- Baseline Electroencephalogram (EEG):
In this test, electrodes are placed on the scalp to measure electrical activity produced by the brain when you are not experiencing a seizure. This test can suggest general areas of the brain that may be affected.
A continuous EEG with video monitoring records your seizures as they occur. Because your seizure medications have to be reduced or temporarily stopped so that seizures will occur, you’ll be admitted to the hospital for this test. Evaluating the changes in your EEG with your body’s movements during a seizure helps pinpoint the area of your brain in which your seizures are starting.
- Magnetic Resonance Imaging (MRI):
This imaging test uses a magnetic field and radio waves to create detailed images that allow doctors to identify damaged cells, tumors or other abnormalities that can cause seizures.
Your surgical team may order additional tests to localize the source of seizures and to characterize the nature of the abnormal activity. These tests may include:
If an EEG test does not show where seizures begin, monitoring may be done with surgically placed electrodes. The surgeon places either grids or strips of electrodes on the surface of the brain or places electrodes deeper inside the brain. EEG monitoring is done while you’re unconscious.
- Video EEG with Invasive Electrodes:
Surgically placed electrodes are needed for a video EEG procedure. After the surgery, the video and EEG data are captured during a hospital stay while you’re awake but not taking anti-seizure medications.
- Positron Emission Tomography (PET):
This specialized imaging device is used to measure brain function when you are seizure-free. The images alone — or combined with MRI data — can help identify the source of your seizures.
- Single-photon emission computerized tomography (SPECT):
This procedure measures blood flow in the brain during a seizure. Typically, blood flow is higher in the part of the brain where seizures occur. You will be admitted to hospital to undergo this test.