Limitations of Motor Seizure Monitoring in Ect

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.