scholarly journals Computational comparison of conventional and novel electroconvulsive therapy electrode placements for the treatment of depression

2019 ◽  
Vol 60 ◽  
pp. 71-78 ◽  
Author(s):  
Siwei Bai ◽  
Donel Martin ◽  
Tianruo Guo ◽  
Socrates Dokos ◽  
Colleen Loo
Keyword(s):  
Electroconvulsive Therapy ◽  
Regional Differences ◽  
Computational Modelling ◽  
Human Head ◽  
Brain Regions ◽  
Electrical Stimulus ◽  
Electrode Placement ◽  
Treatment Of Depression ◽  
Mri Scans ◽  
Average Electric Field

AbstractBackground:Electroconvulsive therapy (ECT) is a highly effective treatment for severe psychiatric disorders. Despite its high efficacy, the use of ECT would be greater if the risk of cognitive side effects were reduced. Over the last 20 years, developments in ECT technique, including improvements in the dosing methodology and modification of the stimulus waveform, have allowed for improved treatment methods with reduced adverse cognitive effects. There is increasing evidence that the electrode placement is important for orienting the electrical stimulus and therefore modifying treatment outcomes, with potential for further improvement of the placements currently used in ECT.Objective:We used computational modelling to perform an in-depth examination into regional differences in brain excitation by the ECT stimulus for several lesser known and novel electrode placements, in order to investigate the potential for an electrode placement that may optimise clinical outcomes.Methods:High resolution finite element human head models were generated from MRI scans of three subjects. The models were used to compare regional differences in average electric field (EF) magnitude among a total of thirteen bipolar ECT electrode placements, i.e. three conventional placements as well as ten lesser known and novel placements.Results and conclusion:In this exploratory study on a systemic comparison of thirteen ECT electrode placements, the EF magnitude at regions of interest (ROIs) was highly dependent upon the position of both electrodes, especially the ROIs close to the cortical surface. Compared to conventional right-unilateral (RUL) ECT using a temporo-parietal placement, fronto-parietal and supraorbito-parietal RUL also robustly stimulated brain regions considered important for efficacy, while sparing regions related to cognitive functions, and may be a preferrable approach to the currently used placement for RUL ECT. The simulations also found that regional average EF magnitude varied between individual subjects, due to factors such as head size, and results also depended on the size of the defined ROI.

Computational models of Bitemporal, Bifrontal and Right Unilateral ECT predict differential stimulation of brain regions associated with efficacy and cognitive side effects

2017 ◽  
Vol 41 (1) ◽  
pp. 21-29 ◽  
Author(s):  
S. Bai ◽  
V. Gálvez ◽  
S. Dokos ◽  
D. Martin ◽  
M. Bikson ◽  
...  
Keyword(s):  
Side Effects ◽  
Computational Models ◽  
Computational Modelling ◽  
Human Head ◽  
Distribution Patterns ◽  
Brain Regions ◽  
Electrode Placement ◽  
Direct Stimulation ◽  
Cognitive Side Effects ◽  
Stimulation Of

AbstractBackgroundExtensive clinical research has shown that the efficacy and cognitive outcomes of electroconvulsive therapy (ECT) are determined, in part, by the type of electrode placement used. Bitemporal ECT (BT, stimulating electrodes placed bilaterally in the frontotemporal region) is the form of ECT with relatively potent clinical and cognitive side effects. However, the reasons for this are poorly understood.ObjectiveThis study used computational modelling to examine regional differences in brain excitation between BT, Bifrontal (BF) and Right Unilateral (RUL) ECT, currently the most clinically-used ECT placements. Specifically, by comparing similarities and differences in current distribution patterns between BT ECT and the other two placements, the study aimed to create an explanatory model of critical brain sites that mediate antidepressant efficacy and sites associated with cognitive, particularly memory, adverse effects.MethodsHigh resolution finite element human head models were generated from MRI scans of three subjects. The models were used to compare differences in activation between the three ECT placements, using subtraction maps.Results and conclusionIn this exploratory study on three realistic head models, Bitemporal ECT resulted in greater direct stimulation of deep midline structures and also left temporal and inferior frontal regions. Interpreted in light of existing knowledge on depressive pathophysiology and cognitive neuroanatomy, it is suggested that the former sites are related to efficacy and the latter to cognitive deficits. We hereby propose an approach using binarised subtraction models that can be used to optimise, and even individualise, ECT therapies.

Electrode Placement, Stimulus Dosing and Seizure Monitoring during ECT

1994 ◽  
Vol 28 (4) ◽  
pp. 675-683 ◽  
Author(s):  
G. Murugesan
Keyword(s):  
Cognitive Impairment ◽  
Electroconvulsive Therapy ◽  
Electrical Stimulus ◽  
Electrode Placement ◽  
Treatment Modalities ◽  
Points Of View ◽  
Bilateral Treatment

Electroconvulsive therapy is one of the most useful, safe and predictable treatment modalities in psychiatry. For optimal results proper application of the procedure is essential. Over the years the procedure has undergone considerable refinement, yet not all those who administer the treatment are fully conversant with this. This paper addresses issues relating to electrode placement, stimulus dosing and seizure monitoring from practical and clinical points of view. Right unilateral ECT, if administered with high electrical stimulus, produces results close to bilateral treatment with substantially less cognitive impairment. However, certain patients may only respond to bilateral ECT. Adequate training for clinicians administering ECT is recommended.

Perceptual Learning with Right Unilateral versus Bilateral Electroconvulsive Therapy

1984 ◽  
Vol 145 (4) ◽  
pp. 394-400 ◽  
Author(s):  
Walter F. Daniel ◽  
Herbert F. Crovitz ◽  
Richard D. Weiner
Keyword(s):  
Perceptual Learning ◽  
Electroconvulsive Therapy ◽  
Group Learning ◽  
Electrical Stimulus ◽  
Electrode Placement ◽  
Theoretical Issue ◽  
Seizure Duration ◽  
Stimulus Waveform ◽  
Stimulus Energy

SummaryPerceptual learning was examined with respect to variations in ECT electrode placement (bilateral versus right unilateral) and ECT stimulus waveform (sinusoidal versus brief-pulse). While patients receiving right unilateral ECT demonstrated more perceptual learning than did those receiving bilateral ECT, no difference in perceptual learning resulted from the variation in electrical stimulus waveform. Furthermore, the amount of perceptual learning was unaffected by EEG seizure duration and by the total amount of electrical stimulus energy delivered. The theoretical issue of whether an electrical or a seizure difference between bilateral and right unilateral ECT is responsible for inter-group learning or memory differences is discussed, as well as practical issues related to the choice of electrode placement.

Electroconvulsive therapy: Brief versus ultrabrief pulse right unilateral electroconvulsive therapy

2016 ◽  
Vol 33 (S1) ◽  
pp. S618-S618
Author(s):  
M.R. Raposo ◽  
M.L. Medina ◽  
A.L. González ◽  
I. Martínez ◽  
A. Gil ◽  
...  
Keyword(s):  
Side Effects ◽  
Electroconvulsive Therapy ◽  
Meta Analysis ◽  
Electrode Placement ◽  
Current Evidence ◽  
List Type ◽  
Treatment Of Depression ◽  
The Subject ◽  
Competing Interest ◽  
Cognitive Side Effects

IntroductionElectroconvulsive therapy (ECT) is an effective depression treatment, but it has potential cognitive side effects. Bitemporal ECT has been traditionally used, but in recent decades, right unilateral (RUL) electrode placement has been proposed to decrease the cognitive side effects of ECT. Ultrabrief pulse (UBP) right unilateral (RUL) ECT is an increasingly used treatment option that can potentially combine efficacy with lesser cognitive side effects.ObjectivesTo evaluate whether ultrabrief pulse (UBP) right unilateral (RUL) electroconvulsive therapy (ECT) is as effective as brief pulse (BP) RUL ECT in addition to cause lesser cognitive side effects.Material and methodsA search is performed in the available scientific literature on systematic review and meta-analysis of the subject under study, through the database PubMed.Results– Current evidence supports the efficacy of right unilateral (RUL) electroconvulsive therapy (ECT) given with an ultrabrief pulse width in the treatment of depression;– ultrabrief pulse RUL ECT leads to lesser cognitive side effects than traditional forms of ECT;– ultrabrief pulse RUL ECT may be slightly less effective than traditional forms of ECT.ConclusionsBP compared with UBP RUL ECT was slightly more efficacious in treating depression and required fewer treatment sessions, but led to greater cognitive side effects. The decision of whether to use BP or UBP RUL ECT should be made on an individual patient basis and should be based on a careful weighing of the relative priorities of efficacy versus minimization of cognitive impairment.Disclosure of interestThe authors have not supplied their declaration of competing interest.

scholarly journals Electroconvulsive therapy, electric field, neuroplasticity, and clinical outcomes

2021 ◽  
Author(s):  
Zhi-De Deng ◽  
Miklos Argyelan ◽  
Jeremy Miller ◽  
Davin K. Quinn ◽  
Megan Lloyd ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electroconvulsive Therapy ◽  
Brain Regions ◽  
Cognitive Outcomes ◽  
Electrode Placement ◽  
Whole Brain ◽  
Underlying Mechanisms ◽  
Stimulation Current ◽  
Depressive Episodes

AbstractElectroconvulsive therapy (ECT) remains the gold-standard treatment for patients with depressive episodes, but the underlying mechanisms for antidepressant response and procedure-induced cognitive side effects have yet to be elucidated. Such mechanisms may be complex and involve certain ECT parameters and brain regions. Regarding parameters, the electrode placement (right unilateral or bitemporal) determines the geometric shape of the electric field (E-field), and amplitude determines the E-field magnitude in select brain regions (e.g., hippocampus). Here, we aim to determine the relationships between hippocampal E-field strength, hippocampal neuroplasticity, and antidepressant and cognitive outcomes. We used hippocampal E-fields and volumes generated from a randomized clinical trial that compared right unilateral electrode placement with different pulse amplitudes (600, 700, and 800 mA). Hippocampal E-field strength was variable but increased with each amplitude arm. We demonstrated a linear relationship between right hippocampal E-field and right hippocampal neuroplasticity. Right hippocampal neuroplasticity mediated right hippocampal E-field and antidepressant outcomes. In contrast, right hippocampal E-field was directly related to cognitive outcomes as measured by phonemic fluency. We used receiver operating characteristic curves to determine that the maximal right hippocampal E-field associated with cognitive safety was 112.5 V/m. Right hippocampal E-field strength was related to the whole-brain ratio of E-field strength per unit of stimulation current, but this whole-brain ratio was unrelated to antidepressant or cognitive outcomes. We discuss the implications of optimal hippocampal E-field dosing to maximize antidepressant outcomes and cognitive safety with individualized amplitudes.

Electroconvulsive Therapy: Electric Stimulus Variables and the Convulsive Response

1991 ◽  
Vol 36 (9) ◽  
pp. 630-636 ◽  
Author(s):  
G.J. Bean ◽  
A.E. Rhodes ◽  
B.A. Martin
Keyword(s):  
Electroconvulsive Therapy ◽  
Electrical Energy ◽  
Electrical Stimulus ◽  
Routine Clinical Practice ◽  
Electrode Placement ◽  
Treatment Protocols ◽  
Electric Stimulus ◽  
Stimulus Waveform ◽  
Stimulus Energy ◽  
Grand Mal

The ability of an electrical stimulus to induce a grand mal convulsion during electroconvulsive therapy (ECT) was investigated using four clinical treatment protocols during which the stimulus waveform, the electrical energy and/or the electrode placement were varied. The statistically significant results support the view that a pulsatile square wave stimulus is effective in inducing convulsions, provided that the d'Elia and not the Muller unilateral electrode placement is used. Higher stimulus energy may be required for older patients. The results illustrate successive attempts to remedy a previously reported problem with the effectiveness of the pulsatile waveform as a convulsive stimulus. The benefit of maintaining a database of treatment variables in order to monitor the effect of changes in the protocol under conditions of routine clinical practice is also demonstrated.

scholarly journals Cortical neurons exhibit diverse myelination patterns that scale between mouse brain regions and regenerate after demyelination

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cody L. Call ◽  
Dwight E. Bergles
Keyword(s):  
Cortical Neurons ◽  
Regional Differences ◽  
Brain Regions ◽  
Axon Diameter ◽  
Neuronal Identity ◽  
Cortical Areas ◽  
Myelin Sheaths ◽  
Parvalbumin Interneurons ◽  
Selection Of

ABSTRACTAxons in the cerebral cortex show a broad range of myelin coverage. Oligodendrocytes establish this pattern by selecting a cohort of axons for myelination; however, the distribution of myelin on distinct neurons and extent of internode replacement after demyelination remain to be defined. Here we show that myelination patterns of seven distinct neuron subtypes in somatosensory cortex are influenced by both axon diameter and neuronal identity. Preference for myelination of parvalbumin interneurons was preserved between cortical areas with varying myelin density, suggesting that regional differences in myelin abundance arises through local control of oligodendrogenesis. By imaging loss and regeneration of myelin sheaths in vivo we show that myelin distribution on individual axons was altered but overall myelin content on distinct neuron subtypes was restored. Our findings suggest that local changes in myelination are tolerated, allowing regenerated oligodendrocytes to restore myelin content on distinct neurons through opportunistic selection of axons.

scholarly journals In vivo synaptic density relates to glucose metabolism at rest in healthy subjects, but is strongly modulated by regional differences

2021 ◽  
pp. 0271678X2098150
Author(s):  
June van Aalst ◽  
Jenny Ceccarini ◽  
Stefan Sunaert ◽  
Patrick Dupont ◽  
Michel Koole ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Medial Temporal Lobe ◽  
Regional Differences ◽  
Specific Binding ◽  
Aerobic Glycolysis ◽  
Glucose Consumption ◽  
Brain Regions ◽  
Synaptic Density ◽  
Energy Demands

Preclinical and postmortem studies have suggested that regional synaptic density and glucose consumption (CMRGlc) are strongly related. However, the relation between synaptic density and cerebral glucose metabolism in the human brain has not directly been assessed in vivo. Using [11C]UCB-J binding to synaptic vesicle glycoprotein 2 A (SV2A) as indicator for synaptic density and [18F]FDG for measuring cerebral glucose consumption, we studied twenty healthy female subjects (age 29.6 ± 9.9 yrs) who underwent a single-day dual-tracer protocol (GE Signa PET-MR). Global measures of absolute and relative CMRGlc and specific binding of [11C]UCB-J were indeed highly significantly correlated ( r > 0.47, p < 0.001). However, regional differences in relative [18F]FDG and [11C]UCB-J uptake were observed, with up to 19% higher [11C]UCB-J uptake in the medial temporal lobe (MTL) and up to 17% higher glucose metabolism in frontal and motor-related areas and thalamus. This pattern has a considerable overlap with the brain regions showing different levels of aerobic glycolysis. Regionally varying energy demands of inhibitory and excitatory synapses at rest may also contribute to this difference. Being unaffected by astroglial and/or microglial energy demands, changes in synaptic density in the MTL may therefore be more sensitive to early detection of pathological conditions compared to changes in glucose metabolism.

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