Our experienced specialists perform a comprehensive epilepsy evaluation that includes several tests to determine if surgery is right for your child.
- Phase 1 epilepsy evaluation will include a complete history, records and medication review. It may also include EEGs, neurological testing, imaging studies and a Wada test or functional MRI.
- Phase 2 epilepsy evaluation may be performed if surgery is recommended after Phase I, and will include more invasive monitoring.
Routine EEG, or electroencephalography, records brain waves using electrodes placed at defined locations on the scalp using conductive paste or glue. Your child will lie still on a bed and may be asked to perform some simple tasks. Flashing lights and hyperventilation may be used during the test to provide additional information. The test typically takes one to two hours.
This test records brain waves for a longer period of time (24 hours) and possibly during seizures or events that are concerning for seizures. Electrodes, which are held in place with a special adhesive, are placed on the scalp to continuously record brain waves. You will be asked to push a button for any events or seizures, and maintain a detailed log of your child's activities and events.
Video EEG records actual events or seizures, which can assist with diagnosis and surgical evaluation. As with ambulatory EEG, electrodes are glued onto the scalp. During the test, which takes place in the hospital, antiepileptic medications are often reduced or stopped to improve the chances of recording seizures. A typical admission lasts three to five days, although it may be shorter or longer depending on how long it takes to obtain the necessary data. Your child will be closely monitored by a large team including physicians, nurses, technologists and other staff to ensure accurate data collection and patient safety. Video EEG can also be performed using electrodes that have been surgically implanted on or in the brain. This allows for more precise mapping of brain function, as well as the part of the brain from which seizures are originating, which may be performed in patients going Phase 2 evaluation for epilepsy surgery.
MRI, PET and SPECT are used to create high-quality images of the brain, and to map brain activity.
- MRI can detect obvious or subtle abnormalities that may indicate a potential seizure focus.
- Functional MRI uses an MRI scan to detect brain areas involved in particular functions, and uses special settings to detect changes in blood flow in the brain.
- PET (positron emission tomography) measures the brain's metabolic activity, which can indicate how much energy a particular part of the brain is using.
- SPECT (single-photon emission computed tomography) may be performed during a video EEG. Unlike PET, it does not require radioactive solution.
A series of tests including interviews, puzzles, questionnaires and timed tasks. Your child's performance is compared to data from matched (similar age and education levels) control subjects. By looking at areas of relative strength and weaknesses, the neuropsychologist can determine parts of the brain that might not be functioning normally. This can be helpful in the evaluation for epilepsy surgery. By better defining strengths and weaknesses, it may also lead to suggestions/strategies for improving your child's function.
The Wada Test
Also known as the intracarotid amytal test, this test may be used during evaluation for epilepsy surgery to determine language and memory function on the left versus right side of the brain. A catheter is threaded from a blood vessel in the leg to the brain. The catheter is used to inject a short-acting anesthetic into just one side of the brain, effectively putting that side to sleep for five to ten minutes. During this time your child's language and memory are tested. After recovery, the procedure is repeated on the other side of the brain. The entire procedure takes two to three hours and your child will typically go home the same day.
Functional MRI Imaging
Brain mapping locates parts of the brain responsible for movement, sensation, language and vision. It is used to reduce the risk of loss of function from surgery. Brain mapping can be performed in the operating room using electrodes placed directly on the brain, or outside the operating room using electrodes that were previously implanted in/on the brain. Brief pulses of electrical current are passed through these electrodes. These may produce a brief response like a muscle jerk or tingling.