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

Neurostimulation is a mainstream treatment option for major depression. Neuromodulation techniques apply repetitive magnetic or electrical stimulation to some neural target but significantly differ in their invasiveness, spatial selectivity, mechanism of action, and efficacy. Despite these differences, recent analyses of transcranial magnetic stimulation (TMS) and deep brain stimulation (DBS)-treated individuals converged on a common neural network that might have a causal role in treatment response. We set out to investigate if the neuronal underpinnings of electroconvulsive therapy (ECT) are similarly associated with this causal depression network (CDN). Our aim here is to provide a comprehensive analysis in three cohorts of patients segregated by electrode placement (N = 246 with right unilateral, 79 with bitemporal, and 61 with mixed) who underwent ECT. We conducted a data-driven, unsupervised multivariate neuroimaging analysis Principal Component Analysis (PCA) of the cortical and subcortical volume changes and electric field (EF) distribution to explore changes within the CDN associated with antidepressant outcomes. Despite the different treatment modalities (ECT vs TMS and DBS) and methodological approaches (structural vs functional networks), we found a highly similar pattern of change within the CDN in the three cohorts of patients (spatial similarity across 85 regions: r = 0.65, 0.58, 0.40, df = 83). Most importantly, the expression of this pattern correlated with clinical outcomes (t = -2.35, p = 0.019). This evidence further supports that treatment interventions converge on a CDN in depression. Optimizing modulation of this network could serve to improve the outcome of neurostimulation in depression.

Changes in postictal cerebral perfusion are related to the duration of electroconvulsive therapy-induced seizures.

OBJECTIVE: Postictal symptoms may result from cerebral hypoperfusion, which is possibly a consequence of seizure-induced vasoconstriction. Longer seizures have previously been shown to cause more severe postictal hypoperfusion in rats and epilepsy patients. We studied cerebral perfusion after generalized seizures elicited by electroconvulsive therapy (ECT) and its relation to seizure duration. METHODS: Patients with a major depressive episode who underwent ECT were included. During treatment, 21-channel continuous electroencephalogram (EEG) was recorded. Arterial spin labeling magnetic resonance imaging scans were acquired before the ECT course (baseline) and approximately 1 h after an ECT-induced seizure (postictal) to quantify global and regional gray matter cerebral blood flow (CBF). Seizure duration was assessed from the period of epileptiform discharges on the EEG. Healthy controls were scanned twice to assess test-retest variability. We performed hypothesis-driven Bayesian analyses to study the relation between global and regional perfusion changes and seizure duration. RESULTS: Twenty-four patients and 27 healthy controls were included. Changes in postictal global and regional CBF were correlated with seizure duration. In patients with longer seizure durations, global decrease in CBF reached values up to 28 mL/100 g/min. Regional reductions in CBF were most prominent in the inferior frontal gyrus, cingulate gyrus, and insula (up to 35 mL/100 g/min). In patients with shorter seizures, global and regional perfusion increased (up to 20 mL/100 g/min). These perfusion changes were larger than changes observed in healthy controls, with a maximum median global CBF increase of 12 mL/100 g/min and a maximum median global CBF decrease of 20 mL/100 g/min. SIGNIFICANCE: Seizure duration is a key factor determining postictal perfusion changes. In future studies, seizure duration needs to be considered as a confounding factor due to its opposite effect on postictal perfusion.

Cortical excitation/inhibition ratios in patients with major depression treated with electroconvulsive therapy: an EEG analysis.

Electroconvulsive therapy (ECT) is an effective treatment for major depression, but its working mechanisms are poorly understood. Modulation of excitation/inhibition (E/I) ratios may be a driving factor. Here, we estimate cortical E/I ratios in depressed patients and study whether these ratios change over the course of ECT in relation to clinical effectiveness. Five-minute resting-state electroencephalography (EEG) recordings of 28 depressed patients were recorded before and after their ECT course. Using a novel method based on critical dynamics, functional E/I (fE/I) ratios in the frequency range of 0.5-30 Hz were estimated in frequency bins of 1 Hz for the whole brain and for pre-defined brain regions. Change in Hamilton Depression Rating Scale (HDRS) score was used to estimate clinical effectiveness. To account for test-retest variability, repeated EEG recordings from an independent sample of 31 healthy controls (HC) were included. At baseline, no differences in whole brain and regional fE/I ratios were found between patients and HC. At group level, whole brain and regional fE/I ratios did not change over the ECT course. However, in responders, frontal fE/I ratios in the frequencies 12-28 Hz increased significantly (pFDR < 0.05 [FDR = false discovery rate]) over the ECT course. In non-responders and HC, no changes occurred over time. In this sample, frontal fE/I ratios increased over the ECT course in relation to treatment response. Modulation of frontal fE/I ratios may be an important mechanism of action of ECT.

Severe Postictal Confusion After Electroconvulsive Therapy: A Retrospective Study.

OBJECTIVES: Severe postictal confusion (sPIC) is an important but poorly investigated adverse effect of electroconvulsive therapy (ECT). In this retrospective study, prevalence of sPIC and potential risk factors were explored. METHODS: Medical charts of 295 ECT patients (mean ± SD age, 57 ± 15 years; male, 36%) were scrutinized for occurrence of sPIC, as well as demographic, clinical, and treatment characteristics. Patients showing sPIC were compared with patients who did not, using univariate statistics. Multivariate analyses with a split-sample validation procedure were used to assess whether predictive models could be developed using independent data sets. RESULTS: O 295 patients, 74 (25.1%) showed sPIC. All patients showing sPIC needed extra medication, 9% (n = 7) required physically restraints, and 5% (n = 4) had to be secluded. Univariate analyses showed several trends: patients with sPIC were more often males (P = 0.05), had more often history of cerebrovascular incident (P = 0.02), did not use concomitant selective serotonin reuptake inhibitors (P = 0.01), received higher median dosage of succinylcholine (P = 0.02), and received pretreatment with flumazenil more often (P = 0.07), but these associations did not remain significant after correction for multiple comparisons. Multiple logistic regression analysis did not result in a model that could predict sPIC in the holdout data set. CONCLUSIONS: In this retrospective naturalistic study in 295 ECT patients, the prevalence of sPIC appeared to be 25%. Patients showing sPIC were characterized by male sex, history of cerebrovascular incident, use of higher-dose succinylcholine, and pretreatment with flumazenil. However, multivariate analysis revealed no significant model to predict sPIC in independent data.

A Multicenter Retrospective Chart Review on the Effectiveness and Tolerability of Electroconvulsive Therapy in Adolescents and Young Adults With Major Depressive Disorder or Bipolar Depression.

BACKGROUND: Major depressive disorder and bipolar depression in adolescents and young adults are prevalent and major contributors to the global burden of disease, whereas effective interventions are limited. Available evidence is insufficient to assess effectiveness and tolerability of electroconvulsive therapy in depressed adolescents and young adults. METHODS: A retrospective chart review was conducted in patients with major depressive disorder or bipolar depression who underwent electroconvulsive therapy from 2001 to 2021 in 12 centers in the Netherlands. Patients were classified as young (15-25 years) and older adults (26-80 years). Primary outcome was effectiveness, expressed as response (≥50% reduction in rating scale score compared with baseline) and remission. Rating scale scores were cross-sectionally assessed at baseline and at the end of the index course. Outcomes of remitters were included in responders. Secondary outcome was occurrence of subjective cognitive impairment and adverse events. Long-term outcomes were not available. RESULTS: In the young (n = 57) and older adult (n = 41) group, 40.4% and 56.1% (P = 0.153) of patients achieved response and 28.1% and 39.0% (P = 0.281) remission, respectively. Subjective cognitive impairment (80.5% vs 56.3%; P = 0.001) and transient cardiac arrhythmia (14.6% vs 2.8%; P = 0.020) were reported significantly more frequently in the older adult group. CONCLUSIONS: Despite significantly more comorbidity of personality disorders, autism spectrum disorders, and anxiety disorders, effectiveness in the young was similar to the older adults. Tolerability was even superior in the young, despite significantly more bilateral treatment. Electroconvulsive therapy could be considered a viable treatment option in depressed adolescents and young adults.

Pharmacological interventions to diminish cognitive side effects of electroconvulsive therapy: A systematic review and meta-analysis.

OBJECTIVE: The authors conducted a systematic review and meta-analysis of pharmacological interventions to diminish cognitive side effects of ECT. METHODS: Electronic databases of Pubmed, PsycInfo, Embase and Scopus were searched from inception through 1 April, 2021, using terms for ECT (e.g. electroconvulsive therapy), cognitive outcome (e.g. cogni*) and pharmacological intervention (e.g. calcium channel blocker and general terms, like protein). Original studies with humans receiving ECT were included, which applied pharmacological interventions in comparison with placebo or no additive intervention to diminish cognitive side effects. Data quality was assessed using Risk of Bias and GRADE. Random-effects models were used. PROSPERO registration number was CRD42021212773. RESULTS: Qualitative synthesis (systematic review) showed 52 studies reporting sixteen pharmacological intervention-types. Quantitative synthesis (meta-analysis) included 26 studies (1387 patients) describing twelve pharmacological intervention-types. Low-quality evidence of efficacy was established for memantine (large effect size) and liothyronine (medium effect size). Very low-quality evidence shows effect of acetylcholine inhibitors, piracetam and melatonin in some cognitive domains. Evidence of no efficacy was revealed for ketamine (very low-quality), herbal preparations with anti-inflammatory properties (very low to low-quality) and opioid receptor agonists (low-quality). CONCLUSION: Memantine and liothyronine are promising for further research and future application. Quality of evidence was low because of differences in ECT techniques, study populations and cognitive measurements. These findings provide a guide for rational choices of potential pharmacological intervention research targets to decrease the burden of cognitive side effects of ECT. Future research should be more uniform in design and attempt to clarify pathophysiological mechanisms of cognitive side effects of ECT.

Intoxicated persons showing challenging behavior demand complexity interventions: a pilot study at the interface of the ER and the complexity intervention unit.

Intoxicated persons showing challenging behavior (IPCBs) under influence of alcohol and/or drugs frequently have trouble finding appropriate acute care. Often IPCBs are stigmatized being unwilling or unable to accept help. Separated physical and mental healthcare systems hamper integrated acute care for IPCBs. This pilot aimed to substantiate the physical, psychiatric, and social health needs of IPCBs visiting the emergency room (ER) during a 3-month period. All ER visits were screened. After triage by the ER physician, indicated IPCBs were additionally assessed by the consultation-liaison-psychiatry physician. If needed, IPCBs were admitted to a complexity intervention unit for further examinations to provide integrated treatments and appropriate follow-up care. The INTERMED and Health of the Nation Outcome Scale (HoNOS) questionnaires were used to substantiate the complexity and needs. Field-relevant stakeholders were interviewed about this approach for acute integrated care. Alongside substance abuse, almost half of identified IPCBs suffered from comorbid psychiatric disturbances and one third showed substantial physical conditions requiring immediate medical intervention. Almost all IPCBs (96%) accepted the acute medical care voluntarily. IPCBs showed high mean initial scores of INTERMED (27.8 ± 10.0) and HoNOS (20.8 ± 6.9). At discharge from the complexity intervention unit, the mean HoNOS score decreased significantly (13.4 ± 8.6; P < 0.001). Field-relevant stakeholders strongly supported the interdisciplinary approach and ER-facility for IPCBs and acknowledged their unmet health needs. A biopsychosocial assessment at the ER, followed by a short admission if necessary, is effective in IPCBs. This approach helps to merge separated healthcare systems and may reduce stigmatization of IPCBs needing help.

The postictal state - What do we know?

This narrative review provides a broad and comprehensive overview of the most important discoveries on the postictal state over the past decades as well as recent developments. After a description and definition of the postictal state, we discuss postictal sypmtoms, their clinical manifestations, and related findings. Moreover, pathophysiological advances are reviewed, followed by current treatment options.

Electroconvulsive Therapy as a Powerful Treatment for Delirium: A Case Report.

OBJECTIVE: The aim of the study was to describe the successful treatment of delirium with electroconvulsive therapy (ECT). METHODS: The method of the study was a case report. RESULTS: A 75-year-old man, with a recently diagnosed carcinoma of the parotid gland, was admitted with a fluctuating psychiatric syndrome. Delirium was diagnosed, although an acute underlying somatic cause could not be readily established. Antipsychotics and benzodiazepines were not effective. After 7 sessions of ECT, all symptoms ceased. This enabled him to receive radiotherapy for his tumor and enjoy a good quality of life for the remaining 8 months of his life. CONCLUSIONS: Electroconvulsive therapy is not only a powerful treatment for catatonia, neuroleptic malignant syndrome, and delirious mania but also for the most commonly occurring fluctuating psychiatric syndrome--delirium.

Repeated dose titration versus age-based method in electroconvulsive therapy: a pilot study.

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.

Restoration of postictal cortical activity after electroconvulsive therapy relates to recovery of orientation in person, place, and time.

BACKGROUND: Most patients show temporary impairments in clinical orientation after electroconvulsive therapy (ECT)-induced seizures. It is unclear how postictal reorientation relates to electroencephalography (EEG) restoration. This relationship may provide additional measures to quantify postictal recovery and shed light on neurophysiological aspects of reorientation after ECT. METHODS: We analyzed prospectively collected clinical and continuous ictal and postictal EEG data from ECT patients. Postictal EEG restoration up to 1 h was estimated by the evolution of the normalized alpha-delta ratio (ADR). Times to reorientation in the cognitive domains of person, place, and time were assessed postictally. In each cognitive domain, a linear mixed model was fitted to investigate the relationships between time to reorientation and postictal EEG restoration. RESULTS: In total, 272 pairs of ictal-postictal EEG and reorientation times of 32 patients were included. In all domains, longer time to reorientation was associated with slower postictal EEG recovery. Longer seizure duration and postictal administration of midazolam were related to longer time to reorientation in all domains. At 1-hour post-seizure, most patients were clinically reoriented, while their EEG had only partly restored. CONCLUSIONS: We show a relationship between postictal EEG restoration and clinical reorientation after ECT-induced seizures. EEG was more sensitive than reorientation time in all domains to detect postictal recovery beyond 1-hour post-seizure. Our findings indicate that clinical reorientation probably depends on gradual cortical synaptic recovery, with longer seizure duration leading to longer postsynaptic suppression after ECT seizures.

Longitudinal resting-state network connectivity changes in electroconvulsive therapy patients compared to healthy controls.

OBJECTIVE: Electroconvulsive therapy (ECT) is effective for major depressive episodes. Understanding of underlying mechanisms has been increased by examining changes of brain connectivity but studies often do not correct for test-retest variability in healthy controls (HC). In this study, we investigated changes in resting-state networks after ECT in a multicenter study. METHODS: Functional resting-state magnetic resonance imaging data, acquired before start and within one week after ECT, from 90 depressed patients were analyzed, as well as longitudinal data of 24 HC. Group-information guided independent component analysis (GIG-ICA) was used to spatially restrict decomposition to twelve canonical resting-state networks. Selected networks of interest were the default mode network (DMN), salience network (SN), and left and right frontoparietal network (LFPN, and RFPN). Whole-brain voxel-wise analyses were used to assess group differences at baseline, group by time interactions, and correlations with treatment effectiveness. In addition, between-network connectivity and within-network strengths were computed. RESULTS: Within-network strength of the DMN was lower at baseline in ECT patients which increased after ECT compared to HC, after which no differences were detected. At baseline, ECT patients showed lower whole-brain voxel-wise DMN connectivity in the precuneus. Increase of within-network strength of the LFPN was correlated with treatment effectiveness. We did not find whole-brain voxel-wise or between-network changes. CONCLUSION: DMN within-network connectivity normalized after ECT. Within-network increase of the LFPN in ECT patients was correlated with higher treatment effectiveness. In contrast to earlier studies, we found no whole-brain voxel-wise changes, which highlights the necessity to account for test-retest effects.

Clinical predictors of seizure threshold in electroconvulsive therapy: a prospective study.

At the start and during the course of electroconvulsive therapy (ECT), estimation of the seizure threshold (ST) is useful in weighing the expected effectiveness against the risks of side effects. Therefore, this study explores clinical factors predicting initial ST (IST) and levels of ST during the ECT course. This prospective observational study included patients aged ≥18 years receiving ECT without contraindications for dose titration. At the first and every sixth consecutive ECT session, ST level was measured. Using multivariate linear regression and multilevel models, predictors for IST and change in ST levels were examined. A total of 91 patients (mean age, 59.1 ± 15.0 years; 37 % male; 97 % diagnosis of depression) were included. In multivariable analysis, higher age (ß = 0.24; P = 0.03) and bifrontotemporal (BL) electrode placement (ß = 0.42; P < 0.001) were independent predictors for higher IST, explaining 49 % of its variation. Also, these two variables independently predicted higher ST levels at different time points during the course. Using multilevel models, absence of a previous ECT course(s) predicted a steeper rise in ST during the course (P = 0.03 for the interaction term time*previous ECT). The age-adjusted dose-titration method is somewhat crude, resulting in some measurement error. Concomitant medication use could have influenced ST levels. Increasing age and BL electrode placement predicted higher (I)ST, which should be taken into account when selecting ECT dosage. Previous ECT course(s) may avoid an increase in ST during the course of ECT.

Patient, treatment, and anatomical predictors of outcome in electroconvulsive therapy: a prospective study.

OBJECTIVES: Baseline predictors of effectiveness and cognitive adverse effects of electroconvulsive therapy (ECT) were prospectively examined. METHODS: Before and after ECT, the Montgomery-Åsberg Depression Rating Scale (MADRS) and Mini Mental State Examination (MMSE) were assessed. Before ECT, a magnetic resonance imaging of the head was performed. Outcome predictors were investigated using multivariable regression analyses. RESULTS: Of 83 patients (mean ± SD age, 59.2 ± 15.3 years; 39% men), 28% had a psychotic depressive disorder, 16% had a bipolar depression, 30% had had previous ECT course(s), and 66% used concomitant antipsychotics. Presence of psychotic depression (ß = -0.25; P = 0.04) and having had previous ECT (ß = -0.35; P = 0.003) predicted lower post-ECT MADRS score. Baseline magnetic resonance imaging characteristics were not predictive of post-ECT MADRS and MMSE scores. The use of concomitant antipsychotics predicted a lower post-ECT MMSE score (ß = -0.21; P = 0.02), whereas the presence of bipolar depression at baseline predicted higher post-ECT MMSE score (ß = 0.23; P = 0.01). The post-ECT MADRS score seemed to be a confounder for the post-ECT MMSE score (ß = -0.20; P = 0.02). CONCLUSIONS: Effectiveness of ECT was better in the patients with a baseline psychotic depression and those who had had ECT before. Cognitive outcome was better in the patients with baseline bipolar depression but worse in those who used antipsychotics during ECT and those who showed more persistent depressive symptoms after ECT.

Medication preventing postictal hypoperfusion and cognitive side-effects in electroconvulsive therapy: A retrospective cohort study.

Background: Electroconvulsive therapy (ECT) is associated with postictal confusion and cognitive side-effects. In rats, acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs) and calcium antagonists decreased postictal cerebral hypoperfusion along with reduction in postictal symptoms. In this study, in ECT-patients, we explore associations between use of these potentially protective medications and occurrence of postictal confusion and cognitive outcome. Materials and methods: In this retrospective, naturalistic cohort study, patient-, treatment-, and ECT-characteristics, were collected from medical files of patients treated with ECT for major depressive disorder (MDD) or bipolar depressive episode. To test for associations of use of these medications with occurrence of postictal confusion, 295 patients could be included. Cognitive outcome data were available in a subset of 109 patients. Univariate analyses and multivariate censored regression models were used to test for associations. Results: Occurrence of severe postictal confusion was not associated with use of acetaminophen, NSAIDs or calcium antagonists (n = 295). Regarding the cognitive outcome measure (n = 109), use of calcium antagonists was associated with higher post-ECT cognitive scores (i.e., better cognitive outcome; ß = 2.23; p = 0.047), adjusted for age (ß = -0.02; p = 0.23), sex (ß = -0.21; p = 0.73), pre-ECT cognitive score (ß = 0.47; p < 0.0001), and post-ECT depression score (ß = -0.02; p = 0.62), but use of acetaminophen (ß = -1.55; p = 0.07) as well as NSAIDs (ß = -1.02; p = 0.23) showed no associations. Conclusion: This retrospective study does not find arguments for protective effects of acetaminophen, NSAIDs or calcium antagonists against severe postictal confusion in ECT. As a preliminary finding, the use of calcium antagonists was associated with improved cognitive outcome after ECT in this cohort. Prospective controlled studies are necessary.

[IV esketamine for patients with a treatment-resistant depression]. / Intraveneuze esketamine als redmiddel bij depressie.

We present three patients off-label treated with intravenous (IV) esketamine for treatment-resistant depression (TRD) of whom two (patients A and B, aged 72 and 77 years, respectively) were admitted to the psychiatric unit with depressive symptoms and one outpatient (patient C, aged 66 years). After six esketamine treatments over a period of three weeks, two patients showed improvement, as measured with the Hamilton Rating Scale for Depression (HRSD): the HRSD-score of patient A decreased from 36 to 9 and of patient C from 18 to 10. Patient B had no response to esketamine but was treated successfully with electroconvulsive therapy (ECT). Despite the presence of various somatic comorbidities, esketamine treatment appeared safe and well-tolerated by the patients. After the index treatment, patients A and C received maintenance treatment with esketamine (once every 4-6 weeks). We recommend to consider off-label IV esketamine treatment in patients suffering TRD with or without suicidality.

[Consider (es)ketamine for treatment-resistant depression]. / Overweeg (es)ketamine bij therapieresistente depressie.

Major depressive disorder has a high prevalence globally. Although pharmacotherapy and psychotherapy are effective for most patients, about one third is treatment resistant. Ketamine, known as an anesthetic, is a new treatment option that can be effective in patients with treatment-resistant depression. (es)ketamine works relatively fast. However, the long-term effects are still relatively unknown. In the Netherlands, S-Ketamine is currently administered in various forms, of which only the nasal spray is registered for treatment-resistant depression. Currently, many studies have been conducted on the use of (es)ketamine. In this article we describe the latest state of affairs regarding its effectiveness and safety.

Seizure duration predicts postictal electroencephalographic recovery after electroconvulsive therapy-induced seizures.

OBJECTIVE: We aim to provide a quantitative description of the relation between seizure duration and the postictal state using features extracted from the postictal electroencephalogram (EEG). METHODS: Thirty patients with major depressive disorder treated with electroconvulsive therapy (ECT) were studied with continuous EEG before, during, and after ECT-induced seizures. EEG recovery was quantified as the spectral difference between postictal and baseline EEG using the temporal brain symmetry index (BSI). The postictal temporal EEG evolution was modeled with a single exponential. The parameters of the model, including the time constant τ, describe the change and speed of postictal EEG recovery. The change from baseline EEG at t = 60 minutes post-seizure (ΔBSI) was calculated from the exponential fit. Postictal clinical reorientation time (ROT) was clinically established. A multivariate generalized multi-level Bayesian model was estimated with seizure duration and ROT as predictors of τ and ΔBSI. RESULTS: EEG features of 290 seizures and postictal states were used for analyses. The model faithfully described the dynamics of the postictal EEG in nearly all patients. Seizure duration was associated with the recovery time constant, τ, and ΔBSI. ROT was associated with τ, but not with ΔBSI. CONCLUSIONS: Longer seizures are associated with slower postictal EEG recovery and more enduring EEG changes compared to baseline. SIGNIFICANCE: Quantitative EEG allows objective assessment of the postictal state.

Effective resting-state connectivity in severe unipolar depression before and after electroconvulsive therapy.

BACKGROUND: Electroconvulsive therapy (ECT) is one of the most effective treatments for severe depressive disorders. A recent multi-center study found no consistent changes in correlation-based (undirected) resting-state connectivity after ECT. Effective (directed) connectivity may provide more insight into the working mechanism of ECT. OBJECTIVE: We investigated whether there are consistent changes in effective resting-state connectivity. METHODS: This multi-center study included data from 189 patients suffering from severe unipolar depression and 59 healthy control participants. Longitudinal data were available for 81 patients and 24 healthy controls. We used dynamic causal modeling for resting-state functional magnetic resonance imaging to determine effective connectivity in the default mode, salience and central executive networks before and after a course of ECT. Bayesian general linear models were used to examine differences in baseline and longitudinal effective connectivity effects associated with ECT and its effectiveness. RESULTS: Compared to controls, depressed patients showed many differences in effective connectivity at baseline, which varied according to the presence of psychotic features and later treatment outcome. Additionally, effective connectivity changed after ECT, which was related to ECT effectiveness. Notably, treatment effectiveness was associated with decreasing and increasing effective connectivity from the posterior default mode network to the left and right insula, respectively. No effects were found using correlation-based (undirected) connectivity. CONCLUSIONS: A beneficial response to ECT may depend on how brain regions influence each other in networks important for emotion and cognition. These findings further elucidate the working mechanisms of ECT and may provide directions for future non-invasive brain stimulation research.