Phase Synchronization Using Continuous Wavelet Transform of the EEG for Interictal Focus Localization in Mesial Temporal Lobe Epilepsy
Abstract number :
1.116
Submission category :
Year :
2001
Submission ID :
2102
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
A. Kraskov, John von Neumann Institut for Computing, Forschungszentrum Juelich, Juelich, Germany; T. Kreuz, Department of Epileptology, University of Bonn, Bonn, Germany; R. Quian Quiroga, PhD, John von Neumann Institut for Computing, Research Centre Juel
RATIONALE: The notion of synchronization has become an important issue in neuroscience. Several recent papers have reported on the application of the concept of phase synchronization for the purpose of investigating the spatio-temporal dynamics of the epileptogenic process. In this study we use a recently proposed concept of phase synchronization in which the extraction of phase is based on continuous wavelet transform. We apply this method to the EEG of epilepsy patients and evaluate its ability for interictal focus localization.
METHODS: Intracranial multichannel EEGs recorded during the interictal state from patients suffering from mesial temporal lobe epilepsy were analyzed using a moving-window technique. After application of continuous wavelet transform, the phase was determined from the complex wavelet coefficients. The wavelet used in this analysis was the complex Morlet wavelet. Focus lateralization was done by comparing the degree of synchronization for the ipsi- and contralateral hemisphere after averaging over time.
RESULTS: Despite the inherent problem of attributing the phase synchronization obtained from a pair of electrodes to a single point in space, it was possible to correctly lateralize the primary epileptogenic area in the majority of the patients analyzed. Taking into account an intrinsic background synchronization, we were able to localize the primary epileptogenic area even more exactly in some cases.
CONCLUSIONS: The results suggest that the concept of phase synchronization based on the definition of the phase through continuous wavelet transform may provide additional information for the interictal localization of the primary epileptogenic area in mesial temporal lobe epilepsy. This technique might thus contribute to an improvement of the presurgical evaluation.
Support: U.S. Civilian Research Development Foundation for the Independent States of the Former Soviet Union, Award No REC-006
Deutsche Forschungsgemeinschaft