Focal Electroconvulsive Therapy for Depression

This pilot, open label investigation evaluates the safety and efficacy of a new form of electroconvulsive therapy (ECT). Both the efficacy and adverse cognitive effects of ECT are highly contingent on the intracerebral current paths and current density of the ECT stimulus. However, the impedance of the skull and individual differences in skull anatomy severely limit the spatial targeting of stimulation, and create marked individual differences in intracerebral current density. To address these problems, the investigators are exploring various means of overcoming this limitation. An approach is to modify the electrical stimulus to induce focal seizures. The most common methods of ECT administration in the US use a bidirectional, constant current, brief pulse, with large (approximately 3 sq. in. surface area) and identically sized and shaped electrodes. In contrast, in this protocol the investigators have coupled unidirectional current flow with an electrode geometry involving a small and large electrode that differ by more than 3:1 in surface area. Unidirectional currents were widely used in ECT during the, 1940's and continue to be used in European and American devices today. Transcranial electrical stimulation can be made focal by stimulating with an anode-cathode arrangement, with the electrodes differing in surface area. The investigators have shown in nonhuman primates the capacity to produce focal frontal seizure induction under conditions when a unidirectional current flows from a small anterior anode (placed on the forehead over the nasion) to a large posterior cathode just anterior to the motor strip. Furthermore, the investigators expect that some, if not all, of these seizures do not result in motor convulsions. Thirty outpatients referred for ECT will participate. Relative to concurrent reference data from our ongoing ECT protocols, the investigators hypothesize that acute and subacute adverse cognitive effects of FEAST will be substantially less than those in patients receiving state-of-the art ECT, but with a traditional bidirectional, nonfocal stimulus. The investigators also hypothesize that the majority of patients will remit with FEAST. Thus, by improving the efficiency of the ECT stimulus with the switch to unidirectional current and the use of a new electrode geometry, the investigators expect to be able to induce focal seizures. The investigators hypothesize that this pilot study will provide evidence that this treatment is superior to traditional ECT in having lower dosing requirements and a superior side effect profile.