How to do artefact detection without EOG

Discussions
1

Hi everyone

I had a problem about operating artifact detection without ECG and EOG reference channels (Elekta), so I can’t correct the artifact.

Although I had run the ICA component, it seem no any result.

Does anyone have good suggestion to remove blinking/heartbeats without EOG channels ?

Chunhan

2

Hi Chunhan,

If your artifacts are strong enough, it should be captured by one or several ICA components. Try different combinations of parameters (with a PCA first or not for instance):
http://neuroimage.usc.edu/brainstorm/Tutorials/Epilepsy#Artifact_cleaning_with_ICA

Otherwise, if you see your artifacts in your data, you can mark them directly yourself with the file viewer in Brainstorm.
Create new categories, one for each event type (cardiac, blink, saccade), then run the SSP process on them.

Cheers,
Francois

3

Thank you so much, Francois

However, I was updating brainstorm last night. Suddenly, I can’t run ICA anymore.
It showed error “matrix dimensions must agree”.
How could I deal with this error ?

Chunhan

4

Can you please copy-paste here the full error message?

5

[process_ica] Artifacts > ICA components

Line 414: +
Matrix dimensions must agree

Call stack:
>process_ssp2.m>Run at 414
>process_ssp2.m at 29
>process_ica.m>Run at 130
>process_ica.m at 27
>bst_process.m>Run at 229
>bst_process.m at 36
>Panel_process1.m>RunProcess at 141
>Panel_process1.m at 27
>gui_brainstrom.m>CreatWindow/ProcessRun_Callback at 712
>bst_call.m at 28
>gui_brainstrom.m>@(h,ev)bst_call(@ProcessRun_Callback) at 262

File: Subject103_1@rawrun2_sss_low/data_0raw_run2_sss_low.mat

6

Hello,
I think I have now fixed this bug.
Please update Brainstorm and try again (menu Help > Update Brainstorm).
Francois

7

Hi, Francois

Thanks for fixing this bug and Brainstorm do ICA very well and smoothly.
However, the following errors are coming.
I click the data with processing ICA component.
It shows:
"Line 91: Index exceeds matrix dimensions.

Call stack:
>view_timeseries.m at 91
>tree_callbacks.m at 239
>bst_call.m at 28
>panel_protocols.m>Createpanel/protocolTreeClicked_Callback at 103

-------------------------------------------------------------------"

And then I click other files , it always shows:

"Time definition for this file is not compatible with other files already loaded in Brainstorm.

Close existing windows before opening this file, or use the Navigator. "

But I did’t open any window yet.
Could it be another bug, too?

BEST

Chunhan

8

Hi Chunhan,

I could not reproduce the error you are describing. I would you to give me more information about your data and the processing steps, in order for me to reproduce and fix it.
Can you please post screen captures showing:

  • your database explorer with all the files you are trying to process,
  • the window you get with the menu “Edit channel file”
  • the content of the raw file link (right-click on the “Link to raw file” > File > View file contents"): If this is larger than two screen captures, please copy-paste the text on this forum
  • a window showing the EEG signals (menu “View time series”)
  • all the options of the ICA process, the results of the ICA decompositions (window “Select active projectors”, IC topographies and time series)?

Thanks,
Francois

9

PS: Have you tried first to simply delete your subject and start again from scratch?

10

Thank you, Francois.

I deleted the filtering data with ICA processing and then start again to filtering the raw data and do ICA.

Now, it works well.

BEST

Chunhan