Soft, comfortable polymer dry electrodes for high quality ECG and EEG recording

Conventional gel electrodes are widely used for biopotential measurements despite important drawbacks such as severe discomfort, skin irritation and very long set-up time. Dry electrodes with metal pins overcome most of these problems, however, their rigidity causes discomfort and pain. Flexible polymer-based dry electrodes with high user comfort are presented in this paper, fabricated from EPDM rubber containing various additives for optimum conductivity, flexibility and fabrication yield. The impedance of those electrodes is measured on phantoms and human skin. Polymer electrodes with optimum composition show contact impedances only ~10 times larger than gel electrodes, and are easily capable of recording strong biopotential signals such as ECG. For low-amplitude signals, such as EEG, the electrodes need to be coupled with a small active circuit. EEG recordings using active dry electrodes connected to a clinical EEG recording system show very promising results: alpha-waves can be observed clearly when subjects close their eyes, and correlation and coherence analyses reveal high similarity between dry and gel electrode signals. Also, all subjects reported that our polymer electrodes were not causing discomfort.To conclude, the polymer-based dry electrodes are promising alternatives for the rigid dry electrodes in development and the conventional gel electrodes.

Publication year:2014

Accessibility:Open