Seizure Threshold in Electroconvulsive Therapy: Effect of Instrument Titration Schedule

Background: Determination of seizure threshold can help guide selection of stimulus dosage in electroconvulsive therapy (ECT); however, this threshold is subject to a variety of influences. Objective: To compare the effect of two stimulus-titration schedules on initial seizure threshold, in 88 patients. Method: One strategy was to use the factory-set stimulus characteristics on the Thymatron DGx instrument, which includes uniform stimulus dose increments of 5% of maximum charge. The other strategy was our approximation of stimulus dose increments of 5% of maximum charge on the MECTA SR1 instrument. Subjects were assigned randomly in groups with three age-related stratifications. Results: Measured seizure thresholds were higher with the stimuli used from the MECTA schedule than with Thymatron in 79% of patients. Conclusions: The stimulus titration schedule used in ECT administration is clinically significant since it may affect both adverse consequences and therapeutic insufficiency (German J. Psychiatry 2001;51-56).