Brain source localization using reduced EEG sensors
Brain source activation is caused due to certain mental or physical task, and such activation is localized by using various optimization techniques. This localization has vital application for diagnoses of various brain disorders such as epilepsy, schizophrenia, Alzheimer, depression, Parkinson and stress. Various neuroimaging techniques (such as EEG, fMRI, MEG) are used to record brain activity for inference and estimation of active source locations. EEG employs set of sensors which are placed on scalp to measure electric potentials. These sensors have significant role in overall system complexity, computational time and system cost. Hence, sensor reduction for EEG source localization has been a topic of interest for researchers to develop a system with improved localization precision, less system complexity and reduced cost. This research work discusses and implements the brain source localization for real-time and synthetically generated EEG dataset with reduced number of sensors. For this, various optimization algorithms are used which include Bayesian framework-based multiple sparse priors (MSP), classical low-resolution brain electromagnetic tomography (LORETA), beamformer and minimum norm estimation (MNE). The results obtained are then compared in terms of negative variational free energy, localization error and computational time measured in seconds. It is observed that multiple sparse priors (MSP) with increased number of patches performed best even with reduced number of sensors, i.e., 7 instead of 74. The results are shown valid for synthetic EEG data at low SNR level, i.e., 5 dB and real-time EEG data, respectively.
KeywordsElectroencephalography Source localization Electrode reduction Multiple sparse priors Free energy Localization error
This research was fully supported by the Fundamental Research Grant Scheme, (FRGS/1/2015/TK04/UTP/02/5), Ministry of Higher Education, Malaysia.
- 1.Sanei, S., Chambers, J.A.: EEG Signal Processing. Wiley, New York (2013)Google Scholar
- 9.Pascual-Marqui, R.D., Esslen, M., Kochi, K., Lehmann, D.: Functional imaging with low-resolution brain electromagnetic tomography (LORETA): a review. Methods Find. Exp. Clin. Pharmacol. 24, 91–95 (2002)Google Scholar
- 16.Pascual-Marqui, R.D.: Standardized low-resolution brain electromagnetic tomography (sLORETA): technical details. Methods Find. Exp. Clin. Pharmacol. 24, 5–12 (2002)Google Scholar
- 17.Pascual-Marqui, R.D.: Discrete, 3D distributed, linear imaging methods of electric neuronal activity. Part 1: exact, zero error localization, (2007) arXiv preprint arXiv:0710.3341
- 19.Khemakkhem, R., Zouch, W., Taleb-Ahmed, A., Hamida, A.B.: A new combining approach to localizing the EEG activity in the brain: WMN and LORETA solution. In: International Conference on Biomedical Engineering and Informatics. BMEI 2008, vol. 2008, pp. 821–824 (2008)Google Scholar
- 20.SPM. http://www.fil.ion.ucl.ac.uk/spm/software/spm12/-. Accessed 24 Jan 2017
- 21.ENOBIO. http://www.neuroelectrics.com/products/enobio/-. Accessed 24 Jan 2017
- 22.EasyCap. http://www.easycap.de/e/products/products.htm-. Accessed 24 Jan 2017