Hello everyone,

I am trying to obtain the alpha assymetry from a EEG. When I try to obtain the spectral power I realize I only have power in the first 3 or 4 frequencies. Therefore I think I have some problems with the raw data obtained from the EDF. The file has been exported from EmotivPro software.

When I check the data from each channel I have values from ~3700-4600 microvolts. When I researche, I see the EEG signals used to calculate biomarks usually go from -100 to 100 microvolts. I have also used EEGlab toolbox in MATLAB to filter the data from 0.5 to 43Hz. That causes the data to change to values from -600 to 600.

Anyone knows the process to correctly reference these signals and obtain a correct EEG? I think the problem is in that prepocessing and I am missing something.

Thanks in advance.