An EEG is interpreted by a neurologist or a neurophysiologist. If an EEG that is recorded during wakefulness is normal or only reveals nonspecific abnormalities, your physician may request an EEG during sleep. Similarly, your physician may request a sleep-deprived EEG. For this, you will be instructed not to sleep the night before the test. This may at times help to reveal abnormalities that would otherwise go undetected.
It is possible to record the EEG over a period of one or more days, during both daytime activities and sleep, using a small portable EEG recorder which is worn on a waist belt. This is known as ambulatory EEG monitoring.
In certain circumstances, a patient may need to be admitted to an epilepsy monitoring unit in order to record the brain wave activity while simultaneously maintaining video camera surveillance for several days. The information is stored on a computer where it can be reviewed at a later time by a neurologist or neurophysiologist.