Electroencephalography (EEG)

Electroencephalography is a test to detect problems in the electrical activity of the brain. Brain cells communicate with each other by producing tiny electrical impulses. In an EEG, this faint electrical activity is measured by putting electrodes on the scalp.

The test is performed by an EEG technician. You will be asked to lie on your back on a bed or in a reclining chair.The technician will apply between 16 and 25 flat metal disks (electrodes) in different positions on your scalp. The disks are held in place with a sticky paste. The electrodes are connected by wires to an amplifier and a recording machine. The recording machine converts the electrical impulses into patterns that can be seen on a computer screen, and the electical activity looks like a series of wavy lines. You will need to lie still with your eyes closed because any movement can alter the results.

You may be asked to do certain things during the recording, such as breathe deeply and rapidly for several minutes or look at a bright flashing light.