EEG Cup Electrode

Pure silver electrodes are electrodes which can be polarised. They set slow EEG frequencies 

below 10 Hz against a resistance rising exponentially steeply with the decrease in frequency 

and therefore lead to a distortion of the EEG signal. Pure silver electrodes are therefore not 

suited to EEG conductance, but are the preferred choice for EP conductance, as slow 

frequencies (undesirable drift) are not recorded.