Convulsive Therapy With Amplitude Modulated Unidirectional Currents (Reiter)

Impastato, David J.; Berg, Seymour

doi:10.1176/ajp.112.11.932

Cited by 5 publications

(3 citation statements)

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“…In a retrospective analysis of outcomes from over 800 patients, Epstein found unidirectional ECT to be as clinically efficacious but with significantly less memory deficits compared with bidirectional ECT (Epstein J and Wender L, 1956). Several uncontrolled studies reported “Amplitude Modulated Unidirectional” (AMU) currents to be highly efficient in seizure induction and to have less impact on cognition (Impastato and Berg, 1956). Interest in unidirectional stimulation was renewed in several review papers in the 1980’s (Hyrman V et al , 1985; Varghese FT and Singh BS, 1985), but in the subsequent two decades, there was a notable lack of research on the potential benefits of unidirectional ECT.…”

Section: Introductionmentioning

confidence: 99%

Focal Electrically Administered Seizure Therapy: A Novel form of ECT Illustrates the Roles of Current Directionality, Polarity, and Electrode Configuration in Seizure Induction

Spellman

Peterchev

Lisanby

2009

Neuropsychopharmacol

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Electroconvulsive therapy (ECT) is a mainstay in the treatment of severe, medication resistant depression. The antidepressant efficacy and cognitive side effects of ECT are influenced by the position of the electrodes on the head and by the degree to which the electrical stimulus exceeds the threshold for seizure induction. However, surprisingly little is known about the effects of other key electrical parameters such as current directionality, polarity, and electrode configuration. Understanding these relationships may inform the optimization of therapeutic interventions to improve their risk/benefit ratio. To elucidate these relationships, we evaluated a novel form of ECT (focal electrically administered seizure therapy, FEAST) that combines unidirectional stimulation, control of polarity, and an asymmetrical electrode configuration, and contrasted it with conventional ECT in a nonhuman primate model. Rhesus monkeys had their seizure thresholds determined on separate days with ECT conditions that crossed the factors of current directionality (unidirectional or bidirectional), electrode configuration (standard bilateral or FEAST (small anterior and large posterior electrode)), and polarity (assignment of anode and cathode in unidirectional stimulation). Ictal expression and post-ictal suppression were quantified via scalp EEG. Findings were replicated and extended in a second experiment with the same subjects. Seizures were induced in each of 75 trials, including 42 FEAST procedures. Seizure thresholds were lower with unidirectional than with bidirectional stimulation (p<0.0001), and lower in FEAST than in bilateral ECS (p=0.0294). Ictal power was greatest in posterior-anode unidirectional FEAST, and post-ictal suppression was strongest in anterior-anode FEAST (p=0.0008 and p=0.0024, respectively). EEG power was higher in the stimulated hemisphere in posterior-anode FEAST (p=0.0246), consistent with the anode being the site of strongest activation. These findings suggest that current directionality, polarity, and electrode configuration influence the efficiency of seizure induction with ECT. Unidirectional stimulation and novel electrode configurations such as FEAST are two approaches to lowering seizure threshold. Furthermore, the impact of FEAST on ictal and post-ictal expression appeared to be polarity-dependent. Future studies may examine whether these differences in seizure threshold and expression have clinical significance for patients receiving ECT.

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Section: Introductionmentioning

confidence: 99%

Focal Electrically Administered Seizure Therapy: A Novel form of ECT Illustrates the Roles of Current Directionality, Polarity, and Electrode Configuration in Seizure Induction

Spellman

Peterchev

Lisanby

2009

Neuropsychopharmacol

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“…Early ECT studies with unidirectional stimuli reported substantially lower seizure thresholds, comparable clinical efficacy, and significantly lower memory deficits compared with bidirectional ECT 68,104,105,148,149. In these studies, however, current directionality was confounded with other factors such as pulse amplitude, shape, and width, and train frequency and duration.…”

Section: Understanding the Ect Stimulus Parametersmentioning

confidence: 99%

“…Theta-burst stimulation has been used in long-term potentiation (LTP) and long-term depression (LTD) protocols, and in rTMS paradigms to effect rapid, strong neuromodulatory effects that can be excitatory or inhibitory depending on the specific stimulus parameters 171,172. Intermittent ECT stimuli similar to theta-burst have been deployed in a number of older ECT studies,58,68,104,105,120,123,148 were in common use for decades in Europe as a feature of the Siemens Konvulsator device (50-Hz bursts of 4 unidirectional quarter-sine pulses, repeated at 6 Hz),58,147 and are an option is some modern devices such as the Thymatron System IV 173. Some researchers have recommended the use of intermittent stimuli as superior to continuous pulse trains;147 however, a systematic comparison of these two paradigms is lacking and should be addressed in future studies.…”

Section: Understanding the Ect Stimulus Parametersmentioning

confidence: 99%

Electroconvulsive Therapy Stimulus Parameters

Peterchev¹,

Rosa²,

Deng³

et al. 2010

The Journal of ECT

174

151

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

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Die Krampfbehandlung

Solms¹

1963

Grundlagen Und Methoden Der Klinischen Psychiatrie

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Convulsive Therapy With Amplitude Modulated Unidirectional Currents (Reiter)

Cited by 5 publications

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Focal Electrically Administered Seizure Therapy: A Novel form of ECT Illustrates the Roles of Current Directionality, Polarity, and Electrode Configuration in Seizure Induction

Focal Electrically Administered Seizure Therapy: A Novel form of ECT Illustrates the Roles of Current Directionality, Polarity, and Electrode Configuration in Seizure Induction

Electroconvulsive Therapy Stimulus Parameters

Die Krampfbehandlung

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