A motion-artifact tracking and compensation technique for dry-contact EEG monitoring system

Abstract

A digital online technique for motion artifact (MA) tracking and compensation is reported for electroencephalogram (EEG) monitoring using dry-contact electrodes. A safe, low-level pseudorandom noise (PN) signal is driven to the body through a reference electrode as a test signal to measure the bio-potential acquisition-path gain (APG) of the electrode-tissue interface (ETI). The measurement result is then utilized by a digitaldomain gain compensator to act in the opposite way to the MAinduced APG variation, thereby compensating the multiplicative motion artifact (MMA) in real time. The remaining baseline wander or additive motion artifact (AMA) is treated by a digital high-pass filter (HPF). The interference of the test signal to the EEG signal acquisition is negligible in this technique due to the nearly white spectrum of the PN signal.

Motion Artifact Removal Techniques for Wearable EEG and PPG Sensor Systems

“…where Z path R Body + Z ESI + Z E . This formula emphasizes the impact of Z ESI variation, which directly changes the amplitude of the output signal due to gain distortion (Song et al, 2014;Dabbaghian et al, 2019).…”

“…For the ESI monitoring, an additional sensor is required that monitors the ESI impedance. This impedance sensor 1) injects current to the ESI and measures voltage at the ESI (Bertrand et al, 2013;Song et al, 2014), or 2) applies intentional DC bias to the ESI and measures amplified current induced by movement based on Eq. 2 (Dabbaghian and Kassiri, 2020).…”