FastICA peel-off for ECG interference removal from surface EMG.

Maoqi Chen,Mingxing Zhu,Guanglin Li,Xiang Chen,Ping Zhou,Xu Zhang

doi:10.1186/s12938-016-0196-8

Abstract

BackgroundMulti-channel recording of surface electromyographyic (EMG) signals is very likely to be contaminated by electrocardiographic (ECG) interference, specifically when the surface electrode is placed on muscles close to the heart.MethodsA novel fast independent component analysis (FastICA) based peel-off method is presented to remove ECG interference contaminating multi-channel surface EMG signals. Although demonstrating spatial variability in waveform shape, the ECG interference in different channels shares the same firing instants. Utilizing the firing information estimated from FastICA, ECG interference can be separated from surface EMG by a “peel off” processing. The performance of the method was quantified with synthetic signals by combining a series of experimentally recorded “clean” surface EMG and “pure” ECG interference.ResultsIt was demonstrated that the new method can remove ECG interference efficiently with little distortion to surface EMG amplitude and frequency. The proposed method was also validated using experimental surface EMG signals contaminated by ECG interference.ConclusionsThe proposed FastICA peel-off method can be used as a new and practical solution to eliminating ECG interference from multichannel EMG recordings.

Highlights

Multi-channel recording of surface electromyographyic (EMG) signals is very likely to be contaminated by electrocardiographic (ECG) interference, when the surface electrode is placed on muscles close to the heart
It was observed that the fast independent component analysis (FastICA) based peel off method imposes little distortion to the EMG component in both amplitude and frequency
Different channels of synthetic ECG contaminated EMG signals had a large range of variation for each of all the three indices before the denoising processing, which can be used to evaluate the performance of the proposed ECG removal method under different interference levels

Summary

Introduction

Multi-channel recording of surface electromyographyic (EMG) signals is very likely to be contaminated by electrocardiographic (ECG) interference, when the surface electrode is placed on muscles close to the heart. Methods: A novel fast independent component analysis (FastICA) based peel-off method is presented to remove ECG interference contaminating multi-channel surface EMG signals. To remove ECG interference from EMG signals, a high-pass filter [1, 2] is often used with a cutoff frequency of approximately 30 Hz to 60 Hz, or even higher. Such a setting will unavoidably distort useful EMG signal components due to the frequency overlapping. Other more complicated methods have been developed including ECG template subtraction, wavelet thresholding, adaptive filtering, etc. [3,4,5,6,7] With the development of blind source separation techniques, independent component analysis (ICA) has been used for ECG interference removal from surface EMG

Methods

Results

Discussion

Conclusion