An electroencephalogram (EEG) is a recording of the electrical waves in the brain. It measures electrical impulses that are sent between nerve cells.
The healthcare professional may order an EEG to investigate the cause of these symptoms: amnesiaconfusiondizzinessfaintingheadachesseizuresstaring or other attention problemsunusual behavior
An EEG may be used to monitor blood flow to the brain during surgery on the carotid arteries. It is also used to determine brain death in a person who is in a coma.
An EEG uses small electrodes to measure the electrical activity within the brain. It does not deliver any electricity of its own. The technician will use a paste to attach about 20 small electrodes to the person's scalp.
The electrodes carry information about the brain's electrical activity to an amplifier. A special machine records the amplified brain waves and produces a pattern of tracings on paper.
During the recording, the patient may be asked to breathe deeply or to look at a flashing light. Occasionally, an EEG is performed both during sleep and while the patient is awake.
Instructions for an EEG usually include the following preparation: Avoid caffeine for 24 hours before the EEG.eat normally and take all prescribed medications.get no more than 6 hours of sleep.shampoo the night before the EEG. Do not apply hair spray or gel.
A normal EEG does not necessarily rule out abnormalities in the brain. However, the following conditions can be detected on an EEG: brain deathbrain infectionbrain tumorschemical disturbances that affect the braindegenerative neurological diseasesepilepsyhead injuryintracerebral hemorrhage, or bleeding into the brainsleep disordersstroke