Electroencephalogram (EEG) | Neurology | Loyola Medicine

Electroencephalogram (EEG)

Diagnostic Test to Measure Electrical Brain Activity

An electroencephalogram (EEG) is a test that measures the brain’s electrical activity. The EEG test records the electrical signals sent between brain cells and plots the brain activity in a chart. Loyola Medicine’s technicians are highly skilled in conducting all forms of EEG testing.

Your Loyola doctor may order this test for you as a baseline or to determine whether you have certain conditions, such as:

Why Choose Loyola for EEG Testing?

Loyola's neurology and neurosurgery services provide the most advanced care in an academic setting, training future leaders in the neurosciences. Loyola’s neuro intensive care unit is equipped with continuous EEG and video monitoring for adults and children and is staffed by certified technologists and trained neurology nurses, who have earned Magnet status.

What to Expect with EEG Testing

At Loyola, your EEG is catered to your particular case. Depending on the information your doctor needs to gather from your test, you may or may not be given a sedative, or asked to try to sleep. Most EEGs take 60 minutes to perform, but some may take longer especially if you are being evaluated for a sleep disorder. 

An EEG technician will have you lie down and will apply electrodes to your scalp with an adhesive, which will be removed after the test is completed. You will be asked to lie still and close your eyes. Rapid breathing and flashing lights may be part of your test. This will stimulate your brain and provide your doctor with information about your brain activity.

In some cases, your doctor will want you to sleep during the test. Because of this, you may be asked to sleep just a few hours the night before so that you are sleepy enough for the test. In some cases, your doctor may request a specific type of EEG or monitoring to detect signals related to complex seizures:

  • Ambulatory EEG — With this test, patients are able to leave the hospital. Fewer electrodes are attached and the patient carries a portable signal recorder.
     
  • Prolonged monitoring — This is conducted at a hospital and may last from three to seven days.  This procedure may be used to diagnose complex seizure disorders.
     
  • Video EEG monitoring — This allows the doctor to see seizures in conjunction with recorded brain signal charts.

What are the Risks of EEG Testing?

The EEG is an extremely safe test. While hyperventilation or flashing lights during the test may trigger a seizure, your technician is well-trained to care for you should this occur. You may also experience some scalp itchiness or redness where the electrodes were applied, but this will disappear within a few days.