Abstract
Surgery is recommended for epilepsy diagnosis in cases where patients do not respond well to anti-epilepsy medications. Successful surgery is essentially dependent on the area suffered from epilepsy, i.e., focal area. Electroencephalogram (EEG) signals are considered a powerful tool to identify focal or non-focal (normal) areas. In this work, we propose an automated method for focal and non-focal EEG signal identification, taking into account non-linear features derived from rhythms in the empirical wavelet transform (EWT) domain. The research paradigm is related to the decomposition of EEG signals into the delta, theta, alpha, beta, and gamma rhythms through the development of the EWT. Specifically, various non-linear features are extracted from rhythms composed of Stein’s unbiased risk estimation entropy, threshold entropy, centered correntropy, and information potential. From a statistical point of view, Kruskal–Wallis (KW) statistical test is then used to identify the significant features. The significant features obtained from the KW test are fed to support vector machine (SVM) and k-nearest neighbor (KNN) classifiers. The SURE entropy provides an average classification accuracy of 93% and 82.6% for small and entire datasets by utilizing SVM and KNN classifiers with a tenfold cross-validation method, respectively. It is observed that the proposed method is better and competitive in comparison with other studies for small and large data, respectively. The obtained outcome concludes that the proposed framework could be used for people with epilepsy and can help the physicians to validate the assessment.
Similar content being viewed by others
References
Li S, Zhou W, Yuan Q, Geng S, Cai D (2013) Feature extraction and recognition of ictal EEG using emd and SVM. Comput Biol Med 43(7):807–816
Zhu G, Li Y, Wen PP, Wang S, Xi M (2013) Epileptogenic focus detection in intracranial eeg based on delay permutation entropy. In AIP conference proceedings, vol 1559. American Institute of Physics, pp 31–36
Das AB, Bhuiyan MIH (2016) Discrimination and classification of focal and non-focal EEG signals using entropy-based features in the EMD-DWT domain. Biomed Signal Process Control 29:11–21
Bhattacharyya A, Sharma M, Pachori RB, Sircar P, Acharya UR (2018) A novel approach for automated detection of focal eeg signals using empirical wavelet transform. Neural Comput Appl 29(8):47–57
Singh P, Pachori RB (2017) Classification of focal and nonfocal EEG signals using features derived from fourier-based rhythms. J Mech Med Biol 17(07):1740002
Gupta V, Pachori R (2019) A new method for classification of focal and non-focal EEG signals. In: Pachori R (ed) Machine intelligence and signal analysis. Springer, New York, pp 235–246
Sharma R, Pachori RB, Acharya UR (2015) Application of entropy measures on intrinsic mode functions for the automated identification of focal electroencephalogram signals. Entropy 17(2):669–691
Sharma R, Pachori RB, Gautam S (2014) Empirical mode decomposition based classification of focal and non-focal eeg signals. In: 2014 International Conference on Medical Biometrics, IEEE. pp 135–140
Sharma M, Dhere A, Pachori RB, Acharya UR (2017) An automatic detection of focal EEG signals using new class of time–frequency localized orthogonal wavelet filter banks. Knowl-Based Syst 118:217–227
Sharma R, Pachori RB, Acharya UR (2015) An integrated index for the identification of focal electroencephalogram signals using discrete wavelet transform and entropy measures. Entropy 17(8):5218–5240
Bhattacharyya A, Pachori RB, Upadhyay A, Acharya UR (2017) Tunable-q wavelet transform based multiscale entropy measure for automated classification of epileptic EEG signals. Appl Sci 7(4):385
Sharma R, Kumar M, Pachori RB, Acharya UR (2017) Decision support system for focal EEG signals using tunable-q wavelet transform. J Comput Sci 20:52–60
Dalal M, Tanveer M, Pachori RB (2019) Automated identification system for focal eeg signals using fractal dimension of fawt-based sub-bands signals. In Pachori RB (eds) Machine intelligence and signal analysis, pages 583–596. Springer, New York
Gupta V, Priya T, Yadav AK, Pachori RB, Acharya UR (2017) Automated detection of focal EEG signals using features extracted from flexible analytic wavelet transform. Pattern Recogn Lett 94:180–188
Rahman MM, Bhuiyan MIH, Das AB (2019) Classification of focal and non-focal EEG signals in vmd-dwt domain using ensemble stacking. Biomed Signal Process Control 50:72–82
Taran S, Bajaj V (2018) Clustering variational mode decomposition for identification of focal EEG signals. IEEE Sens Lett 2(4):1–4
Ghofrani S, Akbari H (2019) Comparing nonlinear features extracted in EEMD for discriminating focal and non-focal EEG signals. In: Tenth International Conference onsSignal processing systems, vol 11071. International Society for Optics and Photonics, p 1107106
Gilles J (2013) Empirical wavelet transform. IEEE Trans Signal Process 61(16):3999–4010
Sadiq MT, Yu X, Yuan Z, Fan Z, Rehman AU, Li G, Xiao G (2019) Motor imagery EEG signals classification based on mode amplitude and frequency components using empirical wavelet transform. IEEE Access 7:127678–127692
Sadiq MT, Yu X, Yuan Z, Fan Z, Rehman AU, Ullah I, Li G (2019) Motor imagery EEG signals decoding by multivariate empirical wavelet transform based framework for robust brain-computer interfaces. IEEE Access 7:171431–171451
Sadiq MT, Yu X, Yuan Z, Aziz MZ (2020) Motor imagery BCI classification based on novel two-dimensional modelling in empirical wavelet transform. Electron Lett 56:1367
Sadiq MT, Shabbir N, Kulesza WJ (2013) Spectral subtraction for speech enhancement in modulation domain. Int J Comput Sci Issues (IJCSI) 10(4):282
Sadiq MT, Yu X, Yuan Z, Aziz MZ (2020) Identification of motor and mental imagery EEG in two and multiclass subject-dependent tasks using successive decomposition index. Sensors 20(18):5283
Sadiq MT, Yu X, Yuan Z (2020) Exploiting dimensionality reduction and neural network techniques for the development of expert brain-computer interfaces. Expert Syst Appl 164:114031
Andrzejak RG, Schindler K, Rummel C (2012) Nonrandomness, nonlinear dependence, and nonstationarity of electroencephalographic recordings from epilepsy patients. Phys Rev E 86(4):046206
Daubechies I (1992) Ten lectures on wavelets, vol 61. Siam, Philadelphia
Hosseini SA, Naghibi-Sistani MB (2011) Emotion recognition method using entropy analysis of eeg signals. Int J Image Graph Signal Proces 3(5):30
Gunduz A, Principe JC (2009) Correntropy as a novel measure for nonlinearity tests. Sig Process 89(1):14–23
Liu W, Pokharel PP, Príncipe JC (2007) Correntropy: properties and applications in non-gaussian signal processing. IEEE Trans Signal Process 55(11):5286–5298
Patidar S, Pachori RB, Upadhyay A, Acharya UR (2017) An integrated alcoholic index using tunable-q wavelet transform based features extracted from EEG signals for diagnosis of alcoholism. Appl Soft Comput 50:71–78
Reddy GRS, Rao R (2017) Automated identification system for seizure eeg signals using tunable-q wavelet transform. Eng Sci Technol 20(5):1486–1493
Kumar M, Pachori RB, Acharya UR (2017) Characterization of coronary artery disease using flexible analytic wavelet transform applied on ECG signals. Biomed Signal Process Control 31:301–308
Xu D, Erdogmuns D (2010) Renyi’s entropy, divergence and their nonparametric estimators. Information theoretic learning. Springer, New York, pp 47–102
Akhter M P, Jiangbin Z, Naqvi I R, Abdelmajeed M, Sadiq M T (2020) Automatic detection of offensive language for urdu and roman urdu. IEEE Access 8:91 213–91 226
Akhter M P, Jiangbin Z, Naqvi I R, Abdelmajeed M, Mehmood A, Sadiq M T (2020) Document-level text classification using single-layer multisize filters convolutional neural network. IEEE Access 8:42 689–42 707
Akbari H, Ghofrani S (2019) Fast and accurate classification f and nf EEG by using sodp and EWT. Int J Image Graph Signal Process 11:29–35
Huang NE, Shen Z, Long SR, Wu MC, Shih HH, Zheng Q, Yen NC, Tung CC, Liu HH (1998) The empirical mode decomposition and the hilbert spectrum for nonlinear and non-stationary time series analysis. Proc R Soc Lond 454(1971):903–995
Sriraam N, Raghu S (2017) Classification of focal and non focal epileptic seizures using multi-features and SVM classifier. J Med Syst 41(10):160
Raghu S, Sriraam N (2018) Classification of focal and non-focal eeg signals using neighborhood component analysis and machine learning algorithms. Expert Syst Appl 113:18–32
Acharya UR, Hagiwara Y, Deshpande SN, Suren S, Koh JW, Oh S.L., Arunkumar N, Ciaccio EJ, Lim CM (2019) Characterization of focal eeg signals: a review. Future Gener Comput Syst 91:290–299
Chen D, Wan S, Bao FS (2016) Epileptic focus localization using discrete wavelet transform based on interictal intracranial eeg. IEEE Trans Neural Syst Rehabil Eng 25(5):413–425
Acknowledgements
Hesam Akbari and Muhammad Tariq Sadiq are co-first authors. This work is a part of the Final year Master’s thesis of Hesam Akbari. The authors are thankful to “Iranian Army Ground Forces” for providing access to research labs for calculating the features of the entire dataset.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Akbari, H., Sadiq, M.T. Detection of focal and non-focal EEG signals using non-linear features derived from empirical wavelet transform rhythms. Phys Eng Sci Med 44, 157–171 (2021). https://doi.org/10.1007/s13246-020-00963-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13246-020-00963-3