Document Type : Full Research Paper

Authors

1 Ph.D Student, Biomedical Eng. Department, Electrical and Computer Eng. College, TarbiatModares University

2 Associate Professor, Biomedical Eng. Department, Electrical and Computer Eng. College, TarbiatModares University

10.22041/ijbme.2013.13079

Abstract

A critical issue in designing a self-paced brain computer interface (BCI) system is onset detection of the mental task from the continuous electroencephalogram (EEG) signal to produce a brain switch. This work shows significant improvement in a movement based self-paced BCI by applying a new sparse learning classification algorithm, probabilistic classification vector machines (PCVMs) to classify EEG signal. Constant-Q filters instead of constant bandwidth filters for frequency decomposition are also shown to enhance the discrimination of movement related patterns from EEG patterns associated with idle state. Analysis of the data recorded from seven subjects executing foot movement using the constant-Q filters and PCVMs shows a statistically significant 16% (p<0.03) average improvement in true positive rate (TPR) and a 2% (p<0.03) reduction in false positive rate (FPR) compared with applying constant bandwidth filters and SVM classifier.

Keywords

Main Subjects

[1]  Wolpaw J.R., Birbaumer N., McFarland D.J., Pfurtscheller G., Vaughan T.M., Brain-computer interfaces for communication and control; Clin. Neurophysiol., 2002;  131: 767-791.
[2]  Scherer R., Schloegl A., Lee F., Bischof H., Jansa J., Pfurtscheller G., The self-paced Graz brain–computer interface: methods and applications; Comput. Intell. Neurosci., 2007; 7982.
[3]  Mason S.G., Birch G.E. A brain-controlled switch for asynchronous control applications; IEEE Trans. Biomed. Eng., 2000; 47: 1297-1307.
[4]  Pfurtscheller G., Lopes da Silva F.H., Event-related EEG/MEG synchronization and     desynchronization: basic principles; Clin Neurophysiol., 1999; 110: 1842-1857.
[5]  Kosslyn S.M., Ganis G., Thompson W.L., Neural foundations of imagery; Nat Rev Neurosci., 2001; 2(9): 635-642.
[6]  Pfurtscheller G., Neuper C., Motor imagery activates primary sensorimotor area in humans; Neuroscience Letters, 1997; 239: 65-68.
[7]  Hasan B.A.S., Gan J.Q., Unsupervised movement onset detection from EEG recorded during self-paced real hand movement; Med. Biol. Eng. Comput., 2010; 48: 245-253.
[8]  Millan J. del R., Mourino J., Asynchronous BCI and local neural classifiers: An overview of the adaptive brain interface project; IEEE Trans.  Neural Syst. Rehabil. Eng., 2003; 11: 159-161.
[9]  Mason S.G., Birch.G.E., A brain-controlled switch for asynchronous control applications; IEEE Trans. Biomed. Eng., 2000; 47: 1297-1307.
[10]             Bashashati A., Mason S., Ward R.K., Birch G.E.,   An improved asynchronous brain interface: making use of the temporal history of the LF-ASD feature vectors; J. Neural. Eng., 2006; 3: 87-94.
[11]             Fatourechi M., Ward R.K., Birch G.E.A., self-paced brain–computer interface system with a low false positive rate; J. Neural Eng., 2008; 5: 9-23.
[12]             Gala´n F., Oliva F., Guardia J., Using mental tasks transitions detection to improve spontaneous mental activity classification; J. Med. Biol. Eng Comput., 2007; 45(6): 603–612.
[13] Solis-Escalante T., Muller-Putz G.R., Pfurtscheller G.,  Overt foot movement detection in one single Laplacian EEG derivation; J. Neurosci. Methods, 2008; 175: 148-153.
[14]             Pfurtscheller G., Solis-Escalante T., Could the beta rebound in the EEG be suitable to realize a ‘‘brain switch’’?; Clin. Neurophysiol., 2009; 120: 24-29.
[15]             Pfurtscheller G., Solis-Escalante T., Ortner R., Linortner P., Müller-Putz G.R., Self-Paced Operation of an SSVEP-Based Orthosis With and Without an Imagery-Based “Brain Switch:” A Feasibility Study Towards a Hybrid BCI; IEEE Trans. Neural Syst. Rehabil. Eng., 2010; 18(4): 409-414.
[16]             Yong X., Fatourechi M., Ward R.K., Birch G.E., The Design of a Point-and-Click System by Integrating a Self-Paced Brain–Computer Interface With an Eye-Tracker; IEEE J. Emerg. & selected topics in circuits and syst., 2011; 1(4): 590-602.
[17]             Yong X., Fatourechi M., Ward R.K., Birch G.E., Automatic artifact removal in a self-paced hybrid brain- computer interface system; J. of NeuroEng. and Rehab., 2012; 9:50.
[18]             Chen H., Tiˇno P., Yao X., Probabilistic Classification Vector Machines; IEEE Trans. Neural Net., 2009; 20: 901-914. 
[19] Leeb R., Friedman D., Müller-Putz G.R., Scherer R., Slater M., Pfurtscheller G., Self-Paced (Asynchronous) BCI Control of a Wheelchair in Virtual Environments: A Case Study with a Tetraplegic, Computational Intelligence and Neuroscience, 2007; Article ID 79642, 8 pages, 2007. doi:10.1155/2007/79642.
[20]             Leeb R., Friedman D., Scherer R., Slater M., Pfurtscheller G., EEGbased "walking" of a tetraplegic in virtual reality In Maia Brain Computer Interfaces; Workshop-Challenging Brain Computer Interfaces: Neural Eng. Meets Clin. Needs in Neurorehabil., 2006; 43-44.
[21]             Lotte F., Renard Y., Lécuyer A., Self-Paced Brain-Computer interaction with virtual worlds: A quantitative and qualitative study ‘Out-Of-The-Lab’ Proc; 4th Int’l Brain-Computer Interface Workshop and Training Course, 2008.
[22]             Mohammadi R., Mahloojifar A., Coyle D A Combination of Pre- and Postprocessing Techniques to Enhance Self-Paced BCIs Advances in Human-Computer Interaction; 2012; Article ID 185320, 10 pages, 2012. doi:10.1155/2012/185320
[23]             Bello J., Daudet L., Abdallah S., Duxbury C., Davies M., Sandler M, A tutorial on onset detection in musical signa.ls; IEEE Trans. Speech and Audio Proc., 2005; 13: 1035–1047.
[24]             Belankertz B., “Constant-Q transform” http://www.user.tu-berlin.de/blanker/drafts.html
[25] Wang T., Deng J., He B Classifying EEG-based motor imagery tasks by means of time–frequency synthesized spatial patterns; Clin. Neurophysiol., 2004; 115: 2744-2753.
[26] Graimann B., Huggins J.E., Levine S.P., Pfurtscheller G., Visualization of Significant ERD/ERS patterns in multichannel EEG and ECoG data; Clin. Neurophysiol, 2002; 113: 43- 47.
[27]             Lotte F., Congedo M., Lecuyer A., Lamarche F., Arnaldi B.,  A review of classification algorithms for EEG-based brain-computer interfaces; J. Neural Eng., 2007; 4: 1-13.
[28]             Platt J., Probabilistic outputs for support vector machines and comparison to regularize likelihood methods; in Advances in Large Margin Classifiers, A.J. Smola, P. Bartlett, B. Schoelkopf, and D. Schuurmans, Eds. Cambridge, MA: MIT Press, 2000; pp. 61–74.
[29]             Tipping M.E., sparse Bayesian learning and the relevance vector machine; J. Mach. Learn. Res., 2001; 1: 211–244.
[30]             Rätsch G., Onoda T., Müller K.R., Soft margins for adaboost; Mach. Learn., 2001; 42(3): 287–320.
[31]             http://www.cs.bham.ac.uk/~hxc/
[32]             Townsend G., Graimann B., Pfurtscheller G., Continuous EEG classification during motor imagery-simulation of an asynchronous BCI; IEEE Trans. Neural Syst. Rehabil. Eng., 2004; 12: 258–265.
[33]             Chang C.C., Lin C.J., 2001 LIBSVM: a library for support vector machines. Software available at <http://www.csie.ntu.edu.tw/cjlin/libsvm>.
[34]             Mohammadi R., Mahloojifar A., Onset foot movement detection using 1-channel EEG in self-paced Brain Computer Interface; 20th Iranian Conference on Biomedical Engineering, Tehran, Iran, 2011.
[35]             Qian K., Nikolov P., Huang D., Fei D., Chen X., Bai O., A motor imagery-based online interactive brain-controlled switch: Paradigm development and preliminary test; Clin Neurophysiol, 2010; 121: 1304-1313.
[36] Mohammadi R., Mahlooji A., Chen H., Coyle D., EEG Based Foot Movement Onset Detection with the Probabilistic Classification Vector Machine; ICONIP 2012; Part IV, LNCS 7666, 356–363.