Inverse relation between stimulus intensity and seizure duration: implications for ECT procedure

Perspectives in treatment-resistant depression: esketamine and electroconvulsive therapy

Modern electroconvulsive therapy (ECT) and the approval of nasal esketamine for clinical use have significantly improved the approach to treatment-resistant depression (TRD), which is defined as non-response to at least two different courses of antidepressants with verified adherence to treatment, adequate dosage, and duration of treatment. The goal of this literature review is to present the newest evidence regarding efficacy and safety. Furthermore, we aim to provide an overview of future perspectives in this field of research, for example, regarding structural and molecular effects. Both treatment methods will be critically evaluated for their individual advantages, disadvantages, and response rates. Firstly, we will discuss the well-established method of ECT and its different treatment modalities. Secondly, we will discuss the properties of ketamine, the discovery of its antidepressive effects and the route to clinical approval of the esketamine nasal spray. We will comment on research settings which have evaluated intravenous ketamine against ECT. The decision-making process between esketamine nasal spray or ECT should include the assessment of contraindications, age, severity of disease, presence of psychotic symptoms, patient preference and treatment accessibility. We conclude that both treatment options are highly effective in TRD. If both are indicated, pragmatically esketamine will be chosen before ECT; however, ECT studies in ketamine non-responders are missing.

Augmentation of Electroconvulsive Therapy with Oral Caffeine: A Retrospective Analysis of 40 Patients with Major Depression

OBJECTIVE

Studies have demonstrated the efficacy of injectable caffeine as an augmentation method in electroconvulsive therapy (ECT). This study investigated whether orally administered caffeine increases seizure duration during ECT.

METHODS

Medical records of 40 patients treated with a series of ECT were retrospectively analyzed. Patients whose electroencephalogram (EEG) seizure duration had dropped<30 s, or motor seizure duration<15 s were included. They subsequently received oral caffeine (0.2 g) before ECT sessions. Primary outcomes were EEG seizure duration and motor seizure duration, compared with those from the last pre-caffeine session (baseline) and the first five caffeine-augmented sessions. The mental state was assessed with the Global Assessment of Functioning (GAF). In addition, data on maximum heart rate, maximal arterial pressure, and adverse effects were collected.

RESULTS

The EEG seizure duration increased by 14.9 s (52%) on average between baseline and the first caffeine-augmented session. The increased length remained widely stable over the subsequent ECT sessions. EEG seizure duration was>30 s in more than 80% of sessions. A statistically significant increase in motor seizure duration appeared only in the 2nd and 3rd of five sessions with augmentation. Oral caffeine pretreatment was overall well tolerated. The percentage of patients with at least serious mental impairment (GAF score≤50) dropped from 77.5 to 15%.

CONCLUSIONS

Results suggest the utility of oral caffeine (0.2 g) to increase ECT-induced seizures in patients with durations below clinically significant thresholds.

Effects of Anesthesia Changes During Maintenance ECT: A Longitudinal Comparison of Seizure Quality Under Anesthesia Using Propofol/Esketamine Versus Methohexital

INTRODUCTION

The effectiveness of ECT relies on the induction of a generalized cerebral seizure. Among others, seizure quality (SQ) is potentially influenced by the anesthetic drug used. Commonly used anesthetics comprise barbiturates, etomidate, propofol, and esketamine, with different characteristics and impacts on seizure parameters. So far, no studies have compared the influence of methohexital vs. a combination of propofol/esketamine on established SQ parameters.

METHODS

This retrospective longitudinal study compared eight established SQ parameters (PSI, ASEI, MSC, midictal amplitude, motor and electroencephalography (EEG) seizure duration, concordance, PHR) before and after the change from propofol/esketamine to methohexital in 34 patients under maintenance ECT. Each patient contributed four measurements, two before and two after the anesthesia change. Anesthesia dose, stimulus dose, electrode placement, and concomitant medication remained unchanged throughout the analyzed treatments.

RESULTS

Under methohexital (M=88.97 mg), ASEI (p=0.039 to 0.013) and midictal amplitude (p=0.022 to<0.001) were significantly lower, whereas seizure duration (motor and EEG) was significantly longer when compared to propofol/esketamine (M=64.26 mg/51.18 mg; p=0.012 to<0.001). PSI, MSC, seizure concordance, and PHR were not affected by the anesthetic used.

DISCUSSION

Although to what extent these parameters correlate with the therapeutic effectiveness remains ambiguous, a decision for or against a particular anesthetic could be considered if a specific SQ parameter needs optimization. However, no general superiority for one specific substance or combination was found in this study. In the next step, anesthetic effects on treatment response and tolerability should be focused on.

Comparison of etomidate and methohexital as anesthetic agents for continuation and maintenance electroconvulsive therapy: A retrospective analysis of seizure quality and safety

BACKGROUND

The ideal hypnotic agent for electroconvulsive therapy (ECT) is still under debate and previous studies comparing etomidate and methohexital have produced conflicting results. This retrospective study compares etomidate and methohexital as anesthetic agents in continuation and maintenance (m)ECT with regard to seizure quality and anesthetic outcomes.

METHODS

All subjects undergoing mECT at our department between October 1st, 2014 and February 28th, 2022 were included in this retrospective analysis. Data for each ECT session were obtained from the electronic health records. Anesthesia was performed with either methohexital/succinylcholine or etomidate/succinylcholine. Standard seizure quality parameters, anesthesiological monitoring data, pharmacological interventions and side-effects were recorded.

RESULTS

573 mECT treatments in 88 patients were included (methohexital n = 458, etomidate n = 115). Seizures lasted significantly longer after using etomidate (electroencephalography: +12.80 s [95 %-CI:8.64-16.95]; electromyogram +6.59 s [95 %-CI:4.14-9.04]). Time to maximum coherence was significantly longer with etomidate (+7.34 s [95 %-CI:3.97-10.71]. Use of etomidate was associated with longer procedure duration (+6.51 min [95 %-CI:4.84-8.17]) and higher maximum postictal systolic blood pressure (+13.64 mmHg [95 %-CI:9.33-17.94]). Postictal systolic blood pressure > 180 mmHg, the use of antihypertensives, benzodiazepines and clonidine (for postictal agitation), as well as the occurrence of myoclonus was significantly more common under etomidate.

CONCLUSIONS

Due to longer procedure duration and an unfavorable side effect profile, etomidate appears inferior to methohexital as an anesthetic agent in mECT despite longer seizure durations.

Increased Stimulation Intensity Helped to Cope with Prolonged Seizures During the Next Round of Modified Electroconvulsive Therapy: A Case Report

Background

Case Presentation

Conclusion

Selecting right unilateral placement to facilitate continuation of electroconvulsive therapy following prolonged seizures

Available literature remains limited in the identification of risk factors for prolonged seizures in electroconvulsive therapy and much less is reported about the continuation of electroconvulsive therapy after prolonged seizures. We describe two cases with prolonged seizures early in their course of electroconvulsive therapy and the subsequent adjustment made that allowed for safe and effective continuation of electroconvulsive therapy. In both cases, right unilateral electroconvulsive therapy was continued at a suprathreshold stimulus dose of six times relative to seizure threshold. Both patients continued their course of electroconvulsive therapy with no further episodes of prolonged seizures. They did not experience significant cognitive side effects and were discharged after showing marked improvement in their clinical symptoms. Prolonged seizures do not preclude the use of electroconvulsive therapy. The selection of ultrabrief right unilateral electroconvulsive therapy allows for a higher suprathreshold dose with less cognitive side effects compared to bilateral placements. This mitigates the risk of prolonged seizures, allowing for safe and effective continuation of electroconvulsive therapy.

Changes in seizure duration during acute course electroconvulsive therapy

BACKGROUND

Seizure duration has long been measured as a potential marker of ECT treatment efficacy, with concern that short seizures may be clinically ineffective. Relatively small studies have documented a trend towards shorter seizures during acute course ECT, but data from large cohorts would help provide normative data on seizure duration changes during treatment.

OBJECTIVE

This study analyzes the effects of age, sex, ECT dose, and treatment number on the duration of electrographic seizures during acute course ECT in a large single-center cohort.

METHODS

A single-center retrospective chart review was conducted of adult patients receiving a first course of ECT from 2000 to 2017 at a large freestanding psychiatric hospital.

RESULTS

3648 patients met inclusion criteria, receiving 32,879 acute course ECT treatments. There was a shortening of mean ECT seizure duration over the acute course, with the greatest decrease in duration over the first 3 treatments but continuing decreases over the entire acute course. Older age, higher ECT dose, and increasing treatment number were all associated with shorter seizures, while sex was not significantly associated. Increasing treatment dose was associated with shorter seizures relative to no dose increase, with those patients receiving the highest cumulative doses also having the shortest cumulative seizure time.

CONCLUSIONS

Among patients undergoing acute-course ECT treatment, seizure duration decreased over the treatment course, and increases in applied electrical charge were associated with shorter seizures.

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.

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.

Effect of different charges of modified electroconvulsive seizure on the cognitive behavior in stressed rats: Effects of GluR1 phosphorylation and CaMKIIα activity

Electroconvulsive therapy (ECT) is an efficient therapy for major depression and modern ECT requires anesthesia to enhance safety. However, the commonly used anesthetic, propofol, may weaken the treatment efficacy. A recent study confirmed that ketamine rapidly reduced the symptoms of depression in affected patients. A previous study found that electroconvulsive seizure (ECS), the animal model for ECT, under anesthesia of low-dose ketamine combined with propofol could enhance the antidepressant efficacy and improve the cognitive performance. The present study aimed to investigate the responses to different charges (0, 60, 120, 180 or 240 mC) of ECS under compound anesthetics, ketamine combined with propofol, in stressed rats and the underlying mechanisms to aid in optimization of treatment regimens. The results indicated that ECS exhibited an improved antidepressant effects at 120 mC compared with 60 mC, however, no significant differences in antidepressant effects were identified among the 120, 180 and 240 mC groups. Furthermore, rats subjected to ECS at 120 mC exhibited the best cognitive performance. The phosphorylation levels of calcium/calmodulin-dependent protein kinase IIα (CaMKIIα) at Thr286, glutamate receptor 1 (GluR1) at Ser831 and cAMP-response element-binding protein (CREB) at the Ser133 were higher in the 120-mC group compared with all other groups. These results indicated that the ECS at medium intensity (120 mC) with administration of compound anesthetics may exert an improved therapeutic effect on depression compared with other intensities (0, 60, 180 and 240 mC). The results also suggested that the improvement in cognitive function in stressed rats may be attributed to the phosphorylation of CaMKIIα (Thr286), GluR1 (Ser831) and CREB (Ser133).

Brief vs. ultrabrief pulse ECT: focus on seizure quality

The effect of electroconvulsive therapy (ECT) performed with ultrabrief pulse (UBP) stimulation has been found inferior to brief pulse (BP) ECT in various studies. We reinvestigated this issue using a new dosing strategy that is based on seizure quality instead of seizure threshold. There is a long history of studies associating ictal characteristics of ECT with the clinical outcome. Accordingly, we used the clinical status of the patient and the quality of the prior seizure to determine the dosage for the upcoming treatment-referred to as Clinical and Seizure Based Stimulation (CASBAS). This approach aims at continuously providing high-quality seizures to optimize the outcome. While this dosing strategy was applied in our department, the pulse width was changed for a period of time from BP to UBP. It was hypothesized that the procedure would: (1) maintain seizure quality and clinical outcome under both conditions and would; and (2) compensate the lesser clinical efficacy of UBP by an increase in stimulus intensity. 245 patients received an ECT course according to the dosing strategy described, 162 with brief pulse (BP) and 83 with ultrabrief pulse ECT (UBP). In a retrospective evaluation, seizure quality and clinical outcome (available in a 20% subgroup of patients) did not differ between both groups in most of the examined parameters, while stimulus intensity was found to be significantly higher in the UBP group. As hypothesized, UBP was less efficient than BP in providing comparable ictal quality and clinical outcome. In a first test of concept the dosing strategy CASBAS seemed suitable to continuously adjust the stimulus intensity in ECT and maintain the seizure quality.

Differences in Seizure Expression Between Magnetic Seizure Therapy and Electroconvulsive Shock

OBJECTIVE

Evidence suggests that magnetic seizure therapy (MST) results in fewer side effects than electroconvulsive treatment, both in humans treated with electroconvulsive therapy (ECT) as well as in the animal preclinical model that uses electroconvulsive shock (ECS). Evidence suggests that MST results in fewer cognitive side effects than ECT. Although MST offers enhanced control over seizure induction and spread, little is known about how MST and ECT seizures differ. Seizure characteristics are associated with treatment effect. This study presents quantitative analyses of electroencephalogram (EEG) power after electrical and magnetic seizure induction and anesthesia-alone sham in an animal model. The aim was to test whether differential neurophysiological characteristics of the seizures could be identified that support earlier observations that the powers of theta, alpha, and beta but not delta frequency bands were lower after MST when compared with those after ECS.

METHODS

In a randomized, sham-controlled trial, 24 macaca mulatte received 6 weeks of daily sessions while scalp EEG was recorded. Electroencephalogram power was quantified within delta, theta, alpha, and beta frequency bands.

RESULTS

Magnetic seizure therapy induced lower ictal expression in the theta, alpha and beta frequencies than ECS, but MST and ECS were indistinguishable in the delta band. Magnetic seizure therapy showed less postictal suppression than ECS. Increasing electrical dosage increased ictal power, whereas increasing MST dosage had no effect on EEG expression.

CONCLUSIONS

Magnetic seizure therapy seizures have less robust electrophysiological expression than ECS, and these differences are largest in the alpha and beta bands. The relevance of these differences in higher frequency bands to clinical outcomes deserves further exploration.

SIGNIFICANCE

Contrasting EEG in ECS and MST may lead to insights on the physiological underpinnings of seizure-induced amnesia and to finding ways to reduce cognitive side effects.

The Clonic Phase of Seizures in Patients Treated with Electroconvulsive Therapy is Related to Age and Stimulus Intensity

BACKGROUND

Electroconvulsive therapy (ECT) is effective in the treatment of major depressive disorder and schizophrenia in patients who are drug-naïve or less-receptive to antipsychotic drugs. Several studies have discussed the correlation between patient characteristics, input-current volume, and seizure duration. According to the present principle of ECT guidelines, the therapeutic effect of ECT mostly correlates with seizure duration. As the tonic phase is different from the clonic phase with respect to brain function and activity, it is informative to analyze both the tonic and clonic phases. Thus, this study sought to clarify the relationship between the features of the two phases, and to re-examine and refine guidelines regarding ECT treatment.

METHOD

ECT-course data from 44 schizophrenia or bipolar I patients were recollected, including the number of treatments that they had received, their gender, age, and the association of these characteristics with motor seizure duration was analyzed. A two-factor correlation was employed to test the relationship between each of the two factors.

RESULT

The post-analysis results indicate that seizure duration and age are significantly correlated. Older patients had relatively short seizure durations after ECT-treatment. Notably, a negative correlation was only found between age and the clonic phase of the seizure, not between age and the tonic phase. Furthermore, this study also found an inverse relationship between ECT-intensity and the clonic phase, but not between ECT-intensity and the tonic phase.

CONCLUSION

This study demonstrated that age and ECT-intensity are negatively correlated with seizure duration, particularly in the clonic phase. The present observations are not fully consistent with the basic guidelines of the APA-ECT practical manual. Accordingly, the predictions regarding the therapeutic effect of ECT can be based on both the seizure duration and the clonic phase.

Influence of age on effectiveness and tolerability of electroconvulsive therapy

OBJECTIVES

The effectiveness of electroconvulsive therapy (ECT) in pharmacotherapy-resistant major depressive disorder and schizophrenia has been shown for all age groups. Nevertheless, age-specific adverse effects such as greater cognitive impairment and higher somatic risks due to medical comorbidities and concomitant medication may be limiting factors in geriatric patients.

METHODS

We retrospectively evaluated 4457 treatments in 380 patients to investigate the influence of age on ECT outcome, safety, and adverse effects. Clinical variables, treatment modalities, and neurophysiological parameters were analyzed. For modeling the influence of age on these variables of interest, linear and logistic regression models were performed.

RESULTS

The mean (SD) age of our patients was 51.2 (15) years; 30% were older than 60 years. Diagnoses were major depressive disorder in 74.4% and schizophrenia in 25.6%. We found a considerable clinical improvement in all age groups. A higher severity of disease at admission corresponded to a better clinical response. Analyzing treatment modalities of elderly patients older than 60 years, no significant differences in need and number of concomitant psychotropic medications were seen, but significant differences were seen in medical co-medication. Ictal and postictal neurophysiological parameters were only in part predictive for clinical outcome, but age had a significant influence on most of them. Transient cardiovascular adverse effects and cognitive disturbances were more frequent in the elderly. In most cases, there was no need for any specific treatment.

CONCLUSIONS

Our data confirm previous studies indicating the good effectiveness of ECT irrespective of age. We also found an excellent tolerability profile in the elderly in our patient sample. There was no mortality, and only transient and no life-threatening adverse events occurred.

Seizure length in electroconvulsive therapy as a function of age, sex, and treatment number

Most electroconvulsive therapy (ECT) research indicates that seizure length does not correlate with clinical efficacy. However, it is common in practice for clinicians to undertake measures to prolong seizures if the duration seems to be too short, although there is no universally agreed upon minimum seizure duration for ECT. We felt it would be informative for the ECT field to report mean seizure durations over the course of treatments based on age and sex in a very large cohort to provide norms for reference. We studied 519 patients' courses of ECT and recorded treatment number, sex, and age along with motor and electroencephalogram seizure duration. We found that women have longer seizures, but only at the first treatment session. There is a strong inverse correlation between age and seizure length. The biggest drop in seizure duration along a course of treatments occurs between the first and second treatments; beyond that, seizure duration remains relatively constant.

The influence of concomitant neuroleptic medication on safety, tolerability and clinical effectiveness of electroconvulsive therapy

BACKGROUND

Electroconvulsive therapy (ECT) is still considered to be the most efficacious treatment option in major depressive disorder and treatment-resistant schizophrenia. Unfortunately, in some cases patients do not respond sufficiently to conventional unilateral ECT, or even to bilateral or high dose ECT. In these cases, concomitant pharmacotherapy can be a useful augmentation strategy to improve clinical effectiveness. Interestingly, there is not much data about ECT and concomitant neuroleptic medication.

METHOD

We evaluated 5482 treatments in 455 patients in our retrospective study to see whether there might be differences between combination therapies (ECT and concomitant neuroleptic medication) and ECT monotherapy. We focused on clinical effectiveness and tolerability; furthermore we investigated treatment modalities and ictal neurophysiological parameters that might influence the treatment.

RESULTS

A total of 18.2% of all treatments were done with no psychotropic medication, 2.8% with a neuroleptic monotherapy. Seizure duration according to EEG derivations turned out to be significantly longer in patients treated with neuroleptics of lower antipsychotic potency, whereas seizure duration in EMG was shorter in treatments done with atypical substances. Postictal suppression was highest in treatments done with atypical neuroleptics, whereas the same group was lowest regarding convulsion energy and convulsion concordance indices. The best therapeutic effectiveness was seen in treatments done with atypical substances. Adverse effects were not influenced significantly by concomitant neuroleptic medication.

CONCLUSION

Our study suggests that there might be a clinical benefit by combining ECT treatment with neuroleptic medication; especially atypical substances seem to enhance improvement. The tolerability of ECT treatment was not influenced by concomitant neuroleptic medication.

The influence of concomitant antidepressant medication on safety, tolerability and clinical effectiveness of electroconvulsive therapy

BACKGROUND

A major problem in the treatment of severe depression is the onset latency until clinical improvement. So far, electroconvulsive therapy (ECT) is the most effective somatic treatment of depression. This holds especially true for treatment-refractory disturbances. However, not all patients respond to conventional unilateral ECT. In certain cases, subsequent clinical response can be achieved using bilateral or high-dose unilateral ECT. Also, a concomitant pharmacotherapy can be utilized to augment therapeutic effectiveness. Surprisingly, data in this field are widely lacking and only few studies showed advantages of an ECT/tricyclic antidepressant combination.

METHOD

We retrospectively evaluated 5482 treatments in 455 patients to investigate possible therapeutic advantages in combination therapies versus ECT monotherapy. Main outcome criteria were clinical effectiveness and tolerability. Moreover, treatment modalities and ictal neurophysiological parameters that might influence treatment outcome were analysed.

RESULTS

A total of 18.2% of our treatments were ECT monotherapy, 8.87% were done with one antidepressant. Seizure duration was unaffected by the most antidepressants. SSRI caused a lengthened seizure activity. Postictal suppression was lower in mirtazapine and higher in SSRI and SNRI treated patients. A significant enhancement of therapeutic effectiveness could be seen in the patient group receiving tricyclics, SSRI or mirtazapine. Serious adverse events were not recorded.

CONCLUSION

Our study supports the hypothesis that mirtazapine can be used to enhance the therapeutic effectiveness of ECT. Controlled studies are necessary to further investigate the possible advantages of ECT and pharmacotherapy combinations, especially the use of modern dually acting antidepressants which have proven their good effectiveness in treatment-resistant depression.

[Electroconvulsive therapy at the Department of Psychiatry and Psychotherapy, University of Munich. Development during the years 1995-2002]

BACKGROUND

So far, electroconvulsive therapy (ECT) has been proven to be a reliable and the most effective somatic treatment of depression or schizophrenia. This holds especially true for disturbances, which are refractory to pharmacological treatments.

PATIENTS AND METHODS

We evaluated 4803 treatments in 445 patients. Main outcome criteria were efficacy and tolerability of treatment. Moreover, prospectively recorded neurophysiological parameters that might influence treatment outcome and treatment modalities and were assessed in a retrospective study design.

RESULTS

During the last 7 years developmental changes show an increasing call for ECT treatment. Despite not being able to satisfy all demands the number of treatments more than doubled during the time period investigated. According to the latest scientific knowledge, especially in unipolar ECT, higher stimulation energy has been used to provide better treatment efficacy. Nevertheless, this was accompanied by a lower incidence of cognitive side effects. Due to the better tolerability of the treatment and the prospective neurophysiological indices, it appears that treatment quality has improved in recent years. Overall treatment efficacy was not improved, but could be maintained on a stable high level. This is presumably due to a stronger negative selection of patients with more pharmacotherapy-refractory disturbances.

CONCLUSION

ECT still represents an important option in the treatment of therapy-resistant depression and schizophrenia despite recent progress in neuropsychopharmacology.

Electroconvulsive therapy dosage in continuation/maintenance electroconvulsive therapy: when is a new threshold titration necessary?

Treatment effects and side effects of electroconvulsive therapy (ECT) depend on the level of applied energy in relation to the individual patient's seizure threshold. The threshold is known to increase during a course of frequently repeated ECT treatments and to return to baseline 6 months after cessation of treatment. In continuation ECT, however, as well as after early relapses, the interval between treatments is often longer than a few days but shorter than 6 months. Seizure thresholds for such cases have not been examined. We retrospectively examined 19 patients who had undergone repeated ECT treatments that had been separated by intervals of at least 14 days. We found significant changes in seizure duration, as measured by EEG and the cuff technique, when treatments were separated by durations exceeding 60 days. This is compatible with a decrease in seizure threshold or a loss of anticonvulsant action after 2 months and indicates the necessity to retitrate seizure threshold after this time.

Effect of stimulus intensity and number of treatments on ECS-related seizure duration and retrograde amnesia in rats

BACKGROUND

Animal models are frequently used to generate and test hypotheses about amnesia resulting from electroconvulsive therapy (ECT). Although many predictors of ECT-induced amnesia are known, their relative effects have been inadequately researched in the context of the animal models.

OBJECTIVE

We sought to determine the relative retrograde amnestic effects of electroconvulsive shock (ECS) stimulus intensity (dose) and number on strong memories in rats. We also sought to identify dose-dependent ceiling amnestic effects, if any.

METHODS

Adult rats (n = 144) were overtrained in a passive avoidance task using a step down apparatus. The rats were then randomized in a factorial design to receive one, two, or three once-daily bilateral ECS at 0-mC (sham ECS), 30-mC, 60-mC, 120-mC, or 180-mC doses. Recall of the pre-ECS training was assessed 1 day after the last ECS.

RESULTS

Retrograde amnesia was observed only in rats that received 3 ECS; dose-dependent amnestic effects did not emerge. Higher stimulus intensity was associated with a small (13%) but significant increase in motor seizure duration, but only at the first ECS; stimulus intensity did not influence the attenuation of seizure duration across repeated occasions of ECS.

CONCLUSION

With bilateral ECS, the number of ECSs administered is a more important variable than the ECS dose in weakening a strong, recently acquired, noxious memory; this finding may have important clinical implications. Higher stimulus intensity marginally increases motor seizure duration at the first ECS but does not influence the decrease in seizure duration across repeated ECSs.

Relationships between seizure duration and seizure threshold and stimulus dosage at electroconvulsive therapy: implications for electroconvulsive therapy practice

Recent studies cast doubt on the usefulness of seizure duration as an index for stimulus dosage adjustment at electroconvulsive therapy (ECT). A retrospective analysis on the relationships between seizure duration and seizure threshold and stimulus dosage was performed for 54 patients who received a standardized ECT dose titration and treatment protocol. Subjects receiving stimulus dosage at seizure threshold had a highly variable motor seizure duration, ranging from 15 to 89 s, and 7.4% of subjects had seizures longer than 60 s. Regression analysis showed that initial seizure threshold and height were independent predictors of motor seizure duration during dose titration and accounted for 34% of its variance. Stimulus dosage was increased by 40-67% between the first and second ECT session; however, 60% of subjects had no lengthening of seizures and motor seizure duration was significantly shorter at the second treatment (mean +/- SD: 35.7 +/- 12.3 vs 31.0 +/- 10.6 s; paired t = 2.9, d.f. = 34, P = 0.006). At the first and second ECT treatment, motor seizure duration was significantly related to stimulus dosage (r = -0.45 and r = -0.41, respectively). Given the negative correlation between seizure duration and stimulus intensity, a policy that recommends an increase of stimulus dosage and its reduction for patients with short and long seizures, respectively, does not necessarily result in 'optimal' seizure duration. A better dosing policy that places less emphasis on seizure duration is proposed.

Augmentation of seizure induction in electroconvulsive therapy: a clinical reappraisal

OBJECTIVE

Missed or abortive seizures during electroconvulsive therapy (ECT) may preclude completion of an effective course of treatment in some cases. Seizure augmentation, using proconvulsant agents, has been used to overcome resistance to the induction and continuation of seizure activity. In this review, we analyze published clinical data on the effects and safety of seizure augmentation techniques.

METHOD

Clinical studies and case reports were obtained through a MEDLINE literature search from 1966 to 2001, cross-referencing ECT and proconvulsant agents. Article references were also scanned for relevant studies.

RESULTS AND CONCLUSIONS

Data from clinical trials indicate that augmentation facilitates seizure induction when maximal electrical stimuli fail. Anesthetic modifications, including hyperventilation and substitution with etomidate, ketamine, or other agents, often are successful in overcoming seizure resistance and compare favorably with the use of caffeine. In a few studies, augmentation enabled the use of lower stimulus intensities and fewer treatments without loss of efficacy, even in patients not resistant to seizure induction. However, effects of proconvulsants must be reconciled with increasing evidence of the importance of stimulus dosing relative to seizure threshold and other parameters, now considered key to the efficacy of ECT. Further investigations of pharmacologic augmentation could facilitate the administration of ECT and could provide further insights concerning parameters of seizure efficacy and the mechanism of action underlying convulsive therapies.

High but not low ECS stimulus intensity augments apomorphine-stimulated dopamine postsynaptic receptor functioning in rats

BACKGROUND

Clinical research shows that the antidepressant and cognitive adverse effects of electroconvulsive therapy are both dependent on the administered electrical stimulus intensity (dose); however, dose-dependent neurotransmitter system changes in the brain, which might underlie the therapeutic or adverse effects, remain to be demonstrated.

OBJECTIVE

We used a behavioral model to examine dose-related effects of electroconvulsive shock (ECS) on dopamine postsynaptic receptor functioning in the rat brain.

METHODS

In a factorially designed study, rats (n = 100) were treated with five once-daily ECSs at three levels (sham ECS, 30 mC ECS, and 120 mC ECS), and with drug at two levels (saline, and 1 mg/kg s.c. apomorphine). Motility was assessed in the small open field.

RESULTS

Apomorphine-elicited, dopamine postsynaptic receptor-mediated hypermotility was significantly increased by 120 mC ECS but not by 30 mC ECS. An additional but unrelated finding was that, while the ECS seizure duration expectedly decreased across time, no dose-dependent effects were observed.

CONCLUSION

ECS-induced dopamine postsynaptic receptor up-regulation may depend on the intensity of the administered electrical stimulus.