Additional Pre-Surgical Evaluation
Before it is decided whether or not you are a surgery candidate, we need to learn more about your brain and how it works. More tests help us decide what type of treatment would be best for you. The following tests are usually done on outpatient basis for further evaluation.
Intracarotid amobarbital procedure (IAP) or Wada test
This test tells us where your memory or language is in your brain, how well it is working, and how speech or memory may be affected by the surgery. If we do surgery, we want to know what effect, if any, it may have on these areas. This test is done as an important study after Phase I admission is completed.
If you have an allergy to dyes or seafood, it is vital that you tell the nurse or physician. You will require special medicine before this test.
The doctors must do a special test called an "angiogram" before the Wada test. During this test, you will lie on a table with your head held still. The doctor will insert a thin flexible tube (called a "catheter") through an area at the top of your thigh. They will shave the hair in the groin area first. The doctor will thread the tube through your blood vessels to the carotid artery in your neck. Once the tube is positioned; the doctor will inject a small amount of x-ray dye into it to look at the blood vessels. When they inject the dye, you may feel a hot flushed sensation. This stops in a few seconds.
After the tube is positioned, the doctor will inject a medicine called sodium amytal through the tube. This will put one side of the brain to sleep and will make you weak on one side and/or may stop your ability to talk (this usually lasts 5-10 minutes). They will ask you to name and remember some words, colors and objects. This may be hard to do because part of your brain is asleep. The effects of the medicine will only last a few minutes. After about an hour, the doctor will do the same test for the other side of your brain.
Children may or may not have this test depending on how well they can cooperate.
After the Wada test, you will go to the recovery area for a short time. Then we will take you to the short stay unit on a hospital floor. In the short stay unit, you will get lunch and be able to watch television if you wish. They will be checking your thigh area to be sure it isn't bleeding. Most patients go home that evening, but some must spend the night in the hospital.
Visual Field Testing
The Visual Field Test is an eye test that measures how much you can see out of the sides of your eyes (peripheral fields). It is performed by an ophthalmology technologist. The test lasts about 45 minutes. Pediatric patients may or may not have this test.
A PET (Positron Emission Tomography) / CT study is a special test used with a CT scanner to try to find an area of your brain that isn't working correctly. The part of your brain that isn't functioning very well may show up on this study after you get a special injection. This abnormal area may match where seizures are coming from. Some patients may get just a SPECT scan, a PET scan or both.
Epilepsy surgery conference
After all of these tests, members of the epilepsy surgery program including neurologists, neurosurgeons, neuroradiologists, neuropsychologists, speech therapists and a psychologist will meet to review your test results and discuss the best treatment for you.
After the Epilepsy Surgery Conference, you may be contacted by your neurologist by phone or return to the clinic to discuss the test results and recommendations about treatment options for you.
The team will recommend one of several treatment options. The three most common options are:
- You may have the brain surgery without any more tests
- You may need more testing (called Phase II) to locate the spot where seizures start, or map out if the area to be removed could leave you with new problems
- You may not be a good candidate for the surgery
If you are a surgical candidate, we will explain the surgery to you. The benefits and risks of surgery will be explained. You and your family play an important and active role in this decision-making process. You will have plenty of time to ask questions during this discussion and afterward.