[Eeglablist] Filtering before or after Averaging ... does it make a difference ?

[Lester John]

Dear All, 

Does someone know if filtering (ie. bandpass filter eg. alpha band) EEG
waveforms before averaging (eg. to detect an ERP) is equivalent to
filtering after averaging ? Theoretically it should be the same, or are
there some specific theoretical or practical issues that need to be
taken into account when doing this ?

regards,
Lester

-- 
Lester John, BScEng(Electronic) PhD(Biomedical Engineering)
MRC/UCT Medical Imaging Research Unit
Department of Human Biology
Faculty of Health Sciences
University of Cape Town 
Observatory 7925
South Africa
Tel: +27 21 406-6548
Fax: +27 21 448-7226
ljohn at cormack.uct.ac.za
http://www.uct.ac.za/departments/humanbio