Invasive Studies (Phase II)

epilespy invasive monitoring


Once patients have completed their Phase I monitoring in the Epilepsy Monitoring Unit (EMU), our patient management conference decides whether invasive EEG studies (Phase II) are required to better characterize the patient’s epilepsy. In general, invasive Phase I studies are carried out when the noninvasive data (the MRI scan, Phase I monitoring and other ancillary tests) do not provide sufficient information for an epilepsy surgery to be recommended directly. Instead, Phase II studies clarify the nature of the patient’s epilepsy further, by taking a ‘closer look’ at the brain during and between seizures, with EEG recorded directly from within the substance of the brain. The two methods of doing so are

Subdural Electrode Monitoring and

Stereo EEG Monitoring (SEEG)

In recent years, SEEG has become the favored method all over the world, and is the method used in the majority of our patients.

Information for patients

Once all the information from your video-EEG monitoring in the hospital, MRI scan, neuropsychology tests and any other tests have been discussed, our team may recommend further tests to pinpoint the areas in the brain causing the seizures in greater detail. In general, these tests involve recording seizures from electrodes that are placed inside the brain, rather than on the scalp surface. Our team is highly experienced in performing these electrode placements inside the brain and analyzing the signals from seizures recorded in this manner. Placement of the internal electrodes requires an operation under anesthesia and monitoring of your brain signals for several days afterwards while you remain in the intensive care unit for added safety. Following data analysis, the electrodes are removed and you will proceed to the actual epilepsy surgery either immediately or after a few weeks. The details of such an ‘invasive’ or ‘Phase II’ evaluation will be thoroughly discussed with you and your care takers so that you fully understand why and how the procedure is done, and how the brain signal data will help your medical team to offer the best surgical treatment for your seizures.