An electroencephalogram or EEG test helps diagnose seizure disorders by providing a visual representation of the patient's brain wave patterns so that medical professionals can check for abnormalities, according to Everyday Health. Even if a seizure does not occur during the test, abnormalities in the activity of the brain waves still provide information for diagnosing the disorder.
During a standard EEG test, the patient lies on a table in a darkened room, maintains Everyday Health. A technician attaches flat metal disks to the patient's head with glue. The disks pick up the brain waves and transfer them via wires to an amplifier. The waves appear as wavy lines on a screen for the technician or doctor to analyze.
An EEG does not cause pain or discomfort in most patients, states Everyday Health. The test typically takes less than an hour total and records up to 40 minutes of the patient's brain waves. Sometimes it is necessary to do another EEG with special electrodes that insert into the patient's skin or nose to get a better reading. In other situations a special ambulatory EEG is necessary to learn more about brain wave patterns that might lead to seizures. This test records brain waves for a period of up to 72 hours while the patient participates in his normal life activities.