[Eeglablist] Is the false QRS detection of the fMRI plug-in for EEGLAB?

[Makoto Miyakoshi]

Dear TsungHao,

If your ECG signal is noisy QRS detection fails of course.
I used VisEd to manually correct/input the qrs markers as long as my
eyeballs can tell where they are. If you can't even see it, then your ECG
is gone. There is no magic to recover it.

Clean ECG recording is as important as EEG recording in fMRI-EEG. You have
to be VERY careful when you place ECG channel AND ITS CABLE.

Makoto


2014/1/22 謝宗澔 <eleachaose at gmail.com>

> Dear all
>
> this is my first time to using fMRI plug-in.
>
> for practice, i following the tutorial and using the sample data.
>
> After removing gradient artifacts from EEG data, i only keep C3 CZ C4 F3
> FZ F4 and ECG to further processing.
>
>
> But a lot of false detection was found in heart rate detection as showing
> attachments.
>
> Like this example:    http://imgur.com/xGTSHN1
> Most of times, the algorithm indicated the anterior negative peak as the R
> peak.
>
> But for the signal, the strong artifact is evoked by the largest positive
> peak.
> Like this example:    http://imgur.com/xGTSHN1
>
>
> i refer the literature (" *Improved ballistocardiac artifact removal from
> the electroencephalogram recored in FMRI *") which the plug-in cited.
>
> In the paper, the K-TEO index of QRS detection was corresponding the
> anterior negative peak.
>
> However, the amplitude of negative peak was more higher than positive.
>  But sample is just the opposite.
>
> So, i hope some one can explain this false detection
>
> Best wishes,
>
> TSUNG - HAO
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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