TY - JOUR
T1 - Information flow and application to epileptogenic focus localization from intracranial EEG
AU - Sabesan, Shivkumar
AU - Good, Levi B.
AU - Tsakalis, Konstantinos
AU - Spanias, Andreas
AU - Treiman, David M.
AU - Iasemidis, Leon D.
N1 - Funding Information:
Manuscript received February 02, 2008; revised November 06, 2008; accepted November 22, 2008. First published June 02, 2009; current version published July 06, 2009. This work was supported in part by the American Epilepsy Research Foundation and the Ali Paris Fund for LKS Research and Education, in part by the National Science Foundation under Grant ECS-0601740, and in part by the Science Foundation Arizona under Competitive Advantage Award CAA 0281-08.
PY - 2009/6
Y1 - 2009/6
N2 - Transfer entropy (${\rm TE}$) is a recently proposed measure of the information flow between coupled linear or nonlinear systems. In this study, we suggest improvements in the selection of parameters for the estimation of ${\rm TE}$ that significantly enhance its accuracy and robustness in identifying the direction and the level of information flow between observed data series generated by coupled complex systems. We show the application of the improved ${\rm TE}$ method to long (in the order of days; approximately a total of 600 h across all patients), continuous, intracranial electroencephalograms (EEG) recorded in two different medical centers from four patients with focal temporal lobe epilepsy (TLE) for localization of their foci. All patients underwent ablative surgery of their clinically assessed foci. Based on a surrogate statistical analysis of the ${\rm TE}$ results, it is shown that the identified potential focal sites through the suggested analysis were in agreement with the clinically assessed sites of the epileptogenic focus in all patients analyzed. It is noteworthy that the analysis was conducted on the available whole-duration multielectrode EEG, that is, without any subjective prior selection of EEG segments or electrodes for analysis. The above, in conjunction with the use of surrogate data, make the results of this analysis robust. These findings suggest a critical role ${\rm TE}$ may play in epilepsy research in general, and as a tool for robust localization of the epileptogenic focus/foci in patients with focal epilepsy in particular.
AB - Transfer entropy (${\rm TE}$) is a recently proposed measure of the information flow between coupled linear or nonlinear systems. In this study, we suggest improvements in the selection of parameters for the estimation of ${\rm TE}$ that significantly enhance its accuracy and robustness in identifying the direction and the level of information flow between observed data series generated by coupled complex systems. We show the application of the improved ${\rm TE}$ method to long (in the order of days; approximately a total of 600 h across all patients), continuous, intracranial electroencephalograms (EEG) recorded in two different medical centers from four patients with focal temporal lobe epilepsy (TLE) for localization of their foci. All patients underwent ablative surgery of their clinically assessed foci. Based on a surrogate statistical analysis of the ${\rm TE}$ results, it is shown that the identified potential focal sites through the suggested analysis were in agreement with the clinically assessed sites of the epileptogenic focus in all patients analyzed. It is noteworthy that the analysis was conducted on the available whole-duration multielectrode EEG, that is, without any subjective prior selection of EEG segments or electrodes for analysis. The above, in conjunction with the use of surrogate data, make the results of this analysis robust. These findings suggest a critical role ${\rm TE}$ may play in epilepsy research in general, and as a tool for robust localization of the epileptogenic focus/foci in patients with focal epilepsy in particular.
KW - Epilepsy
KW - Epileptogenic focus localization
KW - Information flow
KW - Transfer entropy (TE)
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U2 - 10.1109/TNSRE.2009.2023291
DO - 10.1109/TNSRE.2009.2023291
M3 - Article
C2 - 19497831
AN - SCOPUS:67650799407
SN - 1534-4320
VL - 17
SP - 244
EP - 253
JO - IEEE Transactions on Neural Systems and Rehabilitation Engineering
JF - IEEE Transactions on Neural Systems and Rehabilitation Engineering
IS - 3
ER -