Motion-Induced Imbalance of Contact Impedance in ECG Capture: Comparison
of Electrode Materials in Capacitive Coupling
Abstract
Differences in contact impedance of the ECG measurement electrodes lead
to asymmetries of the signal paths and thus result in reduced
common-mode rejection and artifacts. Here, the imbalance of contact
impedance is investigated for
different types of electrodes with capacitive coupling in terms of
static imbalance as well as dynamic variation during body movement.
Flexible and incompressible materials like conductive foam and fabric
showed the best overall performance. The negative effect of rigidity can
partly be compensated by adding conducting foam, while soft materials
can profit from an increase of electrode area.