Seizure moitoring: a new tool in electroencephalography.

A seizure monitoring system, based on telemetry and computer techniques, has been developed to provide a reliable means of recording the patient's spontaneous seizures. It allows a patient's EEG to be monitored for hours or days with 16 channels of EEG from surface, sphenoidal or stereotaxically implanted depth electrodes, from any ward or room within the hospital. The EGG is delayed in time by up to 4 min by a mini-computer so that either the patient can push a button when he experiences his aura or others can push the button when they observe his seizure. Since the delayed EEG is written out, the preictal, ictal and postictal are recorded on paper, without many pages of uneventful interictal information. During the past 16 months, the seizure monitoring system has been used as a clinical service to examine patients with surface electrodes (42), sphenoidal wires (25) and depth electrodes (7) during 146 recording sessions for over 3200 h of monitoring time while over 200 seizures have been recorded.