[Eeglablist] Rejecting continuous data with script: "events were corrupted" (BUG 1971)

[Delorme, Arnaud]

Dear Shaoyun Yu,

Yes, the message appear when you enter "EEG = eeg_eegrej(EEG, [0 100; 500 600]);” 
I have tried two other datasets and it does not appear when you enter "EEG = eeg_eegrej(EEG, [1 100; 500 600]);” 

Note that the EEGLAB history will never generate a limit with 0 (since the first sample is 1) so this is only if you manually enter the limit when calling the function. Therefore most often this bug (which only occurs in EEGLAB version up to 2016) is not a problem. More details are available at https://sccn.ucsd.edu/wiki/EEGLAB_bug1971

We now have a complex process that checks the consistency of different methods and show this warning when there is lack of consistency. The issue is usually about adding boundary events at the data limits when you reject the beginning or the end of the data and I have not seen any discrepancy associated with actual rejection. In any case, would you mind to share your dataset so we can look into it at https://drive.google.com/open?id=1ob2DUgGQWVf2xAbbo6o3yMfdMWRPyFZJ (just drag and drop).

Best wishes,

Arno

> On Oct 22, 2019, at 8:56 PM, Shaoyun Yu <s.yu at nagoya-u.jp> wrote:
> 
> Hello,
> 
> I am trying to reject the data during rest breaks before cleaning with ASR because these periods often contain a lot of EMG and other noises. I also decided to remove the idle periods before and after the experiment.
> 
> If I pass an array of time regions to eeg_eegrej, e.g.:
> 
> ```EEG = eeg_eegrej(EEG, [0 100; 500 600]);
> ```
> 
> Bug 1971 will occur with the warning:
> 
> BUG 1971 WARNING: IF YOU ARE USING A SCRIPT WITTEN FOR A PREVIOUS VERSION OF
> EEGLAB TO CALL THIS FUNCTION, BECAUSE YOU ARE REJECTING THE ONSET OF THE DATA,
> EVENTS WERE CORRUPTED. EVENT LATENCIES ARE NOW CORRECT (SEE https://sccn.ucsd.edu/wiki/EEGLAB_bug1971);
> 
> Interestingly, the bug will still happen even if point 0 is not included: eeg_eegrej(EEG, [500 600])
> What are the implications of this bug when I do rejection in scripts? Would it cause any distortion to the data?
> I am running on EEGLAB v14.1.2.
> 
> Thank you,
> 
> Shaoyun Yu
> Doctoral student, Graduate School of Humanities
> Nagoya University
> s.yu at nagoya-u.jp <mailto:s.yu at nagoya-u.jp> | s.yu at pm.me <mailto:s.yu at pm.me>
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