Continuous Monitoring of Electrode--Skin Impedance Mismatch During Bioelectric Recordings

In bioelectric recordings, an electrode--skin imped-ance mismatch leads to a reduced common-mode rejection ratio (CMRR) of the amplifier. For this reason, the impedance of each individual electrode--skin contact is usually measured prior to a recording. The measurement circuit itself degrades the CMRR and is switched off during the bioelectric recording. In this paper, we present a new method that allows to monitor the electrode--skin impedance in a continuous way without reducing the CMRR of the amplifier. The new method is based on an additional common-mode signal that is superimposed on the bioelectric signal.

[1]  C. A. Grimbergen,et al.  A method for the measurement of the properties of individual electrode-skin interfaces and the implications of the electrode properties for preamplifier design , 1992, 1992 14th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[2]  J. McNames,et al.  Variable frequency bioimpedance instrumentation , 2004, The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[3]  L. Kirkup,et al.  A direct comparison of wet, dry and insulating bioelectric recording electrodes. , 2000, Physiological measurement.

[4]  J. Webster,et al.  The origin of skin-stretch-caused motion artifacts under electrodes. , 1996, Physiological measurement.

[5]  C A Grimbergen,et al.  High-quality recording of bioelectric events , 1991, Medical and Biological Engineering and Computing.

[6]  P Zipp,et al.  A model of bioelectrode motion artefact and reduction of artefact by amplifier input stage design. , 1979, Journal of biomedical engineering.

[7]  Ramon Pallàs-Areny,et al.  A practical approach to electrode-skin impedance unbalance measurement , 2006, IEEE Transactions on Biomedical Engineering.

[8]  P.S. Hamilton,et al.  Comparison of methods for adaptive removal of motion artifact , 2000, Computers in Cardiology 2000. Vol.27 (Cat. 00CH37163).

[9]  Heinz Jäckel,et al.  Enhancing interference rejection of preamplified electrodes by automated gain adaption , 2004, IEEE Transactions on Biomedical Engineering.

[10]  S Odman.  Potential and impedance variations following skin deformation. , 1981, Medical & biological engineering & computing.

[11]  John G. Webster,et al.  Driven-right-leg circuit design , 1983, IEEE Transactions on Biomedical Engineering.