Effect of quantitative consciousness index on seizure parameters during electroconvulsive therapy in patients with major depressive disorder

BACKGROUND

Electroconvulsive therapy (ECT) is both an effective treatment for patients with major depressive disorder (MDD) and a noxious stimulus. Although some studies have explored the effect of sedation depth on seizure parameters in ECT, there is little research on the noxious stimulation response to ECT. In this study, we used two electroencephalography (EEG)-derived indices, the quantitative consciousness (qCON) index and quantitative nociceptive (qNOX) index, to monitor sedation, hypnosis, and noxious stimulation response in patients with MDD undergoing acute ECT.

AIM

To evaluate the effect of anesthesia depth based on the qCON and qNOX indices on seizure parameters.

METHODS

Patients with MDD (n = 24) underwent acute bilateral temporal ECT under propofol anesthesia. Before ECT, the patients were randomly divided into three groups according to qCON scores (qCON60-70, qCON50-60, and qCON40-50). Continuous qCON monitoring was performed 3 minutes before and during ECT, and the qCON, qNOX, vital signs, EEG seizure parameters, and complications during the recovery period were recorded. The 24-item Hamilton Rating Scale for Depression, Zung's Self-rating Depression Scale, and Montreal Cognitive Assessment scores were evaluated before the first ECT session, after the fourth ECT session, and after the full course of ECT.

RESULTS

A total of 193 ECT sessions were performed on 24 participants. The qCON index significantly affected the EEG seizure duration, peak mid-ictal amplitude, and maximum heart rate during ECT (P < 0.05). The qNOX index significantly affected the post-ictal suppression index (P < 0.05). Age, number of ECT sessions, and anesthetic-ECT time intervals also had a significant effect on EEG seizure parameters (P < 0.05). However, there were no significant differences in complications, 24-item Hamilton Rating Scale for Depression scores, Zung's Self-rating Depression Scale scores, or Montreal Cognitive Assessment scores among the three groups (P > 0.05).

CONCLUSION

Electrical stimulation at a qCON index of 60-70 resulted in better EEG seizure parameters without increasing complications in patients with MDD undergoing bilateral temporal ECT under propofol anesthesia.

Assessment of seizure duration and utility of using SedLine® EEG tracing in veterans undergoing electroconvulsive therapy: a retrospective analysis

BACKGROUND

Electroconvulsive therapy (ECT) endures as a definitive treatment for refractory depression and catatonia and is also considered an effective treatment for a number of other severe psychiatric disorders (Lisanby, N Engl J Med 357:1939-1945, 2007)(Weiner and Prudic, Biol Psychiatry 73:105-106, 2013). GA is an essential component of the ECT procedure for various reasons (Lee, Jenkins and Sparkle, Life 11, 2021). Monitoring anesthetic effects on the brain is desirable as anesthetic agents affect seizure duration and recovery (Rasulo, Hopkins, Lobo, et al,  Neurocrit Care 38:296-311, 2023) (Jones , Nittur , Fleming and Applegate,  BMC Anesthesiol 21:105, 2021) (Soehle , Kayser , Ellerkmann and Schlaepfer,  BJA 112:695-702, 2013). Perioperative anesthetic effects on consciousness can be assessed with brain function monitoring using raw electroencephalogram (EEG) traces and processed EEG indices.

OBJECTIVE

We examined the usefulness and utility of the SedLine® anesthetic effect monitor during ECT procedures. We hypothesized that the seizure duration as measured by the EEG tracing of the ECT machine is equivalent to the duration assessed by the SedLine® EEG tracing. A secondary objective was to describe the SedLine® patient state indices (PSI) at different phases of treatment.

METHODS

Following IRB approval, we analyzed the data of the electronic medical records of 45 ECT treatments of 23 patients in an urban VA medical center between July 01, 2021, and March 30, 2022. We compared the seizure duration in minutes and seconds as measured either by the ECT machine EEG tracing or the SedLine® EEG tracing. We then collected SedLine® processed EEG indices at four different stages during the treatment. Appropriate comparative and observational statistical analyses were applied.

RESULTS

There was no significant difference in measured seizure duration between the two methods examined (p < 0.05). We observed a lag of the SedLine PSI value at the time before stimulus delivery and limited PSI utility during the course of ECT.

CONCLUSION

The SedLine® EEG tracing can be an alternative to the machine EEG tracing for the determination of seizure duration. The SedLine® processed EEG indices are not consistently useful before and after ECT delivery. Anesthetic effect monitoring during ECT is feasible.

[Practice of anaesthesia for electroconvulsive therapy]

Electroconvulsive therapy (ECT) is an established therapeutic method for the treatment of severe mental disorders refractory to pharmaco- and psychotherapy. ECT is a first-line treatment option in delusional disorders, severe depression with acute suicidal tendency or life-threatening catatonia. Usually, ECT is performed as a treatment series. Under short-term anaesthesia and muscle relaxation, tonic-clonic seizures are induced using an external stimulation electrode. Convulsion can be exerted by uni- or bipolar stimulation using an electric charge up to 1000 millicoulomb (mC) with an amperage of 900 mA. Muscular relaxation is necessary to prevent injuries caused by uncontrolled movements during convulsion. During paralysis, consciousness is blocked by general anaesthesia, although ECT is associated with antegrade amnesia for seizure induction and the seizure itself. In the context of ECT, the ideal hypnotic should be characterised by rapid onset, short duration of action and negligible anticonvulsive effects (i.e., least possible impact on seizure quality and duration). As mutual awareness of psychiatric and anaesthesiologic techniques is essential for safe and effective conduction of ECT, this article presents ECT both from the psychiatrist's and the anaesthesiologist's perspective.

Comparison of Efficacy and Safety of Magnetic Seizure Therapy and Electroconvulsive Therapy for Depression: A Systematic Review

Objectives: As a new physical therapeutic technique, magnetic seizure therapy (MST) has established efficacy in the treatment of depression with few cognitive side effects, and thus appears to be a potential alternative to electroconvulsive therapy (ECT). The findings of randomized controlled trials (RCTs) examining the efficacy and safety of MST versus ECT for depression are inconsistent. This systematic review of RCTs was designed with the aim of assessing the safety and efficacy of MST versus ECT for patients with depression. Methods: The WanFang, Chinese Journal Net (CNKI), EMBASE, PubMed, Cochrane Library, and PsycINFO databases were systematically searched by three independent investigators, from their inceptions to July 24, 2021. Results: In total, four RCTs (n = 86) were included and analyzed. Meta-analyses of study-defined response (risk ratio (RR) = 1.36; 95% CI = 0.78 to 2.36; p = 0.28; I2 = 0%), study-defined remission (RR = 1.17; 95% CI = 0.61 to 2.23; p = 0.64; I2 = 0%), and the improvement in depressive symptoms (standardized mean difference (SMD) = 0.21; 95% CI = −0.29 to 0.71; p = 0.42; I2 = 0%) did not present significant differences between MST and ECT. Three RCTs evaluated the cognitive effects of MST compared with ECT using different cognitive measuring tools, but with mixed findings. Only two RCTs reported adverse drug reactions (ADRs), but these lacked specific data. Only one RCT reported discontinuation due to any reason. Conclusions: This preliminary study suggests that MST appears to have a similar antidepressant effect as ECT for depression, but mixed findings on adverse cognitive effects were reported.

Relationship Between Anesthesia Depth and Quality of Seizures in Patients Undergoing Electroconvulsive Therapy: A Prospective Observational Study

OBJECTIVES

Electroconvulsive therapy under general anesthesia is an established treatment for mood disorders, such as therapy-resistant depression. As most anesthetic drugs used for induction of anesthesia increase the seizure threshold, adequate depth of anesthesia without diminishing the therapeutic efficacy of interventions is crucial. The aim of this study was to investigate whether anesthesia depth as assessed by Narcotrend (NCT) monitoring correlates with maximum seizure quality.

METHODS

An observational study was performed in psychiatric patients undergoing multiple interventions of electroconvulsive therapy. Seizure quality of each attendance was assessed evaluating electroencephalogram end point, electromyogram end point, postictal suppression index, the midictal amplitude, and a 3-step overall graduation. Narcotrend was used to assess anesthesia depth according to index-based electroencephalogram findings. Measurements were obtained before induction of anesthesia, before stimulation, and after arousal. Data were analyzed by means of linear mixed models and generalized estimating equations models.

RESULTS

A total of 105 interventions in 12 patients were analyzed. Anesthesia depth before stimulation was significantly associated with seizure quality (standardized β = 0.244, P = 0.010), maximum sustained coherence (β = 0.207, P = 0.022), and electroencephalogram duration (β = 0.215, P = 0.012). A cutoff value of 41 or greater versus 40 or less for the NCT index was found appropriate to differentiate between good and less satisfactory overall seizure quality.

CONCLUSIONS

Anesthesia depth index assessed by NCT monitoring was positively associated with seizure quality. Narcotrend monitoring may be useful in assessment of optimal anesthesia depth before stimulation.

Depth of Anesthesia Monitoring

The electroencephalogram (EEG) can be analyzed in its raw form for characteristic drug-induced patterns of change or summarized using mathematical parameters as a processed electroencephalogram (pEEG). In this article we aim to summarize the contemporary literature pertaining to the commonly available pEEG monitors including the effects of commonly used anesthetic drugs on the EEG and pEEG parameters, pEEG monitor pitfalls, and the clinical implications of pEEG monitoring for anesthesia, pediatrics, and intensive care.

Processed EEG from depth of anaesthesia monitors and seizures: A scoping review

PURPOSE

Processed electroencephalogram (EEG) is used peri-operatively for monitoring depth of anaesthesia. Because these utilise EEG data, attempts have been made to investigate their use in diagnosing and monitoring seizures. This is important as formal EEG monitoring can be hard to obtain in many critical care environments. We undertook a scoping review of the evidence for using processed EEG (pEEG) from depth of anaesthesia monitors for this indication.

METHODS

Medline, Psych INFO, and Embase were searched for peer-reviewed journals until 20 March 2021. Data and conclusions taken from the study of pEEG in both critical care and peri-operative settings have been included in a qualitative synthesis about the current evidence for the use of pEEG in the detection and monitoring of seizures.

RESULTS

Searches yielded 8 observational studies, 1 randomised trial and 15 case reports in which the use of pEEG in critical care and peri-operative medicine was described. Most concerned the Bispectral Index (BIS) device. The majority of observational studies reported the use of BIS for optimisation of burst suppression in patients with refractory status-epilepticus (RSE), or in the comparison of pEEG data with conventional EEG during epileptic activity. Multiple case reports describe the application of pEEG in the presence of disorders of consciousness as a tool for detection of non-convulsive status-epilepticus, finding variable trends in the pEEG output.

CONCLUSIONS

Processed EEG may be helpful in monitoring pharmacologically induced burst suppression. Despite this, its use in the diagnosing or monitoring seizure activity is controversial and currently not evidenced, with numerous confounding variables that requires systematic assessment in future studies.

Resting-state electroencephalographic functional network alterations in major depressive disorder following magnetic seizure therapy

Magnetic seizure therapy (MST) is emerging as a safe and well-tolerated experimental intervention for major depressive disorder (MDD), with very minimal cognitive side-effects. However, the underlying mechanism of action of MST remains uncertain. Here, we used resting-state electroencephalography (RS-EEG) to characterise the physiological effects of MST for treatment resistant MDD. We recorded RS-EEG in 21 patients before and after an open label trial of MST applied over the prefrontal cortex using a bilateral twin coil. RS-EEG was analysed for changes in functional connectivity, network topology, and spectral power. We also ran further baseline comparisons between the MDD patients and a cohort of healthy controls (n = 22). Network-based connectivity analysis revealed a functional subnetwork of significantly increased theta connectivity spanning frontal and parieto-occipital channels following MST. The change in theta connectivity was further found to predict clinical response to treatment. An additional widespread subnetwork of reduced beta connectivity was also elucidated. Graph-based topological analyses showed an increase in functional network segregation and reduction in integration in the theta band, with a decline in segregation in the beta band. Finally, delta and theta power were significantly elevated following treatment, while gamma power declined. No baseline differences between MDD patients and healthy subjects were observed. These results highlight widespread changes in resting-state brain dynamics following a course of MST in MDD patients, with changes in theta connectivity providing a potential physiological marker of treatment response. Future prospective studies are required to confirm these initial findings.

Challenges and pitfalls in anesthesia for electroconvulsive therapy

Electroconvulsive therapy (ECT) refers to the application of electricity to the patients' scalp to treat psychiatric disorders, most notably, treatment-resistant depression. It is a safe, effective, and evidence-based therapy that is performed with general anesthesia. Muscle relaxation is used to prevent injuries related to the tonic-clonic seizure caused by ECT. Hypnotics are administered to induce amnesia and unconsciousness, so that, patients do not experience the period of muscle relaxation, while the generalized seizure is left unnoticed. For the anesthesiologist, ECT is associated with the challenges and pitfalls that are related to informed consent, social acceptance of ECT, airway management (especially in COVID-19 patients), and the interaction between ventilation and anesthetics from one viewpoint, and seizure induction and maintenance from another. The exact mode of action of the therapy is as unknown as the optimal choice or combination of anesthetics used.

Bispectral EEG (BSEEG) to assess arousal after electro-convulsive therapy (ECT)

OBJECTIVES

Postictal confusion is encountered among most patients following electro-convulsive therapy (ECT). This study aimed to test the capabilities of a point-of-care electroencephalography (EEG) method to quantitatively measure and monitor postictal confusion immediately following ECT. We evaluated whether a two-channel frontal EEG device may provide a purely quantitative measure of the postictal state that could aid in the continuous, clinical monitoring of patients following ECT.

METHODS

50 patients receiving ECT at the University of Iowa Hospitals and Clinics were recruited for this study. Subsequently, we obtained 5 min of frontal bispectral EEG (BSEEG) recording from a hand-held EEG device at baseline and 10-20 min following ECT. We performed power spectral density analysis to yield a "BSEEG" score and to capture the difference between patients at baseline and after ECT.

RESULTS

The BSEEG score was demonstrated to be a significant indicator of postictal confusion compared to baseline. For 5 patients, we also obtained continuous EEG recordings following ECT to determine the time course required for a patient's BSEEG score to return to baseline. In this subset of patients, it took between 2 and 3 h in duration for the BSEEG score to return to the baseline range.

CONCLUSIONS

In this pilot study, we showed that BSEEG score was able to distinguish between baseline condition and postictal confusion in patients treated with ECT, and assess the duration for recovery from postictal confusion following ECT. BSEEG may provide a more sensitive measure of arousal in patients following ECT compared to traditional survey-based methods.

Magnetic Seizure Therapy: Towards Personalized Seizure Therapy for Major Depression

Magnetic seizure therapy (MST) is a noninvasive neuromodulation therapy under investigation for the treatment of severe neuropsychiatric disorders. MST involves inducing a therapeutic seizure under anesthesia in a setting similar to electroconvulsive therapy (ECT). To date, randomized controlled trials suggest that MST has similar antidepressant efficacy as ECT, but without significant cognitive adverse effects. Large scale clinical trials are currently underway to confirm these preliminary findings. So far, there has only been one study evaluating the clinical predictors of response to MST and more research is needed. This study found that patients with fewer episodes of depression and a positive family history of depression had a better response to MST. Overall, the ability of MST to focus the delivery of the electric field and the resultant seizure makes targeting seizure therapy to specific brain regions possible, and further research will be helpful in identifying personalized targets to maximize clinical benefit. In this review, we describe MST methodology and how it could be individualized to each patient. We also summarize the clinical and cognitive effects of MST and provide indications of which patients may be most likely to benefit. Finally, we summarize the studied neurophysiological predictors of response.

Pharmacokinetics and pharmacodynamics of propofol: changes in patients with frontal brain tumours

Background

Models of propofol pharmacokinetics and pharmacodynamics developed in patients without brain pathology are widely used for target-controlled infusion (TCI) during brain tumour excision operations. The goal of this study was to determine if the presence of a frontal brain tumour influences propofol pharmacokinetics and pharmacodynamics and existing PK-PD model performance.

Methods

Twenty patients with a frontal brain tumour and 20 control patients received a propofol infusion to achieve an induction-emergence-induction anaesthetic sequence. Propofol plasma concentration was measured every 4 min and at each transition of the conscious state. Bispectral index (BIS) values were continuously recorded. We used non-linear mixed-effects modelling to analyse the effects of the presence of a brain tumour on the pharmacokinetics and pharmacodynamics of propofol. Subsequently we calculated the predictive performance of Marsh, Schnider, and Eleveld models in terms of median prediction error (MdPE) and median absolute prediction error (MdAPE).

Results

Patients with brain tumours showed 40% higher propofol clearance than control patients. Performance of the Schnider model (MdPEpk -20.0%, MdAPEpk 23.4%) and Eleveld volunteer model (MdPEpk -8.58%, MdAPEpk 21.6%) were good. The Marsh model performed less well (MdPEpk -14.3%, MdAPEpk 41.4%), as did the Eleveld patient model (MdPEpk -30.8%, MdAPEpk 32.1%).

Conclusions

Brain tumours might alter the pharmacokinetics of propofol. Caution should be exerted when using propofol TCI in patients with frontal brain tumours due to higher clearance.

Trial registry number

NCT01060631.

Cognitive and Neurophysiological Recovery Following Electroconvulsive Therapy: A Study Protocol

Electroconvulsive therapy (ECT) employs the elective induction of generalizes seizures as a potent treatment for severe psychiatric illness. As such, ECT provides an opportunity to rigorously study the recovery of consciousness, reconstitution of cognition, and electroencephalographic (EEG) activity following seizures. Fifteen patients with major depressive disorder refractory to pharmacologic therapy will be enrolled (Clinicaltrials.gov, NCT02761330). Adequate seizure duration will be confirmed following right unilateral ECT under etomidate anesthesia. Patients will then undergo randomization for the order in which they will receive three sequential treatments: etomidate + ECT, ketamine + ECT, and ketamine + sham ECT. Sessions will be repeated in the same sequence for a total of six treatments. Before each session, sensorimotor speed, working memory, and executive function will be assessed through a standardized cognitive test battery. After each treatment, the return of purposeful responsiveness to verbal command will be determined. At this point, serial cognitive assessments will begin using the same standardized test battery. The presence of delirium and changes in depression severity will also be ascertained. Sixty-four channel EEG will be acquired throughout baseline, ictal, and postictal epochs. Mixed-effects models will correlate the trajectories of cognitive recovery, clinical outcomes, and EEG metrics over time. This innovative research design will answer whether: (1) time to return of responsiveness will be prolonged with ketamine + ECT compared with ketamine + sham ECT; (2) time of restoration to baseline function in each cognitive domain will take longer after ketamine + ECT than after ketamine + sham ECT; (3) postictal delirium is associated with delayed restoration of baseline function in all cognitive domains; and (4) the sequence of reconstitution of cognitive domains following the three treatments in this study is similar to that occurring after an isoflurane general anesthetic (NCT01911195). Sub-studies will assess the relationships of cognitive recovery to the EEG preceding, concurrent, and following individual ECT sessions. Overall, this study will lead the development of biomarkers for tailoring the cogno-affective recovery of patients undergoing ECT.

Degree of Postictal Suppression Depends on Seizure Induction Time in Magnetic Seizure Therapy and Electroconvulsive Therapy

OBJECTIVES

Anesthesia is required for both magnetic seizure therapy (MST) and electroconvulsive therapy (ECT), although it has anticonvulsant properties. In this case, bispectral index (BIS) monitoring, a specific electroencephalogram-derived monitoring, can be used to find the optimal seizure induction time during anesthesia to elicit adequate seizures. A measurement of seizure adequacy in electroencephalogram is the postictal suppression. The purpose of this study was to investigate the influence of seizure induction time on the degree of postictal suppression by comparing BIS versus no-BIS monitoring in MST and ECT.

METHODS

Twenty patients with treatment-resistant depression were randomly assigned to either MST or ECT. Each patient underwent 3 treatments with the determination of seizure induction time by defined prestimulation BIS (BIS condition) and 3 treatments with determination of seizure induction time by controlled clinical trial protocol (no-BIS condition). Statistical analysis was calculated by repeated-measures analysis of variance.

RESULTS

The degree of postictal suppression was more pronounced in both MST and ECT, with BIS monitoring. In this connection, no differences between MST and ECT were found. Seizure induction time was significantly later in the BIS condition (181.3 ± 6 seconds) compared with the no-BIS condition (114.3 ± 12 seconds) (P < 0.001).

CONCLUSIONS

Adequacy of seizures, in the form of the degree of postictal suppression, was superior by determining the seizure induction time with BIS in both MST and ECT. Further research is needed to investigate the correlation between the degree of postictal suppression and treatment response.

Update on Neuromodulation for Treatment-Resistant Depression

About 30% of patients suffering from a major depressive disorder do not respond sufficiently to established pharmacological, psychotherapeutic, or somatic treatments. Advances in technology and emerging knowledge about the dysfunctional brain circuits underlying depression have led to the development of different neuromodulation techniques. The aim of the present review is to give an update on noninvasive techniques, such as electroconvulsive therapy (ECT), magnetic seizure therapy (MST), transcranial magnetic stimulation (TMS), and invasive techniques requiring brain surgery, such as vagus nerve stimulation (VNS) and deep brain stimulation (DBS). First, the clinical relevance for therapy-resistant depression, including the current level of evidence, are presented. Neuroethics is concerned with the ethical, legal and social policy implications of neuroscience. A second focus of the review is the application of fundamental ethical principles, such as patient autonomy, patient well-being and justice to neuromodulation therapies. Due to reduced availability and lacking long-term efficacy data, most patients with treatment-resistant depression face a trial-and-error approach to therapeutics. This contravenes the ethical criteria of patient autonomy and justice. In order to raise the level of evidence, financial support of long-term studies, including large samples and randomized control trials, are necessary.