نوع مقاله : مقاله کامل پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد، گروه مهندسی پزشکی، دانشکده مهندسی برق، دانشگاه علم و صنعت ایران، تهران

2 استادیار، گروه مهندسی پزشکی، دانشکده مهندسی برق، دانشگاه علم و صنعت ایران، تهران

چکیده

هجی‌کنندة P300، یکی از رایج‌ترین واسط‌های مغز-کامپیوتر مبتنی‌بر ثبت الکتروانسفالوگرام است که توانایی‌های ارتباطی ساده‌ای را برای افراد دچار عارضه‌های شدید گفتاری یا حرکتی فراهم می‌کند، تا قادر باشند بهتر با محیط اطراف خود ارتباط برقرار کنند. استفاده از الگوی صفحة شطرنجی معرفی‌شده توسط Townsend و همکارانش [1]، به‌جای الگوی سطری-ستونی، یکی از موفق‌ترین الگوهای تحریک ارائه‌شده در مطالعات قبلی برای افزایش دقت هجی‌کننده بوده است. هدف روش پیشنهادی این مطالعه، که با عنوان الگوی شطرنجی با تحریک شکلک-تصویری نام‌گذاری شده است، بررسی اثر جایگزینی تحریک شکلک-تصویری در الگوی صفحة شطرنجی و مقایسة کارآیی آن با تحریک چشمک زدن کاراکترها است. در این مطالعه، چشمک زدن کاراکترها در الگوی شطرنجی را با نمایش یک شکلک-تصویری به‌جای کاراکتر‌ها جایگزین کردیم. برای ارزیابی و مقایسة کارایی الگوی پیشنهادی با الگوی شطرنجی، برای هر‌یک از دو الگو، هجی‌کننده روی داده‌های ثبت‌شده از ده فرد سالم در فاز برون خط، تعلیم داده شد و دقت هجی‌کننده در فاز برخط محاسبه شد. ارزیابی آزمون برخط نشان داد، میانگین دقت طبقه‌بندی هجی‌کننده با استفاده از الگوی پیشنهادی این مطالعه نسبت به الگوی شطرنجی، 14% بهبود یافته است. یافته‌های این مطالعه نشان می‌دهد که تحریک ناشی از نمایش شکلک-تصویری به‌جای چشمک زدن کاراکترها، نقش مؤثری در افزایش دقت طبقه‌بندی هجی‌کننده داشته است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Using Emoji Stimuli for Checker-Board P300 Speller

نویسندگان [English]

  • Hesam Moradkhani 1
  • Vahid Shalchyan 2

1 MSc. Student, Electrical Engineering Faculty, Iran University of Science and Technology, Tehran, Iran

2 Assistant Professor, Electrical Engineering Faculty, Iran University of Science and Technology, Tehran, Iran

چکیده [English]

P300 Speller as a most commonly used brain–computer interface (BCI) has been able to provide simple communication capabilities for people with severe motor or speech disabilities in order to have a better interaction with the outer world over the past years. Checker-board paradigm introduced by Townsend et al. [1] is one of the most practical alternatives for row-column paradigm, enhancing the performance of the speller by preventing row-column induced errors. In this study, we investigated the effect of substituting presentation of an emoji stimulus instead of flashing the characters in the performance of a checker-board P-300 speller. The performance of the proposed paradigm was evaluated and compared to the traditional stimuli in checker-board paradigm in an online experiment over ten healthy subjects. For each paradigm, the recorded data from an offline session was used to calibrate the speller classifier; and consequently, the classification accuracy was calculated over online sessions. The proposed paradigm, showed 14% enhancement in classification accuracy with respect to the checker-board paradigm. The results of this study obviously showed that the stimuli obtained by presenting emoji instead of character flashing, effectively improved the speller classification accuracy.

کلیدواژه‌ها [English]

  • Brain-Computer Interface (BCI)
  • P300 Speller
  • Checker-Board Paradigm
[1]     G. Townsend, B.K. LaPallo,C.B. Boulay, D.J. Krusienski, G.E. Frye, C. Hauser, N.E. Schwartz, T. Vaughan, J.R. Wolpaw, E.W. Sellers, "A novel P300-based brain–computer interface stimulus presentation paradigm: moving beyond rows and columns," Clinical Neurophysiology, vol. 121, pp. 1109-1120, 2010.
[2]     J.R. Wolpaw, N. Birbaumer,D.J. McFarland ,G. Pfurtscheller, T.M. Vaughan, "Brain computer interfaces for communication and control," Clinical Neurophysiology, vol. 113, p. 767–791, 2002.
[3]     L.A. Farwell, E. Donchin, "Talking off the top of your head: toward a mental prosthesis utilizing event-related brain potential," Electroencephalography and clinical Neurophysiology, vol. 70, pp. 510-523, 1988.
[4]     Y. Shahriari, A. Erfanian, "Improving the performance of P300-based brain–computer interface through subspace-based filtering," Neurocomputing, vol. 121, pp. 434-441, 2013.
[5]     Y. Zhang, G. Zhou, Q. Zhao, J. Jin, X. Wang, A. Cichocki, "Spatial-temporal discriminant analysis for ERP-based brain-computer interface," IEEE Transactions on Neural Systems and Rehabilitation Engineering, vol. 21, pp. 233-243, 2013.
[6]     D.J. Krusienski, E.W. Sellers, F. Cabestaing, S. Bayoudh, D.J. McFarland,T.M. Vaughan, J.R. Wolpaw, "A comparison of classification techniques for the P300 Speller," Journal of neural engineering, vol. 3, p. 299, 2006.
[7]     A. Rakotomamonjy, V. Guigue, "BCI competition III: dataset II-ensemble of SVMs for BCI P300 speller," IEEE transactions on biomedical engineering, vol. 55, pp. 1147-1154, 2008.
[8]     D.J. Krusienski, E.W. Sellers, D.J. McFarland, T.M. Vaughan, J.R. Wolpaw, "Toward enhanced P300 speller performance," Journal of neuroscience methods, vol. 167, pp. 15-21, 2008.
[9]     T. Demiralp, A. M. Ademoglu, M. Schürmann,C. Basar-Eroglu,E. Basar, "Detection of P300 waves in single trials by the wavelet transform (WT)," Brain and language, vol. 66, pp. 108-128, 1999.
[10] V. Bostanov, "BCI competition 2003-data sets Ib and IIb: feature extraction from event-related brain potentials with the continuous wavelet transform and the t-value scalogram," IEEE Transactions on Biomedical engineering, vol. 51, pp. 1057-1061, 2004.
[11] M. Salvaris, F. Sepulveda, "Wavelets and ensemble of FLDs for P300 classification," in 4th International IEEE/EMBS Conference , 2009.
[12] M. Kaper, P. Meinicke, U. Grossekathoefer, T. Lingner, H. Ritter, "BCI competition 2003-data set IIb: support vector machines for the P300 speller paradigm," IEEE Transactions on Biomedical Engineering, vol. 51, pp. 1073-1076, 2004.
[13] M. Thulasidas,C. Guan, J. Wu, "Robust classification of EEG signal for brain-computer interface," IEEE Transactions on Neural Systems and Rehabilitation Engineering, vol. 14, pp. 24-29, 2006.
[14] E. Donchin, K.M. Spencer, R. Wijesinghe, "The mental prosthesis: assessing the speed of a P300-based brain-computer interface," IEEE transactions on rehabilitation engineering, vol. 8, pp. 174-179, 2000.
[15] U. Hoffmann, J.M. Vesin,T. Ebrahimi, K. Diserens, "An efficient P300-based brain–computer interface for disabled subjects," Journal of Neuroscience methods, vol. 167, pp. 115-125, 2008.
[16] M. Salvaris, F. Sepulveda, "Visual modifications on the P300 speller BCI paradigm," Journal of neural engineering, vol. 6, p. 046011, 2009.
[17] D.J. McFarland, W.A. Sarnacki, G. Townsend, T. Vaughan, J.R. Wolpaw, "The P300-based brain–computer interface (BCI): effects of stimulus rate," Clinical Neurophysiology, vol. 122, pp. .731-737, 2011.
[18] T. Kaufmann, S.M. Schulz, C. Grünzinger, A. Kübler, "Flashing characters with famous faces improves ERP-based brain–computer interface performance," Journal of neural engineering, vol. 8, p. 056016, 2011.
[19] M. Eimer, "Event-related brain potentials distinguish processing stages involved in face perception and recognition," Clinical neurophysiology, vol. 111, pp. 694-705, 2000.
[20] O. Churches, M. Nicholls, M. Thiessen, M. Kohler, H. Keage, "Emoticons in mind: An event-related potential study," Social neuroscience, vol. 9, pp. 196-202, 2014.
[21] E.W. Sellers, E. Donchin, "A P300-based brain–computer interface: initial tests by ALS patients," Clinical neurophysiologغ, vol. 117, pp. 538-548, 2006.
[22] R.A. Fisher, "The use of multiple measurements in taxonomic problems," Annals of human genetics, vol. 7, pp. 179-188, 1936.
[23] J. Cohen, J. Polich, "On the number of trials needed for P300," International Journal of Psychophysiology, vol. 25, pp. 249-255, 1997.
[24] T. Kaufmann, S.M. Schulz, A. Köblitz, G. Renner, C. Wessig, A. Kübler, "Face stimuli effectively prevent brain–computer interface inefficiency in patients with neurodegenerative disease," Clinical Neurophysiology, vol. 124, pp. 893-900, 2013.
[25] Jin, J., Daly, I., Zhang, Y., Wang, X. and             Cichocki, "An optimized ERP brain–computer interface based on facial expression changes," Journal of neural engineering, vol. 11, p. 036004, 2014.
[26] Chen, L., Jin, J., Zhang, Y., Wang, X. and Cichocki, A, "A survey of the dummy face and human face stimuli used in BCI paradigm," Journal of neuroscience methods, vol. 239, pp. 18-27, 2015.
[27] Daly, I., Chen, L., Zhou, S. and Jin, J, " An  
[28] investigation into the use of six facially encoded emotions in brain-computer interfacing," Brain-computer interfaces, vol. 3, pp. 59-73, 2016.
[29] Zhao, Q., Zhang, Y., Onishi, A. and Cichocki, A, "An affective BCI using multiple ERP components associated to facial emotion processing," In Brain-Computer Interface Research Springer Berlin Heidelberg., no. Springer Berlin Heidelberg, pp. 61-72, 2013.