SOURCE LOCALIZATION OF EPILEPTIC ACTIVITY FROM INTRACRANIAL EEG BY DIRECTION OF ARRIVAL ESTIMATION METHOD

P. Vergallo, R. Janca, A. Lay-Ekuakille, R. Cmejla, P. Krsek

Abstract

Brain activity source localization is an important issue related to origins of neurological epilepsy disorders which reveal oneself by specific EEG activity. Epilepto-surgery treatment is based on complete removing or disconnecting of epilepsy bearing which is responsible for seizure. However precise localization of epileptogenic tissue partly depends on an accurate localization sources of seizure activity or/and inter-ictal specific activity. In this work the DOA (Direction of Arrival) estimation method Multiple Signal Classification (MUSIC) is used to locate distinct sources of specific epileptic activity from intracranial EEG. It is a subspace-based method which allows distinguishing more sources if they are not very close to each other and the Signal to Noise Ratio (SNR) is not low. Due to the fact that the number of active brain activity sources is usually unknown the estimation of DOAs is difficult as well as the MUSIC. It does not allow in some case to achieve an accurate result. We try to overcome these limits by normalizing the MUSIC spectrum with an estimated noise spatial spectrum which does not require the a priori knowledge of the number of active sources. <BR />The preliminary results show that used DOA Estimation method is able to identify distinct sources of specific activity as inter-ictal epileptiform discharges in intracranial EEG. We conclude, the method could be useful for revealing the epileptogenic zone boundaries.

Keywords

intracranial electroencephalography, DOA estimation, sources localization

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IMEKO TC

TC13 - Measurements in Biology and Medicine

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