The Embedding of Flexible Conductive Silver-Coated Electrodes into ECG Monitoring Garment for Minimizing Motion Artefacts

Using an easy screen-printing process, we fabricated a flexible silver-coated polyurethane based dry electrocardiogram (ECG) electrode that was readily embedded into stretchable garment for ECG recording, and showed its robustness to motion. The electrical and mechanical characteristics of the proposed dry electrode were first assessed by benchtop measurement in terms of DC resistance in repeated washings and stretches and AC skin contact impedance. To assess the level of motion artifacts during the daily monitoring, single-lead ECGs with the dry electrode integrated garment were recorded during fast walking, twisting waist, climbing stairs, and seated rest in eight healthy adults. We evaluated the recorded R wave amplitude, signal to noise ratio (SNR), signal to artifact ratio (SAR), and positive predictive value (PPV) of R wave detection, and compared them to those of conventional Ag/AgCl electrodes. Experimental results demonstrated that the proposed dry electrode preserves its electrical properties and functionality for up to 40 washing cycles. Meanwhile, dry electrodes of the stretchable garment are more robust to motion artifacts, mainly attributed to the stable skin-contact and anti-artefact configurations of the wearable monitoring system, which is comparable or better than that of conventional gelled wet electrodes. Additionally, a seven-day continuous wearability test showed that the quality of the ECG signal did not degrade over time, and skin reactions such as itching or erythema were not observed. We recommend the proposed dry electrode and the developed stretchable ECG monitoring garment in applications where flexibility, comfort and durability are required in addition to good electrical characteristics.