Electrode placement in ECT: cognitive effects

Abstract

SYNOPSIS Forty patients suffering from a major depressive disorder, for whom electroconvulsive therapy (ECT) was clinically indicated, were assigned to one of three electrode placement groups: bitemporal (BT), right unilateral (RU) or bifrontal (BF). Comparisons of these groups in terms of cognitive status showed that the BF placement, which avoided both temporal regions, spared both verbal and nonverbal functions. These differential effects, which were independent of the degree of clinical depression, were not, however, evident three months after the last ECT.

Bifrontal Versus Right Unilateral and Bitemporal Electroconvulsive Therapy in Major Depressive Disorder

“…[7][8][9] Changing the placement of electrodes has been a major method of attempting to decrease the cognitive side effects of ECT. 8 The most common electrode placements have been bitemporal (BT) and right unilateral (RUL). The American Psychiatric Association 4 Task Force on ECT recommends the routine use of RUL method for ECT.…”

“…8 In comparison with BT placement, BF may have less impact on both verbal and nonverbal memory by avoiding both temporal regions. 5,[7][8][9] In one study, there was no difference in the BT and BF groups in the number of ECT sessions required to meet the remission criteria of depression.…”

Brain stimulation in psychiatry and its effects on cognition

“…studies investigating the use of bifrontal eCt indicate that this technique could be as efficacious as temporal Bl eCt while producing less-severe cognitive impairment. [20][21][22][23] such findings suggest that eCt may exert its primary therapeutic effect in the frontal lobes; however, an insufficient number of high-quality studies have adequately addressed this question to date. 24 the most recently investigated eCt modification involves shortening the width of the electrical pulse delivered.…”

Asymmetric Bilateral Right Frontotemporal Left Frontal Stimulus Electrode Placement for Electroconvulsive Therapy

“…The angles between electrode axes for bifrontotempo ral placement, the constructed placement, and bifrontal ^ placement [24] approximate 180,90 and 0°C, respective ly; the interelectrode distances for the latter two are 80 and 45% of bifrontotemporal, respectively. Figure 1 illus trates a skull cross-section traced from a normal MRI scan just above the eyes, which are noted; graphically, the cross-sectional area associated with the constructed place ment is about 80% of that for bifrontotemporal place ment, while that for bifrontal placement is under 10%.…”

“…The lateral edge of the left electrode is medial to the bony intersection ridge between the temple and the forehead; visual survey reveals that this intersection commonly varies from above the lateral canthus to above the center of the eye. The left electrode is 3-5 cm anterior to a described bifrontal place ment site [24] and 5-7 cm anterior to the standard fronto temporal site. Previous report of this placement is not known.…”