What is Epilepsy?

Epilepsy is a neurological condition affecting about 2-3% of people at some time in their lives. People with epilepsy experience recurrent, unprovoked seizures which are caused by a brief change in the electrical and chemical activity in the brain. These seizures can result in the person experiencing unusual sensations, loss of awareness, or unusual movements and postures lasting from a few seconds to several minutes. The part of the brain affected determines what a person experiences during the seizure.

What are seizures?

There are many different types of seizures, which are divided into two groups – focal (or partial) seizures where the seizure starts on one side or in one specific place in the brain, and generalised seizures where the seizure involves both sides of the brain simultaneously. It is important to work out what type of seizure(s) a person might be experiencing as this informs which medications a doctor will prescribe and what the expected long term outcome will be.

Our team have recently been involved in leading the first classification of seizures since 1981 as part of our work with the International League Against Epilepsy (ILAE). This revised classification will improve recognition and care for seizures and epilepsies. Details about the new terminology of seizure types can be found on the ILAE web site.

How do we investigate Epilepsy?

The Comprehensive Epilepsy Program uses many different tools to investigate epilepsy including monitoring brain activity with electroencephalography (with or without video monitoring) known as EEG/VEM, imaging the brain with tools such as MRI, SPECT, and PET, capturing clinical functioning with neuropsychology investigations, and we do surgical investigations. Each of these tools is described below. 

EEG/VEM

EEG (electroencephalography) records the electrical activity of the brain. It is useful for investigation for patients who have had a seizure and for management for patients with epilepsy.

 

Routine and Sleep Deprived EEG

A routine EEG takes approximately 45 minutes to perform. Electrodes applied to the patient's head record the brain's electrical activity. Video may also be recorded to monitor any clinical seizures. The EEG scientist will ask the patient to do some deep breathing for three minutes, and to watch a flashing light whilst opening and closing their eyes. It is important to be relaxed and still for the test.

A specialised service is provided for patients who have recently had their first suspected seizure. The EEG test is most helpful if performed within 24 hours of the seizure, although there is still value in performing it later. If the initial EEG is negative, an EEG may be performed after a night of sleep deprivation which can increase the chances of recording an abnormality in the EEG.

Long Term Video EEG Monitoring

Video EEG monitoring (VEM) records your EEG and behaviour during a seizure. If you are being considered for epilepsy surgery the doctors need to know the type and location of  seizure the activity in your brain. It can be difficult to distinguish seizures from some other types of events and VEM can help to clarify this.

VEM is done while you are an inpatient. At the beginning of your stay the EEG technicians will apply EEG electrodes to your head. You will be constantly connected to an EEG monitor and videotaped during your stay. The average stay is 8 days but may be up to 12 days. For children, admission is usually Monday to Friday. All patients require a sitter (family member or friend to identify seizures) to stay with them throughout the admission. The room has with a video camera and computer that record information about seizures and brain function. Cameras are linked to monitors outside the room that are monitored during the day by nursing staff in order to ensure we receive all available information.

During the monitoring you must remain in the room at all times except for going to the toilet; the room has an ensuite. This means you need to bring enough with you to keep yourself occupied during your stay. For more information about what you can and cannot do during the monitoring please read the Patient Information Brochure. For more information about EEG and VEM procedure please read Austin Health's EEG patient information and VEM patient information documents.

This is what the EEG scientist looks at. The squiggly lines represent the electrical activity of your brain!
 
MRI

An MRI scan produces pictures of the brain’s structure. It is used to identify any abnormalities in the brain that cause seizures.

The MRI (Magnetic Resonance Imaging) machine uses magnetic fields to produce the images. There are no x-rays or radiation involved. Because the machine uses magnets to take the pictures it is important to tell the radiology staff if you have any metal implants.

MRI scans take about one hour to complete. During this time you need to lie still on your back. You will lie on a narrow bed which moves into a tunnel in the scanner. Some people find this a bit unpleasant as there is not a lot of room, but the machine is well lit and ventilated and you will be given music to listen to.

We are constantly trying to gain more information from MRI. You may be asked to have a scan at the Brain Research Institute which has a more powerful instrument than that used routinely.

More information about MRI can be found at the Brain Research Institute website or the Royal Children's Hospital Epilepsy Program site.

 
Our radiographers make sure patients are comfortable in the scanner
We keep an eye on you during the scan to check you're ok while we snap some pictures of your brain!
SPECT and PET

SPECT (Single photon emission computed tomography) and PET (Positron emission tomography) scans provide information about the function of your brain.  They use very low levels of radioactivity.

 

 

 

 

 

 

 

 

 

 

 

 

SPECT

SPECT scans measure blood flow in the brain. This is done by injecting a compound (ECD) into a vein.  Blood flow increases at the time of a seizure so we compare scans performed during a seizure with scans performed when seizures are not occurring. The patient is injected as early as possible after the seizure begins. This is one reason that it is necessary to have a sitter/parent with the patient to identify the seizure as soon as it begins. The ECD localizes in the brain within 30 seconds to give a picture of the blood flow to the brain at that point in time. The scan itself can be taken up to 2 hours after the injection and scanning occurs in the nuclear medicine department. ECD can only be injected between the hours of 8 am and 4.30 pm, as the scanner is closed out of hours.

PET

PET scans use an injection of 'labelled' glucose (sugar) to show how your brain is using glucose. Often the area in the brain causing seizures may use less sugar in between seizures. This scan is usually performed if you have not had a seizure for 24 hours. You must not eat or drink for 4 hours prior to the test.

More information about SPECT and PET can be found at the Austin Health Nuclear Medicine web site and the SPECT page of the Royal Children’s Hospital Children’s Epilepsy Program site.

This is the kind of picture we see when we do a PET scan of your brain.
 
Neuropsychology

There are two aspects of the neuropsychology assessment. The first assesses your memory, concentration, language and other thinking functions. This provides us with important information that can assist in the assessment and treatment of your seizures. If appropriate, the second phase involves a detailed assessment of issues related to surgery. Should you have surgery, you will be followed up and reassessed to see whether there are any alterations in functioning.

 
Epilepsy Surgery

Austin has a well established epilepsy surgery program. Surgery is helpful for a minority of patients with epilepsy who have not responded to antiepileptic medication.

 

We have been performing epilepsy surgery for 30 years with over 500 patients benefiting from the program. Patients admitted under the Comprehensive Epilepsy Program are considered for their suitability for epilepsy surgery. This includes all the tests above and a detailed multidisciplinary evaluation regarding suitability for surgery and the risks and benefits of epilepsy surgery for each person.

In addition to the medical tests, we have a wide ranging pre- and post-operative support program for patients undergoing surgery. This involves a detailed assessment of you and your family to assess psychological and social issues related to surgery. It is important to know how you and your family are feeling about surgery. Careful management of psychological illnesses such as co-existent depression or anxiety is also provided. In order to make a decision regarding epilepsy surgery, you will be counselled about the likely outcome with regard to seizure control, the likely effects on your everyday life and the risks, so that you will be able to make an informed decision.

Our program has been internationally recognised, and provides a range of multidisciplinary services. These include specialist medical and neuropsychological reviews, and psychosocial counselling which are routinely provided at regular intervals after surgery. This is complemented by post-operative phone follow-up by specialist staff.

The Comprehensive Epilepsy Program has established a wide-ranging pre- and post-operative support program for patients who are considered for surgery. More information on the seizure surgery follow-up program.

 

© 2020 by Epilepsy Research Centre