Preproc - thresholding negative z-scores too?

Alexander Maye a.maye at UKE.DE
Mon Oct 27 16:04:56 CET 2008

Dear List!

In my dataset I have a nice EOG signal, in which the respective artifact detection routines 
nonetheless do not detect artifacts,since its polarity is negative. Consequently the 
z-scores also deviate towards negative, and are always below (the positive) threshold 
value. So, shouldn't artifact_zvalue threshold the *absolute* z-value instead of the raw 
z-score? I know this has been asked last year, but couldn't find an answer. Any 
opinions/preferred solutions? Ah, and yes, I played with hilbert and rectify, but hilbert does 
not change the polarity (what does it anyway?), and rectify rectifies the data, not the 



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