Evaluation Process for Epilepsy Surgery
Patients at the Swedish Epilepsy Center generally go through a four-phase evaluation process for surgery, which is outlined below. If you would like to make an appointment with one of our epilepsy physicians to see if you are a candidate for epilepsy surgery, call 206-320-3492.
Stage 1: Non-Invasive Studies
During this first phase, you and your physician will meet and discuss your seizure history. Your physician will learn from you and your family how your seizures developed and what they are like, what types of testing you have had in the past, and what types of treatment you have tried. Your physician will gather a detailed history of how you have responded to various types of therapy. He or she may recommend additional studies to help further characterize your seizures, including:
Electroencephalogram (EEG) – An EEG measures and records your brain's electrical activity. This test may show abnormalities that point towards a specific type of epilepsy and may help guide your physician in his or her treatment recommendations. An EEG takes about 40 minutes and involves pasting small wires on the head.
Video/EEG telemetry monitoring (VEEG monitoring) – VEEG monitoring continuously record your spells, using EEG and video, while you are a hospital inpatient. Recording your brain waves 24/7 over a period of several days allows us to capture your spells, determine if they are seizures or some other condition, and possibly pinpoint their origin in your brain.
Brain MRI – An MRI scanner uses a strong magnet to take very detailed pictures of the brain. These pictures may show structural abnormalities which can give rise to seizures and may help define treatment options. The Swedish Epilepsy Center uses the strongest clinical MRI magnets to provide the clearest picture of the brain possible. Special protocols are used to identify the often subtle changes in the brain that indicate where seizures may be arising.
Functional Imaging – Special MRI protocols may be used to visualize where motor, language, visual or even memory tasks are performed in an individual's brain.
Blood Flow and Metabolism Imaging – Studies such as single photon emission computerized tomography (SPECT) or positron emission tomography (PET) may give clues to where seizures are originating in the brain.
Neuropsychological Testing – Specialized tests for cognitive, language, memory and motor skills may reveal changes due to seizures in focal brain areas.
After obtaining all necessary non-invasive studies, the Swedish epilepsy team discusses patient test results at its weekly multidisciplinary conference. Here all of the members of the epilepsy team review the studies and determine if a patient is a candidate for epilepsy surgery, vagus nerve stimulation, or other experimental treatments for seizure such as the responsive neurostimulator system. The epilepsy team comprises several epileptologists, an epilepsy surgeon, a neuropsychologist specializing in epilepsy, an epilepsy social worker, epilepsy nurses and EEG technologists.
If the team agrees that the benefits of epilepsy surgery outweigh the risks, we will arrange for a consultation with our epilepsy surgeon. Our surgeon will discuss the type of surgical options available, as well as any further testing that may be necessary prior to surgery.
Stage 2: Wada Test
If you and your doctor decide to pursue epilepsy surgery, your doctor may recommend a procedure called a Wada test. This test provides information that can help determine the risks of surgery to your language and memory functions, and help your doctor decide whether epilepsy surgery is safe for you.
Stage 3: Intracranial Monitoring
Sometimes VEEG monitoring with electrodes on the scalp does not provide enough information to show exactly where your seizures begin. In this situation, we may recommend additional VEEG monitoring, this time using very thin, soft electrodes placed on the surface of the brain by the surgeon in the operating room. This type of monitoring, called intracranial VEEG monitoring, gives much more precise information about where seizures begin. Functional testing may also be performed at this time to determine if seizures arise from critical brain areas.
Stage 4: Surgical Resection
Once there is an understanding of precisely which brain region is responsible for generating your seizures, a decision regarding treatment can be made. The risks of surgery will be discussed, and all other options will be weighed. You and your doctor will make a decision together about which treatment strategy is best for you. This may involve the removal of brain areas responsible for seizures such as focal excision, lobectomy or hemispherectomy. Or treatment may be a disconnection therapy, such as corpus callosotomy or multiple subpial transactions. Alternatively, stimulation therapies may be recommended such as vagus nerve stimulation or an experimental therapy employing responsive cortical stimulation.