filter.
You can see the history of any function since 2016 on github:
https://github.com/brainstorm-tools/brainstorm3/commits/master/toolbox/process/functions/process_bandpass.m
The major changes you are referring to were committed on February 20th. So if you used a Brainstorm version from Feb 21st, it should already be using the new filters. But if you were using on Feb 21st a version of Brainstorm downloaded before Feb 20th, then it should be using the old implementation.
The safest way is maybe to filter again one file from the older batch of subjects with the new filter (if that you kept the original non-filtered files), and see if it produces exactly the same output.
and Is there too much of a difference between 2019 and previous versions of the Band-pass filter
Yes, the differences can be signficant, you don't want to introduce such bias in your analysis. Organize your analysis so that all your subjects use the same implementation of the filters (either the new one if you don't mind reprocessing the old files, or the old implementation if you really don't want to have to reprocess the old files).
HI Francois,
oh ok I see! Thank you so much for the explanation it is much appreciated.
-Gloria