Electroconvulsive therapy stimulus parameters: rethinking dosage

Confirmatory Efficacy and Safety Trial of Magnetic Seizure Therapy for Depression (CREST-MST): study protocol for a randomized non-inferiority trial of magnetic seizure therapy versus electroconvulsive therapy

BACKGROUND

Electroconvulsive therapy (ECT) is well-established and effective for treatment-resistant depression (TRD), but in Canada and the USA, less than 1% of patients with TRD receive ECT mainly due to its cognitive adverse effects (i.e. amnesia). Thus, new treatment alternatives for TRD are urgently needed. One such treatment is magnetic seizure therapy (MST). ECT involves applying a train of high-frequency electrical stimuli to induce a seizure, whereas MST involves applying a train of high-frequency magnetic stimuli to induce a seizure.

METHODS

In this manuscript, we introduce our international, two-site, double-blinded, randomized, non-inferiority clinical trial to develop MST as an effective and safe treatment for TRD. This trial will compare the efficacy of MST to right unilateral ultra-brief pulse width electroconvulsive therapy (RUL-UB-ECT) with a combined primary endpoint of remission of depression and superior cognitive adverse effects in 260 patients with TRD. Amelioration of suicidal ideation will be assessed as a secondary endpoint. Inpatients or outpatients, over 18 years of age with a MINI International Neuropsychiatric Interview (MINI) diagnosis of non-psychotic major depressive disorder (MDD) can be enrolled in the study provided that they meet illness severity and full eligibility criteria. Participants are randomized to receive MST or RUL-UB ECT, 2-3 days per week over seven weeks, or a maximum of 21 treatments. The study will involve before-, during-, and after-treatment assessments of depression severity, suicidal ideation, subjective side-effects, and cognitive performance consistent with an intent-to-treat study design approach.

DISCUSSION

Positive results from this trial could have an immediate and tremendous impact for patients with TRD. If MST demonstrates comparable antidepressant treatment efficacy to ECT, but with greater cognitive safety, it could rapidly be adopted into clinical practice. Indeed, given that the administration of MST is nearly identical to ECT, the majority of ECT facilities in North America could readily adopt MST. Furthermore, the potential for cognitive safety could lead to improved treatment acceptability. Healthcare providers, patients and care partners, and policymakers would therefore demand this form of convulsive therapy.

TRIAL STATUS

Enrollment for this study began on June 26, 2018, and is estimated to complete recruitment by July 2024. At the time of submission, we have enrolled and randomized 117 participants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03191058 , Registered on June 19, 2017. Primary sponsor: Daniel Blumberger (DMB), Principal Investigator Daniel.Blumberger@camh.ca , 416-535-8501 x 33662 Contact for public queries: DMB, Daniel.Blumberger@camh.ca Contact for scientific queries: ZJD, Zdaskalakis@health.ucsd.edu.

Electric neurostimulation regulates microglial activation via retinoic acid receptor α signaling

Brain stimulation by electroconvulsive therapy is effective in neuropsychiatric disorders by unknown mechanisms. Microglial toxicity plays key role in neuropsychiatric, neuroinflammatory and degenerative diseases. We examined the mechanism by which electroconvulsive seizures (ECS) regulates microglial phenotype and response to stimuli. Microglial responses were examined by morphological analysis, Iba1 and cytokine expression. ECS did not affect resting microglial phenotype or morphology but regulated their activation by Lipopolysaccharide stimulation. Microglia were isolated after ECS or sham sessions in naïve mice for transcriptome analysis. RNA sequencing identified 141 differentially expressed genes. ECS modulated multiple immune-associated gene families and attenuated neurotoxicity-associated gene expression. Blood brain barrier was examined by injecting Biocytin-TMR tracer. There was no breakdown of the BBB, nor increase in gene-signature of peripheral monocytes, suggesting that ECS effect is mainly on resident microglia. Unbiased analysis of regulatory sequences identified the induction of microglial retinoic acid receptor α (RARα) gene expression and a putative common RARα-binding motif in multiple ECS-upregulated genes. The effects of AM580, a selective RARα agonist on microglial response to LPS was examined in vitro. AM580 prevented LPS-induced cytokine expression and reactive oxygen species production. Chronic murine experimental autoimmune encephalomyelitis (EAE) was utilized to confirm the role RARα signaling as mediator of ECS-induced transcriptional pathway in regulating microglial toxicity. Continuous intracerebroventricular delivery of AM580 attenuated effectively EAE severity. In conclusion, ECS regulates CNS innate immune system responses by activating microglial retinoic acid receptor α pathway, signifying a novel therapeutic approach for chronic neuroinflammatory, neuropsychiatric and neurodegenerative diseases.

Total Charge Required to Induce a Seizure in a Retrospective Cohort of Patients Undergoing Dose Titration of Right Unilateral Ultrabrief Pulse Electroconvulsive Therapy

OBJECTIVES

The use of ultrabrief pulse (UBP) stimuli and individual seizure threshold determination have been proposed as ways of minimizing the cognitive side effects of electroconvulsive therapy (ECT), but large samples of patients receiving UBP ECT are lacking. This study reports a retrospective cohort of patients receiving an index course of right unilateral UBP ECT and characterizes the amount of charge required to induce a seizure.

METHODS

A single-center retrospective chart review was conducted of adult patients receiving a first lifetime course of ECT using an UBP titration from 2005 to 2017.

RESULTS

There were 2328 patients that received a dose titration during the study period, with a mean dose of 21.82 ± 21.61 mC applied to induce a seizure. During the early part of the study period, a mean dose of 18.73 ± 8.99 mC was used, with 28% of patients seizing at a dose of less than 19.2 mC. In the later period, the initial step of dose titration was standardized at 19.2 mC, yielding a mean initial dose to induce a seizure of 22.72 ± 24.00 mC.

CONCLUSIONS

Mean seizure thresholds may be lower than reported in previous studies, and a significant proportion of patients may have a seizure threshold lower than the first step of many existing dose titration protocols.

Factors Associated With Seizure Adequacy Along the Course of Electroconvulsive Therapy

OBJECTIVES

Eliciting a generalized seizure is essential to electroconvulsive therapy (ECT), but there is still a need to understand how patient and session variables interact to generate a seizure of adequate quality. Here, we investigate factors associated with motor seizure length as a measure of quality in a large database of patients who underwent ECT.

METHODS

This is a retrospective cohort including data from all adult inpatients who underwent ECT at a university hospital in Brazil from 2009 to 2015. We used linear mixed models to investigate the effects of patient, session, and medication on seizure length.

RESULTS

Session information was available for 387 patients, a total of 3544 sessions and 4167 individual stimulations. Multiple stimulations were necessary in 12.4% of sessions. Median seizure length was 30 seconds. Seizure length was directly correlated with stimulus dosage and inversely correlated with the session number, patient age, prescription of anticonvulsants in the day before and β-blockers during the session, and the thiopental dose. Use of benzodiazepines was not associated with a shorter seizure duration, irrespective of dose.

CONCLUSIONS

We demonstrate here how motor seizure length evolves during a course of ECT. With a large number of sessions, we are able to integrate a host of factors in a prediction model. Seizure quality was influenced by a number of the studied factors, many of which are potentially modifiable and could be assessed before initiating and handled during treatment.

Electric field strength induced by electroconvulsive therapy is associated with clinical outcome

The clinical effect of electroconvulsive therapy (ECT) is mediated by eliciting a generalized seizure, which is achieved by applying electrical current to the head via scalp electrodes. The anatomy of the head influences the distribution of current flow in each brain region. Here, we investigated whether individual differences in simulated local electrical field strength are associated with ECT efficacy. We modeled the electric field of 67 depressed patients receiving ECT. Patient's T1 magnetic resonance images were segmented, conductivities were assigned to each tissue and the finite element method was used to solve for the electric field induced by the electrodes. We investigated the correlation between modelled electric field and ECT outcome using voxel-wise general linear models. The difference between bilateral (BL) and right unilateral (RUL) electrode placement was striking. Even within electrode configuration, there was substantial variability between patients. For the modeled BL placement, stronger electric field strengths appeared in the left hemisphere and part of the right temporal lobe. Importantly, a stronger electric field in the temporal lobes was associated with less optimal ECT response in patients treated with BL-ECT. No significant differences in electric field distributions were found between responders and non-responders to RUL-ECT. These results suggest that overstimulation of the temporal lobes during BL stimulation has negative consequences on treatment outcome. If replicated, individualized pre-ECT computer-modelled electric field distributions may inform the development of patient-specific ECT protocols.

Electroconvulsive Therapy Pulse Amplitude and Clinical Outcomes

INTRODUCTION

Electroconvulsive therapy (ECT) pulse amplitude, which determines the induced electric field magnitude in the brain, is currently set at 800-900 milliamperes (mA) on modern ECT devices without any clinical or scientific rationale. The present study assessed differences in depression and cognitive outcomes for three different pulse amplitudes during an acute ECT series. We hypothesized that the lower amplitudes would maintain the antidepressant efficacy of the standard treatment and reduce the risk of neurocognitive impairment.

METHODS

This double-blind investigation randomized subjects to three treatment arms: 600, 700, and 800 mA (active comparator). Clinical, cognitive, and imaging assessments were conducted pre-, mid- and post-ECT. Subjects had a diagnosis of major depressive disorder, age range between 50 and 80 years, and met clinical indication for ECT.

RESULTS

The 700 and 800 mA arms had improvement in depression outcomes relative to the 600 mA arm. The amplitude groups showed no differences in the primary cognitive outcome variable, the Hopkins Verbal Learning Test-Revised (HVLT-R) retention raw score. However, secondary cognitive outcomes such as the Delis Kaplan Executive Function System Letter and Category Fluency measures demonstrated cognitive impairment in the 800 mA arm.

DISCUSSION

The results demonstrated a dissociation of depression (higher amplitudes better) and cognitive (lower amplitudes better) related outcomes. Future work is warranted to elucidate the relationship between amplitude, electric field, neuroplasticity, and clinical outcomes.

Rate of continuing acute course treatment using right unilateral ultrabrief pulse electroconvulsive therapy at a large academic medical center

Right unilateral ultrabrief pulse (RUL-UBP) ECT has emerged as a promising technique for minimizing cognitive side effects of ECT while retaining clinical efficacy, but it is unknown how often patients will require alternative treatment parameters and at what point in the treatment course this occurs. To better define this problem, this study analyzes continuation in RUL-UBP ECT in a retrospective cohort of patients beginning acute course treatment. A single-center retrospective chart review was conducted of adult patients receiving a first lifetime course of ECT from 2010 to 2017 starting with RUL-UBP treatment parameters. 1793 patients met study criteria. Patients received a mean of 10.0 ± 3.2 ECT treatments, of which a mean of 8.4 ± 3.4 were RUL-UBP treatments; proportion using RUL-UBP through 12 treatments was 57.8%. In total, 65.6% of patients were treated with RUL-UPB ECT exclusively. Mean dose increased from 7.6 × seizure threshold at the second RUL-UBP treatment to 14.3 × seizure threshold at the twelfth RUL-UBP treatment. Rates of continuation in RUL-UBP ECT did not differ based on age or on primary diagnosis of major depression vs. bipolar disorder. Among patients beginning acute-course treatment using RUL-UPB ECT, two thirds were treated with these parameters exclusively. Among patients who received twelve RUL-UBP treatments, mean final dose was 14.3 × seizure threshold. Further studies regarding optimal dosing of RUL-UBP ECT are indicated.

Double-Blinded Randomized Pilot Clinical Trial Comparing Cognitive Side Effects of Standard Ultra-Brief Right Unilateral ECT to 0.5 A Low Amplitude Seizure Therapy (LAP-ST)

BACKGROUND

Concerns over cognitive side effects (CSE) of electroconvulsive therapy (ECT) still limit its broader usage for treatment-resistant depression (TRD). The objectives of this study were to (1) examine the CSE of Low Amplitude Seizure Therapy (LAP-ST) at 0.5 A compared to Ultra-brief Right Unilateral (UB-RUL) ECT using Time to Reorientation (TRO) as the main acute primary outcome, and (2) to compare effects on depressive symptoms between the two treatment groups.

METHODS

Participants were referred for ECT, consented for the study, and were randomized to a course of LAP-ST or standard UB-RUL ECT. TRO and depression were measured by the Montgomery-Åsberg Depression Rating Scale (MADRS).

RESULTS

Eleven patients consented. Of these, eight with a current major depressive episode (MDE) of unipolar or bipolar disorders were randomized. TRO was faster for the LAP-ST (mean = 6.8 min; SE = 4.9) than standard RUL ECT (mean = 15.5 min; SE = 6.5). Depression improved similarly in the two arms of the study from baseline (MADRS: LAP-ST = 41.0; SE = 2.0, RUL = 39.0; SE = 3.8) to endpoint (MADRS score: LAP-ST = 8.0; SE7.2, RUL = 9.5; SE = 3.8).

CONCLUSIONS

This pilot, randomized and blinded clinical trial, suggests that the LAP-ST (at 0.5 A) has faster reorientation and possibly lower CSE compared to standard RUL-UB ECT. Caution is advised in interpreting these results due to the small sample size of this pilot study. Thus, future studies with similar design are warranted for replicating these findings.

The clinical relevance of dose titration in electroconvulsive therapy: A systematic review of the literature

Electroconvulsive therapy is a highly effective treatment of several psychiatric disorders. The debate regarding which charge dosing method offers the most favorable risk-benefit ratio remains. Our objective was to review the comparative evidence regarding efficacy and tolerability of dose titration (DT) vs other charge dosing methods, such as the age-based method (ABM) and the fixed dose method. Our secondary objective was to examine which populations would most benefit from DT. We conducted a systematic review of the literature in March 2020. Studies comparing DT to another charge dosing method were included. Fourteen articles depicting hypothetical comparisons between DT and another dosing method were found and seven articles made hypothetical comparisons without measurement of clinical outcomes. Although there is a trend in favor of DT in these articles, no clear recommendations could be drawn regarding the clinical superiority of one method. Older patients could be at higher risk of overstimulation with ABM, especially older women. The lack of high-quality prospective trials was a limitation as well as the fact that many studies used suprathreshold stimulus intensity deemed insufficient according to recent guidelines. This review emphasizes that more studies are needed to establish the differential clinical relevance of each method.

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.

Electroconvulsive stimulation attenuates chronic neuroinflammation

Electroconvulsive therapy is highly effective in resistant depression by unknown mechanisms. Microglial toxicity was suggested to mediate depression and plays key roles in neuroinflammatory and degenerative diseases, where there is critical shortage in therapies. We examined the effects of electroconvulsive seizures (ECS) on chronic neuroinflammation and microglial neurotoxicity. Electric brain stimulation inducing full tonic-clonic seizures during chronic relapsing-progressive experimental autoimmune encephalomyelitis (EAE) reduced spinal immune cell infiltration, reduced myelin and axonal loss, and prevented clinical deterioration. Using the transfer EAE model, we examined the effect of ECS on systemic immune response in donor mice versus ECS effect on CNS innate immune activity in recipient mice. ECS did not affect encephalitogenicity of systemic T cells, but it targeted the CNS directly to inhibit T cell-induced neuroinflammation. In vivo and ex vivo assays indicated that ECS suppressed microglial neurotoxicity by reducing inducible NOS expression, nitric oxide, and reactive oxygen species (ROS) production, and by reducing CNS oxidative stress. Microglia from ECS-treated EAE mice expressed less T cell stimulatory and chemoattractant factors. Our findings indicate that electroconvulsive therapy targets the CNS innate immune system to reduce neuroinflammation by attenuating microglial neurotoxicity. These findings signify a potentially novel therapeutic approach for chronic neuroinflammatory, neuropsychiatric, and neurodegenerative diseases.

A two-site, open-label, non-randomized trial comparing Focal Electrically-Administered Seizure Therapy (FEAST) and right unilateral ultrabrief pulse electroconvulsive therapy (RUL-UBP ECT)

BACKGROUND

Focal Electrically-Administered Seizure Therapy (FEAST) is a form of electroconvulsive therapy (ECT) that spatially focuses the electrical stimulus to initiate seizure activity in right prefrontal cortex. Two open-label non-comparative studies suggested that FEAST has reduced cognitive side effects when compared to historical data from other forms of ECT. In two different ECT clinics, we compared the efficacy and cognitive side effects of FEAST and Right Unilateral Ultrabrief Pulse (RUL-UBP) ECT.

METHODS

Using a non-randomized, open-label design, 39 depressed adults were recruited after referral for ECT. Twenty patients received FEAST (14 women; age 45.2 ± 12.7), and 19 received RUL-UBP ECT (16 women; age 43.2 ± 16.4). Key cognitive outcome measures were the postictal time to reorientation and the Columbia University Autobiographical Memory Interview: Short-Form (CUAMI-SF). Antidepressant effects were assessed using the Hamilton Rating Scale for Depression (HRSD24).

RESULTS

In the Intent-to-treat sample, a repeated measures mixed model suggested no between group difference in HRSD24 score over time (F1,35 = 0.82, p = 0.37), while the response rate favored FEAST (FEAST: 65%; RUL-UBP ECT: 57.9%), and the remission rate favored RUL-UBP ECT (FEAST: 35%; RUL-UBP ECT: 47.4%). The FEAST group had numeric superiority in average time to reorientation (FEAST: 6.6 ± 5.0 min; RUL-UBP ECT: 8.8 ± 5.8 min; Cohens d = 0.41), and CUAMI-SF consistency score (FEAST: 69.2 ± 14.2%; RUL-UBP ECT: 63.9 ± 9.9%; Cohens d = 0.43); findings that failed to meet statistical significance.

CONCLUSIONS

FEAST exerts similar efficacy relative to an optimal form of conventional ECT and may have milder cognitive side effects. A blinded, randomized, non-inferiority trial is needed.

Magnetic seizure therapy is efficacious and well tolerated for treatment-resistant bipolar depression: an open-label clinical trial

BACKGROUND

Treatment-resistant bipolar depression can be treated effectively using electroconvulsive therapy, but its use is limited because of stigma and cognitive adverse effects. Magnetic seizure therapy is a new convulsive therapy with promising early evidence of antidepressant effects and minimal cognitive adverse effects. However, there are no clinical trials of the efficacy and safety of magnetic seizure therapy for treatment-resistant bipolar depression.

METHODS

Participants with treatment-resistant bipolar depression were treated with magnetic seizure therapy for up to 24 sessions or until remission. Magnetic seizure therapy was applied over the prefrontal cortex at high (100 Hz; n = 8), medium (50 or 60 Hz; n = 9) or low (25 Hz; n = 3) frequency, or over the vertex at high frequency (n = 6). The primary outcome measure was the 24-item Hamilton Rating Scale for Depression. Participants completed a comprehensive battery of neurocognitive tests.

RESULTS

Twenty-six participants completed a minimally adequate trial of magnetic seizure therapy (i.e., ≥ 8 sessions), and 20 completed full treatment per protocol. Participants showed a significant reduction in scores on the Hamilton Rating Scale for Depression. Adequate trial completers had a remission rate of 23.1% and a response rate of 38.5%. Per-protocol completers had a remission rate of 30% and a response rate of 50%. Almost all cognitive measures remained stable, except for significantly worsened recall consistency on the autobiographical memory inventory.

LIMITATIONS

The open-label study design and modest sample size did not allow for comparisons between stimulation parameters.

CONCLUSION

In treatment-resistant bipolar depression, magnetic seizure therapy produced significant improvements in depression symptoms with minimal effects on cognitive performance. These promising results warrant further investigation with larger randomized clinical trials comparing magnetic seizure therapy to electroconvulsive therapy.

CLINICAL TRIAL REGISTRATION

NCT01596608; clinicaltrials.gov

Intracranial alternating current stimulation facilitates neurogenesis in a mouse model of Alzheimer's disease

BACKGROUND

Neurogenesis is significantly impaired in the brains of both human patients and experimental animal models of Alzheimer's disease (AD). Although deep brain stimulation promotes neurogenesis, it is an invasive technique that may damage neural circuitry along the path of the electrode. To circumvent this problem, we assessed whether intracranial electrical stimulation to the brain affects neurogenesis in a mouse model of Alzheimer's disease (5xFAD).

METHODS AND RESULTS

We used Ki67, Nestin, and doublecortin (DCX) as markers and determined that neurogenesis in both the subventricular zone (SVZ) and hippocampus were significantly reduced in the brains of 4-month-old 5xFAD mice. Guided by a finite element method (FEM) computer simulation to approximately estimate current and electric field in the mouse brain, electrodes were positioned on the skull that were likely to deliver stimulation to the SVZ and hippocampus. After a 4-week program of 40-Hz intracranial alternating current stimulation (iACS), neurogenesis indicated by expression of Ki67, Nestin, and DCX in both the SVZ and hippocampus were significantly increased compared to 5xFAD mice who received sham stimulation. The magnitude of neurogenesis was close to the wild-type (WT) age-matched unmanipulated controls.

CONCLUSION

Our results suggest that iACS is a promising, less invasive technique capable of effectively stimulating the SVZ and hippocampus regions in the mouse brain. Importantly, iACS can significantly boost neurogenesis in the brain and offers a potential treatment for AD.

Electric Stimulation of Neurogenesis Improves Behavioral Recovery After Focal Ischemia in Aged Rats

The major aim of stroke therapies is to stimulate brain repair and to improve behavioral recuperation after cerebral ischemia. Despite remarkable advances in cell therapy for stroke, stem cell-based tissue replacement has not been achieved yet stimulating the search for alternative strategies for brain self-repair using the neurogenic zones of the brain, the dentate gyrus and the subventricular zone (SVZ). However, during aging, the potential of the hippocampus and the SVZ to generate new neuronal precursors, declines. We hypothesized that electrically stimulation of endogenous neurogenesis in aged rats could increase the odds of brain self-repair and improve behavioral recuperation after focal ischemia. Following stroke in aged animals, the rats were subjected to two sessions of electrical non-convulsive stimulation using ear-clip electrodes, at 7- and 24 days after MCAO. Animal were sacrificed after 48 days. We report that electrical stimulation (ES) stimulation of post-stroke aged rats led to an improved functional recovery of spatial long-term memory (T-maze) but not on the rotating pole or the inclined plane, both tests requiring complex sensorimotor skills. Surprisingly, ES had a detrimental effect on the asymmetric sensorimotor deficit. Histologically, there was a robust increase in the number of doublecortin-positive cells in the dentate gyrus and SVZ of the infarcted hemisphere and the presence of a considerable number of neurons expressing tubulin beta III in the infarcted area. Among the gene that were unique to ES, we noted increases in the expression of seizure related 6 homolog like which is one of the physiological substrate of the β-secretase BACE1 involved in the pathophysiology of the Alzheimer’s disease and Igfbp3 and BDNF receptor mRNAs which has been shown to have a neuroprotective effect after cerebral ischemia. However, ES was associated with a long-term down regulation of cortical gene expression after stroke in aged rats suggesting that gene expression in the peri-infarcted cortical area may not be related to electrical stimulation induced-neurogenesis in the subventricular zone and hippocampus.

Dynamics of a neuron-glia system: the occurrence of seizures and the influence of electroconvulsive stimuli : A mathematical and numerical study

In this paper, we investigate the dynamics of a neuron-glia cell system and the underlying mechanism for the occurrence of seizures. For our mathematical and numerical investigation of the cell model we will use bifurcation analysis and some computational methods. It turns out that an increase of the potassium concentration in the reservoir is one trigger for seizures and is related to a torus bifurcation. In addition, we will study potassium dynamics of the model by considering a reduced version and we will show how both mechanisms are linked to each other. Moreover, the reduction of the potassium leak current will also induce seizures. Our study will show that an enhancement of the extracellular potassium concentration, which influences the Nernst potential of the potassium current, may lead to seizures. Furthermore, we will show that an external forcing term (e.g. electroshocks as unidirectional rectangular pulses also known as electroconvulsive therapy) will establish seizures similar to the unforced system with the increased extracellular potassium concentration. To this end, we describe the unidirectional rectangular pulses as an autonomous system of ordinary differential equations. These approaches will explain the appearance of seizures in the cellular model. Moreover, seizures, as they are measured by electroencephalography (EEG), spread on the macro-scale (cm). Therefore, we extend the cell model with a suitable homogenised monodomain model, propose a set of (numerical) experiment to complement the bifurcation analysis performed on the single-cell model. Based on these experiments, we introduce a bidomain model for a more realistic modelling of white and grey matter of the brain. Performing similar (numerical) experiment as for the monodomain model leads to a suitable comparison of both models. The individual cell model, with its seizures explained in terms of a torus bifurcation, extends directly to corresponding results in both the monodomain and bidomain models where the neural firing spreads almost synchronous through the domain as fast traveling waves, for physiologically relevant paramenters.

When to consider electroconvulsive therapy (ECT)

OBJECTIVE

To familiarize the reader with the role of electroconvulsive therapy (ECT) in current psychiatric medicine.

METHOD

We review clinical indications for ECT, patient selection, contemporary ECT practice, maintenance treatment and ECT in major treatment guidelines.

RESULTS

ECT is underutilized largely due to persisting stigma and lack of knowledge about modern ECT technique.

CONCLUSION

ECT remains a vital treatment for patients with severe mood disorders, psychotic illness and catatonia.

Precision non-implantable neuromodulation therapies: a perspective for the depressed brain

Current first-line treatments for major depressive disorder (MDD) include pharmacotherapy and cognitive-behavioral therapy. However, one-third of depressed patients do not achieve remission after multiple medication trials, and psychotherapy can be costly and time-consuming. Although non-implantable neuromodulation (NIN) techniques such as transcranial magnetic stimulation, transcranial direct current stimulation, electroconvulsive therapy, and magnetic seizure therapy are gaining momentum for treating MDD, the efficacy of non-convulsive techniques is still modest, whereas use of convulsive modalities is limited by their cognitive side effects. In this context, we propose that NIN techniques could benefit from a precision-oriented approach. In this review, we discuss the challenges and opportunities in implementing such a framework, focusing on enhancing NIN effects via a combination of individualized cognitive interventions, using closed-loop approaches, identifying multimodal biomarkers, using computer electric field modeling to guide targeting and quantify dosage, and using machine learning algorithms to integrate data collected at multiple biological levels and identify clinical responders. Though promising, this framework is currently limited, as previous studies have employed small samples and did not sufficiently explore pathophysiological mechanisms associated with NIN response and side effects. Moreover, cost-effectiveness analyses have not been performed. Nevertheless, further advancements in clinical trials of NIN could shift the field toward a more “precision-oriented” practice.

A Descriptive Study of Data Collection Systems Used in Electroconvulsive Therapy Units in the Province of Quebec, Canada

OBJECTIVES

This study aimed to describe the data collection systems routinely used by electroconvulsive therapy (ECT) units across the province of Quebec, Canada.

METHODS

We conducted a descriptive, cross-sectional study. Using an online survey, 31 ECT units delivering inpatient or outpatient ECT treatments in the province of Quebec provided information on the data collection systems used, data recorded, data collection strategies, indicators of satisfaction, limitations of the current data collection systems, and expectations toward the improvement of ECT data collection.

RESULTS

Most units routinely collected information on individuals receiving ECT treatments, mainly on the medical chart (80%) and in paper format (71%). Most units (88.9%) collected ECT data manually. Electroconvulsive therapy parameters are collected by 66% to 80% of units, but only 16% of them have computerized records. The main limitations of the current systems are as follows: (a) the low frequency of computerization, (b) the underutilization of data, and (c) difficulties in the integration of information from different ECT units. Although 83.3% were satisfied with the current data collection strategies, 80% had a very positive opinion about the development and implementation of an innovative ECT provincial data collection registry.

CONCLUSIONS

An integrated ECT provincial data collection system could overcome the variability documented in existing strategies and respond to the current provincial needs and expectations. Also, an integrated ECT provincial data collection system could support both clinical research and quality assurance necessary to inform standards of ECT practice in Quebec.

Magnetic seizure therapy (MST) for major depressive disorder

Electroconvulsive therapy (ECT) is effective for major depressive disorder (MDD) but its effects on memory limit its widespread use. Magnetic seizure therapy (MST) is a potential alternative to ECT that may not adversely affect memory. In the current trial, consecutive patients with MDD consented to receive MST applied over the prefrontal cortex according to an open-label protocol. Depressive symptoms and cognition were assessed prior to, during and at the end of treatment. Patients were treated two to three times per week with high-frequency MST (i.e., 100 Hz) (N = 24), medium frequency MST (i.e., 60 or 50 Hz) (N = 26), or low-frequency MST (i.e., 25 Hz MST) (N = 36) using 100% stimulator output. One hundred and forty patients were screened; 86 patients with MDD received a minimum of eight treatments and were deemed to have an adequate course of MST; and 47 completed the trial per protocol, either achieving remission (i.e., 24-item Hamilton Rating Scale for Depression score <10 and a relative reduction of >60% at two consecutive assessments; n = 17) or received a maximum of 24 sessions (n = 30). High-frequency (100 Hz) MST produced the highest remission rate (33.3%). Performance on most cognitive measures remained stable, with the exception of significantly worsened recall consistency of autobiographical information and significantly improved brief visuospatial memory task performance. Under open conditions, MST led to clinically meaningful reduction in depressive symptoms in patients with MDD and produced minimal cognitive impairment. Future studies should compare MST and ECT under double-blind randomized condition.

Less memory complaints with reduced stimulus dose during electroconvulsive therapy for depression

BACKGROUND

Electroconvulsive therapy (ECT) is an effective treatment for depression, but there is risk of cognitive adverse events. This risk has been partially attributed to electrical charge, thus the optimal electrical stimulus dose is still under discussion. The aim of this study was to evaluate how the risk of subjective memory worsening was changed after lowering stimulus dose during ECT for patients with major depression.

METHOD

A retrospective register-based intervention study of the effects of reduced electrical charges for patients receiving ECT for depression was conducted. The primary outcome was subjective memory worsening and the secondary outcome change in effect on depressive symptoms.

RESULTS

A total of 154 patients were enrolled in the study (High dosage group: n = 57; Lower dosage group: n = 97). Subjective memory worsening after ECT occurred in 44% of patients in the high dosage group and in 25% of patients in the lower dosage group(p = 0.014). There was no significant between-group difference in the anti-depressive effect of ECT.

LIMITATIONS

The study was register-based and the two groups were not randomized. A large portion of patients were initially excluded due to missing data in the register. The study lacks a long-term follow up.

CONCLUSION

After implementing a change of treatment protocol, that lowered ECT stimulus doses from high to moderate, the occurrence of subjective memory worsening was significantly reduced without compromising treatment results.

Neurostimulation Therapies

Depression is one of the most disabling conditions in the world. In many cases patients continue to suffer with depressive disorders despite a series of adequate trials of medication and psychotherapy. Neuromodulation treatments offer a qualitatively different modality of treatment that can frequently prove efficacious in these treatment-refractory patients. The field of neuromodulation focuses on the use of electrical/electromagnetic energy, both invasively and noninvasively, to interface with and ultimately alter activity within the human brain for therapeutic purposes. These treatments provide another set of options to offer patients when clinically indicated, and knowledge of their safety, risks and benefits, and appropriate clinical application is essential for modern psychiatrists and other mental health professionals. Although neuromodulation techniques hold tremendous promise, only three such treatments are currently approved by the United States Food and Drug Administration (FDA) for the treatment of major depressive disorder: electroconvulsive therapy (ECT), vagus nerve stimulation (VNS), and repetitive transcranial magnetic stimulation (rTMS). Additionally, numerous other neurostimulation modalities (deep brain stimulation [DBS], magnetic seizure therapy [MST], transcranial electric stimulation [tES], and trigeminal nerve stimulation [TNS]), though currently experimental, show considerable therapeutic promise. Researchers are actively looking for ways to optimize outcomes and clinical benefits by making neuromodulation treatments safer, more efficacious, and more durable.

Transcranial electrical stimulation nomenclature

Transcranial electrical stimulation (tES) aims to alter brain function non-invasively by applying current to electrodes on the scalp. Decades of research and technological advancement are associated with a growing diversity of tES methods and the associated nomenclature for describing these methods. Whether intended to produce a specific response so the brain can be studied or lead to a more enduring change in behavior (e.g. for treatment), the motivations for using tES have themselves influenced the evolution of nomenclature, leading to some scientific, clinical, and public confusion. This ambiguity arises from (i) the infinite parameter space available in designing tES methods of application and (ii) varied naming conventions based upon the intended effects and/or methods of application. Here, we compile a cohesive nomenclature for contemporary tES technologies that respects existing and historical norms, while incorporating insight and classifications based on state-of-the-art findings. We consolidate and clarify existing terminology conventions, but do not aim to create new nomenclature. The presented nomenclature aims to balance adopting broad definitions that encourage flexibility and innovation in research approaches, against classification specificity that minimizes ambiguity about protocols but can hinder progress. Constructive research around tES classification, such as transcranial direct current stimulation (tDCS), should allow some variations in protocol but also distinguish from approaches that bear so little resemblance that their safety and efficacy should not be compared directly. The proposed framework includes terms in contemporary use across peer-reviewed publications, including relatively new nomenclature introduced in the past decade, such as transcranial alternating current stimulation (tACS) and transcranial pulsed current stimulation (tPCS), as well as terms with long historical use such as electroconvulsive therapy (ECT). We also define commonly used terms-of-the-trade including electrode, lead, anode, and cathode, whose prior use, in varied contexts, can also be a source of confusion. This comprehensive clarification of nomenclature and associated preliminary proposals for standardized terminology can support the development of consensus on efficacy, safety, and regulatory standards.

Comparative modeling of transcranial magnetic and electric stimulation in mouse, monkey, and human

Transcranial magnetic stimulation (TMS) and transcranial electric stimulation (TES) are increasingly popular methods to noninvasively affect brain activity. However, their mechanism of action and dose-response characteristics remain under active investigation. Translational studies in animals play a pivotal role in these efforts due to a larger neuroscientific toolset enabled by invasive recordings. In order to translate knowledge gained in animal studies to humans, it is crucial to generate comparable stimulation conditions with respect to the induced electric field in the brain. Here, we conduct a finite element method (FEM) modeling study of TMS and TES electric fields in a mouse, capuchin and macaque monkeys, and a human model. We systematically evaluate the induced electric fields and analyze their relationship to head and brain anatomy. We find that with increasing head size, TMS-induced electric field strength first increases and then decreases according to a two-term exponential function. TES-induced electric field strength strongly decreases from smaller to larger specimen with up to 100x fold differences across species. Our results can serve as a basis to compare and match stimulation parameters across studies in animals and humans.

Factors Affecting Electroconvulsive Therapy Ictal Outcomes: Duration and Postictal Suppression

Electroconvulsive therapy (ECT) is an effective and rapid treatment for severe depression, however predictors of therapeutic outcomes remain insufficiently understood. Ictal duration and postictal suppression are two outcomes that may be correlated with patient response, yet patient and treatment variables which may influence these outcomes have not been thoroughly explored. We collected ECT stimulus metrics, EEG parameters, patient demographics, primary diagnosis, and anesthesia type for retrospective ECTs. Univariate and multivariate mixed-effects linear regression models were used to identify variables associated with ictal duration and postictal suppression index. For both outcomes, multivariate models which included all variables resulted in the best fit, reflecting the complex influences of a variety of factors on the ictal response. These results are an important step forward in elucidating patterns in retrospective ECT clinical data which may lead to new clinical knowledge of modifiable factors to optimize ECT treatment outcomes.

Electroconvulsive therapy electrode placement for bipolar state-related targeted engagement

Background

Electroconvulsive therapy (ECT) is an effective treatment for all bipolar states. However, ECT remains underutilized, likely stemming from stigma and the risk of neurocognitive impairment. Neuroimaging research has identified state-specific areas of aberrant brain activity that may serve as targets for therapeutic brain stimulation. Electrode placement determines the geometry of the electric field and can be either non-focal (bitemporal) or more focal (right unilateral or bifrontal). Previous research has shown that electrode placement can impact clinical and cognitive outcomes independent of seizure activity. This review critically examines the evidence that focal (unilateral or bifrontal) electrode placements target specific aberrant circuitry in specific bipolar states to optimize clinical outcomes. We hypothesize that optimal target engagement for a bipolar state will be associated with equivalent efficacy relative to bitemporal non-focal stimulation with less neurocognitive impairment.

Methods

We performed a literature search in the PubMed database. Inclusion criteria included prospective, longitudinal investigations during the ECT series with specific electrode placements within a bipolar state from 2000 to 2018.

Results

We identified investigations that met our inclusion criteria with bipolar mania (n = 6), depression (n = 6), mixed (n = 3) and catatonia (n = 1) states. These studies included clinical outcomes and several included cognitive outcomes, which were discussed separately.

Conclusions

While the heterogeneity of the studies makes comparisons difficult, important patterns included the reduced cognitive side effects, faster rate of response, and equivalent efficacy rates of the focal electrode placements (right unilateral and bifrontal) when compared to non-focal (bitemporal) placement. Further avenues for research include more robust cognitive assessments to separate procedure-related and state-related impairment. In addition, future studies could investigate novel electrode configurations with more specific target engagement for different bipolar states.

Reconsidering the seizure threshold? A retrospective study about seizure quality among patients with maintenance ECT

OBJECTIVES

Electroconvulsive therapy (ECT) is a safe and validated technique used to treat various psychiatric conditions. It triggers an artificially-induced seizure. This seizure is defined using several parameters such as the amount of energy, duration, frequency, pulse width and intensity. Efficacy and adverse events depend on the amount of energy delivered. Due to technical control, the amount of energy delivered by our unit's ECT device was limited to 614 mC, 60% of the maximum possible output of the device. We wondered if lowering the dose would lead to better seizure quality among maintenance ECT patients.

METHODS

We assessed seizure quality based on the EEG, using a validated tool created by MacPherson. Two evaluators independently rated the seizures. Pre- and post-control scores were compared using Student's t-test for paired samples.

RESULTS

We analysed data from 15 patients. Mean age was 65 years old. Twelve had depressive disorder, two had schizophrenia and one had schizo-affective disorder. Mean duration of seizure before control was 41.1 s [95% confidence interval (95CI)=26.1, 51.1]. The mean MacPherson's score was 20.3 (95CI=16.2, 24.4). After control, the mean MacPherson's score was 28.2 (23.1, 33.3), showing a significant difference with the pre-control dataset (p=0.032; t=-2.4; df=14). Specifically, peak mid-ictal amplitude increased from 6.9 (95CI=5.1, 8.7) to 10.0 (95CI=7.2, 12.8). Other sub-scores remained unchanged.

CONCLUSION

Lowering the energy delivered led to an overall increase of seizure quality among our sample. This highlights the necessity and utility of retitration during ECT maintenance, possibly leading to better management of our patients.

A Critical Review and Synthesis of Clinical and Neurocognitive Effects of Noninvasive Neuromodulation Antidepressant Therapies

There is a plethora of current and emerging antidepressant therapies in the psychiatric armamentarium for the treatment of major depressive disorder. Noninvasive neuromodulation therapies are one such therapeutic category; they typically involve the transcranial application of electrical or magnetic stimulation to modulate cortical and subcortical brain activity. Although electroconvulsive therapy (ECT) has been used since the 1930s, with the prevalence of major depressive disorder and treatment-resistant depression (TRD), the past three decades have seen a proliferation of noninvasive neuromodulation antidepressant therapeutic development. The purpose of this critical review was to synthesize information regarding the clinical effects, neurocognitive effects, and possible mechanisms of action of noninvasive neuromodulation therapies, including ECT, transcranial magnetic stimulation, magnetic seizure therapy, and transcranial direct current stimulation. Considerable research has provided substantial information regarding their antidepressant and neurocognitive effects, but their mechanisms of action remain unknown. Although the four therapies vary in how they modulate neurocircuitry and their resultant antidepressant and neurocognitive effects, they are nonetheless useful for patients with acute and chronic major depressive disorder and TRD. Continued research is warranted to inform dosimetry, algorithm for administration, and integration among the noninvasive neuromodulation therapies and with other antidepressant strategies to continue to maximize their safety and antidepressant benefit.

Cognitive functioning in patients treated with electroconvulsive therapy

BACKGROUND

Electroconvulsive therapy (ECT) is an effective treatment method for severe mental illnesses. ECT has gone through significant modernization. Side effects of ECT have largely decreased. Temporary disturbance of cognitive performance can be still present as a side effect of electroconvulsive treatment.

METHODS

Cognitive functioning in the sample of patients with severe and acute mental illness treated with electroconvulsive therapy (ECT) was assessed. Basic assessment of cognitive functions was applied in the beginning, in the middle, and at the end of ECT course treatment with the Montreal Cognitive Assessment (MoCA). Complex and detailed testing of cognitive functions using the MATRICS Consensus Cognitive Battery (MCCB) was done at two points in time - within the first week of and then 6 weeks after the end of ECT.

RESULTS

Participants had cognitive deficits at baseline, which were most likely influenced markedly by the psychopathology of the illness itself. The improvement in cognition came together with the reduction in psychopathology; psychopathology scores were significantly reduced during ECT treatment. Compared to the baseline, all scores for cognitive testing were significantly improved but remained low in comparison with the controls. After 6 weeks, there was further significant improvement.

CONCLUSION

Our results confirm the safety and efficacy of ECT in the treatment of severe mental disorders.

Characteristics of ictal EEG in Magnetic Seizure Therapy at various stimulation frequencies

OBJECTIVES

The first objective of this study aimed to elucidate the relationship between seizure characteristics and Magnetic Seizure Therapy (MST) treatment outcome. The second objective was to determine the effect of stimulation frequency on seizure characteristics.

METHODS

Using a between-subjects design, we compared the seizures of patients with unipolar depression receiving MST at three separate stimulation frequencies: 25 Hz (n = 34), 50 Hz (n = 16) and 100 Hz (n = 11). Seizures were rated for overall seizure adequacy on a scale of 0-6, with one point given for each measure that was considered to be adequate according to the ECT literature: (1) seizure EEG duration (2) motor duration, (3) post-ictal suppression, (4) ictal EEG maximum amplitude, (5) Global Seizure Strength, and (6) Symmetry. Mixed-effect models were used to evaluate the effect of frequency on seizure characteristics and the relationships between seizure characteristics and clinical outcome.

RESULTS

(1) 100 Hz induced seizures that were less adequate than seizures induced with 50 Hz and 25 Hz stimulations. Seizures induced by 50 Hz stimulations had longer slow-wave phase durations and total EEG durations than the 100 Hz and 25 Hz groups. Global seizure strength was less robust in seizures induced by 100 Hz MST compared to the other stimulation frequencies. (2) Shorter polyspike durations and smaller slow-wave amplitude predicted reductions in overall symptoms of depression as measured by the 24-item Hamilton Depression Scale.

CONCLUSION

Analysis of our first objective revealed stimulation frequency significantly influences measures of overall seizure adequacy. However, our results also revealed these descriptions of seizure adequacy based on ECT literature may not be useful for MST-induced seizures, as the characteristics of MST-induced seizure characteristics may predict clinical response in a different manner.

SIGNIFICANCE

These results may help to distinguish the biological processes impacted by stimulation frequency and may suggest different mechanisms of action between convulsive therapies and challenge the current understanding of seizure adequacy for MST.

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

PURPOSE OF REVIEW

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.

RECENT FINDINGS

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.

SUMMARY

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.

Electroconvulsive therapy stimulus titration: Not all it seems

OBJECTIVE

To examine the provenance and implications of seizure threshold titration in electroconvulsive therapy.

BACKGROUND

Titration of seizure threshold has become a virtual standard for electroconvulsive therapy. It is justified as individualisation and optimisation of the balance between efficacy and unwanted effects.

RESULT

Present day threshold estimation is significantly different from the 1960 studies of Cronholm and Ottosson that are its usual justification. The present form of threshold estimation is unstable and too uncertain for valid optimisation or individualisation of dose. Threshold stimulation (lowest dose that produces a seizure) has proven therapeutically ineffective, and the multiples applied to threshold to attain efficacy have never been properly investigated or standardised. The therapeutic outcomes of threshold estimation (or its multiples) have not been separated from simple dose effects. Threshold estimation does not optimise dose due to its own uncertainties and the different short-term and long-term cognitive and memory effects. Potential harms of titration have not been examined.

CONCLUSION

Seizure threshold titration in electroconvulsive therapy is not a proven technique of dose optimisation. It is widely held and practiced; its benefit and harmlessness assumed but unproven. It is a prematurely settled answer to an unsettled question that discourages further enquiry. It is an example of how practices, assumed scientific, enter medicine by obscure paths.

Electroconvulsive Therapy for Super Refractory Status Epilepticus

OBJECTIVES

Super refractory status epilepticus (SRSE) is a stage beyond refractory status that requires general anesthesia as management. Electroconvulsive therapy (ECT) is recommended only as a potential treatment option beyond general anesthesia and after all other options have been exhausted. Its effect on aborting status has been minimally researched. We present the largest case series to our knowledge exploring the effect of ECT on SRSE.

METHODS

Eight adults hospitalized for SRSE received ECT in an attempt to abort status after other treatment modalities were exhausted. Electroconvulsive therapy consisted of a 504-mC (≈99.4 J) stimulus delivered bifrontotemporally with a constant 0.5-millisecond pulse width. Seizure activity during ECT was monitored visually and correlated to the single-channel recording provided by the apparatus.

RESULTS

There was neurotelemetry or clinical evidence of improvement within 24 hours after the full course of ECT treatment in 5 (63%) of the 8 cases. Cases that improved were given an average of 7.8 total ECT stimulations, eliciting an average of 4.2 total seizures.

CONCLUSIONS

Although it is difficult to determine the exact role of ECT in the improvement of 63% of our cases, we present a series of patients for whom pharmacotherapy, ketogenic diet, and general anesthesia otherwise did not produce an appreciable effect on status prior to implementation of ECT. These findings suggest that cases of SRSE may benefit from ECT administration.

A Computational Assessment of Target Engagement in the Treatment of Auditory Hallucinations with Transcranial Direct Current Stimulation

We use auditory verbal hallucinations (AVH) to illustrate the challenges in defining and assessing target engagement in the context of transcranial direct current stimulation (tDCS) for psychiatric disorders. We defined the target network as the cluster of regions of interest (ROIs) that are consistently implicated in AVH based on the conjunction of multimodal meta-analytic neuroimaging data. These were prescribed in the New York Head (a population derived model) and head models of four single individuals. We appraised two potential measures of target engagement, tDCS-induced peak electric field strength and tDCS-modulated volume defined as the percentage of the volume of the AVH network exposed to electric field magnitude stronger than the postulated threshold for neuronal excitability. We examined a left unilateral (LUL) montage targeting the prefrontal cortex (PFC) and temporoparietal junction (TPJ), a bilateral (BL) prefrontal montage, and a 2 × 1 montage targeting the left PFC and the TPJ bilaterally. Using computational modeling, we estimated the peak electric field strength and modulated volume induced by each montage for current amplitudes ranging 1-4 mA. We found that the LUL montage was inferior to both other montages in terms of peak electric field strength in right-sided AVH-ROIs. The BL montage was inferior to both other montages in terms of modulated volume of the left-sided AVH-ROIs. As the modulated volume is non-linear, its variability between montages reduced for current amplitudes above 3 mA. These findings illustrate how computational target engagement for tDCS can be tailored to specific networks and provide a principled approach for future study design.

Structural-functional brain changes in depressed patients during and after electroconvulsive therapy

OBJECTIVES

Electroconvulsive therapy (ECT) is a non-pharmacological treatment that is effective in treating severe and treatment-resistant depression. Although the efficacy of ECT has been demonstrated to treat major depressive disorder (MDD), the brain mechanisms underlying this process remain unclear. Structural-functional changes occur with the use of ECT as a treatment for depression based on magnetic resonance imaging (MRI). For this reason, we have tried to identify the changes that were identified by MRI to try to clarify some operating mechanisms of ECT. We focus to brain changes on MRI [structural MRI (sMRI), functional MRI (fMRI) and diffusion tensor imging (DTI)] after ECT.

METHODS

A systematic search of the international literature was performed using the bibliographic search engines PubMed and Embase. The research focused on papers published up to 30 September 2015. The following Medical Subject Headings (MESH) terms were used: electroconvulsive therapy AND (MRI OR fMRI OR DTI). Papers published in English were included. Four authors searched the database using a predefined strategy to identify potentially eligible studies.

RESULTS

There were structural changes according to the sMRI performed before and after ECT treatment. These changes do not seem to be entirely due to oedema. This investigation assessed the functional network connectivity associated with the ECT response in MDD. ECT response reverses the relationship from negative to positive between the two pairs of networks.

CONCLUSION

We found structural-functional changes in MRI post-ECT. Because of the currently limited MRI data on ECT in the literature, it is necessary to conduct further investigations using other MRI technology.

Feasibility, safety, and preliminary efficacy of Low Amplitude Seizure Therapy (LAP-ST): A proof of concept clinical trial in man

BACKGROUND

Current pulse amplitude used in clinical ECT may be higher than needed. Reducing pulse amplitude may improve focality of the electric field and thus cognitive adverse effects. Here we examine the feasibility, safety, and whether Low Pulse Amplitude Seizure Therapy (LAP-ST, 0.5-0.6A) minimizes cognitive adverse effects while retaining efficacy.

METHODS

Patients with treatment-resistant primary mood (depressive episodes) or psychotic disorders who were clinically indicated to undergo ECT were offered to be enrolled in an open-label study. The study consisted of a full acute course of LAP-ST under standard anesthesia and muscle relaxation. The primary outcome was feasibility of seizure induction. Clinical outcome measures were: time to reorientation (TRO), Mini Mental State Examination, Montgomery Aberg Depression Scale, and Brief Psychiatric Rating Scale, and Clinical Global Impression Scale.

RESULTS

Twenty-two patients consented for enrollment in the study. LAP-ST was feasible, and all patients had seizures in the first session. Participants had a quick orientation with median TRO of 4.5min. Treatment was efficacious for both depressive and psychotic symptoms.

LIMITATIONS

Relatively small sample size, non-blinded, and no randomization was performed in this initial proof of concept study.

CONCLUSIONS

This first human preliminary data of a full course of focal LAP-ST demonstrates that seizure induction is feasible. These results, although preliminary, suggest that the LAP-ST compared to the standard ECT techniques may result in less cognitive side effects, but comparable efficacy. Larger studies are needed to replicate these findings.

Genetics-based manipulation of adipose tissue sympathetic innervation

There is renewed interest in leveraging the thermogenic capacity of brown adipose tissue (BAT) and browning of white adipose tissue (WAT) to improve energy balance and prevent obesity. In addition to these effects on energy expenditure, both BAT and WAT secrete large numbers of hormones and cytokines that play important roles in maintaining metabolic health. Both BAT and WAT are densely innervated by the sympathetic nervous system (SNS) and this innervation is crucial for BAT thermogenesis and WAT browning, making it a potentially interesting target for manipulating energy balance and treatment of obesity and metabolic disease. Peripheral neuromodulation in the form of electrical manipulation of the SNS and parasympathetic nervous system (PSNS) has been used for the management of pain and many other conditions, but progress is hampered by lack of detailed knowledge of function-specific neurons and nerves innervating particular organs and tissues. Therefore, the goal of the National Institutes of Health (NIH) Common Fund project "Stimulating Peripheral Activity to Relieve Conditions (SPARC)" is to comprehensively map both anatomical and neurochemical aspects of the peripheral nervous system in animal model systems to ultimately guide optimal neuromodulation strategies in humans. Compared to electrical manipulation, neuron-specific opto- and chemogenetic manipulation, now being extensively used to decode the function of brain circuits, will further increase the functional specificity of peripheral neuromodulation.

Minimum Electric Field Exposure for Seizure Induction with Electroconvulsive Therapy and Magnetic Seizure Therapy

Lowering and individualizing the current amplitude in electroconvulsive therapy (ECT) has been proposed as a means to produce stimulation closer to the neural activation threshold and more focal seizure induction, which could potentially reduce cognitive side effects. However, the effect of current amplitude on the electric field (E-field) in the brain has not been previously linked to the current amplitude threshold for seizure induction. We coupled MRI-based E-field models with amplitude titrations of motor threshold (MT) and seizure threshold (ST) in four nonhuman primates (NHPs) to determine the strength, distribution, and focality of stimulation in the brain for four ECT electrode configurations (bilateral, bifrontal, right-unilateral, and frontomedial) and magnetic seizure therapy (MST) with cap coil on vertex. At the amplitude-titrated ST, the stimulated brain subvolume (23-63%) was significantly less than for conventional ECT with high, fixed current (94-99%). The focality of amplitude-titrated right-unilateral ECT (25%) was comparable to cap coil MST (23%), demonstrating that ECT with a low current amplitude and focal electrode placement can induce seizures with E-field as focal as MST, although these electrode and coil configurations affect differently specific brain regions. Individualizing the current amplitude reduced interindividual variation in the stimulation focality by 40-53% for ECT and 26% for MST, supporting amplitude individualization as a means of dosing especially for ECT. There was an overall significant correlation between the measured amplitude-titrated ST and the prediction of the E-field models, supporting a potential role of these models in dosing of ECT and MST. These findings may guide the development of seizure therapy dosing paradigms with improved risk/benefit ratio.

General Anaesthesia Protocols for Patients Undergoing Electroconvulsive Therapy: Retrospective analysis of 504 sessions over a five-year period at a tertiary care hospital in Oman

OBJECTIVES

This study aimed to review general anaesthesia protocols for patients undergoing electroconvulsive therapy (ECT) at a tertiary care hospital in Oman, particularly with regards to clinical profile, potential drug interactions and patient outcomes.

METHODS

This retrospective study took place at the Sultan Qaboos University Hospital (SQUH), Muscat, Oman. The electronic medical records of patients undergoing ECT at SQUH between January 2010 and December 2014 were reviewed for demographic characteristics and therapy details.

RESULTS

A total of 504 modified ECT sessions were performed on 57 patients during the study period. All of the patients underwent a uniform general anaesthetic regimen consisting of propofol and succinylcholine; however, they received different doses between sessions, as determined by the treating anaesthesiologist. Variations in drug doses between sessions in the same patient could not be attributed to any particular factor. Self-limiting tachycardia and hypertension were periprocedural complications noted among all patients. One patient developed aspiration pneumonitis (1.8%).

CONCLUSION

All patients undergoing ECT received a general anaesthetic regimen including propofol and succinylcholine. However, the interplay of anaesthetic drugs with ECT efficacy could not be established due to a lack of comprehensive data, particularly with respect to seizure duration. In addition, the impact of concurrent antipsychotic therapy on anaesthetic dose and subsequent complications could not be determined.

New directions in the rational design of electrical and magnetic seizure therapies: individualized Low Amplitude Seizure Therapy (iLAST) and Magnetic Seizure Therapy (MST)

Electroconvulsive therapy remains a key treatment option for severe cases of depression, but undesirable side-effects continue to limit its use. Innovations in the design of novel seizure therapies seek to improve its risk benefit ratio through enhanced control of the focality of stimulation. The design of seizure therapies with increased spatial precision is motivated by avoiding stimulation of deep brain structures implicated in memory retention, including the hippocampus. The development of two innovations in seizure therapy-individualized low-amplitude seizure therapy (iLAST) and magnetic seizure therapy (MST), are detailed. iLAST is a method of seizure titration involving reducing current spread in the brain by titrating current amplitude from the traditional fixed amplitudes. MST, which can be used in conjunction with iLAST dosing methods, involves the use of magnetic stimulation to reduce shunting and spreading of current by the scalp occurring during electrical stimulation. Evidence is presented on the rationale for increasing the focality of ECT in hopes of preserving its effectiveness, while reducing cognitive side-effects. Finally, the value of electric field and neural modelling is illustrated to explain observed clinical effects of modifications to ECT technique, and their utility in the rational design of the next generation of seizure therapies.

Effects of stimulus parameters on motor seizure duration in electroconvulsive therapy

OBJECTIVE

This study examined the effect of stimulus parameters on the occurrence of adequate seizures and reconsidered the factors related to motor seizure duration.

METHODS

The medical records of 187 patients who received ECT in Asan Medical Center from January 2007 to May 2014 were retrospectively reviewed. The starting stimulus dose was determined using a preselected-dose method and the cutoff value to determine the adequate motor seizure duration was 20-25 seconds. The association between seizure parameters and the occurrence of adequate seizure was assessed with logistic regression using a generalized estimating equation.

RESULTS

Age (P<0.001), use of mood stabilizers (P=0.002), and benzodiazepine (P<0.001) were significantly lower in sessions with an adequate seizure duration but use of antidepressants (P<0.001) and clozapine (P=0.025) were significantly higher in sessions with an adequate seizure duration. In the generalized estimating equation analyses, after adjustment for age, benzodiazepine dose, and lamotrigine use, charge (odds ratio [OR] =0.999; 95% confidence interval [CI], 0.998-1.000; P=0.005), and train duration (OR =0.632; 95% CI, 0.490-0.817; P<0.001) were significantly associated with the occurrence of adequate seizure.

DISCUSSION

Stimulus charge and train duration are significantly associated with motor seizure duration. However, train duration appears to have a greater effect on motor seizure duration. Additionally, age, benzodiazepine dose, and lamotrigine use independently affect motor seizure duration.

Right Unilateral Ultrabrief Pulse ECT in Geriatric Depression: Phase 1 of the PRIDE Study

OBJECTIVE

The Prolonging Remission in Depressed Elderly (PRIDE) study evaluated the efficacy of right unilateral ultrabrief pulse electroconvulsive therapy (ECT) combined with venlafaxine for the treatment of geriatric depression.

METHOD

PRIDE was a two-phase multisite study. Phase 1 was an acute course of right unilateral ultrabrief pulse ECT, combined with open-label venlafaxine at seven academic medical centers. In phase 2 (reported separately), patients who had remitted were randomly assigned to receive pharmacotherapy (venlafaxine plus lithium) or pharmacotherapy plus continuation ECT. In phase 1, depressed patients received high-dose ECT (at six times the seizure threshold) three times per week. Venlafaxine was started during the first week of treatment and continued throughout the study. The primary outcome measure was remission, assessed with the 24-item Hamilton Depression Rating Scale (HAM-D), which was administered three times per week. Secondary outcome measures were post-ECT reorientation and safety. Paired t tests were used to estimate and evaluate the significance of change from baseline in HAM-D scores.

RESULTS

Of 240 patients who entered phase 1 of the study, 172 completed it. Overall, 61.7% (148/240) of all patients met remission criteria, 10.0% (24/240) did not remit, and 28.3% (68/240) dropped out; 70% (169/240) met response criteria. Among those who remitted, the mean decrease in HAM-D score was 24.7 points (95% CI=23.4, 25.9), with a mean final score of 6.2 (SD=2.5) and an average change from baseline of 79%. The mean number of ECT treatments to remission was 7.3 (SD=3.1).

CONCLUSIONS

Right unilateral ultrabrief pulse ECT, combined with venlafaxine, is a rapidly acting and highly effective treatment option for depressed geriatric patients, with excellent safety and tolerability. These data add to the evidence base supporting the efficacy of ECT to treat severe depression in elderly patients.