CLINICAL HANDBOOK OF SCHIZOPHRENIA

20. Electroconvulsive Therapy 199FIGURE 20.1. Diagram of electrode placement sites. Left: Bitemporal electrode placement—Thecenter of the stimulus electrode is applied 2–3 cm above the midpoint of the line connecting theouter canthus of the eye and the external auditory meatus on each side of the patient’s head. Middle:Unilateral electrode placement—One electrode is positioned as in bitemporal electrode placementon the right side. The center of the other electrode is placed 2–3 cm to the right of the vertexof the skull. Right: Bifrontal electrode placement—The center of each electrode is placed 4–5 cmabove the outer canthus of the eye along a vertical line perpendicular to a line connecting thepupils. From Letemendia et al. (1993). Copyright 1993 by Cambridge University Press. Adapted bypermission.For bitemporal (BT) electrode placement, an electrode is placed on each temple,with the midpoint of each electrode 1 inch above the midpoint of the canthomeatusline.For right unilateral (RUL) electrode placement, one electrode is placed on the righttemple 1 inch above the midpoint of the canthomeatus line, and the other is placed 1 inchto the right side of the vertex of the skull.For bifrontal (BF) electrode placement, each electrode is place 2.5 inches above theouter external canthus of the eye.The general long-standing consensus is that BT electrode placement produces cognitiveside effects with high efficacy. Relative to BT electrode placement, RUL electrodeplacement at low dose may be less effective and slower in relieving depressive symptoms.At high-stimulus doses of greater than 378 mC for RUL, the difference betweenelectrode placements in terms of outcome decreases (McCall, Dunn, Rosenquist, &Hughes, 2002). Patients with schizophrenia may be treated with RUL, BT, or BF electrodeplacement, and electrode placement may be adjusted based on treatment outcomeand side effects.Stimulus DosingStimulus dosing can be influenced by many variables. For example, age and stimulusdosing are positively correlated; that is, the greater the age, the greater the stimulusdosage to elicit seizure activity. Moreover, the placement of the electrodes can influencestimulus dosage. For initial and subsequent treatments, BT electrode placement dosingis the same and generally should be performed at moderately suprathreshold stimulation,defined as 150% above the seizure threshold (1.5 times above seizure threshold).RUL ECT placement should be performed at moderately to markedly suprathresholdstimulation, which is 250–600% above the seizure threshold (2.5 to 6.0 times aboveseizure threshold).The empirical titration procedure (ETP), a commonly used method to ascertainand quantify the seizure threshold, is conducted by administering an initial dose of