Hybrid Wavelet and EMD/ICA Approach for Artifact Suppression in Pervasive EEG

TL;DR

This study compares hybrid wavelet-based algorithms for artifact removal in pervasive EEG, demonstrating that WPTEMD outperforms other methods in both simulated and real-world scenarios without prior artifact knowledge.

Contribution

It introduces and evaluates a novel hybrid WPTEMD algorithm for artifact suppression in pervasive EEG, showing superior performance over existing methods.

Findings

WPTEMD achieves lowest RMSE and ASR scores.

WPTEMD provides clearer scalp topography with fewer artifacts.

Method is effective on real-world pervasive EEG data.

Abstract

Electroencephalogram (EEG) signals are often corrupted with unintended artifacts which need to be removed for extracting meaningful clinical information from them. Typically a priori knowledge of the nature of the artifacts is needed for such purpose. Artifact contamination of EEG is even more prominent for pervasive EEG systems where the subjects are free to move and thereby introducing a wide variety of motion-related artifacts. This makes hard to get a priori knowledge about their characteristics rendering conventional artifact removal techniques often ineffective. In this paper, we explore the performance of two hybrid artifact removal algorithms: Wavelet packet transform followed by Independent Component Analysis (WPTICA) and Wavelet Packet Transform followed by Empirical Mode Decomposition (WPTEMD) in pervasive EEG recording scenario, assuming existence of no a priori knowledge about the artifacts and compare their performance with two existing artifact removal algorithms. Artifact cleaning performance has been measured using Root Mean Square Error (RMSE) and Artifact to Signal Ratio (ASR) - an index similar to traditional Signal to Noise Ratio (SNR), and also by observing normalized power distribution topography over the scalp. Comparison has been made first using semi-simulated signals and then with real experimentally acquired EEG data with commercially available 19-channel pervasive EEG system Enobio corrupted by eight types of artifact. Our explorations show that WPTEMD consistently gives best artifact cleaning performance not only in semi-simulated scenario but also in the case of real EEG data containing artifacts.