1. The record obtained by means of the electroencephalograph which presents a record of electric currents generated in the cortex of the active brain.
2. A technique for studying the electrical currents within the brain.

Electrodes are attached to the scalp and wires attach these electrodes to a machine, which records the electrical impulses.

The results are either printed out or displayed on a computer screen where different patterns of electrical impulses can indicate various forms of epilepsy.

3. A graphic record of the minute changes in electric potential associated with the activity of the cerebral cortex, as detected by electrodes applied to the surface of the scalp.
4. A graphic chart on which is traced the electric potential produced by the brain cells, as detected by electrodes placed on the scalp.

The resulting brain waves are called alpha, beta, delta, and theta rhythms; according to the frequencies they produce, which range from two to twelve cycles per second.

Variations in brain wave activity are correlated with neurological conditions, psychological states, and levels of consciousness.

1. An electroencephalogram (study of electrical current within the brain) indicating the absence of electric potentials of cerebral origin, indicative under certain specified conditions of cerebral death.
2. An electroencephalogram or the graphic recording of the electric discharges of the cerebral cortex as detected by electrodes on the surface of the scalp in which no recognizable waveforms or deviations from the baseline of electrical activity can be discerned as arising from the brain.
3. A graphic chart on which no tracings are recorded during electroencephalography, indicating a lack of brain wave activity.

Flat readings are indicative of brain death except in cases of profound hypothermia and central nervous system depression.