Electrical brain stimulation for assessment and control of epileptic transitions

Objectives. The goal of the present work is to apply a modified version previously developed method for detection of areas involved in epileptogenic circuits and the assessment of the therapeutic effects of Low Frequency Intracranial Theta-burst Electric Neuronal Stimulation (LFITNES). Methods. We use a novel paradigm for stimulation of the brain with 20Hz biphasic cyclic alternating polarity (BiCAP) and compute the relative phase clustering index (rPCI) from the evoked response. The putative therapeutic paradigm is based on the application of 1800 high frequency (200Hz) theta bursts consisting of 6 pulses administered every 2 seconds. Results. We have applied the procedure to four patients undergoing pre-surgical diagnostics for localization of the seizure onset zone SOZ. In all cases the SOZ was determined both by ictal EEG inspection from a board-certified clinical neurophysiologist and our experimental procedure based on rPCI. In all cases the localization indications of the method were concordant with the expert findings. The application of our stimulation protocol at the dominant SOZ led to decrease of the rPCI.