Closed CorentinWicht closed 2 years ago
If your data are numerically ill-conditioned (e.g., rank-deficient), for instance after re-referencing and/or if the clean data are possibly too short for the given # of channels, then the method could fail to calculate some solutions correctly and that can look like it's injecting noise into the data like in your example. Such a thing has been observed in some rare cases in the past.
Dear Dr Kothe,
many thanks for your prompt reply.
You were absolutely right, using a different set of ERP and RESTING-EEG files solved the issue of sudden bursts of noise.
I have briefly compared two methods with the new set of files:
While I was expecting a more efficient pre-processing while providing RESTING data as clean reference (Method 1), the results actually speak in favour of the usual ASR method (2): RED = ERP preprocessed with Method 1 BLUE = ERP preprocessed with Method 2
On the whole recording, most eye-blinks were left undetected with Method 1 while they were adequately detected and corrected with Method 2.
Do these results make sense to you? I know from experience that ERP recordings can be quite noisy (i.e. eye-blinks, muscle movements, etc. especially outside the component time window) and Resting-States are probably the best way to acquire clean EEG data, hence I am a bit surprised..
Thank you Corentin, I am now closing this issue.
Dear developers,
This issue is a follow up on an email exchange I got with Arnaud Delorme and Makoto Miyakoshi a year ago.
I wanted to know whether it was possible to provide (for one given subject)
Clean_rawdata
with resting-state data to build the clean reference to finally preprocess ERP data (which are surely dirtier that resting data). Since the idea of theclean_windows
is to find a clean reference section, I figured a resting-state recording would provide cleaner reference sections compared to portions of the ERP data.Here is the code I used (MATLAB R2019b & EEGLAB 2021.0 & Clean_rawdata2.3):
The code runs smoothly, unfortunately using resting-state data to select the clean reference section seems to generate more noise that it filters them (RED = Raw; BLUE = Cleaned) :
Does anyone have a hint why this is failing? Maybe this is conceptually wrong?
I currently have this procedure registered in an upcoming Registered Report and would like to dig in deeper to see if I can make it work.
Many thanks,
Corentin