Flexible electronic sensors are used for simultaneous non-contact capacitive sympathetic nerve activity (cSKNA) and electrocardiogram signal measurement.
Flexible Electronic Sensor for Non-contact Simultaneous Measurement of
Capacitive Skin Sympathetic Nerve Activity (cSKNA) and cECG
D.-Y. Hsu, Y.-L. Sung, C.-Y. Huang, E.-Z. Lyu, C.-C. Chang, Y.-X. Huang, T.-T. Lin, K.-C. Huang, S.-H. Ni, T.-W. Wang*, “Flexible Electronic Sensor for Non-contact Simultaneous Measurement of Capacitive Skin Sympathetic Nerve Activity (cSKNA) and cECG,” IEEE Transactions on Instrumentation and Measurement, vol. 74, Art no. 4003217, pp. 1-17, 2025
Sympathetic nerve signal sensing system and method (Invention patent, application number: 113135229, application date: 2024/09/18)
Abstract—Non-contact electrocardiogram (ECG) sensors have been widely explored as unobtrusive, long-term solutions for detecting atrial fibrillation (AF). Recent clinical studies have demonstrated that abnormal activation of the autonomic nervous system plays a crucial role in the pathogenesis of AF, highlighting the importance of coordination between autonomic activity and cardiac electrophysiology, which shifts most standalone ECG-based AF detection towards AF prediction. In this study, we present a flexible electronic sensor with a bandwidth of 0.05 Hz to 1000 Hz, utilizing capacitive coupling to enable non-contact simultaneous measurement of capacitive skin sympathetic nerve activity (cSKNA) and capacitive ECG (cECG) signals. The flexible design ensures effective signal capture by conforming to body curvature, enhancing capacitive coupling. Human measurements involving cold pressor tests (CPT) were conducted to validate the cSKNA and cECG functionality and applicability of the proposed sensor under various fabric conditions, including different humidity levels, thicknesses, and materials. Moreover, human trials demonstrated the sensor’s capability to simultaneously capture cSKNA and cECG signals, effectively revealing neuro-cardiac interactions in real-time. Notably, during CPT-induced sympathetic nerve activation interventions, increases in measured cSKNA that exceeded the sympathetic burst threshold were associated with heart rate (HR) acceleration derived from the measured cECG signals, effectively demonstrating the sensor's capability in capturing neuro-cardiac responses. In conclusion, the proposed sensor offers a non-contact unobtrusive sensing solution for monitoring neuro-cardiac interactions, providing new insights for establishing predictive AF models through a more convenient and comfortable sensing system without electrode preparation. Its ease of use and versatility make the sensor suitable for potential applications in wearable chest bands and smart beds in the future.
Index Terms—Capacitive coupling, electrocardiogram, flexible sensor, non-contact measurement, skin sympathetic nerve activity.
Abstract: A sympathetic nerve signal sensing system. The sympathetic nerve signal sensing system includes an electrode pair, a high input impedance receiving circuit, a differential circuit, and a post-processing circuit. The electrode pair is disposed on a subject and includes a first electrode configured to receive a first signal and a second electrode configured to receive a second signal. The high input impedance receiving circuit includes a first coupler configured to receive the first signal and output a third signal and a second coupler configured to receive the second signal and output a fourth signal. The differential circuit is configured to differentially process the third and fourth signals to generate a fifth signal. The post-processing circuit is configured to filter the fifth signal using a first filtering frequency band to output the sympathetic nerve signal.