EEG data preprocessing in matlab and EEGLAB

Hello researchers,

I have one doubt,

I have recorded EEG data using ENOBIO 20. It records data in different file formate .edf and .easy

F1='.easy'file loaded in matlab directly

F2='.edf' file loaded in matlab using EEGLAB toobox.

So my doubt is "what is difference between F1 and F2?"

Another doubt is

S1= applied notch filter + bandpass filter(8-30Hz).

S2=only apllied bandpass filter(8-30Hz).

what is difference between S1 and S2? Is there any difference between in quality of EEG signal?

Thanks in advance.

Answer 1

[Daniel M]

It seems pretty clear what the differences are. F is using a different file format. Choose your favourite. S is an option whether or not to use a notch filter. This is because it is common for EEG signals to have 50 Hz or 60 Hz line noise that needs to be removed. But the fact that your bandpass filter is from 8-30 Hz indicates you're interested in the alpha and beta frequency bands, which kind of hints that you're past the preprocessing stage when line noise should have been removed.

One of the first steps for preprocessing your EEG signal is to use a bandpass filter, typically a 4th order butterworth from 1-150 Hz, (assuming a sampling rate of at least 300). Then perform a notch filter around the line noise and its harmonics. Only then could you start extracting specific frequency bands.