The effects of electrode impedance on data quality and statistical significance in ERP recordings

• DOI: 10.1111/j.1469-8986.2010.01009.x
• Publication Date: 2010-03-29T12:35:19Z
• Authors: Emily S. Kappenman; Steven J. Luck
• Keywords: Adult; Male; Quality Control; Scalp; Adolescent; Electroencephalography; Young Adult; 03 medical and health sciences; 0302 clinical medicine; Skin Physiological Phenomena; Electric Impedance; Humans; Female; Electrodes; Evoked Potentials; Monte Carlo Method; Photic Stimulation

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.