On channel selection for EEG-based mental workload classification

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

Abstract

Electroencephalogram (EEG) is a non-invasive technology with high temporal resolution, widely used in Brain-Computer Interfaces (BCIs) for mental workload (MWL) classification. However, numerous EEG channels in current devices can make them bulky, uncomfortable, and time-consuming to operate in real-life scenarios. A Riemannian geometry approach has gained attention for channel selection to address this issue. In particular, Riemannian geometry employs covariance matrices of EEG signals to identify the optimal set of EEG channels, given a specific covariance estimator and desired channel number. However, previous studies have not thoroughly assessed the limitations of various covariance estimators, which may influence the analysis results. In this study, we aim to investigate the impact of different covariance estimators, namely Empirical Covariance (EC), Shrunk Covariance (SC), Ledoit-Wolf (LW), and Oracle Approximating Shrinkage (OAS), along with the influence of channel numbers on the process of EEG channel selection. We also examine the performance of selected channels using diverse deep learning models, namely Stacked Gated Recurrent Unit (GRU), Bidirectional Gated Recurrent Unit (BGRU), and BGRU-GRU models, using a publicly available MWL EEG dataset. Our findings show that although no universally optimal channel number exists, employing as few as four channels can achieve an accuracy of 0.940 (±0.036), enhancing practicality for real-world applications. In addition, we discover that the BGRU model, when combined with OAS covariance estimators and a 32-channel configuration, demonstrates superior performance in MWL classification tasks compared to other estimator combinations. Indeed, this study provides insights into the effectiveness of various covariance estimators and the optimal channel subsets for highly accurate MWL classification. These findings can potentially advance the development of EEG-based BCI applications.
Original languageEnglish
Title of host publicationMachine Learning, Optimization, and Data Science
Subtitle of host publication9th International Conference, LOD 2023, Grasmere, UK, September 22–26, 2023, Revised Selected Papers, Part II
EditorsGiuseppe Nicosia, Varun Ojha, Emanuele La Malfa, Gabriele La Malfa, Panos M. Pardalos, Renato Umeton
Place of PublicationCham
PublisherSpringer-Verlag
Pages403-417
Number of pages15
ISBN (Electronic)9783031539664
ISBN (Print)9783031539657
DOIs
Publication statusPublished - 15 Feb 2024
EventThird Symposium on Artificial Intelligence and Neuroscience - Grasmere, United Kingdom
Duration: 22 Sept 202326 Sept 2023

Publication series

NameLecture Notes in Computer Science
PublisherSpringer
Volume14506
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

ConferenceThird Symposium on Artificial Intelligence and Neuroscience
Abbreviated titleACAIN 2023
Country/TerritoryUnited Kingdom
CityGrasmere
Period22/09/2326/09/23

Keywords

  • mental workload classification
  • machine learning
  • deep learning
  • channel selection
  • covariance estimator

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