Electroencephalography (EEG)

Electroencephalography (EEG) is the recording of electrical activity along the scalp produced by the firing of neurons within the brain. In clinical contexts, EEG refers to the recording of the brain’s spontaneous electrical activity over a short period of time, usually 20–40 minutes, as recorded from multiple electrodes placed on the scalp. In neurology, the main diagnostic application of EEG is in the case of epilepsy, as epileptic activity can create clear abnormalities on a standard EEG study. EEG is also for the diagnosis of tumors, stroke and other focal brain disorders.

An EEG is a painless test that measures electrical activity of the brain. It helps in the diagnosis of numerous conditions related to the brain. It is similar to an EKG or Heart Test, but it is done on the head.

An EEG takes approximately one hour. A technician will mark and measure your head with a measuring tape and a non-toxic grease pencil. Small metal electrodes are placed on the scalp with adhesive paste. Your child will be resting in a reclining chair or bed in a dark and quiet room while recording. During the test, they will feel no sensation at all from the electrodes. They will be asked to do certain things during the recording, such as breathe deeply and rapidly for several minutes or look at a bright flickering light.

The recording machine converts the electrical signals into a series of wavy lines that are recorded by the computer. These signals are then studied and interpreted by the physician.

How to Prepare for the Test

Routine EEG

  • You will need to wash your child's hair the night before the test.
  • You should not use any oils, sprays or conditioner before the test.
  • No makeup or lotion on face.
  • Continue your usual medicines unless instructed otherwise by your doctor.

Sleep-Deprived EEG

  • You will need to wash your hair the night before the test.
  • You should not use any oils, sprays or conditioner on your hair before the test.
  • You should not wear makeup or put lotion on your face.
  • Your child will need to either: (1) Get up at 3 a.m. on the morning of the test, OR (2) Do not go to bed until 2 a.m. The goal is to be tired and ready to fall asleep at the time of the test.
  • Your child can eat before the test; however, you should avoid all stimulants (e.g., coffee, tea, soda, chocolate, smoking, etc) for 8 hours prior to the test.
  • Continue your usual medicines unless instructed otherwise by your doctor.