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

S. COLLAVINI; J. P. PRINCICH; S.ODDO; E. MAZZONI; M. FERNÁNDEZ CORAZZA; C. H. MURAVCHIK

Bangkok

Congreso; 33rd International Epilepsy Congress; 2020

Purpose:In this paper, we present a drug resistant focal epilepsy patient with extensive occipital-temporal lesion who underwent a deep electrodes implantation (SEEG). The procedure was to define the epileptogenic zone (EZ) and consider a surgery treatment. we aimed to identify a possible ictal zone Using a protocol of deep electrical brain stimulation (DEBS), planned from simulations of the electromagnetic phenomenon in a real head model. During the SEEG procedure, the patient presented several spontaneous seizures of temporal onset and rapid spread to occipital regions. Under conventional DEBS protocol, post-discharges were observed in the temporal contacts, without seizure. Using the same protocol, a seizure was triggered stimulating contacts of the occipital region. After that, we hypothesized a possible ictal onset in a blind region of the placed electrodes. Therefore we decided implement a protocol of DEBS planned from simulations of the electromagnetic phenomenon in a real head model.Method:We selected the possible ictal start contacts in the posterior temporal region and the contacts that have triggered a seizure on the occipito-temporal region (distance between contacts: 21 mm). Simulations were made injecting different current intensities between the different selected contacts. Taking a stimulation threshold of 1 V / m, the morphology of the stimulated volume was analyzed with the location of the lesion. Finally, the injection of an electric current of 1 mA at 50 Hz between occipital and temporal contacts was performed.Results:Seizure was reproduced with identical symptomatology to spontaneous ones using a current threshold of 1mA.Conclusion:The stimulation of low intensity between different deep electrodes allows us to give directionality to the stimulus and unmask blind regions.The electromagnetic phenomenon in a real head model proved to be a very useful tool to increase the accuracy and limits of the ictal zone.