Estimating dynamic cortical connectivity from motor imagery EEG using KALMAN smoother & EM algorithm

S. Balqis Samdin, Chee Ming Ting, Sh Hussain Salleh, Mahyar Hamedi, A. B.Mohd Noor

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

10 Citations (Scopus)

Abstract

This paper considers identifying effective cortical connectivity from scalp EEG. Recent studies use time-varying multivariate autoregressive (TV-MAR) models to better describe the changing connectivity between cortical regions where the TV coefficients are estimated by Kalman filter (KF) within a state-space framework. We extend this approach by incorporating Kalman smoothing (KS) to improve the KF estimates, and the expectation-maximization (EM) algorithm to infer the unknown model parameters from EEG. We also consider solving the volume conduction problem by modeling the induced instantaneous correlations using a full noise covariate. Simulation results show the superiority of KS in tracking the coefficient changes. We apply two derived frequency domain measures i.e. TV partial directed coherence (TV-PDC) and TV directed transfer function (TV-DTF), to investigate dynamic causal interactions between motor areas in discriminating motor imagery (MI) of left and right hand. Event-related changes of information flows around beta-band, in a unidirectional way between left and right hemispheres are observed during MI. A difference in inter-hemispheric connectivity patterns is found between left and right-hand movements, implying potential usage for BCI.

Original languageEnglish
Title of host publication2014 IEEE Workshop on Statistical Signal Processing, SSP 2014
PublisherIEEE, Institute of Electrical and Electronics Engineers
Pages181-184
Number of pages4
ISBN (Print)9781479949755
DOIs
Publication statusPublished - 2014
Externally publishedYes
EventIEEE Workshop on Statistical Signal Processing (SSP) 2014 - Gold Coast, Australia
Duration: 29 Jun 20142 Jul 2014
https://ieeexplore.ieee.org/xpl/conhome/6872768/proceeding (Proceedings)

Conference

ConferenceIEEE Workshop on Statistical Signal Processing (SSP) 2014
Abbreviated titleSSP 2014
Country/TerritoryAustralia
CityGold Coast
Period29/06/142/07/14
Internet address

Keywords

  • dynamic cortical connectivity
  • EEG
  • EM algorithm
  • Multivariate autoregressive model
  • state-space model

Cite this