Electric field distribution models in ECT research

Sartorius, Alexander

doi:10.1038/s41380-022-01516-8

Cited by 9 publications

(6 citation statements)

References 5 publications

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“…The previous ndings were replicated, and the weighted mixing of the EF values according to the number of ECT sessions on different electrode placements proved to be a useful way to calculate the effect of EF on volume change (MIX electrode placement). Our current study further con rms that EF modeling, despite its limitation 34 , is a useful technique to estimate EF, and the growing body of evidence of the correlation between EF and volume changes serves as biological validation of the technique.…”

Section: Discussionsupporting

confidence: 74%

Electroconvulsive therapy-induced volumetric brain changes converge on a common causal circuit in depression

Deng,

Ousdal,

Oltedal

et al. 2023

Preprint

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Neurostimulation is a mainstream treatment option for major depression. Neuromodulation techniques apply repetitive magnetic or electrical stimulation to some neural target but significantly differ in their invasiveness, spatial selectivity, mechanism of action, and efficacy. Despite these differences, recent analyses of transcranial magnetic stimulation (TMS) and deep brain stimulation (DBS)-treated individuals converged on a common neural network that might have a causal role in treatment response. We set out to investigate if the neuronal underpinnings of electroconvulsive therapy (ECT) are similarly associated with this common causal network (CCN). Our aim here is to provide a comprehensive analysis in three cohorts of patients segregated by electrode placement (N = 246 with right unilateral, 79 with bitemporal, and 61 with mixed) who underwent ECT. We conducted a data-driven, unsupervised multivariate neuroimaging analysis (Principal Component Analysis, PCA) of the cortical and subcortical volume changes and electric field (EF) distribution to explore changes within the CCN associated with antidepressant outcomes. Despite the different treatment modalities (ECT vs TMS and DBS) and methodological approaches (structural vs functional networks), we found a highly similar pattern of change within the CCN in the three cohorts of patients (spatial similarity across 85 regions: r = 0.65, 0.58, 0.40, df = 83). Most importantly, the expression of this pattern correlated with clinical outcomes. This evidence further supports that treatment interventions converge on a CCN in depression. Optimizing modulation of this network could serve to improve the outcome of neurostimulation in depression.

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Section: Discussionsupporting

confidence: 74%

Electroconvulsive therapy-induced volumetric brain changes converge on a common causal circuit in depression

Deng,

Ousdal,

Oltedal

et al. 2023

Preprint

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“…Alternating currents with higher frequencies, however, show different EF distributions, making the transfer of EF distributions between these methods difficult to impossible until explicit comparisons between the EFs evoked by different methods have been made (Sartorius 2022). Our findings on correlations in bifrontal stimulation support EF models and contribute to fundamental technical und physiological understanding of ECT.…”

Section: Discussionmentioning

confidence: 61%

Dynamic impedance is correlated with static impedance and seizure quality parameters in bifrontal electroconvulsive therapy

Exner

Deuring

Seifritz

et al. 2023

Acta Neuropsychiatr.

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Background: To evoke a therapeutically effective seizure, electrical stimulation in electroconvulsive therapy (ECT) has to overcome the combined resistivity of scalp, skull and other tissues. Static impedances are measured prior to stimulation using high frequency electrical alternating pulses, dynamic impedances during passage of the stimulation current. Static impedance can partially be influenced by skin preparation techniques. Earlier studies showed a correlation of dynamic and static impedance in bitemporal and right unilateral ECT. Objective: This study aims at assessing the correlation of dynamic and static impedance with patient characteristics and seizure quality criteria in bifrontal ECT. Methods: We performed a cross-sectional single-centre retrospective analysis of ECT treatments at the Psychiatric University Hospital Zurich between May 2012 and March 2020 and used linear mixed-effects regression models in 78 patients with a total of 1757 ECT sessions. Results: Dynamic and static impedance were strongly correlated. Dynamic impedance was significantly correlated with age and higher in women. Energy set and factors positively (caffeine) and negatively (propofol) affecting seizure at the neuronal level were not associated with dynamic impedance. For secondary outcomes Dynamic Impedance was significantly related to Maximum Sustained Power and Average Seizure Energy Index. Other seizure quality criteria showed no significant correlation with Dynamic Impedance. Conclusion: Aiming for low static impedance might reduce dynamic impedance, which is correlated with positive seizure quality parameters. Therefore, good skin preparation to achieve low static impedance is recommended.

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“…Consequently, we suggest a randomized blinded clinical trial is indicated, to compare the therapeutic efficacy and side-effects of MFV2 vs. other placements. Limitations of EF modeling for ECT research have been discussed ( Sartorius, 2022 ), which imply that EFs to brain structures distant from electrodes may be less than calculated, supporting the rationale for the FM orientation avoiding bilateral hippocampal EF effects.…”

Section: Discussionmentioning

confidence: 99%

Fronto-medial electrode placement for electroconvulsive treatment of depression

Steele

Farnan²,

Semple³

et al. 2022

Front. Neurosci.

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

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Electric field distribution models in ECT research

Cited by 9 publications

References 5 publications

Electroconvulsive therapy-induced volumetric brain changes converge on a common causal circuit in depression

Electroconvulsive therapy-induced volumetric brain changes converge on a common causal circuit in depression

Dynamic impedance is correlated with static impedance and seizure quality parameters in bifrontal electroconvulsive therapy

Fronto-medial electrode placement for electroconvulsive treatment of depression

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