Optimizing ECT technique.

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Abstract

To the Editor: The special issue of the Journal of ECT (Vol 24, No 1, 2008) focused on and brought together a wealth of information on cognitive side effects of electroconvulsive therapy (ECT). Some patients still experience unacceptable cognitive impairment from ECT. They should not have to. Numerous strategies are available to optimize ECToutcome: varying ECT technique, anesthesia, and pharmacological interventions. We have reported of a large series of ECT without cognitive deficits. The design of the ECT devices used in these series was based on animal experiments devised to optimize ECT stimulus. Apparently, safe and effective ECT is possible, given proper stimulus characteristics and electrode placement. Electroconvulsive therapy stimulus has several parameters, none of which quantifies it adequately. Pulse shape, width, frequency, peak current, stimulus duration, energy, charge, and power cannot be changed independently. The optimal combination remains unknown, but progress is being made. Ultrabrief pulses and longer stimuli of up to 8-second duration are becoming more common. The optimal frequency and peak current are not yet known. Unilateral ECT (UL) causes less cognitive damage than bilateral ECT, but it may be less effective. Various electrode placements have been used, but others might be more advantageous. The use of UL initially focused on nondominant hemisphere to minimize cognitive deficits; but because laterality does not really matter, most clinicians use right unilateral ECT. R.D. Maxwell suggested alternating sides with UL (verbal communication, circa 1978) on the basis that UL repeated on the same side produced EEG slowing with delta and theta waves consistent with encephalopathy and ECT-induced brain dysfunction, whereas alternating sides did not. In my experience, he was correct, and alternating sides reduces cognitive deficits substantially. He also suggested a diagonal electrode placement of electrodes to maximize the current flow through the centrencephalic regions, placing one electrode frontotemporally on one side and the other occipitally on the other side. This holds a promise of higher efficacy if the generalization of seizure activity to the deeper brain structures is the key to its therapeutic effect. Another idea for electrode placement comes from anesthesia. Electroanalgesia uses placement of one electrode on the forehead and two electrodes behind the ears. This results in the electric current flowing along the CSF duct and surrounding structures, including the limbic system. Further improvements in safety and efficacy of ECT are certainly possible.