Topography is an electroencephalography test, which is used to record the electrical waves of the human brain. The test is recorded indirectly by means of scalp electrodes, and it includes general EEG, video EEG, and 24-hour dynamic EEG. The most common abnormal waveforms examined are epileptic waves, such as sharp, spike, spike-slow, spike-slow, and multi-spike slow waves. The finding of abnormal epileptic waves supports the diagnosis of epileptic disease and is applicable to all types of primary or secondary epilepsy. In addition, organic diseases of the brain, such as encephalitis, prion disease, and herpes simplex virus encephalitis, can have significant EEG abnormalities, such as increased slow waves, when there is extensive involvement of the cerebral cortex. At this time, EEG can be used as a noninvasive adjunct to provide a degree of certainty in the diagnosis of encephalitis, and functional diseases like migraine can sometimes have abnormal EEG, but not characteristically so.