An electroencephalogram (EEG) is a non-invasive diagnostic test that records the electrical activity in your brain using small, flat metal discs (electrodes) attached to your scalp. Your brain cells communicate via electrical impulses and are active all the time, even when you’re asleep. This activity shows up as wavy lines on an EEG recording. The EEG specifically measures the voltage difference resulting from ionic current within the neurons in the brain. The EEG is different than an MRI or CT scan as those tests show physical structures of the brain or spine and the EEG records the physiologic portion or electrical connections of the brain. Our EEG’s are recorded using the American Clinical Neurophysiologic Society (ACNS) guidelines and the International 10-20 System of Electrode Placement.

EEG testing is ordered for a number of neurological disorders. This type of testing is most often used in the diagnosis of seizures or epilepsy, headache, memory disturbances, stroke, spells, syncope (fainting) and other neurological symptoms.

Patient Preparation

  1. Please have clean, dry hair with no hair products, particularly oils.
  2. Refrain from having caffeine the day of your test.
  3. You are encouraged to eat your meals prior to EEG procedures.
  4. Try to get a few hours less of sleep the night before testing as we would like you to be a little tired. If you normally get 8 hours of sleep at night, try not to get more than 6. However, it is not necessary to stay awake all night unless otherwise instructed.

What to Expect

The technician or technologist may ask you some questions about your history of symptoms, your handedness. This helps them to convey that information to the interpreting physician and may aid in the interpretation and diagnosis.

The technician/technologist will measure and mark you head with a grease pencil. This insures that the electrode placement is accurate. This pencil will come off after the testing.

You will be lying down on a table and we will try to ensure that you are comfortable and warm. The technician/technologist will then rub a gel on your scalp that feels rather gritty or scratchy at each electrode location as this step helps the electrodes make a good connection with the scalp. The electrode discs will be attached with a conductive paste and piece of gauze, cotton or special tape. At this time the technician/technologist will also measure the contact between the electrode and scalp. Electrodes will be placed on the upper chest/shoulder area to record your heart rhythm (EKG) as well. Electrodes will be place on the outer portion of your eye area to record eye movements. Occasionally, additional electrodes will be used.

You will be asked to lay relatively quiet and still for at least 30 minutes of recording time and you will feel no sensations from the test and there is nothing harmful like radiation. The tech will ask you to open your eyes several times, ask you to answer some orientation questions out loud, and may give you a mental task or two to complete (simple subtraction etc.). If you are in good health and are able to perform, you may be asked to do a three-minute deep breathing exercise. This breathing exercise may make you feel a little lightheaded or dizzy, may give you a tingling sensation in your fingertips or around your mouth. Don’t be alarmed as this is a normal response and these sensations will go away shortly after you stop the deep breathing. At some time during the recording, a bright flashing strobe-light may be flashed over your eyes intermittently over several minutes of time. We are looking to see how your brain reacts to this stimulation and you may see different colors and/or patterns during this time.

At the completion of the study, the electrodes will be removed and your scalped will be cleaned as best as we can with a damp washcloth. The tech will comb through your hair to remove the paste. There should not be any obvious telltale remains of the paste but you will wish to wash your hair when you have the opportunity to remove any sticky residue. A physician will interpret the study afterward and a report will be sent to your referring provider. Expect to hear from your ordering physician/provider after the test.

Outside Physician Requests

If you would like to schedule a procedure with our office, please fax patient demographic information (including insurance), most recent patient history and physician notes along with an authorization if needed to our office at 602-258-3368. Our technologist or office staff member will contact the patient for scheduling

Should you have any questions regarding electroneurodiagnostic testing, feel free to contact our technologist, Renee Schwarz, R. EEG/EP T., C.M.E.T., R.NCST, CNCT, at 602-258-3354 at extension 132.