Open access peer-reviewed chapter

Is EEG a Useful Examination Tool for Diagnosis of Epilepsy and Comorbid Psychiatric Disorders?

Written By

Hideki Azuma

Submitted: June 24th, 2020 Reviewed: October 6th, 2020 Published: October 28th, 2020

DOI: 10.5772/intechopen.94352

Chapter metrics overview

389 Chapter Downloads

View Full Metrics


Diagnosis of epilepsy usually involves interviewing the patients and the individuals who witnessed the seizure. An electroencephalogram (EEG) adds useful information for the diagnosis of epilepsy when epileptic abnormalities emerge. EEG exhibits nonlinearity and weak stationarity. Thus, nonlinear EEG analysis may be useful for clinical application. We examined only about English language studies of nonlinear EEG analysis that compared normal EEG and interictal EEG and reported the accuracy. We identified 60 studies from the public data of Andrzejak 2001 and two studies that did not use the data of Andrzejak 2001. Comorbid psychiatric disorders in patients with epilepsy were not reported in nonlinear EEG analysis except for one case series of comorbid psychotic disorders. Using a variety of feature extraction methods and classifier methods, we concluded that the studies that used the data of Andrzejak 2001 played a valuable role in EEG diagnosis of epilepsy. In the future, according to the evolution of artificial intelligence, deep learning, new nonlinear analysis methods, and the EEG association with the rating scale of the quality of life and psychiatric symptoms, we anticipate that EEG diagnosis of epilepsy, seizures, and comorbid psychiatric disorders in patients with epilepsy will be possible.


  • epilepsy
  • EEG
  • diagnosis
  • nonlinear analysis
  • comorbid psychiatric disorders

1. Introduction

1.1 EEG and epilepsy

Epileptic seizures usually do not emerge during the consultation. The diagnosis of epilepsy begins with a conversation with the individual and those who witnessed the seizures. [1] An electroencephalogram (EEG) is also used for the diagnosis of epilepsy. The gold standard for diagnosis of epilepsy is simultaneous ictal EEG recording with video, but this method is not applicable for many patients. The presence of epileptic paroxysmal abnormalities can help with the diagnosis. If a non-expert makes the diagnosis based on EEG findings alone rather than seizure symptoms, misinterpretation of the EEG findings may increase the false-positive diagnosis of epilepsy. Many physicians anticipate that EEG diagnosis for epilepsy will become possible with technological advances, even when no EEG abnormalities are present. EEG is useful not only for diagnosis, but also for monitoring during the course of treatment. [2] Psychiatric disorders occur more frequently as comorbidities in patients with epilepsy [3], and they can affect quality of life. [4]

1.2 EEG and nonlinearity

EEG is characterized by its nonlinearity. [5] Nonlinear dynamics is a concept that includes chaos. Therefore, the adaptation of nonlinear EEG analysis is more useful than that of linear EEG analysis. [6] In nonlinear dynamics, the time series data of EEG can be transformed into a reconstructed state space, which is calculated according to the embedded theorem [7, 8], and the dynamic attractors can be reconstructed. The reconstruction enables us to estimate nonlinear statistics such as fractal dimension and bifurcation structure. The attractor here is a set of trajectories where all of the nearest trajectories converge. [9] CD [9, 10, 11], which is a kind of fractal dimension, is a dimension that is occupied by the attractor in phase space. The method of Grassberger et al. is often used. [10] The lyapunov exponent is the degree of exponential separation between orbits, and measures the extent by which nearby points on an attractor diverge or converge with respect to each other while moving along any trajectory of the attractor. [9, 12] If the largest lyapunov exponent is greater than zero, this shows the presence of deterministic chaos. If the lyapunov exponent is less than or equal to zero, this shows a periodic or quasiperiodic motion, respectively. Furthermore, to show the nonlinearity of EEG, generation of surrogate data with linear characteristics and demonstration of a significant difference between them are necessary. In addition, nonlinear analysis is possible with the assumption that EEG exhibits weak stationarity, that the mean and the variance are normally distributed in the evaluated interval, and that no noise is present. [13]

1.3 Epilepsy and nonlinear EEG analysis

Many studies on the nonlinear analysis of EEG and epilepsy have been reported, including reviews concerning ictal EEG detection and machine leaning approaches. [14, 15, 16] Ideally, interictal EEG with no paroxysmal abnormalities should be used to diagnose epilepsy and comorbid psychiatric disorders by using computerized analysis rather than expert observation and interpretation.

1.4 Objectives in this review

Therefore, in the present review, we investigated the reports on the nonlinear analysis of EEG between normal and epileptic groups, focusing on the diagnosis of epilepsy and comorbid psychiatric disorders.


2. Methods

2.1 Public data set in Andrzejak 2001

A literature search of Scopus and PubMed was performed. In addition, we identified other relevant literature. We selected only about English language reports that compared normal and epilepsy groups. Many reports used data from Andrzejak 2001. [17] They prepared and used five different data sets, A-E, which each contain 100 single channels from EEG segments of 23.6-sec duration. These segments were selected and extracted from continuous multichannel EEG recordings after visual inspection for artifacts, e.g., due to muscle activity or eye movements. Set A and set B consisted of EEGs from five healthy volunteers with eyes open and closed, respectively. Set C and set D consisted of EEGs from five patients in the epileptogenic zone (set D) and from the hippocampal formation of the opposite hemisphere of set D (set C). Set E contains ictal activity. Set A and set B were recorded extracranially, whereas set C, set D, and set E were recorded intracranially.

2.2 Nonlinearity of the data set

The objective of the study by Andrzejak 2001 was examination of nonlinearity. They generated 39 surrogate data points from all EEG segments for nonlinear prediction error and CD according to the weak stationarity assumption. Nonlinearity was found except in set A for nonlinear prediction error, but only in set D and set E for CD. They discussed that they cannot rule out the possibility that the surrogate test compared to the surrogate data with linear properties including the weak stationarity may result in a false-positive rejection of nonstationarity, and that the surrogate test has neither high sensitivity nor specificity for nonstationarity in nonlinear dynamics systems. [17] Thuraisingham reexamined the data using MPR complexity and normalized shanon spectral entropy, taking into account the probability distribution function. [18] He carried out a surrogate test using the Amplitude Adjusted Fourier Transform method to generate 1000 surrogate data points for evaluation of entropy and complexity. The degree of nonlinearity was set E > set D > set C > set B > set A. However, when adjusted for the effect of noise, all data showed the same degree of nonlinearity by the above method. Set A showed more nonlinearity than set B, and Thuraisingham concluded that denoising with a wavelet was effective for nonlinearity. In light of these results, we considered all five EEG sets as nonlinear and examined the difference between the normal EEG and interictal EEG among the five EEG sets. There were many studies on the comparison between other sets vs. set E. However, an expert can easily interpret set E as ictal. The diagnosis of epilepsy from interictal EEG with no paroxysmal abnormalities is meaningful for both specialists and non-specialists. Therefore, in this review, in the studies with explicit comparisons with the data set of Andrzejak 2001, A vs. C, A vs. D, AB vs. CD vs. E, A vs. B vs. C vs. D vs. E, B vs. C, B vs. D, A vs. D vs. E, A vs. C vs. E, and AB vs. CD, were examined.


3. Results

3.1 Normal vs. epilepsy

The development of feature extraction with nonlinear analysis methods and machine learning has been reported in studies of various combinations of classifications on EEG diagnosis of epilepsy. (Table 1). [19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79] Table 2 shows the details of the classification. Sixty studies using the Andrzejak 2001 data set were selected, and two studies between normal and epileptic groups were selected. Although set C (the opposite site of the epileptogenic zone) and set D (the site of the epileptogenic zone) were interictal and intracranial EEG, the results for B vs. C (99.3% accuracy) and B vs. D (99.5% accuracy) by Gupta 2018 [29] and the results for A vs. D (100% accuracy) by Kaya 2015 [45] and 2018 [30] and for A vs. C (99.7% and 99.6% accuracy) by Raghu 2017 [36] and Liu 2020 [21] were reported. The feature extraction methods and the classifiers were different in each study. Nevertheless, these results were clinically interesting and reasonable. Gruszczyńska 2019 (86.8% accuracy) reported that interictal Fp1 EEG and normal Fp1 EEG using the feature extraction of RQA and RP were classified by SVM. [80] No detailed descriptions were provided for the focal side. Jacob 2016 (100% accuracy) reported the classification of interictal EEG and normal EEG. [81] However, no detailed description was provided of EEGs that were artifact free or with no paroxysmal abnormalities.

Author (year) [reference number]Feature extractionClassifiersComparisons [accuracy%]
Gao (2020) [19]ApEn, RQACNN, BRBPAB vs. CDE [99.2]
Goshvarpour (2020) [20]PPKNN, PNNA vs. D vs. E [98.3]
Liu (2020) [21]WPE, WEE, TEE, PSD, 1D-LBP, LNDP, 1D-LGP, LSP, SampEn, LSPA, NEO, HSFV*AB*, NB, DA, KNN, SVMA vs. D vs. E [99.0], AB vs. CD vs. E [98.1], AB vs. CD [99], A vs. D [99.5], A vs. C [98.6], B vs. C [99.6], B vs. D [99.6], A vs. CD [98.8], B vs. CD [99.1]
Abedin (2019) [22]Multilevel DWTNonlinear ANNA vs. D vs. E [97.3]
Fasil (2019) [23]ExpEnSVMA vs. D vs. E [89], A vs. C vs. E [91.6]
Ghayab (2019) [24]TQWTKNN*, SVM, BTAB vs. CD vs. E [100], A vs. B vs. C vs. D vs. E [100]
Kaur (2019) [25]DWTBSVMA vs. C [76], B vs. C [81.6], A vs. D [72.8], B vs. D [71.1]
Sun (2019) [26]ESN, ARELMA vs. D vs. E [98.3]
Torse (2019) [27]RP, RQASVM*, ANN, PNNAB vs. CD vs. E [91.2]
Tuncer (2019) [28]LSPLDA-SVM*, QDA, KNNA vs. D vs. E [98.6], A vs. B vs. C vs. D vs. E [93], A vs. D [99.5]
Gupta (2018) [29]DCT, HE, ARMASVMA vs. C [96.5], A vs. D [98.4], B vs. C [99.3], B vs. D [99.5], AB vs. CD [97.7]
Kaya (2018) [30]1D-TP (1; lower features, 2; upper features)ANN*, RF†, FT‡, SVM, BayesNet1; A vs. D vs. E [95.7], A vs. D [99]*, 2; A vs. D vs. E [94] , A vs. D [100]†,‡,
Sairamya (2018) [31]LNGP†, SWLNGPANN*, KNN, QLDA, SVMA vs. D vs. E [99.7] [99.6] , AB vs. CD vs. E [99.5] [99.3] , A vs. D [99.9] †, [99.9]
Zhang (2018) [32]fDistEn, WPDKNN*, Kruskal-Wallis, nonparametric ANOVAA vs. D vs. E [99.3], A vs. B vs. C vs. D vs. E [76]
Abdulhay (2017) [33]ApEn, SampEn, PE, HE, HFD, HOSKNN, SVM, NBA vs. D vs. E [98.5]
Jaiswal (2017) [34]1D-LBP†, LNDP‡, 1D-LGPANN*, NN, SVM, DTA vs. D vs. E [97.0] [98.2] , A vs. D [99.3] [99.9]
Kalbkhani (2017) [35]ST, KPCANNA vs. D vs. E [99.3], AB vs. CD vs. E [99.5], A vs. C vs. E [99.9]
Raghu (2017) [36]WPD, LEEn*, NERENA vs. C [99.7]*, [99.3]
Tiwari (2017) [37]LBPSVMAB vs. CD vs. E [98.8]
Wang (2017) [38]LDWTNSVMA vs. D vs. E [98.4]
Wen (2017) [39]GAFDS, SampEn, HE, LE, MFDFAKNN*, LDA, DT, AB, MLP, NBA vs. D vs. E [97.3]
Zhang (2017) [40]LMD, RE, HEGASVM*, BPNN, KNN, LDA, SVMAB s CD vs. E [98.4]
Hekim (2016) [41]DWT, EWD, EFD, SEANFISAB vs. CD [96.5]
Murugavel (2016) [42]LLE, ApEn, DWTH-MSVM*, ANNA vs. D vs. E [96], AB vs. CD vs. E [95], A vs. B vs. C vs. D vs. E [94]
Peker (2016) [43]DTCWTCVANNA vs. D vs. E [99.3], AB vs. CD vs. E [98.2]
Abalsaud (2015) [44]DCT, DWTNSC*, ANN, NB, KNN, SVMA vs. C vs. E [90]
Kaya (2015) [45]1D-LBPGRAA vs. D [100]
Martis (2015) [46]DWT, LLE, HFD, HE, SampEnRBFSVM*, LSVM, PSVM, QSVM, DT, KNNA vs. D vs. E [98]*
Riaz (2015) [47]EMDSVM*, DT, KNN, ANNA vs. D vs. E [91], A vs. B vs. C vs. D vs. E [94]
Tawfik (2015) [48]WPE, DWTLSVM*, NSVM, ANNA vs. D vs. E [97.2]* [97.5] , A vs. B vs. C vs. D vs. E [91.6]* [93.7]
Kaya (2014) [49]LBP, 1DLBPBayesNet*, SVM, ANN, LR, FTA vs. D vs. E [95.6], A vs. D [95.5]
Sivasankari (2014) [50]ICA, STFT, CD, LEFFBPNN*, ANFISA vs. D vs. E [100], A vs. B vs. C vs. D vs. E [96.2]
Acharya (2013) [51]CWT, HOS, CM, RLM, LBP, LMESVM*, ANOVA, DT, KNN, PNNAB vs. CD vs. E [96]
Alam (2013) [52]EMDANNA vs. D vs. E [100], AB vs. CD vs. E [80]
Fernández-Blanco (2013) [53]GPA vs. D vs. E [98.5], AB vs. CD vs. E [97.8]
Hosseini (2013) [54]HE, LLEANFISAB vs. CD [97.4]
Niknazar (2013) [55]RQA, DWTECOCAB vs. CD vs. E [98.6]
Peker (2013) [56]FCBFACVANNA vs. D vs. E [97]
Seng (2013) [57]HE, FD, ApEn, LLE, CDRBFSVMAB vs. CD vs. E [97.1]
Wang (2013) [58]BD, FISVMA vs. D vs. E [97.1]
Zhu (2013) [59]SampEnMKM*, KMA, SVMA vs. C [95], A vs. D [96]
Acharya (2012) [60]ApEn, SampEn, FD, HOS, HEFSC*, DT, GMM, KNN, RBFSVM, PNNA vs. D vs. E [99.7]
Acharya (2012–2) [61]DWT(23.6 sec), ICARBFSVM*, DT, KNN, PNN, FSC, GMMA vs. D vs. E [96]
Martis (2012) [62]EMDDT*, ANOVAA vs. D vs. E [95.3]
Acharya (2011) [63]RP, RQASVM*, GMM, FSC, KNN, NB, DT, PNNA vs. D vs. E [94.4]
Guo (2011) [64]DWT, GPKNNA vs. D vs. E [93.5]
Mhandoost (2011) [65]DWTGARCH*, MRFA vs. D vs. E [98.8], A vs. C vs. E [98]
Orhan (2011) [66]DWTMLP-NN*, KMCA vs. D vs. E [96.6]
Ballli (2010) [67]HOA, TRA, ApEn, LLE, CD, NPE, HE, ARSFFS-LDAA vs. B vs. C vs. D vs. E [81.4]
Liang (2010) [68]ApEn, AR, GA, PCARBFSVM*, LLS, LDA, BPNN, LISVMA vs. D vs. E [98.6], A vs. B vs. C vs. D vs. E [85.9]
Song (2010) [69]SmpEnELM*, BPNNA vs. D vs. E [95.6]
Acharya (2009) [70]CD, HE, ApEn, LLEGMM*, SVMAB vs. CD vs. E [95]
Übeyli (2009) [71]DWTMLP + LMA NNA vs. D vs. E [94.8]
Übeyli (2008) [72]DWTME*, EMA, MLP-NNA vs. D vs. E [93.1]
Gūler (2007) [73]DWT, LERBFSVM*, MLP-NN, PNN, MSVMA vs. B vs. C vs. D vs. E [99.2]
Tzallas (2007) [74]STFT, PSDFFANNA vs. D vs. E [100], A vs. B vs. C vs. D vs. E [89]
Tzallas (2007–2) [75]SPWVDFFANN, PCAA vs. D vs. E [99.2], AB vs. CD vs. E [97.7]
Übeyli (2007) [76]PM, MUSIC, MN, PSDMME *, MEA vs. B vs. C vs. D vs. E [98.6]
Sadati (2006) [77]DWTANFN*, ANFIS, RBFSVM, FFBPNNA vs. D vs. E [85.9]
Gūler (2005) [78]LE, LMARNNA vs. D vs. E [96.7]
Gūler (2005–2) [79]DWTANFIS*, BP, GDM, LLSA vs. B vs. C vs. D vs. E [98.6]

Table 1.

Results for the data of Andrzejak 2001.

Accuracy = (TP+ TN)/(TP + FP+ TN+ FN); TP, TN, FP and FN mean true positive, true negative, false positive and false negative, respectively.

*, †, ‡The accuracy corresponds to each feature extraction and classifier with the symbol.

ComparisonsMean(SD) [range]Number of results
A vs. D vs. E96.8(2.9) [85.9–100]44 results in 40 studies
A vs. B vs. C vs. D vs. E92.2(6.7) [76–100]14 results in 13 studies
AB vs. CD vs. E96.3(4.9) [80–100]15 results in 14 studies
A vs. C vs. E94.8(4.1) [90–99.9]4 results in 4 studies
AB vs. CD97.6(0.8) [96.5–99]4 results in 4 studies
A vs. D96.7(7.3) [72.8–100]12 results in 10 studies
A vs. C94.1(8.2) [76–99.7]6 results in 5 studies
B vs. D90.0(13.4) [71.1–99.6]3 results in 3 studies
B vs. C93.5(8.4) [81.6–99.6]3 results in 3 studies

Table 2.

The mean (standard deviation) and number of results for each comparison.

3.2 Comorbid psychiatric disorders

No literature on nonlinear EEG analysis for the diagnosis of comorbid psychiatric disorders with epilepsy has been published, and we only found a case series with nonlinear analysis of comorbid psychiatric symptoms with epilepsy. [82] Azuma reported that EEG was artifact free and had no paroxysmal abnormalities and that patients including controls had uncontrolled seizures before and after psychosis. SampEn may not only decrease in the right frontal and frontal-anterior temporal regions before psychosis, but it may also increase in the frontal and frontal-temporal regions during psychosis. Further reports about prodromal periods are needed. Several studies and reviews about forced normalization have been published [8384], but none have reported nonlinear analysis as well.


4. Discussion

4.1 Normal vs. epilepsy

In studies on Andrzejak 2001 data, comparisons of A or B vs. C and A or B vs. D have increased in recent years (Table 1). Set C and set D consist of intracranial EEG. Usually, intracranial EEG is less noisy, but it provides more localized EEG information. [85, 86] Thus, in the future, comparisons using interictal surface EEG data are needed. This review revealed that the studies in Table 1 using nonlinear feature extraction methods and classifier methods play a valuable role on EEG diagnosis for epilepsy (A or B vs. C (93.8% accuracy) and A or B vs. D (93.4% accuracy). These results can be further examined in future studies. Thus, consideration and examination with denoising with wavelets [18] and the date of EEG and seizures [87] in nonlinear EEG analysis may be needed in future studies.

4.2 Comorbid psychiatric disorders

In many studies on the diagnosis of depression and schizophrenia [88, 89, 90, 91, 92, 93, 94, 95, 96, 97], the nonlinear EEG analysis have been reported, but no nonlinear EEG analysis with accuracy has been reported for comorbid psychotic disorders and depression in patients with epilepsy. Psychiatric comorbidities are common in patients with epilepsy [3], and associations for psychosis with the age at onset, duration of epilepsy, and seizure frequency have been reported. [98, 99] Prodromal symptoms should also be considered when evaluating the onset of psychiatric symptoms. [100] Nonlinear EEG analysis of patients with schizophrenia and depression have been reported, but no nonlinear EEG analysis with accuracy has been reported for comorbid psychotic disorders and depression in patients with epilepsy. No study on forced normalization has been reported using nonlinear EEG analysis. Because psychiatric symptoms affect quality of life in patients with epilepsy [4], we expect that the studies of the association between nonlinear EEG analysis, cognitive function [101, 102, 103] and the psychiatric rating scales [104, 105] in the future.


5. Conclusion

EEG exhibits nonlinearity and weak stationarity. Thus, nonlinear EEG analysis is useful to investigate the clinical application for epilepsy, as shown in studies using the public record of Andrzejak 2001. We reviewed the studies using this data set. Using a variety of feature extraction methods and classifier methods, we conclude that these studies played a valuable role in EEG diagnosis for epilepsy. Comorbid psychiatric disorders in patients with epilepsy have not been reported in nonlinear EEG analysis except for one case series of comorbid psychotic disorders. In the future, according to the evolution of artificial intelligence, deep learning, new nonlinear analysis, and the association with the rating scale of the quality of life and psychiatric symptoms, we anticipate that EEG diagnosis for epilepsy, seizures, and comorbid psychiatric disorders in patients with epilepsy will become possible.



The authors would like to thank all of the authors for participating in this review.


Conflict of interest

None of the authors has any conflict of interest to disclose.



ANFISAdaptive neuro-fuzzy inference system
ANFNAdaptive neural fuzzy network
ANNArtificial Neural Network
ApEnApproximate entropy
ARAutoregressive model
ARMAAutoregressive moving average model
BayesNetBayes networks
BDBlancket dimension
BPNNBack propagation neural network
BRBPBayesian regularization back-propagation
BSVMBagged support vector machine
BTBagging tree
CDCorrelation dimension
CMCo-occurrence matrix
CNNConvolutional neural network
CVANNComplex-valued neural networks
CWPSContinuous wavelet power spectra
CWTContinuous wavelet transform
DADiscriminant analysis
DCTDiscrete cosine transform
DTDecision tree
DTCWTDual-tree complex wavelet transformation
DWPSDiscrete wavelet power spectra
DWTDiscrete wavelet transform
ECOCError-correction output codes
EFDEqual frequency discretization
ELMExtreme learning machine
EMAExpectation–maximization algorithm
EMDEmpirical Mode Decomposition
ENSCEnsemble noise-aware signal combination
ESNEcho state network
EWDEqual width discretization
ExpEnExponential energy
FCBFAFast Correlation Based Filter algorithm
FDFractal dimension
fDistEnFuzzy distribution entropy
FEFuzzy entropy
FFANNFeed-forward artificial neural network
FFBPNNFeed forward back-propagation neural network
FIFractal intercept
FPCAFunctional principal component analysis
FSCFuzzy Sugeno Classifier
FTFunctional trees
GAGenetic algorithm
GAFDSGenetic algorithm-based frequency-domain feature search
GASVMGenetic algorithm support vector machine
GARCHGeneralized autoregressive conditional heteroscedasticity
GDMGradient descent method
GEOGradient energy operator
GMMGaussian mixture model
GPGenetic programming
GRAGray relational analysis
HEHurst exponent
HFDHiguchi fractal dimension
H-MSVMHierarchical multi-class support vector machine
HOAHigher order autocovariance
HOSHigher order spectra
HSFVHybrid-selection-feature vector
ICAIndependent component analysis
ICNCInverse correlation network coupling
IShEIndirect shannon entropy
KMAK-means algorithm
KMCK-means clustering
KNNK-nearest neighbor
KPCAKernel principal component analysis
KSEKolmogorov Sinai entropy
LELyapunov exponent
LBPLocal binary pattern
LEEnLog energy entropy
LDALinear discriminant analysis
LLSLinear least squares
LMALevenberg–marquardt algorithm
LMDLocal mean decomposition
LMELaws mask energy
LNDPLocal neighbor descriptive pattern
LNGPLocal neighbor gradient pattern
LRLogistic regression
LSPLocal speed pattern
LSPLocal senary pattern
LSPALorenz scatter plot area
LS-SVMLast squares support vector machine
LSVMLinear support vector machine
MEMixture of experts
MFDFAMultifractal detrended fluctuation analysis
MKMMulti-scale K-means algorithm
MLPMultilayer perceptron
MMEModified mixture of experts
MPEMultiscale permutation entropy
MPErMultiscale permutation renyi entropy
MRFMarkov random field
MSVMMulticlass support vector machine
MUSICMultiple signal classification
NBNaive Bayes
NENorm entropy
NEONonlinear energy operator
NNNearest neighbor
NNNeural network
NPENonlinear prediction error
NSVMNonlinear support vector machine
OCOmega complexity
1D-LBPOne-dimensional local binary pattern
1D-LGPOne-dimensional local gradient pattern
1D-TPOne-dimensional ternary patterns
PCAPrincipal component analysis
PEPermutation entropy
PMPisarenko method
PNNProbabilistic neural network
PPPoincare plot
PSPhase synchrony
PSDPower spectral density
PSVMPolynominal support vector machine
QDAQuadratic discriminant analysis
QLDAQuadratic linear discriminant analysis
QSVMQuadratic support vector machine
RBFSVMRadial basis function support vector machine
RERenyi entropy
RENRecurrent elman neural network
RFRandom trees
RLMRun length matrix
RNNRecurrent neural network
RPRecurrence plots
RQARecurrence quantification analysis
SampEnSample entropy
SEShannon entropy
SELMSparse extreme learning machine
SFFS-LDASequential floating forward search with linear discriminant analysis method
SLMCSpatial linear mode complexity
SSEShannon spectral entropy
STStockwell transform
STFTShort time fourier transform
SPWVDSmoothed pseudo-wigner-ville distribution
SVMSupport vector machine
SWLNGPSymmetrically weighted local neighbor gradient pattern
TEETemporal energy entropy
TQWTTunable Q-factor wavelet transform
TRATime reversal asymmetry
VGAVisibility graph algorithm
WEEWavelet energy entropy
WPEWavelet packet energy
WPEWeighted permutation Entropy
WPDWavelet packet decomposition


  1. 1. NICE Guidelines. Epilepsy: Diagnosis and management. 2012
  2. 2. Krumholz A, Wiebe S, Gronseth G, Shinnar S, Levisohn P, Ting T, et al. Practice Parameter: evaluating an apparent unprovoked first seizure in adults (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology. 2007 Nov;69(21):1996-2007
  3. 3. Clancy MJ, Clarke MC, Connor DJ, Cannon M, Cotter DR. The prevalence of psychosis in epilepsy; a systematic review and meta-analysis. BMC Psychiatry. 2014 Mar;14:75
  4. 4. Azuma H, Akechi T. Effects of psychosocial functioning, depression, seizure frequency, and employment on quality of life in patients with epilepsy. Epilepsy Behav. 2014;41
  5. 5. Stam CJ. Nonlinear dynamical analysis of EEG and MEG: review of an emerging field. Clin Neurophysiol. 2005 Oct;116(10):2266-2301
  6. 6. Holger Kantz TS. Nonlinear Time Series Analysis. 2nd ed. Cambridge: Cambridge University Press; 2003
  7. 7. Roux J-C, Simoyi RH, Swinney HL. Observation of a strange attractor. Phys D Nonlinear Phenom. 1983;8(1):257-266
  8. 8. Takens F. Detecting strange attractors in turbulence BT - Dynamical Systems and Turbulence, Warwick 1980. In: Rand D, Young L-S, editors. Berlin, Heidelberg: Springer Berlin Heidelberg; 1981. p.366-381
  9. 9. Strogatz SH. Nonlinear Dynamics And Chaos: With Applications To Physics, Biology, Chemistry, And Engineering. Perseus Books Publishing, LLC, Westview: 1994
  10. 10. Grassberger P, Procaccia I. Characterization of Strange Attractors. Physical review letters. 1983; 50: 346-349
  11. 11. Grassberger P, Procaccia I. Measuring the Strangeness of Strange Attractors. Physica 9D. 1983; 189-208
  12. 12. Wolf A, Swift J, Swinney H, Vastano JA. Determining lyapnov exponents from a time series. Phys D Nonlinear Phenom. 1985;16:285-317
  13. 13. Blanco S, Garcia H, Quiroga R, Romanelli L, Rosso O. Stationarity of the EEG series. IEEE Eng Med Biol Mag. 1995;14:395-399
  14. 14. Beniczky S, Karoly P, Nurse E, Ryvlin P, Cook M. Machine learning and wearable devices of the future. Epilepsia. 2020 Jul;1-9
  15. 15. Siddiqui MK, Morales-Menendez R, Huang X, Hussain N. A review of epileptic seizure detection using machine learning classifiers. Brain informatics. 2020 May;7(1):5
  16. 16. Abbasi B, Goldenholz DM. Machine learning applications in epilepsy. Epilepsia. 2019 Oct;60(10):2037-2047
  17. 17. Andrzejak RG, Lehnertz K, Mormann F, Rieke C, David P, Elger CE. Indications of nonlinear deterministic and finite-dimensional structures in time series of brain electrical activity: dependence on recording region and brain state. Phys Rev E Stat Nonlin Soft Matter Phys. 2001 Dec;64(6 Pt 1):61907
  18. 18. Thuraisingham RA. Examining nonlinearity using complexity and entropy. Chaos. 2019 Jun;29(6):63109
  19. 19. Gao X, Yan X, Gao P, Gao X, Zhang S. Automatic detection of epileptic seizure based on approximate entropy, recurrence quantification analysis and convolutional neural networks. Artif Intell Med. 2020;102:101711
  20. 20. Goshvarpour A, Goshvarpour A. Diagnosis of epileptic EEG using a lagged Poincare plot in combination with the autocorrelation. Signal, Image Video Process. 2020;14(7):1309-1317
  21. 21. Liu X, Shen J, Zhao W. Epileptic EEG identification based on hybrid feature extraction. J Mech Med Biol. 2020; 2050025
  22. 22. Abedin MZ, Akther S, Hossain MS. An artificial neural network model for epilepsy seizure detection. In: 2019 5th International Conference on Advances in Electrical Engineering, ICAEE 2019. 2019. p. 860-865
  23. 23. Fasil OK, Rajesh R. Time-domain exponential energy for epileptic EEG signal classification. Neurosci Lett. 2019;694:1-8
  24. 24. Al Ghayab HR, Li Y, Siuly S, Abdulla S. A feature extraction technique based on tunable Q-factor wavelet transform for brain signal classification. J Neurosci Methods. 2019;312:43-52
  25. 25. Kaur A, Verma K, Bhondekar AP, Shashvat K.Implementation of Bagged SVM Ensemble Model for Classification of Epileptic States Using EEG. Curr Pharm Biotechnol. 2019;20(9):755-765
  26. 26. Sun L, Jin B, Yang H, Tong J, Liu C, Xiong H. Unsupervised EEG feature extraction based on echo state network. Inf Sci (Ny). 2019;475(January):1-17
  27. 27. Torse DA, Khanai R, Desai VV. Classification of epileptic seizures using recurrence plots and machine learning techniques. In: Proceedings of the 2019 IEEE International Conference on Communication and Signal Processing, ICCSP 2019. 2019. p. 611-615
  28. 28. Tuncer T, Dogan S, Akbal E. A novel local senary pattern based epilepsy diagnosis system using EEG signals. Australas Phys Eng Sci Med. 2019;42(4):939-948
  29. 29. Gupta A, Singh P, Karlekar M. A Novel Signal Modeling Approach for Classification of Seizure and Seizure-Free EEG Signals. IEEE Trans Neural Syst Rehabil Eng. 2018;26(5):925-935
  30. 30. Kaya Y, Ertuğrul ÖF. A stable feature extraction method in classification epileptic EEG signals. Australas Phys Eng Sci Med. 2018;41(3):721-730
  31. 31. Sairamya NJ, Thomas George S, Balakrishnan R, Subathra MSP. An effective approach to classify epileptic EEG signal using local neighbor gradient pattern transformation methods. Australas Phys Eng Sci Med. 2018;41(4):1029-1046
  32. 32. Zhang T, Chen W, Li M. Fuzzy distribution entropy and its application in automated seizure detection technique. Biomed Signal Process Control. 2018;39:360-377
  33. 33. Abdulhay E, Elamaran V, Chandrasekar M, Balaji VS, Narasimhan K. Automated diagnosis of epilepsy from EEG signals using ensemble learning approach. Pattern Recognit Lett. 2017;
  34. 34. Jaiswal AK, Banka H. Local pattern transformation based feature extraction techniques for classification of epileptic EEG signals. Biomed Signal Process Control. 2017;34:81-92
  35. 35. Kalbkhani H, Shayesteh MG. Stockwell transform for epileptic seizure detection from EEG signals. Biomed Signal Process Control. 2017;38:108-118
  36. 36. Raghu S, Sriraam N, Kumar GP. Classification of epileptic seizures using wavelet packet log energy and norm entropies with recurrent Elman neural network classifier. Cogn Neurodyn. 2017;11(1):51-66
  37. 37. Tiwari AK, Pachori RB, Kanhangad V, Panigrahi BK. Automated Diagnosis of Epilepsy Using Key-Point-Based Local Binary Pattern of EEG Signals. IEEE J Biomed Heal informatics. 2017 Jul;21(4):888-896
  38. 38. Wang Y, Li Z, Feng L, Bai H, Wang C. Hardware design of multiclass SVM classification for epilepsy and epileptic seizure detection. IET Circuits, Devices Syst. 2018;12(1):108-115
  39. 39. Wen T, Zhang Z. Effective and extensible feature extraction method using genetic algorithm-based frequency-domain feature search for epileptic EEG multiclassification. Med (United States). 2017;96(19):1-11
  40. 40. Zhang T, Chen W. LMD Based Features for the Automatic Seizure Detection of EEG Signals Using SVM. IEEE Trans Neural Syst Rehabil Eng. 2017;25(8):1100-1108
  41. 41. Hekim M. The classification of EEG signals using discretization-based entropy and the adaptive neuro-fuzzy inference system. Turkish J Electr Eng Comput Sci. 2016;24(1):285-297
  42. 42. Murugavel ASM, Ramakrishnan S. Hierarchical multi-class SVM with ELM kernel for epileptic EEG signal classification. Med Biol Eng Comput. 2016;54(1):149-161
  43. 43. Peker M, Sen B, Delen D. A novel method for automated diagnosis of epilepsy using complex-valued classifiers. IEEE J Biomed Heal Informatics. 2016;20(1):108-118
  44. 44. Abualsaud K, Mahmuddin M, Saleh M, Mohamed A. Ensemble classifier for epileptic seizure detection for imperfect EEG data. Sci World J. 2015;
  45. 45. Kaya Y. Hidden pattern discovery on epileptic EEG with 1-D local binary patterns and epileptic seizures detection by grey relational analysis. Australas Phys Eng Sci Med. 2015;38(3):435-446
  46. 46. Martis RJ, Tan JH, Chua CK, Loon TC, Yeo SWJ, Tong L. Epileptic EEG classification using nonlinear parameters on different frequency bands. J Mech Med Biol. 2015;15(3). 1550040
  47. 47. Riaz F, Hassan A, Rehman S, Niazi IK, Dremstrup K. EMD-based temporal and spectral features for the classification of EEG signals using supervised learning. IEEE Trans Neural Syst Rehabil Eng. 2016;24(1):28-35
  48. 48. Tawfik NS, Youssef SM, Kholief M. A hybrid automated detection of epileptic seizures in EEG records. Comput Electr Eng. 2016;53(February 2019):177-190
  49. 49. Kaya Y, Uyar M, Tekin R, Yildirim S. 1D-local binary pattern based feature extraction for classification of epileptic EEG signals. Appl Math Comput. 2014;243:209-219
  50. 50. Sivasankari K, Thanushkodi K. An improved EEG signal classification using Neural Network with the consequence of ICA and STFT. J Electr Eng Technol. 2014;9(3):1060-1071
  51. 51. Acharya UR, Yanti R, Zheng JW, Krishnan MMR, Tan JH, Martis RJ, et al. Automated diagnosis of epilepsy using CWT, HOS and texture parameters. Int J Neural Syst. 2013;23(3)
  52. 52. Alam SMS, Bhuiyan MIH. Detection of seizure and epilepsy using higher order statistics in the EMD domain. IEEE J Biomed Heal Informatics. 2013;17(2):312-318
  53. 53. Fernández-Blanco E, Rivero D, Gestal M, Dorado J. Classification of signals by means of Genetic Programming. Soft Comput. 2013;17(10):1929-1937
  54. 54. Hosseini SA, Akbarzadeh-T M-R, Naghibi-Sistani M-B. Qualitative and Quantitative Evaluation of EEG Signals in Epileptic Seizure Recognition. Int J Intell Syst Appl. 2013;5(6):41-46
  55. 55. Niknazar M, Mousavi SR, Vosoughi Vahdat B, Sayyah M. A new framework based on recurrence quantification analysis for epileptic seizure detection. IEEE J Biomed Heal Informatics. 2013;17(3):572-578
  56. 56. Peker M. AWERProcedia Information Technology & Computer Science A new complex-valued intelligent system for automated epilepsy diagnosis using EEG signals. 2013;03:1121-1128
  57. 57. Seng KC. Epilepsy risk index (ERI) for diagnosis of epilepsy: A new paradigm features. J Med Imaging Heal Informatics. 2013;3(2):314-320
  58. 58. Wang Y, Zhou W, Yuan Q , Li X, Meng Q , Zhao X, et al. Comparison of ictal and interictal eeg signals using fractal features. Int J Neural Syst. 2013;23(6)
  59. 59. Zhu G, Li Y, Wen P (Paul), Wang S, Zhong N. Unsupervised Classification of Epileptic EEG Signals with Multi Scale K-Means Algorithm BT - Brain and Health Informatics. In: Imamura K, Usui S, Shirao T, Kasamatsu T, Schwabe L, Zhong N, editors. Cham: Springer International Publishing; 2013. p. 158-167
  60. 60. Acharya UR, Sree SV, Ang PCA, Yanti R, Suri JS. Application of non-linear and wavelet based features for the automated identification of epileptic EEG signals. Int J Neural Syst. 2012;22(2)
  61. 61. Acharya UR, Yanti R, Swapna G, Sree VS, Martis RJ, Suri JS. Automated diagnosis of epileptic electroencephalogram using independent component analysis and discrete wavelet transform for different electroencephalogram durations. Proc Inst Mech Eng Part H, J Eng Med. 2013 Mar;227(3):234-244
  62. 62. Martis RJ, Acharya UR, Tan JH, Petznick A, Yanti R, Chua CK, et al. Application of empirical mode decomposition (EMD) for automated detection of epilepsy using EEG signals. Int J Neural Syst. 2012;22(6): 1250027
  63. 63. Acharya UR, Sree SV, Chattopadhyay S, Yu W, Ang PCA. Application of recurrence quantification analysis for the automated identification of epileptic EEG signals. Int J Neural Syst. 2011;21(3):199-211
  64. 64. Guo L, Rivero D, Dorado J, Munteanu CR, Pazos A. Automatic feature extraction using genetic programming: An application to epileptic EEG classification. Expert Syst Appl. 2011;38(8):10425-10436
  65. 65. Mihandoost A. Automatic feature extraction using generalised autoregressive conditional heteroscedasticity model: an application to electroencephalogram classification. IET Signal Process. 2012;6(9):829-838
  66. 66. Orhan U, Hekim M, Ozer M. EEG signals classification using the K-means clustering and a multilayer perceptron neural network model. Expert Syst Appl [Internet]. 2011;38(10):13475-13481
  67. 67. Balli T, Palaniappan R. Classification of biological signals using linear and nonlinear features. Physiol Meas. 2010 Jul;31(7):903-920
  68. 68. Liang SF, Wang HC, Chang WL. Combination of EEG complexity and spectral analysis for epilepsy diagnosis and seizure detection. EURASIP J Adv Signal Process. 2010;2010:17-20
  69. 69. Song Y, Liò P. A new approach for epileptic seizure detection: sample entropy based feature extraction and extreme learning machine. J Biomed Sci Eng. 2010;03(06):556-567
  70. 70. Acharya UR, Chua CK, Lim T-C, Dorithy, Suri JS. Automatic identification of epileptic EEG signals using nonlinear parameters. J Mech Med Biol. 2009;9(4):539-553
  71. 71. Übeyli ED. Combined neural network model employing wavelet coefficients for EEG signals classification. Digit Signal Process A Rev J. 2009;19(2):297-308
  72. 72. Übeyli ED. Wavelet/mixture of experts network structure for EEG signals classification. Expert Syst Appl. 2008;34(3):1954-1962
  73. 73. Güler I, Übeyli ED. Multiclass support vector machines for EEG-signals classification. IEEE Trans Inf Technol Biomed. 2007;11(2):117-126
  74. 74. Tzallas AT, Tsipouras MG, Fotiadis DI. Automatic seizure detection based on time-frequency analysis and artificial neural networks. Comput Intell Neurosci. 2007; doi:10.1155/2007/80510
  75. 75. Tzallas AT, Tsipouras MG, Fotiadis DI. The use of time-frequency distributions for epileptic seizure detection in EEG recordings. Annu Int Conf IEEE Eng Med Biol - Proc. 2007;3-6
  76. 76. Übeyli ED, Güler I. Features extracted by eigenvector methods for detecting variability of EEG signals. Pattern Recognit Lett. 2007;28(5):592-603
  77. 77. Sadati N, Mohseni HR, Maghsoudi A. Epileptic seizure detection using neural fuzzy networks. IEEE Int Conf Fuzzy Syst. 2006;(July 2014):596-600
  78. 78. Güler NF, Übeyli ED, Güler I. Recurrent neural networks employing Lyapunov exponents for EEG signals classification. Expert Syst Appl. 2005;29(3):506-514
  79. 79. Güler I, Übeyli ED. Adaptive neuro-fuzzy inference system for classification of EEG signals using wavelet coefficients. J Neurosci Methods. 2005;148(2):113-121
  80. 80. Gruszczyńska I, Mosdorf R, Sobaniec P, Żochowska-Sobaniec M, Borowska M. Epilepsy identification based on EEG signal using RQA method. Adv Med Sci. 2019;64(1):58-64
  81. 81. Jacob JE, Sreelatha VV, Iype T, Nair GK, Yohannan DG. Diagnosis of epilepsy from interictal EEGs based on chaotic and wavelet transformation. Analog Integr Circuits Signal Process. 2016;89(1):131-138
  82. 82. Azuma H, Nagata H, Akechi T. Linear and non-linear EEG analyses before and after psychosis in patients with epilepsy. Epilepsy & Seizure. 2019;11:20-29
  83. 83. Kawakami Y, Itoh Y. Forced Normalization: Antagonism Between Epilepsy and Psychosis. Pediatr Neurol. 2017 May;70:16-19
  84. 84. Flor-Henry P. Determinants of psychosis in epilepsy: laterality and forced normalization. Biol Psychiatry. 1983 Sep;18(9):1045-1057
  85. 85. Casale M, Marcuse L, Young JJ, Jetté N, Panov FE, Bender H, et al. The Sensitivity of Scalp EEG at Detecting Seizures-A Simultaneous Scalp and Stereo EEG Study. J Clin Neurophysiol. 2020;
  86. 86. Dubey A, Ray S. Cortical Electrocorticogram (ECoG) Is a Local Signal. J Neurosci. 2019 May;39(22):4299-4311
  87. 87. Yin Y, Sun K, He S. Multiscale permutation Rényi entropy and its application for EEG signals. PLoS One. 2018;13(9):e0202558
  88. 88. Čukić M, Stokić M, Simić S, Pokrajac D. The successful discrimination of depression from EEG could be attributed to proper feature extraction and not to a particular classification method. Cogn Neurodyn. 2020 Aug;14(4):443-455
  89. 89. Li X, Hu B, Sun S, Cai H. EEG-based mild depressive detection using feature selection methods and classifiers. Comput Methods Programs Biomed. 2016 Nov;136:151-161
  90. 90. Akdemir Akar S, Kara S, Agambayev S, Bilgic V. Nonlinear analysis of EEGs of patients with major depression during different emotional states. Comput Biol Med. 2015 Dec;67:49-60
  91. 91. Akar SA, Kara S, Agambayev S, Bilgic V. Nonlinear analysis of EEG in major depression with fractal dimensions. Annu Int Conf IEEE Eng Med Biol Soc IEEE Eng Med Biol Soc Annu Int Conf. 2015;2015:7410-7413
  92. 92. Kalev K, Bachmann M, Orgo L, Lass J, Hinrikus H. Lempel-Ziv and multiscale Lempel-Ziv complexity in depression. Annu Int Conf IEEE Eng Med Biol Soc IEEE Eng Med Biol Soc Annu Int Conf. 2015;2015:4158-4161
  93. 93. Siuly S, Khare SK, Bajaj V, Wang H, Zhang Y. A Computerized Method for Automatic Detection of Schizophrenia Using EEG Signals. IEEE Trans neural Syst Rehabil Eng a Publ IEEE Eng Med Biol Soc. 2020 Sep;PP
  94. 94. Goshvarpour A, Goshvarpour A. Schizophrenia diagnosis using innovative EEG feature-level fusion schemes. Australas Phys Eng Sci Med. 2020 Jan;
  95. 95. Jahmunah V, Lih Oh S, Rajinikanth V, Ciaccio EJ, Hao Cheong K, Arunkumar N, et al. Automated detection of schizophrenia using nonlinear signal processing methods. Artif Intell Med. 2019 Sep;100:101698
  96. 96. Cerquera A, Gjini K, Bowyer SM, Boutros N. Comparing EEG Nonlinearity in Deficit and Nondeficit Schizophrenia Patients: Preliminary Data. Clin EEG Neurosci. 2017 Nov;48(6):376-382
  97. 97. Takahashi T, Cho RY, Mizuno T, Kikuchi M, Murata T, Takahashi K, et al. Antipsychotics reverse abnormal EEG complexity in drug-naive schizophrenia: a multiscale entropy analysis. Neuroimage. 2010 May;51(1):173-182
  98. 98. Adachi N, Matsuura M, Okubo Y, Oana Y, Takei N, Kato M, et al. Predictive variables of interictal psychosis in epilepsy. Neurology. 2000 Nov;55(9):1310-1314
  99. 99. Adachi N, Akanuma N, Fenwick P, Ito M, Okazaki M, Ishida S, et al. Seizure activity and individual vulnerability on first-episode interictal psychosis in epilepsy. Epilepsy Behav. 2018 Feb;79:234-238
  100. 100. Adachi N, Akanuma N, Ito M, Kato M, Hara T, Oana Y, et al. Epileptic, organic and genetic vulnerabilities for timing of the development of interictal psychosis. Br J Psychiatry. 2010 Mar;196(3):212-216
  101. 101. Prevey ML, Delaney RC, Cramer JA, Mattson RH. Complex partial and secondarily generalized seizure patients: cognitive functioning prior to treatment with antiepileptic medication. VA Epilepsy Cooperative Study 264 Group. Epilepsy Res. 1998 Mar;30(1):1-9
  102. 102. Pulliainen V, Kuikka P, Jokelainen M. Motor and cognitive functions in newly diagnosed adult seizure patients before antiepileptic medication. Acta Neurol Scand. 2000 Feb;101(2):73-78
  103. 103. Mathon B, Bordes A, Amelot A, Carpentier A, Méré M, Dupont S, et al. Evaluation of psychomotor functions in patients with drug-resistant epilepsy. Epilepsy Behav. 2020 May;106:106985
  104. 104. Tadokoro Y, Oshima T, Fukuchi T, Kanner AM, Kanemoto K. Screening for major depressive episodes in Japanese patients with epilepsy: validation and translation of the Japanese version of Neurological Disorders Depression Inventory for Epilepsy (NDDI-E). Epilepsy Behav. 2012 Sep;25(1):18-22
  105. 105. Gillham R, Bryant-Comstock L, Kane K. Validation of the side effect and life satisfaction (SEALS) inventory. Seizure. 2000 Oct;9(7):458-463

Written By

Hideki Azuma

Submitted: June 24th, 2020 Reviewed: October 6th, 2020 Published: October 28th, 2020