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Ahmad Bakir A, Martin DM, Alduraywish A, Dokos S, Loo CK. Electroconvulsive Therapy With Brain Cyst: A Simulation Study. J ECT 2024:00124509-990000000-00193. [PMID: 39024187 DOI: 10.1097/yct.0000000000001045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
INTRODUCTION Electroconvulsive therapy (ECT) is effective in treating severe depression and other neuropsychiatric disorders, but how the presence of an anatomical anomaly affects the electrical pathways between the electrodes remains unclear. We investigate the difference in electric field (E-field) distribution during ECT in the brain of a patient with an arachnoid cyst relative to hypothetical condition where the cyst was not present. METHODS Magnetic resonance imaging scans of the head of a patient with a large left frontal cyst were segmented to construct a finite element model to study the E-field distribution during ECT. Five electrode configurations were investigated: right unilateral, left unilateral, bifrontal, and bitemporal and left anterior right temporal. The E-field distributions for all montages were compared with a hypothetical condition where brain tissue and electrical conductivity from the right frontal region was mirrored across the longitudinal fissure into the cyst. RESULTS Differences in mean E-field and 90th percentile E-fields were mainly observed in brain regions closest to the cyst including the left inferior frontal gyrus and left middle frontal gyrus. This trend was most pronounced in montages where the electrodes were closest to the cyst such as left unilateral and bitemporal. CONCLUSION The presence of a highly conductive cyst close to the ECT electrode tended to attract current into the cyst region, altering current pathways, with potential implications for therapeutic efficacy and safety. Placing electrodes farther away from the cyst is likely to minimize any effects on the E-field distribution and potentially clinical outcomes.
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Affiliation(s)
- Azam Ahmad Bakir
- From the Smart Manufacturing Systems Research Group, University of Southampton Malaysia, Johor, Malaysia
| | | | | | - Socrates Dokos
- Graduate School of Biomedical Engineering, University of New South Wales
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Dynamic impedance is correlated with static impedance and seizure quality parameters in bifrontal electroconvulsive therapy. Acta Neuropsychiatr 2023; 35:177-185. [PMID: 36803888 DOI: 10.1017/neu.2023.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
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 between 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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Fridgeirsson EA, Deng ZD, Denys D, van Waarde JA, van Wingen GA. Electric field strength induced by electroconvulsive therapy is associated with clinical outcome. Neuroimage Clin 2021; 30:102581. [PMID: 33588322 PMCID: PMC7895836 DOI: 10.1016/j.nicl.2021.102581] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 12/31/2022]
Abstract
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.
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Affiliation(s)
- Egill Axfjord Fridgeirsson
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands; Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands
| | - Zhi-De Deng
- Noninvasive Neuromodulation Unit, Experimental Therapeutics & Pathophysiology Branch, National Institute of Mental Health, United States
| | - Damiaan Denys
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands; The Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, the Netherlands
| | | | - Guido A van Wingen
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands; Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands.
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van Kessel MA, van der Vlugt JJB, Spaans HP, Murre JMJ, Verwijk E. Psychotic depressive subtype and white mater hyperintensities do not predict cognitive side effects in ECT: A systematic review of pretreatment predictors. J Affect Disord 2020; 272:340-347. [PMID: 32553376 DOI: 10.1016/j.jad.2020.03.181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 03/03/2020] [Accepted: 03/29/2020] [Indexed: 01/14/2023]
Abstract
BACKGROUND Most studies regarding cognitive side-effects following ECT for treating depression report transient forms of cognitive disturbances. However, a growing number of studies also report considerable differences among individual patients. OBJECTIVE The aim of this systematic review was to identify pretreatment patient characteristics for predicting the risk of developing cognitive side-effects following ECT. METHODS Online databases PubMed/Medline, Embase, and PsycINFO were searched for articles published from 2002 through May 2019, using the following relevant search terms: #cognitive deficits AND #Electro Convulsive Therapy. Inclusion and exclusion criteria were applied for full-text inclusion. PRISMA guidelines were used. RESULTS Our initial search yielded 2155 publications; 16 studies were included. A total of 16 possible predictive factors were identified. Two factors, psychotic features and white matter hyperintensities, were conclusively found to not predict cognitive side-effects following ECT; the remaining 14 factors were inconclusive. CONCLUSIONS There is robust evidence that psychotic features and white matter hyperintensities are not predictive of cognitive side-effects following ECT. None of the other 14 factors examined were predictive, however these levels of evidence were weak and therefore inconclusive. Additional studies focusing primarily on pretreatment patient characteristics for predicting cognitive side-effects following ECT are needed, including demographic, clinical, physiological, neurobiological, and genetic factors. Finally, we provide suggestions for future research.
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Affiliation(s)
| | | | | | - Jaap M J Murre
- Department of Psychology, Brain & Cognition, University of Amsterdam, Amsterdam, The Netherlands
| | - Esmée Verwijk
- Parnassia PG, The Hague, The Netherlands; Department of Psychology, Brain & Cognition, University of Amsterdam, Amsterdam, The Netherlands.; Department of Medical Psychology, Amsterdam University Medical Center, Amsterdam, The Netherlands
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Abstract
Trends in brain stimulation include becoming less invasive, more focal, and more durable with less toxicity. Several of the more interesting new potentially disruptive technologies that are just making their way through basic and sometimes clinical research studies include low-intensity focused ultrasound and temporally interfering electric fields. It is possible, and even likely, that noninvasive brain stimulation may become the dominant form of brain treatments over the next 20 years. The future of brain stimulation therapeutics is bright.
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Affiliation(s)
- Kevin A Caulfield
- Brain Stimulation Laboratory, Medical University of South Carolina, 67 President Street, 502 North, Charleston, SC 29425, USA; Ralph H. Johnson VA Medical Center, 109 Bee Street, Charleston, SC 29401, USA.
| | - Mark S George
- Brain Stimulation Laboratory, Medical University of South Carolina, 67 President Street, 502 North, Charleston, SC 29425, USA; Ralph H. Johnson VA Medical Center, 109 Bee Street, Charleston, SC 29401, USA
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van den Berg JF, Kruithof HC, Kok RM, Verwijk E, Spaans HP. Electroconvulsive Therapy for Agitation and Aggression in Dementia: A Systematic Review. Am J Geriatr Psychiatry 2018; 26:419-434. [PMID: 29107460 DOI: 10.1016/j.jagp.2017.09.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 09/15/2017] [Accepted: 09/20/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVES Many patients with dementia develop agitation or aggression in the course of their disease. In some severe cases, behavioral, environmental, and pharmacological interventions are not sufficient to alleviate these potentially life-threatening symptoms. It has been suggested that in those cases, electroconvulsive therapy (ECT) could be an option. This review summarizes the scientific literature on ECT for agitation and aggression in dementia. METHODS We performed a systematic review in accordance with PRISMA guidelines. A search was conducted in Ovid MEDLINE, EMBASE, and PsycINFO. Two reviewers extracted the following data from the retrieved articles: number of patients and their age, gender, diagnoses, types of problem behavior, treatments tried before ECT, specifications of the ECT treatment, use of rating scales, treatment results, follow-up data, and adverse effects. RESULTS The initial search yielded 264 articles, 17 of which fulfilled the inclusion criteria. Of these studies, one was a prospective cohort study, one was a case-control study, and the others were retrospective chart reviews, case series, or case reports. Clinically significant improvement was observed in the majority (88%) of the 122 patients described, often early in the treatment course. Adverse effects were most commonly mild, transient, or not reported. CONCLUSIONS The reviewed articles suggest that ECT could be an effective treatment for severe and treatment-refractory agitation and aggression in dementia, with few adverse consequences. Nevertheless, because of the substantial risk of selection bias, the designs of the studies reviewed, and their small number, further prospective studies are needed to substantiate these preliminary positive results.
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Affiliation(s)
- Julia F van den Berg
- Parnassia Psychiatric Institute, The Hague, The Netherlands; Department of Clinical Psychology, Leiden University, Leiden, The Netherlands
| | | | - Rob M Kok
- Parnassia Psychiatric Institute, The Hague, The Netherlands
| | - Esmée Verwijk
- Parnassia Psychiatric Institute, The Hague, The Netherlands; Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands; Department of Medical Psychology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Stephani C, Shoukier M, Ahmed R, Wolff-Menzler C. Polymorphism of the brain-derived neurotrophic factor and dynamics of the seizure threshold of electroconvulsive therapy. Eur Arch Psychiatry Clin Neurosci 2017; 267:787-794. [PMID: 27787610 DOI: 10.1007/s00406-016-0744-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 10/21/2016] [Indexed: 10/20/2022]
Abstract
During a course of electroconvulsive therapy (ECT), the level of currency necessary to induce an epileptic seizure in a patient may either remain relatively stable or-more often-may require repeated upward adjustment over time due to a constantly increasing seizure threshold. We aimed to determine whether a common polymorphism of the brain-derived neurotrophic factor (BDNF), which constitutes an important and ubiquitously expressed neurotrophine in the brain, affects the stimulation threshold of ECTs required to induce an epileptic seizure over time. Twenty-seven adult patients who underwent at least 12 consecutive ECT sessions were analyzed for the stimulation intensities required during the course of the stimulation as well as their BDNF gene status. We could not find a relation between the Val/Met polymorphism of the BDNF and the development of the seizure threshold during the course of the ECT sessions. Mechanisms and predispositions other than the BDNF polymorphism investigated in this study are responsible for the change in seizure thresholds over the course of ECT.
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Affiliation(s)
- C Stephani
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany.
| | - M Shoukier
- Department of Human Genetics, University Medical Center Göttingen, Heinrich-Düker-Weg 12, 37075, Göttingen, Germany
| | - R Ahmed
- Institute for Research and Clinical Studies, Von-Bar-Straße 2/4, 37075, Göttingen, Germany
| | - C Wolff-Menzler
- Department of Psychiatry, University Medical Center Göttingen, von-Siebold-Strasse 5, 37075, Göttingen, Germany.,Clinic for Psychiatry and Psychotherapy, Alexianer-Krankenhaus Aachen GmbH, Alexianergraben 33, 52062, Aachen, Germany
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Peterchev AV, Krystal AD, Rosa MA, Lisanby SH. Individualized Low-Amplitude Seizure Therapy: Minimizing Current for Electroconvulsive Therapy and Magnetic Seizure Therapy. Neuropsychopharmacology 2015; 40:2076-84. [PMID: 25920013 PMCID: PMC4613599 DOI: 10.1038/npp.2015.122] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 03/31/2015] [Accepted: 04/24/2015] [Indexed: 11/09/2022]
Abstract
Electroconvulsive therapy (ECT) at conventional current amplitudes (800-900 mA) is highly effective but carries the risk of cognitive side effects. Lowering and individualizing the current amplitude may reduce side effects by virtue of a less intense and more focal electric field exposure in the brain, but this aspect of ECT dosing is largely unexplored. Magnetic seizure therapy (MST) induces a weaker and more focal electric field than ECT; however, the pulse amplitude is not individualized and the minimum amplitude required to induce a seizure is unknown. We titrated the amplitude of long stimulus trains (500 pulses) as a means of determining the minimum current amplitude required to induce a seizure with ECT (bilateral, right unilateral, bifrontal, and frontomedial electrode placements) and MST (round coil on vertex) in nonhuman primates. Furthermore, we investigated a novel method of predicting this amplitude-titrated seizure threshold (ST) by a non-convulsive measurement of motor threshold (MT) using single pulses delivered through the ECT electrodes or MST coil. Average STs were substantially lower than conventional pulse amplitudes (112-174 mA for ECT and 37.4% of maximum device amplitude for MST). ST was more variable in ECT than in MST. MT explained 63% of the ST variance and is hence the strongest known predictor of ST. These results indicate that seizures can be induced with less intense electric fields than conventional ECT that may be safer; efficacy and side effects should be evaluated in clinical studies. MT measurement could be a faster and safer alternative to empirical ST titration for ECT and MST.
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Affiliation(s)
- Angel V Peterchev
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA
| | - Andrew D Krystal
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
| | - Moacyr A Rosa
- Institute for Advanced Research in Neurostimulation, São Paulo, Brazil
| | - Sarah H Lisanby
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
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Repeated dose titration versus age-based method in electroconvulsive therapy: a pilot study. Eur Arch Psychiatry Clin Neurosci 2015; 265:351-6. [PMID: 25804765 DOI: 10.1007/s00406-015-0591-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 03/15/2015] [Indexed: 10/23/2022]
Abstract
In electroconvulsive therapy (ECT), a dose titration method (DTM) was suggested to be more individualized and therefore more accurate than formula-based dosing methods. A repeated DTM (every sixth session and dose adjustment accordingly) was compared to an age-based method (ABM) regarding treatment characteristics, clinical outcome, and cognitive functioning after ECT. Thirty-nine unipolar depressed patients dosed using repeated DTM and 40 matched patients treated with ABM were compared. Montgomery-Åsberg Depression Rating Scale (MADRS) and Mini-Mental State Examination (MMSE) were assessed at baseline and at the end of the index course, as well as the total number of ECT sessions. Both groups were similar regarding age, sex, psychotic features, mean baseline MADRS, and median baseline MMSE. At the end of the index course, the two methods showed equal outcome (mean end MADRS, 11.6 ± 8.3 in DTM and 9.5 ± 7.6 in ABM (P = 0.26); median end MMSE, 28 (25-29) and 28 (25-29.8), respectively (P = 0.81). However, the median number of all ECT sessions differed 16 (11-22) in DTM versus 12 (10-14.8) in ABM; P = 0.02]. Using regression analysis, dosing method and age were independently associated with the total number of ECT sessions, with less sessions needed in ABM (P = 0.02) and in older patients (P = 0.001). In this comparative cohort study, ABM and DTM showed equal outcome for depression and cognition. However, the median ECT course duration in repeated DTM appeared longer. Additionally, higher age was associated with shorter ECT courses regardless of the dosing method. Further prospective studies are needed to confirm these findings.
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van Waarde JA, Scholte HS, van Oudheusden LJB, Verwey B, Denys D, van Wingen GA. A functional MRI marker may predict the outcome of electroconvulsive therapy in severe and treatment-resistant depression. Mol Psychiatry 2015; 20:609-14. [PMID: 25092248 DOI: 10.1038/mp.2014.78] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 06/01/2014] [Accepted: 06/17/2014] [Indexed: 12/12/2022]
Abstract
Electroconvulsive therapy (ECT) is effective even in treatment-resistant patients with major depression. Currently, there are no markers available that can assist in identifying those patients most likely to benefit from ECT. In the present study, we investigated whether resting-state network connectivity can predict treatment outcome for individual patients. We included forty-five patients with severe and treatment-resistant unipolar depression and collected functional magnetic resonance imaging scans before the course of ECT. We extracted resting-state networks and used multivariate pattern analysis to discover networks that predicted recovery from depression. Cross-validation revealed two resting-state networks with significant classification accuracy after correction for multiple comparisons. A network centered in the dorsomedial prefrontal cortex (including the dorsolateral prefrontal cortex, orbitofrontal cortex and posterior cingulate cortex) showed a sensitivity of 84% and specificity of 85%. Another network centered in the anterior cingulate cortex (including the dorsolateral prefrontal cortex, sensorimotor cortex, parahippocampal gyrus and midbrain) showed a sensitivity of 80% and a specificity of 75%. These preliminary results demonstrate that resting-state networks may predict treatment outcome for individual patients and suggest that resting-state networks have the potential to serve as prognostic neuroimaging biomarkers to guide personalized treatment decisions.
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Affiliation(s)
- J A van Waarde
- Department of Psychiatry, Rijnstate Hospital, Arnhem, The Netherlands
| | - H S Scholte
- Cognitive Neuroscience Group, University of Amsterdam, Amsterdam, The Netherlands
| | | | - B Verwey
- Department of Psychiatry, Rijnstate Hospital, Arnhem, The Netherlands
| | - D Denys
- Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - G A van Wingen
- Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Gálvez V, Hadzi-Pavlovic D, Smith D, Loo CK. Predictors of Seizure Threshold in Right Unilateral Ultrabrief Electroconvulsive Therapy: Role of Concomitant Medications and Anaesthesia Used. Brain Stimul 2015; 8:486-92. [PMID: 25683317 DOI: 10.1016/j.brs.2014.12.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 12/29/2014] [Accepted: 12/30/2014] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND An individualized approach to maximize electroconvulsive therapy (ECT) efficacy and minimize cognitive side effects is to treat patients relative to their seizure threshold (ST). However, although Right Unilateral-Ultrabrief (0.3 ms) (RUL-UB) ECT is increasingly used in clinical settings as an effective form of ECT with minimal cognitive effects, there is sparse data regarding predictors of ST. OBJECTIVE To analyze the relationship between ST and clinical and demographic factors in a sample of patients treated with RUL-UB ECT. METHODS Clinical, demographic and ECT data from 179 patients in ECT research studies were examined. Seizure threshold was titrated at the first ECT session. ECT was performed with a Thymatron(®) or Mecta(®) device, with thiopentone (2.5-5 mg/kg) or propofol (1-2 mg/kg) anaesthesia. Medications taken at the time of ST titration were documented. The association between ST and candidate predictor variables was examined with regression analysis. RESULTS Multiple regression analyses showed that 34% of the variance in ST (P < 0.001) could be predicted. Older age (R(2) = 0.194, P < 0.001), propofol (vs thiopentone) (R(2) = 0.029, P ≤ 0.01) and higher anaesthetic dose (mg in propofol equivalents) (R(2) = 0.029, P < 0.05) were found to be predictors of higher initial ST. Treatment with lithium (R(2) = 0.043, P < 0.01) and study site (R(2) = 0.019, P < 0.05) significantly predicted lower initial ST. CONCLUSIONS Empirical titration is recommended for accurate determination of ST in patients receiving RUL-UB ECT. Novel findings of this study are that propofol anaesthesia resulted in higher ST than thiopentone and concomitant treatment with lithium treatment lowered ST.
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Affiliation(s)
- Verònica Gálvez
- School of Psychiatry, University of New South Wales (UNSW), Hospital Road, 2031, Randwick, Sydney, NSW, Australia; Black Dog Institute, Hospital Road, 2031, Randwick, Sydney, NSW Australia
| | - Dusan Hadzi-Pavlovic
- School of Psychiatry, University of New South Wales (UNSW), Hospital Road, 2031, Randwick, Sydney, NSW, Australia; Black Dog Institute, Hospital Road, 2031, Randwick, Sydney, NSW Australia
| | - Deidre Smith
- The Melbourne Clinic & Department of Psychiatry, University of Melbourne, Grattan St Parkville 3010, Melbourne, VIC, Australia
| | - Colleen K Loo
- School of Psychiatry, University of New South Wales (UNSW), Hospital Road, 2031, Randwick, Sydney, NSW, Australia; Black Dog Institute, Hospital Road, 2031, Randwick, Sydney, NSW Australia; Department of Psychiatry, St George Hospital, Level 2, James Laws House, Gray St, Kogarah 2217, Sydney, NSW, Australia.
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Deng ZD, Lisanby SH, Peterchev AV. Effect of anatomical variability on electric field characteristics of electroconvulsive therapy and magnetic seizure therapy: a parametric modeling study. IEEE Trans Neural Syst Rehabil Eng 2015; 23:22-31. [PMID: 25055384 PMCID: PMC4289667 DOI: 10.1109/tnsre.2014.2339014] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Electroconvulsive therapy (ECT) and magnetic seizure therapy (MST) are conventionally applied with a fixed stimulus current amplitude, which may result in differences in the neural stimulation strength and focality across patients due to interindividual anatomical variability. The objective of this study is to quantify the effect of head anatomical variability associated with age, sex, and individual differences on the induced electric field characteristics in ECT and MST. Six stimulation modalities were modeled including bilateral and right unilateral ECT, focal electrically administered seizure therapy (FEAST), and MST with circular, cap, and double-cone coils. The electric field was computed using the finite element method in a parameterized spherical head model representing the variability in the general population. Head tissue layer thicknesses and conductivities were varied to examine the impact of interindividual anatomical differences on the stimulation strength, depth, and focality. Skull conductivity most strongly affects the ECT electric field, whereas the MST electric field is independent of tissue conductivity variation in this model but is markedly affected by differences in head diameter. Focal ECT electrode configurations such as FEAST is more sensitive to anatomical variability than that of less focal paradigms such as BL ECT. In MST, anatomical variability has stronger influence on the electric field of the cap and circular coils compared to the double-cone coil, possibly due to the more superficial field of the former. The variability of the ECT and MST electric fields due to anatomical differences should be considered in the interpretation of existing studies and in efforts to improve dosing approaches for better control of stimulation strength and focality across patients, such as individualization of the current amplitude. The conventional approach to individualizing dosage by titrating the number of pulses cannot compensate for differences in the spatial extent of stimulation that result from anatomical variability.
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Affiliation(s)
- Zhi-De Deng
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, USA
| | - Sarah H. Lisanby
- Departments of Psychiatry and Behavioral Sciences, and Neuroscience, Duke University, Durham, NC, 27710 USA ()
| | - Angel V. Peterchev
- Departments of Psychiatry and Behavioral Sciences, Biomedical Engineering, and Electrical and Computer Engineering, Duke University, Durham, NC 27710, USA ()
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