[FieldTrip] question about automatic artefact rejection

De Meyer, Kris kris.de_meyer at kcl.ac.uk
Tue Feb 18 09:47:00 CET 2020

Dear Fieldtrippers,

In ft_artifact_muscle<http://www.fieldtriptoolbox.org/reference/ft_artifact_muscle>, an EEG signal is first filtered - usually with a bandpass filter with cutoff frequencies of [110,140]. The documentation then says that the hilbert envelope is calculated, after which the envelope values are z-transformed before they are thresholded.

However, is this sound? Whereas the actual filtered EEG values (the result of the bandpass filter) are usually normally distributed, the hilbert envelope values are far from.

What is the rationale for calculating the z-transform of a non-Gaussian distribution? Doesn't that introduce problems?



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