title: Assessing directionality and strength of coupling through symbolic analysis: an application to epilepsy patients.
abstract: Inferring strength and direction of interactions from electroencephalographic (EEG) recordings is of crucial importance to improve our understanding of dynamical interdependencies underlying various physiological and pathophysiological conditions in the human epileptic brain. We here use approaches from symbolic analysis to investigate--in a time-resolved manner--weighted and directed, short- to long-ranged interactions between various brain regions constituting the epileptic network. Our observations point to complex spatial-temporal interdependencies underlying the epileptic process and their role in the generation of epileptic seizures, despite the massive reduction of the complex information content of multi-day, multi-channel EEG recordings through symbolization. We discuss limitations and potential future improvements of this approach.
authors.affiliation: Department of Epileptology, University of Bonn, Sigmund-Freud-Straße 25, 53105 Bonn, Germany Helmholtz Institute for Radiation and Nuclear Physics, University of Bonn, Nussallee 14-16, 53115 Bonn, Germany Interdisciplinary Center for Complex Systems, University of Bonn, Brühler Straße 7, 53175 Bonn, Germany klaus.lehnertz@ukb.uni-bonn.de.
authors.forename: Klaus
authors.initials: K
authors.lastname: Lehnertz
authors.affiliation: Department of Epileptology, University of Bonn, Sigmund-Freud-Straße 25, 53105 Bonn, Germany Helmholtz Institute for Radiation and Nuclear Physics, University of Bonn, Nussallee 14-16, 53115 Bonn, Germany Interdisciplinary Center for Complex Systems, University of Bonn, Brühler Straße 7, 53175 Bonn, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Dickten
keywords: EEG; epilepsy; epileptic network; symbolic transfer entropy