Comparison of clinical efficacy and side effects for bitemporal and bifrontal electrode placement in electroconvulsive therapy

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.

Factors Associated With Delirium Following Electroconvulsive Therapy: A Systematic Review

OBJECTIVES

Delirium following electroconvulsive therapy (ECT) has been a clinical challenge, which, however, has not been investigated through a systematic literature review. The objective of this study was to systematically synthesize available evidence regarding factors associated with post-ECT delirium.

METHODS

We conducted a systematic literature search for any type of original investigations that reported risk factors of post-ECT delirium, using PubMed.

RESULTS

The literature search identified 43 relevant articles. One study found an association between catatonic feature and increased risk of postictal delirium. Five studies reported that the presence of cerebrovascular disease, Parkinson disease, or dementia was related to higher incidence of post-ECT delirium. Incidence of post-ECT course delirium was increased with bitemporal stimulation (3 studies). One study showed that ultrabrief pulse ECT reduced reorientation time following seizure compared with brief pulse ECT. High stimulus intensity resulted in more prolonged reorientation time after ECT than lower stimulus intensity (2 studies). Longer seizure length was significantly associated with post-ECT delirium in 1 study. Eight studies that examined postictal delirium in association with medications used, including lithium, did not show any consistent finding in their relationships. Four studies showed decreased incidence of postictal delirium in those receiving dexmedetomidine.

CONCLUSIONS

Limited evidence suggests that catatonic feature, cerebrovascular disease, Parkinson disease, dementia, bitemporal electrode placement, high stimulus intensity, or longer seizure length are associated with an increased risk of post-ECT delirium. Moreover, dexmedetomidine and ultrabrief pulse ECT seem to have preventive effects of post-ECT delirium.

Controlling stimulation strength and focality in electroconvulsive therapy via current amplitude and electrode size and spacing: comparison with magnetic seizure therapy

OBJECTIVES

Understanding the relationship between the stimulus parameters of electroconvulsive therapy (ECT) and the electric field characteristics could guide studies on improving risk/benefit ratio. We aimed to determine the effect of current amplitude and electrode size and spacing on the ECT electric field characteristics, compare ECT focality with magnetic seizure therapy (MST), and evaluate stimulus individualization by current amplitude adjustment.

METHODS

Electroconvulsive therapy and double-cone-coil MST electric field was simulated in a 5-shell spherical human head model. A range of ECT electrode diameters (2-5 cm), spacing (1-25 cm), and current amplitudes (0-900 mA) was explored. The head model parameters were varied to examine the stimulus current adjustment required to compensate for interindividual anatomical differences.

RESULTS

By reducing the electrode size, spacing, and current, the ECT electric field can be more focal and superficial without increasing scalp current density. By appropriately adjusting the electrode configuration and current, the ECT electric field characteristics can be made to approximate those of MST within 15%. Most electric field characteristics in ECT are more sensitive to head anatomy variation than in MST, especially for close electrode spacing. Nevertheless, ECT current amplitude adjustment of less than 70% can compensate for interindividual anatomical variability.

CONCLUSIONS

The strength and focality of ECT can be varied over a wide range by adjusting the electrode size, spacing, and current. If desirable, ECT can be made as focal as MST while using simpler stimulation equipment. Current amplitude individualization can compensate for interindividual anatomical variability.

Effectiveness of Bifrontal ECT in Practice: A Comparison with Bitemporal ECT

BACKGROUND

Bifrontal (BF) placement of electrodes in electroconvulsive therapy (ECT) has emerged as an alternative option to the conventional bitemporal (BT) and right unilateral electrode placement in view of fewer cognitive adverse effects. However, the results have been contradictory in terms of clinical efficacy.

MATERIALS AND METHODS

We studied the records of all patients referred for ECT between the months of August 2008 and July 2010 (n=1575). One hundred and five of these patients had received BF-ECT. These records were compared with the records of 105 patients who received BT-ECT. For each patient who received BF-ECT, the very next person posted for BT-ECT was taken as the control. All patients received bilateral ECTs at 1.5-times the threshold stimulus dose. The number of ECTs administered, duration of hospital stay after ECT initiation, seizure threshold and failure to achieve adequate seizures were compared. Two raters who achieved good inter-rater reliability assessed the initial severity using the clinical global impression scale and clinical improvement using a Likert scale.

RESULTS

The speed of response, as assessed by the number of ECTs received and the duration of hospital stay after ECT initiation was similar in the two groups. In addition, both groups were comparable in terms of clinical improvement scores on the Likert scale. BF-ECT patients also had a significantly higher seizure threshold, which remained significant in spite of controlling for age. This study is chart based, with its inherent limitations. Standard outcome measures were not used. Cognitive adverse effects were not studied.

CONCLUSIONS

BF-ECT performed similar to BT-ECT with regard to therapeutic efficacy. Given the consistent results of the former, with fewer cognitive side-effects, the findings of the present study support BF-ECT as the first line for electrode application.

Comparison of electroconvulsive therapy (ECT) with or without anti-epileptic drugs in bipolar disorder

BACKGROUND

Guidelines regarding the combination of anti-epileptic drugs (AEDs) and ECT have been contradictory. Evidence based knowledge about the advantages and disadvantages of this combination is sparse.

METHOD

We studied the records of consecutive non-epileptic bipolar disorder patients referred for ECT between the months of January 2006 and January 2008 in an academic psychiatric hospital. Seizure threshold, failure to achieve adequate seizures, maximum electrical charge received and the number of ECTs administered were compared between those who were on AEDs during ECT (AED patients; n=79) and those who were not on AEDs (NAED patients; n=122). Two raters who achieved good inter-rater reliability assessed the clinical outcome from the records using the Clinical Global Impression (CGI) scale.

RESULTS

AED patients had significantly greater proportion of males, longer duration of episode and treatment and higher co morbidity. AED patients had significantly higher seizure threshold, higher incidence of failure to obtain seizures and shorter duration of motor seizures. Both groups achieved comparable symptomatic improvement at the end of the ECT course [Mean (SD) CGI-I=2.0 (0.4) and 1.96 (0.3) in AED and NAED patients respectively; t=1.4; p=0.15]. However, AED patients had received significantly higher number of ECT sessions [mean (SD)=7.9 (3.0)] than NAED patients [mean (SD)=6.3 (2.1); t=4.3; p<0.01] and stayed for significantly longer time (days) in the hospital [Mean (SD) 25.1 (16.1) and 20.6 (10.5) in AED and NAED patients respectively; t=2.4; p=0.02]. The difference in the outcome remained significant even after controlling for the effects of duration of illness, gender, drug treatment and presence of co morbidity.

CONCLUSIONS

Symptomatic improvement of patients who are on AEDS during ECT is comparable to those who are not. However, AED patients required a significantly higher number of ECT sessions to achieve this. Prospective studies are required to confirm these findings and also to compare cognitive adverse effects.

Electroconvulsive therapy stimulus parameters: rethinking dosage

In this article, we review the parameters that define the electroconvulsive therapy (ECT) electrical stimulus and discuss their biophysical roles. We also present the summary metrics of charge and energy that are conventionally used to describe the dose of ECT and the rules commonly deployed to individualize the dose for each patient. We then highlight the limitations of these summary metrics and dosing rules in that they do not adequately capture the roles of the distinct stimulus parameters. Specifically, there is strong theoretical and empirical evidence that stimulus parameters (pulse amplitude, shape, and width, and train frequency, directionality, polarity, and duration) exert unique neurobiological effects that are important for understanding ECT outcomes. Consideration of the distinct stimulus parameters, in conjunction with electrode placement, is central to further optimization of ECT dosing paradigms to improve the risk-benefit ratio. Indeed, manipulation of specific parameters, such as reduction of pulse width and increase in number of pulses, has already resulted in dramatic reduction of adverse effects, while maintaining efficacy. Furthermore, the manipulation of other parameters, such as current amplitude, which are commonly held at fixed, high values, might be productively examined as additional means of targeting and individualizing the stimulus, potentially reducing adverse effects. We recommend that ECT dose be defined using all stimulus parameters rather than a summary metric. All stimulus parameters should be noted in treatment records and published reports. To enable research on optimization of dosing paradigms, we suggest that ECT devices provide capabilities to adjust and display all stimulus parameters.

Electrode placement in electroconvulsive therapy (ECT): A review of the literature

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.

Quantitative electroencephalographic analysis of bifrontal versus bitemporal electrode placement in a stable maintenance electroconvulsive therapy population

OBJECTIVE

Electrode placement in electroconvulsive therapy (ECT) is one of the many variables that can influence clinical outcome. Quantitative electroencephalographic (EEG) measures of the ECT-induced seizure have been studied in an attempt to determine differences in various electrode placements. The objective of this study was to evaluate the differences in the EEG between bifrontal (BF) and bitemporal (BT) placement.

METHOD

Seventeen patients of maintenance ECT (10 males and 7 females) who received both BT and BF ECTs for a 12-month period starting January 2007 were identified through chart review. Patients were included if their medications, dosages and ECT parameters, and clinical condition remained stable during the study period. Each patient received both BF (n = 124) and BT (n = 112) placements.

RESULTS

We found no significant differences in EEG measures between the 2 placements. We demonstrated that the qualitative EEG measures in both BT and BF electrode placements are similar.

CONCLUSIONS

Our findings support that BF electrode placement produces similar quality seizures when compared with BT placement and may be a viable alternative placement to BT.

Neuropsychologic effects of neuromodulation techniques for treatment-resistant depression: a review

Electroconvulsive therapy (ECT) and ablative neurosurgical procedures are established interventions for treatment-resistant depression (TRD), but their use may be limited in part by neuropsychological adverse effects. Additional neuromodulation strategies are being developed that aim to match or exceed the efficacy of ECT/ablative surgery with a better neurocognitive side effect profile. In this review, we briefly discuss the neurocognitive effects of ECT and ablative neurosurgical procedures, then synthesize the available neurocognitive information for emerging neuromodulation therapies, including repetitive transcranial magnetic stimulation, magnetic seizure therapy, transcranial direct current stimulation, vagus nerve stimulation, and deep brain stimulation. The available evidence suggests these procedures may be more cognitively benign relative to ECT or ablative neurosurgical procedures, though further research is clearly needed to fully evaluate the neurocognitive effects, both positive and negative, of these novel neuromodulation interventions.

Eletroconvulsoterapia na depressão maior: aspectos atuais

OBJETIVO: A eficácia da eletroconvulsoterapia em tratar sintomas depressivos está estabelecida por meio de inúmeros estudos desenvolvidos durante as últimas décadas. A eletroconvulsoterapia é o tratamento biológico mais efetivo para depressão atualmente disponível. O objetivo deste estudo foi demonstrar o papel da eletroconvulsoterapia no tratamento da depressão e destacar aspectos atuais relativos à sua prática. MÉTODO: Foram revisados na literatura estudos de eficácia, remissão de sintomas, fatores preditores de resposta, assim como aspectos atuais acerca da qualidade de vida, percepção dos pacientes, mecanismo de ação, técnica e prejuízo cognitivos. RESULTADOS: Os principais achados desta revisão foram: 1) a eletroconvulsoterapia é mais efetiva do que qualquer medicação antidepressiva; 2) a remissão da depressão com a eletroconvulsoterapia varia, em geral, de 50 a 80%; 3) Ainda é controverso o efeito da eletroconvulsoterapia nos níveis de fator neurotrófico derivado do cérebro (acho que aqui pode colocar entre parenteses o "BNDF"); 4) a eletroconvulsoterapia tem efeito positivo na melhora da qualidade de vida; 5) os pacientes submetidos à eletroconvulsoterapia, em geral, têm uma percepção positiva do tratamento. CONCLUSÃO: A eletroconvulsoterapia permanece sendo um tratamento altamente eficaz em pacientes com depressão resistente. Com o avanço da sua técnica, a eletroconvulsoterapia tornou-se um procedimento ainda mais seguro e útil tanto para a fase aguda, quanto para a prevenção de novos episódios depressivos.

A critical examination of bifrontal electroconvulsive therapy: clinical efficacy, cognitive side effects, and directions for future research

Bifrontal (BF) electroconvulsive therapy (ECT), although researched less extensively than bitemporal (BT) or right unilateral (RUL) ECT, has been suggested to be comparable to the other 2 electrode placements with respect to clinical efficacy while resulting in less cognitive impairment than BT ECT. Imaging studies have indicated that seizures induced by BF ECT affect the brain differently than BT or RUL ECT, in that BF ECT increases cerebral blood flow in the frontal lobes more intensely than either of the other 2 placements. Therefore, it is possible that the cognitive impairment manifested after a course of BF ECT could also be different than the impairment seen with BT and RUL ECT. Research conducted on cognitive impairment from BF ECT to date has been inadequate due to the use of nonspecific cognitive measures (such as the Mini-Mental Status Examination) or an inordinate focus on memory functioning (which is believed to be mostly subsumed in the temporal lobes). Because BF ECT increases cerebral blood flow in the frontal lobes more intensely than either of the other placements, research must instead focus on investigating the possible effects of BF ECT on executive functioning, which is believed to be subsumed in the frontal lobes. This is especially important because of the established relationship between executive dysfunction and depression and also because of the increasing popularity of BF ECT.

Strategies to minimize cognitive side effects with ECT: aspects of ECT technique

The adverse cognitive effects of electroconvulsive therapy are important limitations in the use of this treatment that continues to be a significant therapeutic strategy after 7 decades of use. Among the approaches to mitigation of these side effects are considerations involving the prescription and manipulation of the electrical stimulus itself. The impact of the following electrical factors on the cognitive outcomes of electroconvulsive therapy are surveyed: efficiency of the stimulus as expressed in electrical waveform; targeting of the stimulus, the major concept underlying electrode placement; stimulus dosing; and frequency and number of treatments. The current state of development of knowledge in these areas is summarized, and methods to achieve the best cognitive outcomes without sacrificing clinical efficacy are discussed. Future trends in the further optimization of the electrical stimulus are briefly mentioned.

Clinical efficacy and cognitive side effects of bifrontal versus right unilateral electroconvulsive therapy (ECT): a short-term randomised controlled trial in pharmaco-resistant major depression

BACKGROUND

In most studies right unilateral electroconvulsive therapy (ECT) has been shown to cause fewer cognitive side effects but less antidepressant efficacy compared with bi(fronto)temporal ECT at certain intensities.

AIMS

To compare the short-term efficacy and side effects of right unilateral ECT and bifrontal ECT.

METHODS

In a double-blind randomised controlled clinical trial, 92 patients diagnosed with pharmaco-resistant major depression received either six right unilateral ECT treatments (250% stimulus intensity of titrated threshold) or six bifrontal ECT (150% of threshold) treatments over a 3-week period. Concomitant psychotropic medications were continued during ECT treatments. The severity of depression and cognitive status was assessed prior to the first ECT and one day after the sixth ECT using the 21-item Hamilton Depression Rating Scale and the modified Mini Mental State Examination.

RESULTS

Eight patients did not complete the course of the study due to minor side effects or withdrawal of consent. The mean Hamilton Depression score decreased from 27 to 17 points in both groups of 46 patients, resulting in 12 responders (primary endpoint defined as a decrease >50%) in each patient group (95% confidence interval for the odds ratio from 0.35 to 2.8). There was no reduction in the modified Mini Mental State score (mean score 86 of 100 points).

CONCLUSIONS

Both bifrontal and right unilateral electrode placements in ECT were reasonably safe and moderately efficacious in reducing symptoms of pharmaco-resistant major depression.

Emerging treatments for depression

Established treatments for depression are often effective. However, a significant number of patients show limited or no response. With advancements in the explanation of the underlying neurobiology of depression, several novel therapeutic approaches have been developed. Emerging drug targets include novel monoamine oxidase inhibitors, triple monoamine re-uptake inhibitors, omega-3 fatty acids, melatoninergic agonists and receptor antagonists for corticotropin-releasing factor(1), glucocorticoid, substance-P and NMDA. Developments in therapeutic focal brain stimulation include vagus nerve stimulation, transcranial magnetic stimulation, magnetic seizure therapy and deep brain stimulation. The role of psychotherapy, both as monotherapy and as adjunctive therapy, is an active avenue of investigation. Although data on these treatments are limited, preliminary results are encouraging. A major goal that remains to be achieved is the identification of predictors of response to the various antidepressant treatments that have diverse mechanisms of action.

Recent advances in optimizing electroconvulsive therapy

This review aims to summarize and critically evaluate the evidence for recent advances and alternative approaches in electroconvulsive therapy (ECT) technique. Novel developments in ECT research are also mentioned. An EMBASE literature search was undertaken of clinical trials, case reports and research updates on novel and alternative approaches in ECT practice and research, including alternative electrode placements, variations in stimulus configuration, and novel developments (magnetic seizure therapy, focal electrical stimulation). The evidence for these approaches is reviewed, and implications for the optimizing of ECT in clinical practice are discussed. Evidence from studies suggests that unilateral ECT be given at substantially suprathreshold doses (at least 6 times seizure threshold) for maximizing efficacy, while bilateral ECT is likely to be effective at doses of 1.5-2.5 times seizure threshold. There is some evidence to support the use of bifrontal ECT, although further research is required to establish its efficacy and side-effects relative to standard unilateral and bilateral electrode placements. Other alternative electrode placements have been minimally studied. More advantageous efficacy side-effect outcomes may be achieved by reducing the pulse width and/or frequency of the ECT stimulus. Lastly, novel developments using alternative means of seizure induction (magnetic fields, focal electrical stimulation) may hold promise for the future. Clinical practice should be guided by a careful appraisal of the available evidence for alternative approaches in ECT technique.

Combined use of lamotrigine and electroconvulsive therapy in bipolar depression: a case series

OBJECTIVE

Lamotrigine and electroconvulsive therapy (ECT) are both safe and effective treatments for bipolar depression. Concerns exist that anticonvulsants may interfere with seizure expression during ECT or may exacerbate cognitive side effects, potentially affecting clinical response. This report examines the clinical use of concurrent ECT and lamotrigine for acute bipolar depression and the transition to maintenance therapy.

METHODS

Nine patients with acute bipolar depression were simultaneously treated with a course of ECT while titrating lamotrigine for maintenance therapy. We compared mean stimulus intensity, mean seizure duration, and mean time to orientation after treatment for each patient during treatment with their highest and lowest lamotrigine dose.

RESULTS

All 9 patients were treated to remission. From the lowest daily dose to the highest daily dose, mean increase in lamotrigine was 102.8 mg. Clinically adequate seizures were obtained in each patient. Lamotrigine had minimal effect on each measured ECT parameter. The interval between ECT treatments was spaced to a mean of 15.2 days. The treatment combination was well tolerated, with no serious adverse events, no rashes, and no worsening of cognitive side effects.

CONCLUSIONS

Concurrent use of lamotrigine with ECT in bipolar depression seems safe, did not interfere with routine ECT practice, and allowed for transition to maintenance pharmacotherapy.

Nonconvulsive seizures in electroconvulsive therapy: further evidence of differential neurophysiological aspects of bitemporal versus bifrontal electrode placement

In recent years, attention has been focused on the role of electrode placement in determining efficacy and cognitive side effects of electroconvulsive therapy (ECT). In particular, interest in bifrontal electrode placement has increased. Some evidence indicates differential therapeutic, cognitive, and neurophysiological aspects of bifrontal versus bitemporal ECT. Occasionally in ECT practice, electroencephalographic seizure activity is manifested in the absence of motor convulsive activity, a phenomenon termed nonconvulsive seizures. This probably indicates isolated prefrontal seizure activity in the absence of motor strip involvement. We reviewed our records and found that bifrontally treated patients had a significantly higher incidence of nonconvulsive seizures in ECT than did bitemporally treated patients. Seizure threshold was also higher among the bifrontal patients. We hypothesize that this provides further evidence of differential neurophysiology of seizures induced with these 2 electrode placements.

Advances in the treatment of depression

SUMMARY

Depression is a highly prevalent and disabling condition associated with significant morbidity and mortality. Currently available treatments for depression include tricyclic antidepressants, monoamine oxidase inhibitors, selective serotonin reuptake inhibitors, serotonin norepinephrine reuptake inhibitors, various atypical antidepressants, and electroconvulsive therapy. Although these treatments are effective, a significant number of patients do not respond or achieve sustained remission despite aggressive management. Advances in the neurobiology of depression have suggested a number of novel targets for antidepressant treatment. Based on an improved understanding of the neurobiology of depression, several novel pharmacologic and nonpharmacologic interventions are being developed. Pharmacologic developments include CRF antagonists, glucocorticoid receptor antagonists, substance P receptor antagonists, NMDA glutamate receptor antagonists, transdermal selegiline, so-called "triple" reuptake inhibitors, and augmentation of typical antidepressant medications with atypical antipsychotics. Nonpharmacologic advances have largely involved focal brain stimulation techniques including vagus nerve stimulation, transcranial magnetic stimulation, magnetic seizure therapy, and deep brain stimulation. For the most part, the data on these treatments are preliminary, and more study is needed to clarify their potential clinical benefit. However, it is clear that further study of the neurobiology of depression will continue to provide a rationale for developing innovative targets for antidepressant therapies.