An evaluation of ambulatory, cassette EEG monitoring

Abstract

Ambulatory EEGs using cassette tape recorders have only four channels. Questions have been raised about the limitations this imposes on detection of focal interictal epileptiform events. A review of EEGs from inpatients undergoing prolonged monitoring demonstrated an overwhelming representation of these abnormalities in the frontal and anterior temporal scalp regions. Three-channel montages were designed to sample these regions and were tested by simultaneously recording them with multichannel montages. Successful montages combining a frontal transverse and two longitudinal channels adequately detected 74 to 100% of interictal epileptic events.