Suppressing interferences of EIT on synchronous recording EEG based on comb filter for seizure detection

Lei Wang; Wenjing Zhu; Rong Wang; Weichen Li; Guohua Liang; Zhenyu Ji; Xiuzhen Dong; Xuetao Shi

doi:10.3389/fneur.2022.1070124

Suppressing interferences of EIT on synchronous recording EEG based on comb filter for seizure detection

Front Neurol. 2022 Dec 2:13:1070124. doi: 10.3389/fneur.2022.1070124. eCollection 2022.

Authors

Lei Wang¹, Wenjing Zhu¹, Rong Wang¹, Weichen Li², Guohua Liang¹, Zhenyu Ji³, Xiuzhen Dong³, Xuetao Shi³

Affiliations

¹ Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China.
² School of Life Sciences, Northwest University, Xi'an, China.
³ Department of Medical Electronic Engineering, School of Biomedical Engineering, The Fourth Military Medical University, Xi'an, China.

Abstract

Background and objective: The purpose of this study was to eliminate the interferences of electrical impedance tomography (EIT) on synchronous recording electroencephalography (EEG) for seizure detection.

Methods: The simulated EIT signal generated by COMSOL Multiphysics was superimposed on the clinical EEG signal obtained from the CHB-MIT Scalp EEG Database, and then the spectrum features of superimposed mixed signals were analyzed. According to the spectrum analysis, in addition to high-frequency interference at 51.2 kHz related to the drive current, there was also low-frequency interference caused by switching of electrode pairs, which were used to inject drive current. A low pass filter and a comb filter were used to suppress the high-frequency interference and low-frequency interference, respectively. Simulation results suggested the low-pass filter and comb filter working together effectively filtered out the interference of EIT on EEG in the process of synchronous monitoring.

Results: As a result, the normal EEG and epileptic EEG could be recognized effectively. Pearson correlation analysis further confirmed the interference of EIT on EEG was effectively suppressed.

Conclusions: This study provides a simple and effective interference suppression method for the synchronous monitoring of EIT and EEG, which could be served as a reference for the synchronous monitoring of EEG and other medical electromagnetic devices.

Keywords: EEG signal; comb filter; electrical impedance tomography; epilepsy; low-frequency interference.