Limitations of motor seizure monitoring in ect

Abstract

Seizures were monitored using both cuff method and EEG, during the first ECT session in 158 consecutive patients. All developed adequate EEG seizures (≥25 seconds). Twelve patients (8%) did not develop adequate motor seizures (15 seconds), of whom ten had no convulsive response. EEG seizure duration was less than 120 seconds in 117 patients (Group-A) and 120 or more seconds (prolonged) in the remaining 37 patients (Group-B). Adequate but not prolonged motor seizure (15-89 seconds) occurred in 111 patients in group A and 18 patients in group B. Motor seizure of 90 or more seconds (prolonged seizure) occurred in four patients in group A and 13 patients in group B. Based on the motor seizure criterion, 60% (18/31) of patients with prolonged EEG seizure were missed. The motor and EEG seizure durations correlated significantly in both groups. The correlation coefficient in group A was 0.78 (p< 0.01), which was significantly larger (Fisher's 'Z' transformation test, t=3.12, p< 0.01) than that in group B (0.37; p< 0.05). Out of the total 158 patients, motor seizure monitoring alone did not correctly classify 21.4% of ECT seizure. This could have resulted in either unnecessary re-stimulation or failure to detect prolonged seizure. The findings suggest that in ECT motor seizure monitoring alone is unsatisfactory and therefore the need for EEG seizure monitoring.

Keywords: EEG monitoring; Electroconvulsive therapy; prolonged seizures.