Epileptogenic zone diagnosis by means of deep electrical brain stimulation planned from electromagnetic simulations in a real head model. A case report

COLLAVINI S; ODDO S; FERNANDEZ-CORAZZA M; KOCHEN S; PRINCICH JP; MAZZONI E; MURAVCHIK CH

Bangkok

Congreso; Word Epilepsy Congress; 2019

ILAE

Purpose: In this paper, we present a drug resistant focalepilepsy patient with extensive occipital-temporal lesion who underwent a deepelectrodes implantation (SEEG). The procedure was to define the epileptogeniczone (EZ) and consider a surgery treatment. we aimed to identify a possibleictal zone Using a protocol of deep electrical brain stimulation (DEBS),planned from simulations of the electromagnetic phenomenon in a real headmodel. During the SEEG procedure, the patient presented several spontaneous seizuresof temporal onset and rapid spread to occipital regions. Under conventionalDEBS protocol, post-discharges were observed in the temporal contacts, withoutseizure. Using the same protocol, a seizure was triggered stimulating contactsof the occipital region. After that, we hypothesized a possible ictal onset ina blind region of the placed electrodes. Therefore we decided implement aprotocol of DEBS planned from simulations of the electromagnetic phenomenon ina real head model.Method: We selected the possible ictal start contacts in the posteriortemporal region and the contacts that have triggered a seizure on theoccipito-temporal region (distance between contacts: 21 mm). Simulations weremade injecting different current intensities between the different selectedcontacts. Taking a stimulation threshold of 1 V / m, the morphology of thestimulated volume was analyzed with the location of the lesion. Finally, theinjection of an electric current of 1 mA at 50 Hz between occipital andtemporal contacts was performed.Results: Seizure was reproduced with identical symptomatology tospontaneous ones using a current threshold of 1mA.Conclusion: The stimulation of low intensity between different deepelectrodes allows us to give directionality to the stimulus and unmask blindregions.The electromagnetic phenomenon in a real head model proved to be a very usefultool to increase the accuracy and limits of the ictal zone.