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The Ottawa Hospital Laboratory for electroencephalography (EEG)
An electroencephalogram (EEG) is a test to detect electrical activity in your brain. It uses small, metal cup-like discs attached to your scalp. Your brain cells communicate via electrical impulses, and generate very weak electrical signals. These signals are active all the time, even when you are sleeping. This activity shows up as “wavy lines” and that record is called an EEG.
An EEG is one of the main diagnostic tests for epilepsy. An EEG can also play a role in diagnosing other brain disorders.
The Ottawa Hospital has a full range of EEG studies available, including:
Routine EEG studies and sleep deprived EEG studies: These studies tend to last up to 30 minutes and include video recording.
Ambulatory video EEG studies: These studies can last up to four hours and include video recording. The recording allows us to record your brain activity and match it to your movements and behavior to try and help us identify where your seizures may be coming from. Recording for longer than a routine EEG study also means that we have more chances to capture if something unusual takes place.
Critical care video EEG studies: These are inpatient studies performed on critically ill patients who are admitted to the hospital. They are usually not available to the public.
If you have questions or concerns about your upcoming EEG, please feel free to contact the EEG laboratory, open Monday to Friday from 8 to 4 p.m., at 613 798 5555 ext 14324.
More information
Information about my upcoming EEG
Routine EEGs are performed at either Civic or General campuses. Ambulatory and critical care EEGs are performed exclusively at the Civic Campus
A neuropsychologist will guide you through a series of tests during your assessment. The testing session usually lasts about five hours. If necessary, testing can be completed across multiple appointments.
The assessment may include an interview, questionnaires, as well as testing your brain’s functions:
- Attention and concentration
- Memory
- Visual and Spatial function
- Language function
- Reasoning and problem-solving
- Social and emotional function
The purpose of an assessment is to identify your pattern of strengths and weaknesses. The results will help us make the best possible recommendations for your epilepsy care. This assessment will be one of the things you care team will consider when deciding whether or not epilepsy surgery is right for you because it helps your care team further isolate where in your brain your seizures may be coming from.
Neuropsychological testing must be done in person, but your interview and feedback session will be completed remotely (i.e. via phone or video conference). Testing will be performed at the General Campus following COVID-19 protocols.
MRI stands for Magnetic Resonance Imaging. It is a technique used to create an image of the inside of the human body. An MRI of the head shows in great detail what your brain looks like and how it works. In people with epilepsy, an MRI scan may help to find the cause of the seizures, such as a scar, lesion, or altered anatomy in the brain.
A CT scan is a computerized axial tomography scan and uses x-rays to take pictures of the brain. A CT scan may be the only option if you have a metal device that is surgically implanted in the body.
An MRI can typically produce a clearer and more detailed image than a CT scan.
These tests are usually performed at the General and Civic campuses of The Ottawa Hospital. Other places in the city may perform them, such as the Montfort hospital, the Queensway Carleton Hospital and Pembroke hospital, all of which have MRI capability.
This test is usually ordered for patients diagnosed with epilepsy who may need epilepsy surgery. It is used to get more information on where their seizures are coming from.
A PET scan is a test that combines computed tomography (CT) and nuclear scanning. A tracer (radioactive substance + glucose) is injected into the vein, which travels to the brain and produces a signal on how the brain metabolizes the glucose (builds up and breaks down the glucose).
Areas in the brain that do not metabolize the glucose correctly light up differently and can help identify where the seizures are coming from in the brain.
This test is usually performed at the General Campus.
Your neurologist may ask you to get a genetic test done if they see a pattern of inheritance in your family or syndrome with a strong genetic association playing a role in your epilepsy. They will consult with a neuro geneticist and refer you to them at the Children’s Hospital of Eastern Ontario (who also evaluates adults with genetic conditions).
More specialized tests may be required during your presurgical evaluation. You may need to travel to Toronto Western Hospital or the London Health Sciences Centre to complete the tests. These tests may include functional magnetic resonance imaging (fMRI), WADA testing or SPECT scans.
Tests needing intracranial electrodes to monitor your seizures will also take place in either Toronto or London.
If your epilepsy specialist concludes that surgery might be right for you, they will likely refer you to one of our sister institutions and regional epilepsy surgical centers. The two major centers in the province are the Toronto Western Hospital and the London Health Sciences Centre.
Please discuss these options with your neurologist during your next appointment.
Last updated on: February 1st, 2021