A quick and reliable EEG montage for the detection of seizures in the critical care setting

Abstract

Obtaining an emergent EEG for the diagnosis of nonconvulsive status epilepticus and conconvulsive seizures in the intensive care unit raises logistic problems in most hospitals. Previous studies have looked into the hairline EEG for a broader population than the critically ill, with controversial conclusions. The authors created a montage sufficiently simple to be performed and interpreted by residents and rapidly achievable to meet the time constraints of a busy on-call schedule. Seven electrodes (Fp1, Fp2, T3, T4, O1, O2, and Cz), easily applied without the need for tape measure by using only anatomic landmarks (pupils, ears, vertex, and inion), were used to configure three different montages: double diamond, circumferential, and Cz referential. EEG records obtained with the full 10-20 system in critically ill patients were reformatted into these montages and reviewed retrospectively independently by neurology attending physicians with expertise in EEG interpretation and senior neurology residents. A comparison was done with the previously studied hairline EEG. The average sensitivity of the study montage for seizure detection was 92.5%, whereas the average specificity was 93.5%. These results suggest that the seven-electrode montage could potentially be a quick and reliable EEG montage for the detection of seizures in the intensive care unit, when technical support is not available. Further prospective studies are required to validate these promising results in a larger population sample.