Electroconvulsive Therapy Electrode Placement Research Articles

The Relative Effectiveness of Bilateral and Unilateral Electrode Placement in Electroconvulsive Therapy (ECT) in Patients With Major Depressive Disorder: A Retrospective Cohort Study.

Background This study is focused on the comparative efficacy of bilateral and unilateral electroconvulsive therapy (ECT) on depressive symptoms in patients at the Perth Clinic for the period from 2016 to 2021. Methods This was a retrospective cohort study of 485 patients who received ECT treatment. The expected improvements in depressive symptoms were evaluated by the Depression Anxiety Stress Scale(DASS)assessment tool filled out by the patients on admission and discharge from the hospital. Only the depression score of the DASS scale was utilised for this research. Results The results suggested that both electrode placements resulted in a significant improvement in depressive symptoms. The positive response rates for the bilateral and unilateral electrode placements were 78.3% and 71.6%, respectively. There was no difference between males and females in the average DASS score at discharge for bilateral and unilateral electrode placements. Conclusions This study confirmed that the results obtained at the Perth Clinic are similar to the existing international research results on the same topic. Bifrontal and unilateral ECT electrode placements are equally efficacious in improving depressive symptoms in patients suffering from major depressive disorder (MDD).

Clinical Practice Guidelines for the Use of Electroconvulsive Therapy.

Clinical Practice Guidelines for the Use of Electroconvulsive Therapy.

Fronto-medial electrode placement for electroconvulsive treatment of depression.

Electroconvulsive therapy (ECT) is the most effective treatment for severe treatment-resistant depression but concern about cognitive side-effects, particularly memory loss, limits its use. Recent observational studies on large groups of patients who have received ECT report that cognitive side-effects were associated with electric field (EF) induced increases in hippocampal volume, whereas therapeutic efficacy was associated with EF induced increases in sagittal brain structures. The aim in the present study was to determine whether a novel fronto-medial (FM) ECT electrode placement would minimize electric fields in bilateral hippocampi (HIP) whilst maximizing electric fields in dorsal sagittal cortical regions. An anatomically detailed computational head model was used with finite element analysis, to calculate ECT-induced electric fields in specific brain regions identified by translational neuroimaging studies of treatment-resistant depressive illness, for a range of electrode placements. As hypothesized, compared to traditional bitemporal (BT) electrode placement, a specific FM electrode placement reduced bilateral hippocampal electric fields two-to-three-fold, whilst the electric fields in the dorsal anterior cingulate (dAC) were increased by approximately the same amount. We highlight the clinical relevance of this specific FM electrode placement for ECT, which may significantly reduce cognitive and non-cognitive side-effects and suggest a clinical trial is indicated.

Impact of medications, mood state, and electrode placement on ECT outcomes in treatment-refractory psychosis

BackgroundTreatment-refractory psychosis (TRP) is a significant clinical challenge. While clozapine is frequently effective, alternate or augmentation strategies are often necessary. Evidence supports effectiveness of electroconvulsive therapy (ECT), but questions remain about optimal treatment parameters and impacts of concomitant pharmacotherapy. Objective/Hypothesis: To analyze the impact of clozapine, anticonvulsant medication, mood state, and ECT electrode placement on outcomes in TRP. We hypothesized that ECT would lead to greater reduction in positive symptoms, particularly in patients receiving clozapine. MethodsRetrospective study in a tertiary TRP program. The Positive and Negative Syndrome Scale (PANSS) was used for clinical outcomes, with positive subscore as primary outcome. Clinical and ECT data were analyzed using a linear modelling approach, controlling for relevant covariates. ResultsA total of 309 patients were included. ECT plus clozapine associated with greater improvement in positive, general, and total symptoms than ECT alone. ECT associated with greater improvement in negative symptoms in depressed patients. Bifrontal placement was mostly equivalent to bitemporal, with greater reduction of positive symptoms in patients receiving clozapine, and associated with lower electrical dose in patients on anticonvulsants. Clozapine increased seizure duration, while anticonvulsants decreased it. Anticonvulsant use in ECT patients associated with equivalent to slightly improved symptom reduction. ConclusionsECT's benefit in TRP may be greatest in patients receiving clozapine. ECT can improve negative symptoms in depressed TRP patients. Bifrontal placement is effective in TRP. Clozapine and anticonvulsants have opposite effects on seizure duration, but anticonvulsants may not adversely affect clinical outcomes of ECT for TRP.

Speed of electroconvulsive therapy for depression: Effects of electrode placement.

Electroconvulsive therapy (ECT) is a rapidly effective treatment for severe depression. Treatment with right unilateral (RUL) or bitemporal (BT) ECT may explain individual differences in speed of ECT effectiveness. There is limited evidence for demographic and clinical factors that predict speed of response and remission with ECT. We aimed to investigate differences in speed of improvement as well as achieving response and remission between twice-weekly brief-pulse high-dose (6 × seizure threshold) RUL ECT and moderate-dose (1.5 × seizure threshold) BT ECT. We also explored demographic and clinical characteristics that predict speed of response and remission. Weekly 24-item Hamilton Depression Rating Scale scores were assessed among patients with severe depression who participated in the EFFECT-Dep trial (ISRCTN23577151). Speed of improvement in patients randomised to RUL ECT (n=69) or BT ECT (n=69) was compared using independent sample t tests. Pearson's chi-square and Fisher's exact tests compared proportions of responders and remitters at each weekly assessment. Predictors of speed of response and remission were explored using Cox regression analyses. There were no significant differences between RUL and BT ECT in speed of improvement, response or remission. Exploratory analyses indicated that speed of response and remission were not predicted by a wide variety of demographic and clinical characteristics. ECT electrode placement did not have predictive value when determining speed of improvement, response and remission with ECT. Other clinical factors, such as cognitive side-effects, may be more relevant when making the clinical choice between RUL and BT ECT.

Is There Evidence That Stimulus Parameters and Electrode Placement Affect the Cognitive Side Effects of Electroconvulsive Therapy in Patients With Schizophrenia and Schizoaffective Disorder?: A Systematic Review.

Seventy percent of patients with treatment-resistant schizophrenia do not respond to clozapine. Electroconvulsive therapy (ECT) can potentially offer significant benefit in clozapine-resistant patients. However, cognitive side effects can occur with ECT and are a function of stimulus parameters and electrode placements. Thus, the objective of this article is to systematically review published clinical trials related to the effect of ECT stimulus parameters and electrode placements on cognitive side effects. We performed a systematic review of the literature up to July of 2020 for clinical studies published in English or German examining the effect of ECT stimulus parameters and/or electrode placement on cognitive side effects in patients with schizophrenia or schizoaffective disorder. The literature search generated 3 randomized, double-blind, clinical trials, 1 randomized, nonblinded trial, and 1 retrospective study. There are mixed findings regarding whether pulse width and stimulus dose impact on cognitive side effects. One study showed less cognitive side effect for right unilateral (RUL) than bitemporal (BT) electrode placement, and 2 studies showed a cognitive advantage for bifrontal (BF) compared with BT ECT. Only 1 retrospective study measured global cognition and showed post-ECT cognitive improvement with all treatment modalities using Montreal Cognitive Assessment in comparison to pre-ECT Montreal Cognitive Assessment scores. Current data are limited, but evolving. The evidence suggests that RUL or BF ECT have more favorable cognitive outcomes than BT ECT. Definitive larger clinical trials are needed to optimize parameter and electrode placement selection to minimize adverse cognitive effects.

The left anterior right temporal (LART) placement for electroconvulsive therapy: A computational modelling study

Electrode placement in electroconvulsive therapy (ECT) has a major impact on treatment efficacy and cognitive side effects. Left Anterior Right Temporal (LART) is a lesser utilised bilateral montage which may produce more optimal clinical outcomes relative to standard bitemporal ECT. In this study we used computational modelling to explore how stimulation effects from LART and two novel variants (LART – F3 and LART – Frontal) compared to the more common bilateral placements of bitemporal and bifrontal ECT. High resolution finite element human head models were generated from MRI scans of three subjects with Major Depressive Disorder. Differences in regional stimulation were examined through parametric tests for regions of interest and subtraction maps. Compared to bitemporal ECT, LART – Original resulted in significantly greater stimulation of the left cingulate gyrus (hypothesised to be associated with treatment efficacy), and relatively reduced stimulation of the bilateral hippocampi (potentially associated with cognitive side effects). No additional clinical benefit was suggested with the novel LART placements compared to the original LART. The original LART placement is a promising montage for further clinical investigation.

COMPARISON OF THE SPEED OF REMISSION BETWEEN BILATERAL AND RIGHT UNILATERAL ECT IN A COHORT OF GERIATRIC PSYCHIATRY PATIENTS

Introduction • Electroconvulsive therapy (ECT) has been clinically proven to be an effective form of treatment for severe depression. It is also a safe treatment option when a quick response is needed. ECT is especially useful in the geriatric population where the complications of severe depression like not eating or drinking, self-neglect, deteriorating medical co morbidities lead to increased morbidity and mortality. •Several studies have compared efficacy of the different electrode placements as well as any resulting cognitive side effects from ECT. • A randomized trial comparing bifrontal, bitemporal and right unilateral electrode placement in ECT (commonly referred to as CORE) showed clinical and statistically significant antidepressant outcomes with all three electrode placements. Bitemporal electrode placement in this study however resulted in a more rapid decline in symptoms over the early course of treatment leading to the recommendation that bitemporal leads be considered the preferred placement for urgent clinical situations. Of note the mean age characteristics of these patients was 53.1 and all carrying a diagnosis of Unipolar/bipolar depression with/without psychosis, receiving acute ECT treatment. • In Phase I of the PRIDE study, a sample of geriatric patients with severe depression were given RUL ECT 3?times a week. One of the secondary outcomes they looked at was the speed of remission which was determined by the number of RUL ECT treatments required to achieve remission. In this study, the mean number of RUL ECT treatments to achieve remission was 7.3. • In this retrospective chart review we hypothesized that using bitemporal electrode placement would lead to remission of symptoms with fewer ECT treatments than right unilateral placement among a strictly geriatric population. • Potentially fewer treatments could lead to lower treatment costs, reduce the risk of cognitive impairment and illness burden by achieving quicker response. Methods •Retrospective chart review of 20 inpatient psychiatry patients all over age 65. Diagnoses included Major depressive disorder with psychosis (6), without psychosis (11), Bipolar disorder, depressed (2) and schizoaffective disorder (1). •All 20 patients received and responded positively to acute ECT treatment at Mount Sinai Hospital administered 3 times a week. •10 patients received bitemporal treatment and 10 received right unilateral treatment. •Treatment outcome was measured by the Quick Inventory of Depressive Symptomatology (QIDS) before each ECT treatment. The QIDS-SR is a self-report inventory that measures depressive symptom severity in the following domains: sleep, psychomotor activity, appetite/weight, sad mood, concentration, energy, interest, guilt and suicidal ideations/intent. • We looked at QIDS scores at baseline and over the course determined how many ECT treatments each group received before their QIDS scores were reduced by 50%. Results Of the 20 patient ECT records reviewed, 11 were male and 9 females. 6 patients were between ages 66-70 and the remaining 14 patients were all above age 70. . At the start of ECT the average QIDS score for patients receiving bitemporal ECT was 19.8 and for RUL was 17. This indicates a moderate to severe depression from the QIDS inventory. . The average number of ECT treatments to achieve 50% QIDS score reduction in bitemporal ECT was 4.5 and that for RUL ECT was 4.1. Conclusions The average number of bitemporal ECT treatments to achieve a QIDS score reduction of 50% was 4.5 whilst that for right unilateral ECT was 4.1. • Patients that received bilateral ECT had higher average QIDS scores of 19.8 suggesting that sicker patients are treated with BL ECT. This could potentially have been because of a perceived need for a quicker response compared to RUL ECT which was not consistent with our findings. •We observed that there was little difference in the number of treatments needed to achieve fifty percent reduction in symptoms. From our findings it appears that in the geriatric population both bitemporal and right unilateral electrode placements have rapid onset of action with only a marginal difference. •Our study was limited by it being a retrospective medical chart review with only 20 patients. This research was funded by: Not Applicable

Volume of the Human Hippocampus and Clinical Response Following Electroconvulsive Therapy

BackgroundHippocampal enlargements are commonly reported after electroconvulsive therapy (ECT). To clarify mechanisms, we examined if ECT-induced hippocampal volume change relates to dose (number of ECT sessions and electrode placement) and acts as a biomarker of clinical outcome. MethodsLongitudinal neuroimaging and clinical data from 10 independent sites participating in the Global ECT-Magnetic Resonance Imaging Research Collaboration (GEMRIC) were obtained for mega-analysis. Hippocampal volumes were extracted from structural magnetic resonance images, acquired before and after patients (n = 281) experiencing a major depressive episode completed an ECT treatment series using right unilateral and bilateral stimulation. Untreated nondepressed control subjects (n = 95) were scanned twice. ResultsThe linear component of hippocampal volume change was 0.28% (SE 0.08) per ECT session (p < .001). Volume change varied by electrode placement in the left hippocampus (bilateral, 3.3 ± 2.2%, d = 1.5; right unilateral, 1.6 ± 2.1%, d = 0.8; p < .0001) but not the right hippocampus (bilateral, 3.0 ± 1.7%, d = 1.8; right unilateral, 2.7 ± 2.0%, d = 1.4; p = .36). Volume change for electrode placement per ECT session varied similarly by hemisphere. Individuals with greater treatment-related volume increases had poorer outcomes (Montgomery–Åsberg Depression Rating Scale change –1.0 [SE 0.35], per 1% volume increase, p = .005), although the effects were not significant after controlling for ECT number (slope –0.69 [SE 0.38], p = .069). ConclusionsThe number of ECT sessions and electrode placement impacts the extent and laterality of hippocampal enlargement, but volume change is not positively associated with clinical outcome. The results suggest that the high efficacy of ECT is not explained by hippocampal enlargement, which alone might not serve as a viable biomarker for treatment outcome.

Electroconvulsive therapy (ECT) in schizophrenia: a review of recent literature.

ECT remains an important, yet underutilized, treatment for schizophrenia. Recent research shows that medication-resistant patients with schizophrenia, including those resistant to clozapine, respond well to ECT augmentation. The purpose of this article is to review recent studies of the use of ECT in the treatment of schizophrenia. We performed an electronic database search for articles on ECT and schizophrenia, published in 2017. The main themes of these articles are: epidemiological data on ECT use from various countries; retrospective studies, prospective studies and meta-analyses focusing on efficacy and cognitive side-effects of ECT in schizophrenia; ECT technical parameters and potential biomarkers. There is growing evidence to support the use of ECT for augmentation of antipsychotic response in the treatment of schizophrenia. Cognitive side-effects are generally mild and transient. In fact, many studies show improvement in cognition, possibly related to the improvement in symptoms. There is wide variation among countries in the use of ECT for the treatment of schizophrenia. There are also variations in the choice of ECT electrode placement, parameters and schedules. These technical differences are likely minor and should not interfere with the treatment being offered to patients. Further, long-term studies are needed to optimize ECT treatment parameters, to examine the effect of maintenance ECT and to investigate neuroimaging/biomarkers to understand the mechanism of action and identify potential response predictors to ECT.

Resolution of Cognitive Adverse Effects of Electroconvulsive Therapy in Persons with Schizophrenia: A Prospective Study.

Background:Cognitive impairments are among the most important adverse effects of electroconvulsive therapy (ECT). Although much is known about them in patients with depression, there is very little information about these in persons with schizophrenia.Methods:In this study, we examined the persistence of cognitive impairments in a subsample of patients (n = 49) with schizophrenia who had earlier participated in a clinical trial comparing the therapeutic and cognitive efficacy of bifrontal ECT (BFECT; n = 23) and bitemporal ECT (BTECT; n = 29) electrode placements. Total scores on Hindi Mental State Examination, processing speed, working memory, and verbal fluency were assessed in these patients at two points: first, at the end of their respective ECT course and at the follow-up (mean [standard deviation] = 98.7 [38.3] days). The course of cognitive impairments was assessed in all patients (n = 49) as a single group. Further, BFECT and BTECT patients were also compared with one another.Results:ECT-induced acute cognitive impairments in patients with schizophrenia had normalized by the end of 3 months’ follow-up post-ECT. All the tested parameters in the realm of Hindi Mental Status Examination, speed of processing, sequencing, spatial and working memory and verbal fluency showed recovery. Further, across all tests, BFECT and BTECT ultimately had similar scores at the follow-up though BFECT performed relatively better with regards to the acute effects. In fact, worst performing BTECT group caught up to recover to comparable levels of performance by the end of follow-up.Conclusions:In patients with schizophrenia, most of acute ECT-induced cognitive impairments recover by the end of 3 months’ post-ECT. Further, different electrode placements do not seem to make any difference regarding ultimate recovery of cognitive deficits. Future prospective studies are needed that could address the limitations of this study.

Letter to the Editor: Electrode placement in electroconvulsive therapy - bilateral is still the 'gold standard' for some patients.

Letter to the Editor: Electrode placement in electroconvulsive therapy - bilateral is still the 'gold standard' for some patients.

Letter to the Editor: Electrode placement in electroconvulsive therapy – bilateral is still the ‘gold standard’ for some patients: a reply

Letter to the Editor: Electrode placement in electroconvulsive therapy – bilateral is still the ‘gold standard’ for some patients: a reply

Comparison of electric field strength and spatial distribution of electroconvulsive therapy and magnetic seizure therapy in a realistic human head model

BackgroundThis study examines the strength and spatial distribution of the electric field induced in the brain by electroconvulsive therapy (ECT) and magnetic seizure therapy (MST). MethodsThe electric field induced by standard (bilateral, right unilateral, and bifrontal) and experimental (focal electrically administered seizure therapy and frontomedial) ECT electrode configurations as well as a circular MST coil configuration was simulated in an anatomically realistic finite element model of the human head. Maps of the electric field strength relative to an estimated neural activation threshold were used to evaluate the stimulation strength and focality in specific brain regions of interest for these ECT and MST paradigms and various stimulus current amplitudes. ResultsThe standard ECT configurations and current amplitude of 800–900mA produced the strongest overall stimulation with median of 1.8–2.9 times neural activation threshold and more than 94% of the brain volume stimulated at suprathreshold level. All standard ECT electrode placements exposed the hippocampi to suprathreshold electric field, although there were differences across modalities with bilateral and right unilateral producing respectively the strongest and weakest hippocampal stimulation. MST stimulation is up to 9 times weaker compared to conventional ECT, resulting in direct activation of only 21% of the brain. Reducing the stimulus current amplitude can make ECT as focal as MST. ConclusionsThe relative differences in electric field strength may be a contributing factor for the cognitive sparing observed with right unilateral compared to bilateral ECT, and MST compared to right unilateral ECT. These simulations could help understand the mechanisms of seizure therapies and develop interventions with superior risk/benefit ratio.

The Clinical and Service Outcomes of Unilateral and Bilateral ECT Electrode Placements in Australian Aged Psychiatry Services

The aim of the study was to determine whether depressed aged inpatients treated with brief pulse unilateral electroconvulsive therapy (ECT) differed from those treated with bilateral (bitemporal or bifrontal) ECT with respect to numbers of treatments, length of hospital admission, changes in scores on depression and cognitive scales, and serious adverse effects. An audit of routinely collected data regarding 221 acute ECT courses in 7 public aged psychiatry services in Victoria, Australia. Patients given unilateral, bifrontal, and bitemporal treatments were similar with respect to personal, clinical, and treatment characteristics. Most treatments were administered in line with local clinical guidelines and were rated as effective. Psychiatrists preferred unilateral ECT in the first instance with stimulus dosing based on patients' seizure thresholds. Approximately a quarter of unilateral courses were switched later to bitemporal placement, most probably because of insufficient progress. Bilateral treatments were associated with a larger number of treatments, less improvement in scores on mood and cognitive scales, and more refusals to continue treatment than unilateral-only ECT. Brief pulse unilateral ECT proved more effective than bitemporal and bifrontal ECT for most aged patients, especially when coupled with stimulus dosing based on seizure threshold.

Maximum Fractal Dimension of Cerebral Seizure Remains Constant Through the Course of Electroconvulsive Therapy

Electroconvulsive therapy (ECT), in which electrical current is used to induce seizures, is an effective treatment in psychiatry. Different methods of analyzing the electroencephalogram (EEG) changes during ECT have been studied for predicting clinical outcome. Analysis of the fractal dimension (FD) is one such method. Mid-seizure and post-seizure FD has been shown to correlate with antidepressant effect. In this study, we examined whether the highest fractal dimension achieved during each ECT session changed over the course of 6 ECTs. The sample for this study came from a randomized controlled trial, comparing the efficacy of bifrontal and bitemporal electrode placements in schizophrenia. EEG was recorded using bilateral frontal pole leads during all ECT sessions. In 40 of the 114 randomized patients, we could obtain artifact-free EEGs for the first 6 ECT sessions. FD was calculated using standardized algorithms. For each session, the average of 5 highest FDs was calculated. The change in this value over a course of 6 ECTs was analyzed using repeated-measures analysis of variance. The average highest FD remained virtually unchanged across the 6 ECT sessions. Means (standard deviations) average maximum FDs over the 6 sessions were 1.57 (0.075), 1.57 (0.064), 1.56 (0.064), 1.57 (0.062), 1.55 (0.07), and 1.56 (0.067); occasion effect, F = 0.5, P = .75. Group effect (F = 0.01, P = .92) and group × occasion interaction effect (F = 1.88, P = .1) were not significant, suggesting no influence of electrode placement on maximum FD. Seizure duration, however, showed significant decline over the course of ECT. Maximum FD of ECT-induced EEG seizure remains fairly constant over frontal poles across the first 6 ECT sessions, which is true irrespective of ECT electrode placements.

Could Sleep Characteristics Guide ECT Electrode Placement: Implication for Bipolar Mixed States

Copyright: © 2013 Youssef NA. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Despite advances in treatment of depression, Treatment-Resistant Depression (TRD) is still one of the most serious conditions. Severe depression has a huge negative impact on morbidity and mortality due to both mental and physical health of individuals, families, and society. Whether for Major Depressive Disorder (MDD) or Bipolar Disorder (BD), Electroconvulsive Therapy (ECT) has been the most potent and most rapidly acting form of treatment for TRD and/or sociality over the last 70 years.

Left Unilateral Electroconvulsive Therapy (ECT) After Oligodendroglioma Resection

A 44-year-old man with a previously resected right parietal oligodendroglioma received left unilateral electroconvulsive therapy (ECT). We present images of his brain magnetic resonance imaging, ECT electrode placement, and the electroencephalogram tracing from his ECT.

Regional electric field induced by electroconvulsive therapy in a realistic finite element head model: influence of white matter anisotropic conductivity.

We present the first computational study investigating the electric field (E-field) strength generated by various electroconvulsive therapy (ECT) electrode configurations in specific brain regions of interest (ROIs) that have putative roles in the therapeutic action and/or adverse side effects of ECT. This study also characterizes the impact of the white matter (WM) conductivity anisotropy on the E-field distribution. A finite element head model incorporating tissue heterogeneity and WM anisotropic conductivity was constructed based on structural magnetic resonance imaging (MRI) and diffusion tensor MRI data. We computed the spatial E-field distributions generated by three standard ECT electrode placements including bilateral (BL), bifrontal (BF), and right unilateral (RUL) and an investigational electrode configuration for focal electrically administered seizure therapy (FEAST). The key results are that (1) the median E-field strength over the whole brain is 3.9, 1.5, 2.3, and 2.6 V/cm for the BL, BF, RUL, and FEAST electrode configurations, respectively, which coupled with the broad spread of the BL E-field suggests a biophysical basis for observations of superior efficacy of BL ECT compared to BF and RUL ECT; (2) in the hippocampi, BL ECT produces a median E-field of 4.8 V/cm that is 1.5-2.8 times stronger than that for the other electrode configurations, consistent with the more pronounced amnestic effects of BL ECT; and (3) neglecting the WM conductivity anisotropy results in E-field strength error up to 18% overall and up to 39% in specific ROIs, motivating the inclusion of the WM conductivity anisotropy in accurate head models. This computational study demonstrates how the realistic finite element head model incorporating tissue conductivity anisotropy provides quantitative insight into the biophysics of ECT, which may shed light on the differential clinical outcomes seen with various forms of ECT, and may guide the development of novel stimulation paradigms with improved risk/benefit ratio.

Electrode Placement in Electroconvulsive Therapy (ECT)

Electrode placement in electroconvulsive therapy affects both the efficacy and adverse cognitive effect profile of the treatment. For many years, 2 placements, bitemporal (also referred to as "bifrontotemporal" or simply "bilateral") and right unilateral, were the principal placements in widespread clinical use. More recently, bifrontal placement has joined their ranks as a commonly used placement. In this article, we review the evidence base for the efficacy and safety of each of these electrode placements for the indication of depression, describe another novel placement, and then draw conclusions from this available evidence base, pointing out areas in need of further study.