THE HALF-AGE STIMULATION STRATEGY FOR ECT DOSING

Energy levels affect the treatment efficacy and efficiency of electroc onvulsive therapy (ECT). United States devices require preselection of energy dosage before stimulating patients, and two strategies have be en proposed to determine an effective dosage, i.e., based on the patie nt's age and measured estimates of seizure threshold. The age method i s criticized for overstimulation and an assumed association with incre ased cognitive effects. Threshold determination strategy is cumbersome and requires multiple stimulations, possibly placing patients at incr eased cardiovascular risk. In 35 patients, we examined an energy estim ate for bilateral electrode placement at half the patient's age in ''p ercent of energy'' or joules delivered by the Thymatron and MECTA devi ces. Each patient required one stimulation in the first treatment to e licit motor seizures averaging 51.7 s. Subsequently, 20 patients were randomly assigned to either threshold titration followed by half-age f or the first two treatments or the opposite (AB-BA design). Half-age e nergy was 7 J (30%) higher than titration estimates, corresponding to 55% energy of the age method. The relation of half-age and titration e stimates were confirmed in energy dosing records from two independent centers. Energy dosing by half-age calculation in bilateral ECT is sim ple, practical, avoids overdosing and repeat stimulation, and is a use ful substitute for the more complex strategy based on threshold estima tion.