Epilepsy Diagnosis and Evaluation

The initial evaluation includes a review of your medical history, medical records, and medications, a neurological exam, imaging tests, and electroencephalography (EEG).

Routine EEG (electroencephalography)
Records brain waves using electrodes placed on the scalp. While lying still on a bed, you may be asked to perform some simple tasks or look at a flashing light. In most cases, brain waves are recorded when you are both awake and asleep. You shouldn't experience any pain or discomfort during this one-to-two-hour test.

MRI (Magnetic Resonance Imaging)
Uses magnets to create a high-quality image of the brain and detect abnormalities that may indicate a potential seizures focus. This painless test takes about 30 to 60 minutes.

Ambulatory EEG
Records brain waves for a longer period of time, which increases the chances of recording an irregularity. As with a routine EEG, electrodes are placed on the scalp, but you will go home with the electrodes and a miniature, portable recorder for one to four days. Brain activity is recorded continuously. You will be asked to push a button when any seizures occur and to maintain a detailed log of your activities to help doctors learn more about your seizures.

Video EEG and the Epilepsy Monitoring Unit
Records brain waves and video during actual seizures, which can help doctors with diagnosis and surgical evaluation. Before and during the test, anti-seizure medications are often reduced or stopped to increase the chances of recording a seizure. For three to five days you will be admitted to the hospital and closely monitored in our specialized epilepsy monitoring unit (EMU) by a large team that includes doctors, nurses, technologists, and other staff. Video EEG can also be performed using electrodes that have been surgically placed on or in the brain. This allows for more precise mapping of brain function and targeting seizure origins.

Neurogenetic Testing
Recent research has shown that epilepsy can have a genetic component. A blood test can help inform doctors whether your epilepsy is genetic, which can affect your treatment plan. 

If your initial evaluation results indicate that you may be a candidate for epilepsy surgery, you will need to undergo some additional testing or surgical procedures to pinpoint your seizure focus.

Functional MRI (Magnetic Resonance Imaging)
Similar to a standard MRI, but also detects brain areas involved in particular functions and detects changes in blood flow in the brain. 

DTI (Diffusion Tensor Imaging)
A very specialized MRI that focuses on brain anatomy. Duke’s ultra-high-resolution scanner enables doctors to examine complex microstructures in the brain and identify small abnormalities that wouldn’t be visible on conventional MRI scans.

PET (Positron Emission Tomography)
Investigates chemical activity and shows brain metabolism. Before the scan, a radioactive dye is administered via an IV. This highlights areas of the brain where seizures begin.

SPECT (Single-Photon Emission Computed Tomography)
Shows blood flow and brain function. Like PET, this test requires IV injection of a radioactive dye (in this case, administered at the start of a seizure), which is only active in the body for a brief period.

High-Density EEG and ESI (Electrical Source Imaging)
Similar to a routine EEG, except that many more electrodes are placed on the scalp to give doctors even more information. The resulting data are analyzed with sophisticated computerized programs to determine not only where the seizures start but also how they spread.

Neuropsychological Testing
Neuropsychologists perform interviews and ask you to complete puzzles, questionnaires, and timed tasks over four to six hours. Understanding your strengths and weaknesses helps doctors determine which parts of your brain might not be functioning normally. This can be helpful in improving your cognitive function and determining whether you are eligible for epilepsy surgery.

Robot-Assisted Stereoelectroencephalography (SEEG)
SEEG is also used to pinpoint where a seizure starts. While you are under general anesthesia, neurosurgeons will guide a robotic arm to make tiny holes in your skull through which small electrodes are placed in the brain. This takes about two hours. You’ll recover outside of the operating room and remain in the hospital for about a week. During this time, the electrodes will monitor your brain activity to identify where seizures begin. After a seizure focus is determined, the electrodes are surgically removed, and you’ll remain in the hospital for two to three days to receive antibiotics. Compared with a craniotomy (which requires a larger opening in the skull), the robotic-assisted procedure is quicker and better tolerated. Stereo EEG is ideal for the most challenging cases of epilepsy. In conjunction with SEEG, doctors may be able to produce a 3D model of your brain to better understand where depth electrodes are in relation to each other and in relation to important brain structures. 

Subdural Electrodes
Subdural strip or grid electrodes are surgically placed on the surface of the brain and are used when the seizure focus is difficult to pinpoint. Also, your epileptologist and neurosurgeon can use these electrodes to electrically activate parts of your brain for mapping. As with robot-assisted SEEG, monitoring is usually done for several days so that seizures can be recorded. 

Brain Mapping
Brain mapping identifies vital areas in your brain responsible for movement, sensation, language, and vision. This lowers the risks associated with epilepsy surgery. First, a neurosurgeon will remove a portion of your skull (a craniotomy) to implant electrodes in or on your brain while you are under general anesthesia. You will recover from this surgery for a day or two in the hospital. Once the electrodes are in place, the mapping (which takes one to two hours) can be done while you are awake or under general anesthesia, and either in the operating room or in our specialized epilepsy monitoring unit (EMU), depending on what functions your doctors are testing. In both instances, brief electrical pulses will pass through the implanted electrodes, which may cause mild responses like a muscle jerk or tingling. You may also temporarily (for seconds) be unable to perform certain tasks, like speaking. 

Wada Test
Also known as the intracarotid amytal test, this is used to determine vital brain functions on the left versus right side of the brain. A neuroradiologist will administer a short-acting anesthetic into your right or left carotid artery, effectively putting one side of your brain to sleep for five to ten minutes. During this time, doctors ask questions to test your language, speech, and memory. Then the procedure is repeated on the other side of the brain. The entire procedure lasts about two or three hours. After a brief recovery period, you should be able to go home the same day.