The effects of electrode impedance on data quality and statistical significance in ERP recordings.
To determine whether data quality is meaningfully reduced by high electrode impedance, EEG was recorded simultaneously from low- and high-impedance electrode sites during an oddball task. Low-frequency noise was found to be increased at high-impedance sites relative to low-impedance sites, especially when the recording environment was warm and humid. The increased noise at the high-impedance sites caused an increase in the number of trials needed to obtain statistical significance in analyses of P3 amplitude, but this could be partially mitigated by high-pass filtering and artifact rejection. High electrode impedance did not reduce statistical power for the N1 wave unless the recording environment was warm and humid. Thus, high electrode impedance may increase noise and decrease statistical power under some conditions, but these effects can be reduced by using a cool and dry recording environment and appropriate signal processing methods.
Kappenman
Emily S
ES
Center for Mind & Brain and Department of Psychology, University of California, Davis, Davis, California 95618, USA. eskappenman@ucdavis.edu
Luck
Steven J
SJ
D000293:Adolescent; D000328:Adult; D017097:Electric Impedance; D004566:Electrodes / Q000592:standards*; D004569:Electroencephalography / Q000295:instrumentation* / Q000592:standards*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009010:Monte Carlo Method; D010775:Photic Stimulation; D011786:Quality Control; D012535:Scalp / Q000502:physiology; D012879:Skin Physiological Phenomena; D055815:Young Adult