Procedure
A pair of quadripolar Medtronic DBS electrodes were bilaterally and
stereotaxically inserted into the anterior part of the thalamus during
general anaesthesia. Contact lengths of the electrode are 1.5 mm,
whereas intercontact spacing is 0.5 mm. Electrode diameter is 1.27 mm.
Besides frontal transventricular and extraventricular trajectories, the
posterior parietal extraventricular approaches were used in accordance
with the decisions of the clinical-neurosurgical team. In accordance
with the clinical protocol patients underwent a 48 hour, postsurgical
video-EEG monitoring with externalized thalamic leads, that is thalamic
LFP co-registered with scalp EEG/polygraphy. The first 48 hours were
recorded without thalamic stimulation (DBS-off). One whole-night
seizure-free records of the 48 hours DBS-off records were selected and
analyzed in the present study.