50 Hz and digitized on a Concurrent (Atlanta, GA) 5550 computer at a sampling rate of 256 Hz or a band pass between 0.02 Hz and 100.0 Hz on a Neuroscan system (Version 4.1 to 4.5) (Neurosoft, Inc., El Paso, TX) at sampling rates of 500 Hz or 512 Hz. All six collection sites used identical experimental procedures and EEG acquisition hardware and software programs.
