An EEG measures the electrical activity of the brain, sometimes referred to as brain waves.  This test is
performed to see how the different parts of the brain function. EEGs also help caregivers learn about sleeping
problems, brain injury, brain tumors, and many other problems. The machine records a graph of your brain waves.No electricity is transferred to your brain. 

• Your EEG will be done in a room that is dark and quiet. You will either lie in a bed or sit in a reclining chair during the test.
• A caregiver will measure your head and scrubs (cleans) 20 to 21 areas of your scalp. Then, a cream will be placed on these areas. Electrodes will be placed on the cream. The electrodes will be connected with wires to a computer. An electrode may be put on each earlobe. Lie still with your eyes closed. The EEG machine will record your brain waves on a computer.
• You may be asked to hyperventilate (hi-per-VEN-ti-late). This means you may need to breathe deeply and quickly for three to four minutes. You may be asked to look into a bright flashing light. Caregivers watch to see how these activities change your brain waves. Make sure you are comfortable before the test begins. Do not talk during the test.
• Most EEG’s are completed in 90 minutes.