Concentric bipolar active electrode for noninvasive biopotential measurement in autonomic nervous system

This study investigates a concentric bipolar active (CBA) electrode with ultra-high input impedance for noninvasive measurement of biopotentials from the autonomic nervous system (ANS). Experiments involving Valsalva maneuvers (VM) conducted with 4 male subjects showed spike-like potentials that resembled neural potentials recorded directly with microelectrodes from autonomic nerve. Spike-like bursts in two subjects showed a pattern similar to those observed in previous microneurographic studies following the changes in blood pressure during VM. Comparison of both spike-like potential and spectrogram detected by the CBA electrode with an electromyogram simultaneously recorded from neighboring muscles indicated independence between the signals from the CBA electrode and electromyogram. These results suggest that the biopotential signal recorded using the proposed electrode originates from nerve fascicles in ANS, indicating potential of the proposed electrode in noninvasive ANS measurement.