[Eeglablist] Shifted rejection boundaries in continuous data

[James Desjardins]

Hi Maria,

I just came across a bug in the eegplot function that may account for the shifted rejection boundaries you reported finding while scrolling through your continuous data.

If the paging buttons { [ << ] or [ >> ]} are quickly clicked twice it can happen that the signals will advance two windows, while the events will only advance 1 window (e.g. if you are displaying 50 seconds at a time and the current window starts at 100 seconds... then you double click [ >> ] quickly, the figure will display the signals from 200 to 250 seconds but the events that will be superimposed are the events for the time period of 150 to 200 seconds).

This is a relatively harmless bug as it is only display... any further interaction with the GUI (including selecting time for rejection) refreshes the figure and the offset is corrected.

Let me know if this could account for all of the symptoms that you found while scrolling your continuous data.

I have reported this in EEGLab bugzilla (#1393) and will look into solving the issue over the next few days.

James
________________________________

On 18 Nov 2012, at 20:07, Maria Teresa Wijaya wrote:

Dear Makoto,

I recorded my data using Biosemi Active two system with 64 electrodes at
256Hz. Data were band pass filtered at 0.1-20 Hz and re-referenced
offline first to nose reference to remove bad channels. Removed channels
were interpolated and the data were re-referenced to average reference.
I then checked the continuous data for non-typical artifacts, removed
them, and saved the data with a new name. The shifted rejection
boundaries problem appeared in this new data set.

Kindly let me know if I need to provide any other information.

Thank you.

Regards,
Maria



On Saturday 17,November,2012 01:33 PM, Makoto Miyakoshi wrote:
Dear Maria,

We need more information to identify what caused this.
Could you tell me more detail?

Makoto

2012/11/12 Maria Teresa Wijaya<a0089301 at nus.edu.sg<mailto:a0089301 at nus.edu.sg>>:

Dear list,

I did rejection on continuous data and noticed that the rejection
boundaries shifted from where they are supposed to be (picture here:
http://www.flickr.com/photos/89964745@N02/8178303896/in/photostream).
This happened to several of my subjects, and it also happened to someone
else in our lab before. My questions are:

- What are the possible reasons of this shift?
- Is there any way I can know if any of my event triggers have also been
shifted or if only the rejection boundaries are shifted?

Thank you for your help.

Regards,
Maria
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