Stimulus Titration and ECT Dosing

Abstract

The seizure threshold to electroconvulsive therapy (ECT) is defined entirely by the duration of the induced seizure, is multidetermined, and varies enormously with a wide variety of patient and treatment factors, including especially the parameters of the ECT stimulus. No consistent relationship has ever been detected between the clinical antidepressant response to ECT and either the threshold or the duration of the induced seizure. The stimulus titration method for determining the seizure threshold (titration-threshold dosing) was the central research tool used to reverse years of dogma by proving that the induced seizure of ECT is not alone sufficient to explain the therapeutic properties of ECT, and that the interaction between dosage and treatment electrode placement is critical in this regard. In clinical use, however, titration-threshold dosing has proven less than fully effective in optimizing the stimulus dose for ECT-better results are consistently obtained with age-based or fixed high-dose methods. The lack of a direct correlation between either seizure threshold or duration and clinical ECT response is an irremediable flaw of the titration-threshold method as clinically applied. New approaches are now called for in which ECT stimulus dosage is set and adjusted ("titrated") according to the clinical antidepressant response of the patient or to measurable correlates thereof: maximum sustained electroencephalogram (EEG) ictal power, EEG postictal suppression, induced interictal EEG delta activity, peak heart rate, maximum sustained EEG coherence, and postictal EEG coherence reduction, all of which have been found by various investigators to be related to the clinical antidepressant response to ECT.

Influence of Age on Effectiveness and Tolerability of Electroconvulsive Therapy

“…At least 25 seconds' duration measured in the EEG and 20 seconds measured in the EMG are required, 17 and computer-recorded EEG and EMG estimations of the seizure duration are of sufficient quality in most cases. 19 Nevertheless, up to now, no significant correlations between the clinical effectiveness of ECT and the duration of convulsions 16,20,21 could be shown. Moreover, at least in the case of unilateral ECT, higher stimulation energy may result in a shorter duration of convulsions, 22 although the clinical effectiveness is higher.…”

“…Stimulus intensity was determined using the modified age method in the case of unilateral stimulation and the half-age method in the case of bilateral stimulation as described in detail by Abrams. 16 During the first stimulation, device adjustment was carried out with charge limits ranging between 30% and 60%, representing a charge of 151 and 302 millicoulombs (mC), respectively. Only in very few cases (G5%) was dose titration used before the initial treatment session.…”

Dopamine D3 receptor gene variation: impact on electroconvulsive therapy response and ventral striatum responsiveness in depression

“…In case of insufficient clinical response, another six to 12 sessions were administered depending on clinical improvement. In order to obtain a sufficient response to ECT, in most cases initial stimulus intensity was determined by the modified age method prior to the first ECT treatment session according to Abrams (2002). In cases of insufficient response [seizure activity <25 s according to electroencephalography (EEG)], restimulation and dose titration in 5-10 % steps was carried out to increase seizure activity.…”

The influence of concomitant antidepressant medication on safety, tolerability and clinical effectiveness of electroconvulsive therapy

“…The length of a stimulus train was 0.14 Á/8 s (5.29/1.9 s). Stimulus intensity was determined using the modified age method in case of unilateral stimulation and half-age method in case of bilateral stimulation (Abrams 2002). Lower and upper charge limits during the first stimulation were 30 and 60% device adjustment representing a charge of 151 and 302 mC, respectively.…”

“…In most cases computer-automated electroencephalographic and electromyographic estimation of the seizure duration is of sufficient quality (Swartz et al 1994). But it is also known that there is no significant correlation between the therapeutic effectiveness of ECT and the duration of convulsions (Abrams 1972(Abrams , 2002Nobler et al 1993). Especially during unilateral ECT, a higher stimulation energy together with a higher clinical efficacy ) may lead to shorter convulsions (Frey et al 2001).…”