Invasive Studies (Phase II)
Phase II Video EEG Monitoring
Phase II video-EEG monitoring requires invasive monitoring. Types of invasive monitoring include subdural electrodes or depth electrodes and stereo EEG monitoring. Phase II monitoring is similar to Phase I monitoring except the electrodes are either placed directly on or implanted in the brain.
Subdural Electrode Monitoring – For subdural electrode placement, a craniotomy is performed (opening of the skull) and the brain tissue is exposed. A very thin plastic plate of electrodes, called grids or strips, is placed directly on the surface of the brain over the epileptogenic region.
Stereo EEG Monitoring (SEEG) – Stereo EEG is an invasive procedure where EEG electrodes are strategically inserted in areas of the brain along identified seizure path. SEEG monitoring is less invasive and it allows sampling of epileptogenic areas that may be off limits with subdural electrodes.