Nonrandomness, nonlinear dependence, and nonstationarity of electroencephalographic recordings from epilepsy patients

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• dc.contributor.author Andrzejak, Ralph Gregor
• dc.contributor.author Schindler, Kaspar A.
• dc.contributor.author Rummel, Christian
• dc.date.accessioned 2020-02-12T19:09:25Z
• dc.date.available 2020-02-12T19:09:25Z
• dc.date.issued 2012
• dc.description.abstract To derive tests for randomness, nonlinear-independence, and stationarity, we combine surrogates with a nonlinear prediction error, a nonlinear interdependence measure, and linear variability measures, respectively. We apply these tests to intracranial electroencephalographic recordings (EEG) from patients suffering from pharmacoresistant focal-onset epilepsy. These recordings had been performed prior to and independent from our study as part of the epilepsy diagnostics. The clinical purpose of these recordings was to delineate the brain areas to be surgically removed in each individual patient in order to achieve seizure control. This allowed us to define two distinct sets of signals: One set of signals recorded from brain areas where the first ictal EEG signal changes were detected as judged by expert visual inspection (“focal signals”) and one set of signals recorded from brain areas that were not involved at seizure onset (“nonfocal signals”). We find more rejections for both the randomness and the nonlinear-independence test for focal versus nonfocal signals. In contrast more rejections of the stationarity test are found for nonfocal signals. Furthermore, while for nonfocal signals the rejection of the stationarity test increases the rejection probability of the randomness and nonlinear-independence test substantially, we find a much weaker influence for the focal signals. In consequence, the contrast between the focal and nonfocal signals obtained from the randomness and nonlinear-independence test is further enhanced when we exclude signals for which the stationarity test is rejected. To study the dependence between the randomness and nonlinear-independence test we include only focal signals for which the stationarity test is not rejected. We show that the rejection of these two tests correlates across signals. The rejection of either test is, however, neither necessary nor sufficient for the rejection of the other test. Thus, our results suggest that EEG signals from epileptogenic brain areas are less random, more nonlinear-dependent, and more stationary compared to signals recorded from nonepileptogenic brain areas. We provide the data, source code, and detailed results in the public domain.en
• dc.description.sponsorship R.G.A. acknowledges grant FIS-2010-18204 of the Spanish Ministry of Education and Science. K.S. and C.R. are grateful for support by the Swiss National Science Foundation (projects nos. SNF 320030-122010 and 33CM30- 124089).
• dc.format.mimetype application/pdf
• dc.identifier.citation Andrzejak RG, Schindler K, Rummel C. Nonrandomness, nonlinear dependence, and nonstationarity of electroencephalographic recordings from epilepsy patients. Phys Rev E. 2012 Oct 12;86(4):046206. DOI: 10.1103/PhysRevE.86.046206
• dc.identifier.doi http://dx.doi.org/10.1103/PhysRevE.86.046206
• dc.identifier.issn 2470-0045
• dc.identifier.uri http://hdl.handle.net/10230/43557
• dc.language.iso eng
• dc.publisher American Physiological Society
• dc.relation.ispartof Physical Review E. 2012 Oct 12;86(4):046206.
• dc.relation.isreferencedby http://hdl.handle.net/10230/42829
• dc.relation.projectID info:eu-repo/grantAgreement/ES/3PN/FIS2010-18204
• dc.rights © 2012 the American Physiological Society. http://dx.doi.org/10.1103/PhysRevE.86.046206
• dc.rights.accessRights info:eu-repo/semantics/openAccess
• dc.subject.keyword Nonlinear signal analysisen
• dc.subject.keyword Synchronizationen
• dc.subject.keyword Electroencephalographic recordingsen
• dc.subject.keyword Epilepsyen
• dc.title Nonrandomness, nonlinear dependence, and nonstationarity of electroencephalographic recordings from epilepsy patientsen
• dc.type info:eu-repo/semantics/article
• dc.type.version info:eu-repo/semantics/publishedVersion