Videotaping epileptic attacks during stereoelectroencephalography.

Relating the onset of clinical attacks as recorded on a videotape to surface and depth electrographic events improves our ability to define the local or diffuse origin of seizures. In two patients with complex partial seizures, all 14 attacks appeared 3 to 6 seconds after focal discharges began in the amygdala or hippocampus. This meant that the spread of focal electroencephalographic (EEG) paroxysms caused the eventual clinical seizure. In two other patients with 392 generalized seizures and secondary bilateral synchronous paroxysms, a significant number of clinical attacks preceded the first depth or surface electrographic event. This suggested that the attacks originated from brain regions remote from the recording electrodes.