Tests and Procedures
Electroencephalograph (EEG) records the electrical activity in the brain. Electrodes are pasted to the patient’s head in specific places, and wires are then connected from the electrodes to an EEG machine. Brain wave activity may show a pattern, which helps the doctor determine whether or not someone has epilepsy. Sharp waves support the diagnosis of epilepsy and can help identify the type of epilepsy.
Magnetic Resonance Imaging (MRI) or Computerized Tomography (CT) scan may be performed to look for any growths, scarring, or other conditions in the brain that may be causing seizures.
Epilepsy Surgery Candidate Evaluation
Some people who do not respond to anti-epileptic medications may benefit from epilepsy surgery—50 to 80 percent of patients who are suitable candidates for surgery are seizure-free after surgery. Proper patient selection and a thorough pre-surgical evaluation are the cornerstones of surgical success. The pre-surgical evaluation is a relatively lengthy process which may take several months.
Pre-surgical Evaluation The following tests may be included in the pre-surgical evaluation:
Note: In about 10 percent of patients, the evaluation workup may be inconclusive regarding the exact location of seizure onset. Therefore, in a small number of patients, it may be necessary to insert electrodes directly in or on the brain. Electrodes are placed on the brain using subdural grids or into the brain using depth electrodes to precisely record the seizure onset. These special electrodes provide more accurate information than EEG studies with electrodes on the scalp because they are physically closer to the origin of the seizure. The procedure to place the electrodes occurs in the operating room and typically lasts 4 to 5 hours. The patient will have several wires coming through the scalp, and the head will be wrapped in gauze. Immediately after the procedure, the patient will spend the night in the neurosurgical intensive care unit for close monitoring. The following day, the patient will be transferred to the Epilepsy Monitoring Unit (EMU) for video EEG monitoring. The patient usually spends 7 to 10 days in the EMU. While there, the anti-epileptic medications will be reduced. After several seizures have occurred and have been recorded, the medications are restarted. The doctors then review the video EEG monitoring information and determine if the seizure location has been identified and if it is an area of the brain that can be removed. The electrodes are then removed in the operating room during the resection of the area causing the seizure.
The Epilepsy Management Conference
The test results are presented at a multidisciplinary Epilepsy Management Conference. The team includes a neurologist, neurosurgeon, neuroradiologist, nuclear medicine physician, neuropsychologist, psychiatrist, epilepsy nurses and technicians. The group will decide if the patient is a good candidate for epilepsy surgery and weigh the risks and benefits of surgery.
If the patient is a candidate for surgery, the neurosurgeon will discuss the details of the procedure, the associated risks and postoperative care. With the patient’s consent, a date for the surgery will be scheduled. The patient will then undergo the pre-surgical exams, such as chest x-ray and EKG, to evaluate for any medical conditions which may cause a risk for surgery.