A cap with electrodes is placed over the head.
Our brain is electrically active. Between the different electrodes a potential difference is detected. The computer processes all recordings and produces an EEG trace.
During the recording of an EEG, the eyes are closed. Sometimes one is asked to open the eyes.
An EEG shows:
- The speed and symmetry of the brain activity
- The reaction upon eye opening or closure
- The presence of epileptic activity, which is often more obvious during hyperventilation.