Missed seizure (motor seizure duration <15 seconds and/or EEG seizure duration <20 seconds) in ECT even with the maximum stimulus dose delivered by the machine is clinically challenging. The maximum deliverable dose in many countries is up to 576mC, although in UK and some parts of Europe this is nearly double.

This study examined the incidence of missed seizures at the standard dose of 500mC set on the ECT machine. The effect of using higher stimulus intensity in in-patient with missed seizure was evaluated.

All patients who were initiated a course of ECT over one year period formed the sample (n=70; F=52, M=18). The tool used in data collation included demographic, clinical and ECT parameters. The ECT parameters included stimulus laterality, dosage administered, motor and EEG seizure duration of the last ECT treatment.

Six (8.5%) patients had missed seizures at 500mC. Two of them had adequate seizures at a higher stimulus dose (706 and 760mC each).The remaining four failed to have adequate seizures even when the stimulus dose was set at 1000mC. Of the six patients four were females, five received bilateral ECT and three each were on mood stabilizers and benzodiazepines. The average age and number of ECT treatment were 63.3 years and 12 respectively. All had moderate to severe depression except one (bipolar depression).

In a proportion of patients with missed seizures higher stimulus (>576mC) produces adequate seizures. The effect of this on cognition need to be further studied.