Electroencephalography (EEG) - Reveals different brain patterns
An EEG is a recording of the on-going electrical activity of the brain. An EEG is used to assist in the diagnosis of epilepsy and a variety of neurological symptoms. These symptoms include common headaches, dizziness, seizure disorders, convulsions, changes in awareness, unexplained loss of consciousness, prolonged or unexplained coma, strokes, and degenerative brain disease. EEGs are also used to evaluate the effects of head trauma or the consequences of severe infectious disease. EEG information can help doctors determine medical and surgical treatment of epilepsy. EEGs also are used in determining causes for staring spells or inattentiveness in children.
In Conducting an EEG, highly sensitive monitoring equipment records the activity through electrodes that are placed at measured intervals on a patient's scalp. The test is not painful. The preparations for the test take about 30 minutes. The test itself usually takes about 20 minutes. The principal role of the patient is simply to remain still, relaxed and comfortable. During the test, the patient may be asked to take repeated deep breaths (hyperventilate) and/or be shown a strobe light that flashes at different speeds. It is very helpful to record sleep, so the patient may be asked to stay awake extra hours the night before the test. All of these activities can help reveal different brain patterns that are useful for diagnosis.
The simultaneous recording of EEG and videotaped behavior over extended periods of time is referred to as long-term monitoring (LTM). It is useful in diagnosing patients with intermittent or infrequent disturbances as well as in the diagnosis of seizures and other neurological disorders, such as unexplained coma.