Diagnosing Seizures and Epilepsy
Electroencephalography (EEG)
Our center is fully equipped with the most advanced digital EEG machines that can record up to 32 channels of data. An EEG is a non-invasive test that measures and records electrical activity in the brain. Seizures cause unusual waves of electric activity in the brain and the source of these waves can be measured by an EEG. During an EEG, a technician will paste electrodes on your head. The electrodes are attached to a computer that measures changes in electric activity in your brain. An EEG is painless, as it does not do anything to you – it only measures the information without sending anything back. Short EEGs can be done in our outpatient clinic. Additionally, your doctor might want you to get an ambulatory EEG. This is an EEG in which you go home while wearing the electrodes and a machine that records your brain’s electric activity.
An EEG takes about an hour; an ambulatory EEG may be done over a day or more.
How to Prepare
- Your hair should be clean and free of styling products. Do not braid your hair or use another hairstyle that may interfere with our ability to attach the electrodes to your scalp.
- Be aware that the electrodes will be attached to your scalp with glue that will need to be washed off after you are done with your EEG.
Epilepsy Monitoring Unit with Video electroencephalography (Video EEG)
The Epilepsy Monitoring Unit features a modern eight-bed unit with video EEG for the evaluation of individuals who are candidates for surgery and for differential diagnosis of "spells." Epilepsy patients are admitted for long-term monitoring (LTM) anywhere from 3 to 7 days and are typically weaned off of medications to see what the cause of the seizures are and where they originate. Some patients undergoing this treatment require intracranial electrode monitoring. A number of other diagnostic tools may be used including MRI, MEG, EEG, SPECT and PET to locate the origin of the seizures.
Phase I Monitoring
This stage of epilepsy evaluation involves an electroencephalogram (EEG) in addition to audio & video. We want to record your movements and behavior before, during, and after a seizure. Due to the different parts of video EEG monitoring, you will perform this testing during a hospital admission in our Epilepsy Monitoring Unit (EMU). A technician will paste electrodes on your scalp to record the EEG. These electrodes are attached to a computer that measures changes in electric activity in your brain. Putting the EEG and video information together helps your doctor determine what kind of seizures you have and how severe they are.
Since the objective of Phase I monitoring is to record seizure activity, we will reduce or stop your anti-seizure medications during your admission. A Level 4 Epilepsy Center EMU is the safest place to diagnose your epileptic events.
Phase I Monitoring can last anywhere from 2 days to over a week.
How to Prepare
- Bring comfortable clothes that can be buttoned or zipped from the front, as the wires from the EEG will not allow you to pull clothes over your head.
- You can bring your phone, books, handheld gaming devices, etc. to entertain yourself.
- Your hair should be clean and free of styling products. Do not braid your hair or use another hairstyle that may interfere with our ability to attach the electrodes to your scalp.
- Be aware that the electrodes will be attached to your scalp with glue that will need to be washed off after you are done with Phase I Monitoring.
Phase II Monitoring
Some patients may undergo multiple tests that either fail to let doctors know where the seizures are coming from, or give contradictory results. In these cases, more invasive procedures are required in order to localize the part of the brain responsible for your seizures. In Phase II monitoring, a skilled neurosurgeon places wires and/or electrodes within or on top of your brain and admits you for an inpatient hospital stay. The day after the surgery you will have more testing and will undergo video EEG monitoring similar to that done for Phase I Monitoring. Once your doctor has collected the data needed, you will go back to the operating room and have the electrodes and wires taken out. You will be discharged from the hospital a few days after having the electrodes removed.
Phase II Monitoring, including the surgeries and recovery time, can take 1 to 2 weeks.
How to Prepare
- Be aware that your surgery will last about 6 to 8 hours.
- Bring comfortable clothes that can be buttoned or zipped from the front, as the wires from the EEG will not allow you to pull clothes over your head.
- You can bring your phone, books, handheld gaming devices, etc. to entertain yourself.
Wada Test
The human brain is split into two hemispheres – left and right. Each side controls different functions. A Wada test tells your doctor what side of your brain controls speech and language. This is important to determine whether you are eligible for certain kinds of epilepsy surgery and to try to predict the effects surgery could have on your memory and language. During the Wada test, you will get an anesthetic injected in your carotid artery to inactivate one side of your brain. This allows us to test memory and language in each half of your brain individually.
The Wada test takes about an hour to complete, including the injections.
How to Prepare
- You are not allowed to eat or drink anything after midnight the night before your Wada test. However, you should still take your medications.
Neuropsychological Testing
Epilepsy can cause problems with functioning in your daily activities due to its potential to disturb memory, language, and attention. Neuropsychological testing examines how the areas of the brain controlling these tasks may have been affected. Additionally, information from this test may be helpful in identifying where your seizures are coming from.
Neuropsychological testing can take upwards of 5 hours.
How to Prepare
- Please bring your glasses and hearing aids if you wear them.
- Make sure you have had a good night’s sleep and a good meal before the test.
- Wear comfortable clothing.
Magnetoencephalography (MEG)
A magnetoencephalography (MEG) is a test that allows doctors to measure electric activity in your brain by looking at the magnetic fields these electric currents generate. Seizures cause unusual waves of electric activity in the brain and the source of these waves can be measured by a MEG. When combined with information from an MRI, a MEG can help paint a more accurate picture of how your seizures spread through your brain.
A MEG scan takes about 1 to 2 hours.
MRI
A Magnetic Resonance Imaging (MRI) test allows doctors to look at a picture of your brain. This image is taken using magnetic waves instead of x-rays, so an MRI does not expose you to radiation. Doctors look at the images to try to find a physical cause for your seizures. During an MRI, you will be asked to lie down and remain still while the magnets spin around you. This test usually takes about an hour to complete. If you have any medical devices in your body, they may have to be turned off before your MRI.
Depending on what your doctor wants to look at, an MRI can take anywhere from 15 minutes to 2 hours.
How to Prepare
- Let your doctor know if you have any medical devices or other metal in your body (such as pins, rods, or shrapnel).
- Let your doctor know if you are claustrophobic, as you may be allowed to take medication to calm your anxiety.
- On the day of the MRI, refrain from wearing any metal jewelry as you will have to take it off and put it in a locker during the test.
PET
A Positron Emission Tomography (PET) test shows areas of your brain that are using glucose at higher or lower rates than the rest of the brain. Your doctors are trying to find areas that are using less glucose, as this means that area of the brain is not working optimally. In order to visualize these areas, you will receive an injection of a radiolabeled tracer before actually going in to the scanner.
The PET scan itself takes about 30 minutes, but you may be at the imaging department for 2 to 3 hours.
How to Prepare
- You will be asked to refrain from eating or drinking anything other than plain water for 4 to 6 hours before your test.
- You will be asked to eat a low carbohydrate diet the day before the test.
- You will be asked to refrain from exercise for 2 days before the test.
- Please let your doctor know if you think you may be pregnant, or if you are currently breastfeeding your child.
Single Photon Emission Computed Tomography (SPECT)
A Single Photon Emission Computed Tomography (SPECT) test shows areas of your brain that have higher or lower blood flow than the rest of the brain. Blood flow is associated to how much energy that part of the brain is using. For a SPECT test, you will have a small amount of a radiolabeled tracer injected to allow us to visualize the blood flow.
The SPECT scan itself takes about 30 minutes, but you may be at the imaging department for about 1.5 hours.
How to Prepare
- You will be asked to refrain from eating or drinking anything other than plain water for 4 to 6 hours before your test.
- Please let your doctor know if you think you may be pregnant, or if you are currently breastfeeding your child.