Ferree T C, Luu P, Russell G S, Tucker D M
Electrical Geodesics, Inc., Riverfront Research Park, 1850 Millrace Dr., OR 97403, Eugene, USA.
Clin Neurophysiol. 2001 Mar;112(3):536-44. doi: 10.1016/s1388-2457(00)00533-2.
Breaking the skin when applying scalp electroencephalographic (EEG) electrodes creates the risk of infection from blood-born pathogens such as HIV, Hepatitis-C, and Creutzfeldt-Jacob Disease. Modern engineering principles suggest that excellent EEG signals can be collected with high scalp impedance ( approximately 40 kOmega) without scalp abrasion. The present study was designed to evaluate the effect of electrode-scalp impedance on EEG data quality.
The first section of the paper reviews electrophysiological recording with modern high input-impedance differential amplifiers and subject isolation, and explains how scalp-electrode impedance influences EEG signal amplitude and power line noise. The second section of the paper presents an experimental study of EEG data quality as a function of scalp-electrode impedance for the standard frequency bands in EEG and event-related potential (ERP) recordings and for 60 Hz noise.
There was no significant amplitude change in any EEG frequency bands as scalp-electrode impedance increased from less than 10 kOmega (abraded skin) to 40 kOmega (intact skin). 60 Hz was nearly independent of impedance mismatch, suggesting that capacitively coupled noise appearing differentially across mismatched electrode impedances did not contribute substantially to the observed 60 Hz noise levels.
With modern high input-impedance amplifiers and accurate digital filters for power line noise, high-quality EEG can be recorded without skin abrasion.
在应用头皮脑电图（EEG）电极时划破皮肤会带来感染血源性病原体（如HIV、丙型肝炎病毒和克雅氏病）的风险。现代工程原理表明，在头皮阻抗较高（约40千欧）且无头皮擦伤的情况下，可以采集到优质的EEG信号。本研究旨在评估电极 - 头皮阻抗对EEG数据质量的影响。
本文第一部分回顾了使用现代高输入阻抗差分放大器和受试者隔离进行电生理记录的情况，并解释了头皮 - 电极阻抗如何影响EEG信号幅度和电源线噪声。本文第二部分针对EEG和事件相关电位（ERP）记录中的标准频段以及60赫兹噪声，给出了作为头皮 - 电极阻抗函数的EEG数据质量的实验研究。
当头皮 - 电极阻抗从小于10千欧（皮肤擦伤）增加到40千欧（皮肤完整）时，任何EEG频段均未出现显著的幅度变化。60赫兹噪声几乎与阻抗失配无关，这表明在不匹配的电极阻抗上以差分形式出现的电容耦合噪声对所观察到的60赫兹噪声水平贡献不大。
使用现代高输入阻抗放大器和针对电源线噪声的精确数字滤波器，可以在不擦伤皮肤的情况下记录高质量的EEG。
