Epilepsy Testing & Diagnosis

An EEG test is able to determine the type of epilepsy you have and potential underlying causes by measuring and recording the brain’s electrical activity. During the test, special sensors (electrodes) are attached to your head and a computer will records the brain’s electrical activity.

An EEG technician conducts the test, which can be done in a hospital or in a doctor’s office, and a neurologist reads the results. Over 10,000 EEG tests are performed at University Hospital each year.

An MRI is a tool used for taking pictures of your brain.

For this test, you will be placed into a tube with magnets. While in there, the magnets will collect information about your brain, potentially identifying the causes of your epilepsy. This can identify tumors, strokes, a brain injury, scarring or small to large areas of brain with developmental abnormalities (cortical dysplasias).

Some people with epilepsy don’t respond to medical therapies and are referred to the Epilepsy Monitoring Unit (EMU) for evaluation. In the EMU, your medications are reduced or paused to safely capture and monitor seizures through continuous video-EEG. You will be closely watched by trained staff, with nurses and physicians available around the clock to ensure your safety and respond to emergencies.

This testing helps specialists determine where seizures begin in the brain and whether they come from one specific area. Some people may experience seizure-like episodes without abnormal brain activity. These episodes are diagnosed as a psychogenic nonepileptic event (PNEE), which are often linked to psychological stress. From there, you will be referred to neuropsychologists for a structured outpatient program to help manage and reduce symptoms.

An ECoG uses sensors that are surgically implanted on the brain to record brain activity. ECoG is considered the “gold standard” for detecting an epilepsy episode.

Motor and language mapping shows which parts of the brain perform these functions so doctors can perform surgery with the highest degree of accuracy.

A PET scan shows blood flow and how the brain uses sugar (glucose), measuring changes in the brain’s metabolism and chemistry.

The Single Photon Emission Computed Tomography (SPECT) scan produces images of blood flow to the brain.

During the scan, a radioactive tracer is injected and its distribution in the brain is visible by a special camera. From there, a radiation technologist will be able to determine if blood flow to an area of the brain increases during a seizure or decreases between seizures.

The high-density EEG is similar to a normal EEG test where electrodes are placed on your head in order to measure and record the brain’s electrical activity.

During this test, more electrodes will be used. A high-density EEG uses up to 128 electrodes compared to 26-28 electrodes in the regular EEG.

A position emission tomography (PET) scan shows blood flow and how the brain uses sugar (glucose), measuring the changes in the brain’s metabolism and chemistry.

Brain regions that cause epilepsy demonstrate impaired glucose metabolism.

Neuropsychological testing is used before surgery to evaluate potential risks of the surgery based on where the seizures occur in the brain, and after surgery to evaluate any adverse effects on language or memory functioning.

The testing can help identify areas of the brain that are not functioning normally.

A functional MRI (fMRI) scan captures images of the brain while the patient performs specific tasks that involve thinking, speaking and moving. This allows the radiology and epilepsy teams to see which part of the brain is working.

A TMS delivers magnetic pulses from a hand-held device through the skull onto the surface of the brain. The magnetic pulses will induce small currents that activate or deactivate motor, sensory or language areas of the brain. This provides a map of the brain and show areas that need to be avoided by the neurosurgeon to provide a safe surgery.

The WADA test looks at speech, thinking and memory functions on one side of the brain, at a time.

A specialist will inject medication through a catheter to put one side of the brain to sleep. From there, you will be asked to identify pictures and objects while one side of the brain is asleep. Twenty minutes after the initial questions, you will be asked to recall or recognize the pictures or objects. Once the medication completely wears off, the procedure is repeated on the other side of the brain.

The test helps to predict whether surgery may affect the patient’s speech and memory functions.