A Wearable Electrooculogram System with Parallel Motion Artifact Sensing and Reduction

Abstract

Electrooculogram signal is a well-known physiological metric. Electrooculogram measurements suffer from motion artifact and environmental vibrations. Such artifact are random in nature, may have large dynamic range, and may saturate the overall measurement system output. In this manuscript, we present a single channel, wireless, flexible EOG monitoring system which has capability to reduce motion artifact. The system uses dry non-contact electrodes which makes it mountable with minimal assistance required. The entire EOG system is implemented on a four-layer flexible polyimide substrate, with the EOG acquisition unit on the top layer, noncontact measurement electrodes printed on the bottom layer, circuit ground on the second layer, and active shielding on the third layer. The system uses parallel non-contact electrode pair for EOG signal detection and motion artifact reduction. The battery operated system utilizes only 56 mW of power while using a BLE 5.0 transceiver for wireless EOG data transmission. The system is designed for an effective EOG signal bandwidth of 1 Hz to 40 Hz with an effective signal gain above 35 dB over the signal bandwidth. The capability of the system for motion artifact reduction and EOG detection are experimentally validated. With only 8.75 gram weight the system does not cause any discomfort to the wearer during EOG recording.