Subdural Electrode Monitoring


Subdural grid electrode (SDE) were the predominant method for invasive EEG from the 1980s into the early years of this century. Though SEEG has largely supplanted SDE, the latter remains a useful technique for patients in whom SEEG may not be appropriate or prove inadequate to map the seizure focus.


Information for patients

Subdural grid electrodes are a method of recording brainwaves (EEG) from inside the head. Your treatment team would have made the decision that this is the best next step for us to understand and effectively treat your seizure disorders. The decision for subdural grids is based on the results of your video-EEG monitoring in the hospital, MRI scan, neuropsychology tests and any other tests you may have had. 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 the actual epilepsy surgery performed in the same operation. 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.