Periodic discharges and status epilepticus: A critical reappraisal.

OBJECTIVE: Periodic Discharges (PDs) in Status Epilepticus (SE) are historically related to negative outcome, and the Epidemiology-based Mortality Score in SE (EMSE) identifies PDs as an EEG feature associated with unfavorable prognosis. However, supportive evidence is conflicting. This study aims to evaluate the prognostic significance of interictal PDs during and following SE. METHODS: All 2020-2023 non-hypoxic-ischemic SE patients with available EEG during SE were retrospectively assessed. Interictal PDs during SE (SE-PDs) and PDs occurring 24-72 h after SE resolution (post-SE-PDs) were examined. In-hospital death was defined as the primary outcome. RESULTS: 189 SE patients were finally included. SE-PDs were not related to outcome, while post-SE-PDs were related to poor prognosis confirmed after multiple regression analysis. EMSE global AUC was 0.751 (95%CI:0.680-0.823) and for EMSE-64 cutoff sensitivity was 0.85, specificity 0.52, accuracy 63%. We recalculated EMSE score including only post-SE-PDs. Modified EMSE (mEMSE) global AUC was 0.803 (95%CI:0.734-0.872) and for mEMSE-64 cutoff sensitivity was 0.84, specificity 0.68, accuracy 73%. CONCLUSION: Interictal PDs during SE were not related to outcome whereas PDs persisting or appearing > 24 h after SE resolution were strongly associated to unfavorable prognosis. EMSE performed well in our cohort but considering only post-SE-PDs raised specificity and accuracy for mEMSE64 cutoff. SIGNIFICANCE: This study supports the utility of differentiating between interictal PDs during and after SE for prognostic assessment.

Sustained effort network for treatment of status epilepticus/European academy of neurology registry on adult refractory status epilepticus (SENSE-II/AROUSE).

BACKGROUND: Status Epilepticus (SE) is a common neurological emergency associated with a high rate of functional decline and mortality. Large randomized trials have addressed the early phases of treatment for convulsive SE. However, evidence regarding third-line anesthetic treatment and the treatment of nonconvulsive status epilepticus (NCSE) is scarce. One trial addressing management of refractory SE with deep general anesthesia was terminated early due to insufficient recruitment. Multicenter prospective registries, including the Sustained Effort Network for treatment of Status Epilepticus (SENSE), have shed some light on these questions, but many answers are still lacking, such as the influence exerted by distinct EEG patterns in NCSE on the outcome. We therefore initiated a new prospective multicenter observational registry to collect clinical and EEG data that combined may further help in clinical decision-making and defining SE. METHODS: Sustained effort network for treatment of status epilepticus/European Academy of Neurology Registry on refractory Status Epilepticus (SENSE-II/AROUSE) is a prospective, multicenter registry for patients treated for SE. The primary objectives are to document patient and SE characteristics, treatment modalities, EEG, neuroimaging data, and outcome of consecutive adults admitted for SE treatment in each of the participating centers and to identify factors associated with outcome and refractoriness. To reach sufficient statistical power for multivariate analysis, a cohort size of 3000 patients is targeted. DISCUSSION: The data collected for the registry will provide both valuable EEG data and information about specific treatment steps in different patient groups with SE. Eventually, the data will support clinical decision-making and may further guide the planning of clinical trials. Finally, it could help to redefine NCSE and its management. TRIAL REGISTRATION: NCT number: NCT05839418.

Antiseizure medication ≤48 hours portends better prognosis in new-onset epilepsy.

BACKGROUND: Several studies found that patients with new-onset epilepsy (NOE) have higher seizure recurrence rates if they presented already prior seizures. These observations suggest that timing of antiseizure medication (ASM) is crucial and should be offered immediately after the first seizure. Here, we wanted to assess whether immediate ASM is associated with improved outcome. METHODS: Single-center study of 1010 patients (≥16 years) who presented with a possible first seizure in the emergency department between 1 March 2010 and 1 March 2017. A comprehensive workup was launched upon arrival, including routine electroencephalography (EEG), brain computed tomography/magnetic resonance imaging, long-term overnight EEG and specialized consultations. We followed patients for 5 years comparing the relapse rate in patients treated within 48 h to those with treatment >48 h. RESULTS: A total of 487 patients were diagnosed with NOE. Of the 416 patients (162 female, age: 54.6 ± 21.1 years) for whom the treatment start could be retrieved, 80% (333/416) were treated within 48 h. The recurrence rate after immediate treatment (32%; 107/333) was significantly lower than in patients treated later (56.6%; 47/83; p < 0.001). For patients for whom a complete 5-year-follow-up was available (N = 297, 123 female), those treated ≤48 h (N = 228; 76.8%) had a significantly higher chance of remaining seizure-free compared with patients treated later (N = 69; 23.2%; p < 0.001). CONCLUSIONS: In this retrospective study, immediate ASM therapy (i.e., within 48 h) was associated with better prognosis up to 5 years after the index event. Prospective studies are required to determine the value of immediate workup and drug therapy in NOE patients.

Prognostic value of Salzburg nonconvulsive status epilepticus criteria: The SACE score.

OBJECTIVE: This study was undertaken to investigate the association between the Salzburg nonconvulsive status epilepticus (NCSE) criteria and in-hospital outcome, to determine the predictive accuracy of the Status Epilepticus Severity Score (STESS), modified STESS (mSTESS), Epidemiology-Based Mortality Score in Status Epilepticus (EMSE), and END-IT (encephalitis, NCSE, diazepam resistance, imaging features, and tracheal intubation) in NCSE patients, and to develop a new prognostic score specifically designed for NCSE patients. METHODS: Clinical and electroencephalographic (EEG) data of adult patients treated for NCSE from 2020 to 2023 were retrospectively assessed. Age, sex, modified Rankin Scale at admission, comorbidities, history of seizures, etiology, status epilepticus type, and outcome were collected from the patients' digital charts. EEG data were assessed and categorized applying the Salzburg NCSE criteria. In-hospital death was defined as the primary outcome. RESULTS: A total of 116 NCSE patients were included. Multivariable logistic regression revealed that Salzburg NCSE criterion A2 (ictal morphological, spatial, and temporal evolution) was associated with in-hospital survival. The best STESS cutoff was ≥4 (sensitivity = .62, specificity = .69, accuracy = 67%). mSTESS ≥ 5 reached a sensitivity of .68, a specificity of .57, and an overall accuracy of 60%, EMSE ≥ 64 a sensitivity of .82, a specificity of .39, and an overall accuracy of 52%, and END-IT ≥ 3 a sensitivity of .65, a specificity of .44, and an overall accuracy of 50%. Through a hypothesis-generating approach, we developed the SACE score, which integrates EEG features (criterion A2) with patient age (with a 75-year cutoff), history of seizures, and level of consciousness. With a cutoff of ≥3, it had a sensitivity of .77, a specificity of .74, and an overall accuracy of 76%, performing better than other prognostic scores. SIGNIFICANCE: We developed a new user-friendly scoring system, the SACE score, which integrates EEG features with other established outcome-related variables assessable in early stages, to assist neurologists and neurointensivists in making more tailored prognostic decisions for NCSE patients.

Added value of advanced workup after the first seizure: A 7-year cohort study.

OBJECTIVE: This study was undertaken to establish whether advanced workup including long-term electroencephalography (LT-EEG) and brain magnetic resonance imaging (MRI) provides an additional yield for the diagnosis of new onset epilepsy (NOE) in patients presenting with a first seizure event (FSE). METHODS: In this population-based study, all adult (≥16 years) patients presenting with FSE in the emergency department (ED) between March 1, 2010 and March 1, 2017 were assessed. Patients with obvious nonepileptic or acute symptomatic seizures were excluded. Routine EEG, LT-EEG, brain computed tomography (CT), and brain MRI were performed as part of the initial workup. These examinations' sensitivity and specificity were calculated on the basis of the final diagnosis after 2 years, along with the added value of advanced workup (MRI and LT-EEG) over routine workup (routine EEG and CT). RESULTS: Of the 1010 patients presenting with FSE in the ED, a definite diagnosis of NOE was obtained for 501 patients (49.6%). Sensitivity of LT-EEG was higher than that of routine EEG (54.39% vs. 25.5%, p < .001). Similarly, sensitivity of MRI was higher than that of CT (67.98% vs. 54.72%, p = .009). Brain MRI showed epileptogenic lesions in an additional 32% compared to brain CT. If only MRI and LT-EEG were considered, five would have been incorrectly diagnosed as nonepileptic (5/100, 5%) compared to patients with routine EEG and MRI (25/100, 25%, p = .0001). In patients with all four examinations, advanced workup provided an overall additional yield of 50% compared to routine workup. SIGNIFICANCE: Our results demonstrate the remarkable added value of the advanced workup launched already in the ED for the diagnosis of NOE versus nonepileptic causes of seizure mimickers. Our findings suggest the benefit of first-seizure tracks or even units with overnight EEG, similar to stroke units, activated upon admission in the ED.

Sex-related differences in adult patients with status epilepticus: a seven-year two-center observation.

BACKGROUND: Conflicting findings exist regarding the influence of sex on the development, treatment, course, and outcome of status epilepticus (SE). Our study aimed to investigate sex-related disparities in adult SE patients, focusing on treatment, disease course, and outcome at two Swiss academic medical centers. METHODS: In this retrospective study, patients treated for SE at two Swiss academic care centers from Basel and Geneva from 2015 to 2021 were included. Primary outcomes were return to premorbid neurologic function, death during hospital stay and at 30 days. Secondary outcomes included characteristics of treatment and disease course. Associations with primary and secondary outcomes were assessed using multivariable logistic regression. Analysis using propensity score matching was performed to account for the imbalances regarding age between men and women. RESULTS: Among 762 SE patients, 45.9% were women. No sex-related differences were found between men and women, except for older age and lower frequency of intracranial hemorrhages in women. Compared to men, women had a higher median age (70 vs. 66, p = 0.003), had focal nonconvulsive SE without coma more (34.9% vs. 25.5%; p = 0.005) and SE with motor symptoms less often (52.3% vs. 63.6%, p = 0.002). With longer SE duration (1 day vs. 0.5 days, p = 0.011) and a similar proportion of refractory SE compared to men (36.9% vs. 36.4%, p = 0.898), women were anesthetized and mechanically ventilated less often (30.6% vs. 42%, p = 0.001). Age was associated with all primary outcomes in the unmatched multivariable analyses, but not female sex. In contrast, propensity score-matched multivariable analyses revealed decreased odds for return to premorbid neurologic function for women independent of potential confounders. At hospital discharge, women were sent home less (29.7% vs. 43.7%, p < 0.001) and to nursing homes more often (17.1% vs. 10.0%, p = 0.004). CONCLUSIONS: This study identified sex-related disparities in the clinical features, treatment modalities, and outcome of adult patients with SE with women being at a disadvantage, implying that sex-based factors must be considered when formulating strategies for managing SE and forecasting outcomes.

Early timing of anesthesia in status epilepticus is associated with complete recovery: A 7-year retrospective two-center study.

OBJECTIVE: This study was undertaken to investigate the efficacy, tolerability, and outcome of different timing of anesthesia in adult patients with status epilepticus (SE). METHODS: Patients with anesthesia for SE from 2015 to 2021 at two Swiss academic medical centers were categorized as anesthetized as recommended third-line treatment, earlier (as first- or second-line treatment), and delayed (later as third-line treatment). Associations between timing of anesthesia and in-hospital outcomes were estimated by logistic regression. RESULTS: Of 762 patients, 246 received anesthesia; 21% were anesthetized as recommended, 55% earlier, and 24% delayed. Propofol was preferably used for earlier (86% vs. 55.5% for recommended/delayed anesthesia) and midazolam for later anesthesia (17.2% vs. 15.9% for earlier anesthesia). Earlier anesthesia was statistically significantly associated with fewer infections (17% vs. 32.7%), shorter median SE duration (.5 vs. 1.5 days), and more returns to premorbid neurologic function (52.9% vs. 35.5%). Multivariable analyses revealed decreasing odds for return to premorbid function with every additional nonanesthetic antiseizure medication given prior to anesthesia (odds ratio [OR] = .71, 95% confidence interval [CI] = .53-.94) independent of confounders. Subgroup analyses revealed decreased odds for return to premorbid function with increasing delay of anesthesia independent of the Status Epilepticus Severity Score (STESS; STESS = 1-2: OR = .45, 95% CI = .27-.74; STESS > 2: OR = .53, 95% CI = .34-.85), especially in patients without potentially fatal etiology (OR = .5, 95% CI = .35-.73) and in patients experiencing motor symptoms (OR = .67, 95% CI = .48-.93). SIGNIFICANCE: In this SE cohort, anesthetics were administered as recommended third-line therapy in only every fifth patient and earlier in every second. Increasing delay of anesthesia was associated with decreased odds for return to premorbid function, especially in patients with motor symptoms and no potentially fatal etiology.

Balancing the risks and benefits of anesthetics in status epilepticus.

PURPOSE: According to international guidelines, status epilepticus refractory to first- and second-line antiseizure medication should be treated with anesthetics. Therefore, continuously delivered intravenous midazolam, propofol, or barbiturates are recommended as third-line therapy. While electroencephalographically (EEG)-controlled titration of anesthetics to seizure termination or to the emergence of an EEG burst-suppression pattern makes sense, evidence of the efficacy and tolerability of such third-line treatment is limited and concerns regarding the risks of anesthesia remain. The lack of treatment alternatives and persistent international discord reflecting contradictory results from some studies leave clinicians on their own when deciding to escalate treatment. In this conference-accompanying narrative review, we highlight the challenges of EEG-monitored third-line treatment and discuss recent studies that examined earlier administration of anesthetics. RESULTS: Based on the literature, maintaining continuous burst suppression is difficult despite the constant administration of anesthetics, and the evidence for burst suppression as an adequate surrogate target is limited by methodological shortcomings as acknowledged by international guidelines. In our Swiss cohort including 102 patients with refractory status epilepticus, burst suppression as defined by the American Clinical Neurophysiology Society's Critical Care EEG Terminology 2021 was established in only 21%. Besides case reports suggesting that rapid but short-termed anesthesia can be sufficient to permanently stop seizures, a study including 205 patients revealed that anesthesia as second-line treatment was associated with a shorter median duration of status epilepticus (0.5 versus 12.5 days, p < 0.001), median ICU (2 versus 5.5 days, p < 0.001) and hospital stay (8 versus 17 days, p < 0.001) with equal rates of complications when compared to anesthesia as third-line treatment. CONCLUSIONS: Recent investigations have led to important findings and new insights regarding the use of anesthetics in refractory status epilepticus. However, numerous methodological limitations and remaining questions need to be considered when it comes to the translation into clinical practice, and, in consequence, call for prospective randomized studies. This paper was presented at the 8th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures held in September 2022.

Nonconvulsive status epilepticus following cardiac arrest: overlooked, untreated and misjudged.

AIMS: Seizures and status epilepticus (SE) are detected in almost a third of the comatose cardiac arrest survivors. As the literature is quite exhaustive regarding SE with motor symptoms in those patients, little is known about nonconvulsive SE (NCSE). Our aim was to compile the evidence from the literature of the frequency and outcome of NCSE in adult patients remaining in coma after resuscitation. METHODS: The medical search PubMed was screened for most relevant articles reporting the emergence and outcome of NCSE in comatose post-resuscitated adult patients. RESULTS: We identified 11 cohort studies (four prospective observational, seven retrospective) including 1092 patients with SE in 29-96% and NCSE reported in 1-20%. EEG evaluation started at a median of 9.5 h (range 7.5-14.8) after cardiac arrest, during sedation and targeted temperature management (TTM). Favorable outcome after NCSE occurred in 24.5%. We found no study reporting EEG to detect or exclude NCSE in patients remaining in coma prior to the initiation of TTM and without sedation withing the first hours after ROSC. DISCUSSION: Studies on NCSE after ROSC are scarce and unsystematic, reporting favorable outcome in every fourth patient experiencing NCSE after ROSC. This suggests that NCSE is often overlooked and outcome after NCSE is not always poor. The low data quality does not allow firm conclusions regarding the effects of NCSE on outcome calling for further investigation. In the meantime, clinicians should avoid equating NCSE after ROSC with poor prognosis.

Changes of interictal epileptiform discharges during medication withdrawal and seizures: A scalp EEG marker of epileptogenicity.

Objective: To determine the influence of antiseizure medication (ASM) withdrawal on interictal epileptogenic discharges (IEDs) in scalp-EEG and seizure propensity. Methods: We included 35 adult unifocal epilepsy patients admitted for presurgical evaluation in the EEG and Epilepsy Unit of Geneva between 2016 and 2020, monitored for at least 5 days. ASM was individually tapered down, and automated IED detection was performed using Epilog PreOp (Epilog NV, Belgium, Ghent). We compared spike rate per hour (SR) at day 1 when patients were on full medication (baseline) with SR at the day with the lowest dose of medication. To determine possible peri-ictal changes of SR, we compared SR 8 h before and after a seizure with the SR at the same time of the baseline day. Results: Our results showed a significant increase in spiking activity in the day of lowest drug load if compared to spike rate at day on full medication (p < 0.001). The total amount of spikes during 24 h correlated significantly with seizure occurrence (p < 0.0001). We also revealed significant increase in peri-ictal SR, in particular 2-4 h preceding a seizure (p = 0.05) extending up to 3 h after the seizure (p = 0.03) with a short decrease just before seizure occurrence. Conclusions: Our results suggest that SR increases with medication withdrawal and particularly before and after seizures. There is a complex pattern of increase and decrease around seizure onset which explains divergent results in previous studies. Significance: Precise spike counting at similar circadian periods for a patient could help to determine the risk of seizure occurrence in a personalized fashion.

Acute symptomatic seizures and hippocampal sclerosis: the major contributor for post-stroke epilepsy?

OBJECTIVE: Hippocampal sclerosis (HS) is a prominent biomarker of epilepsy. If acquired later in life, it usually occurs in the context of degenerative or acute inflammatory-infectious disease. Conversely, acute symptomatic seizures (ASS) are considered a risk factor for developing post-stroke epilepsy, but other factors remain unrecognized. Here, we hypothesize that silent hippocampal injury contributes to the development of post-stroke epilepsy. METHODS: We performed a retrospective observational study of patients hospitalized between 1/2007 and 12/2018 with an acute stroke in the Stroke Center of the Geneva University Hospital. Patients were included if they had a documented normal hippocampal complex at onset and a control MRI at ≥ 2 year interval without new lesion in the meantime. RESULTS: 162 patients fulfilled our inclusion criteria. ASS during the first week (p < 0.0001) and epileptiform abnormalities in electroencephalography (EEG; p = 0.02) were more frequently associated with the development of epilepsy. Hemorrhagic stroke was strongly associated to both ASS and future focal epilepsy (p = 0.00097). Three patients (1.8%) developed hippocampal sclerosis ipsilateral to the cerebrovascular event between 2 and 5 years, all with ASS and hemorrhagic stroke. INTERPRETATION: ASS and epileptiform EEG abnormalities are strong predictors of post-stroke epilepsy. HS develops in a minority of patients after hemorrhagic lesions, leading to focal epilepsy. Prospective studies are required, including follow-up with EEG and if characterized by epileptiform discharges, with MRI, to determine the true frequency of HS and to better understand predictors of post-stroke epilepsy (AAS, stroke type, and HS), and their impact on stroke recovery.

Increased delta power as a scalp marker of epileptic activity: a simultaneous scalp and intracranial electroencephalography study.

BACKGROUND AND PURPOSE: The purpose was to evaluate whether intracranial interictal epileptiform discharges (IEDs) that are not visible on the scalp are associated with changes in the frequency spectrum on scalp electroencephalograms (EEGs). METHODS: Simultaneous scalp high-density EEG and intracranial EEG recordings were recorded in nine patients undergoing pre-surgical invasive recordings for pharmaco-resistant temporal lobe epilepsy. Epochs with hippocampal IED visible on intracranial EEG (ic-IED) but not on scalp EEG were selected, as well as control epochs without ic-IED. Welch's power spectral density was computed for each scalp electrode and for each subject; the power spectral density was further averaged across the canonical frequency bands and compared between the two conditions with and without ic-IED. For each patient the peak frequency in the delta band (the significantly strongest frequency band in all patients) was determined during periods of ic-IED. The five electrodes showing strongest power at the peak frequency were also determined. RESULTS: It was found that intracranial IEDs are associated with an increase in delta power on scalp EEGs, in particular at a frequency ≥1.4 Hz. Electrodes showing slow frequency power changes associated with IEDs were consistent with the hemispheric lateralization of IEDs. Electrodes with maximum power of slow activity were not limited to temporal regions but also involved frontal (bilateral or unilateral) regions. CONCLUSIONS: In patients with a clinical picture suggestive of temporal lobe epilepsy, the presence of delta slowing ≥1.4 Hz in anterior temporal regions can represent a scalp marker of hippocampal IEDs. To our best knowledge this is the first study that demonstrates the co-occurrence of ic-IED and increased delta power.

Safety and Efficacy of Coma Induction Following First-Line Treatment in Status Epilepticus: A 2-Center Study.

OBJECTIVE: To explore the safety and efficacy of artificial coma induction to treat status epilepticus (SE) immediately after first-line antiseizure treatment instead of following the recommended approach of first using second-line drugs. METHODS: Clinical and electrophysiologic data of all adult patients treated for SE from 2017 to 2018 in the Swiss academic medical care centers from Basel and Geneva were retrospectively assessed. Primary outcomes were return to premorbid neurologic function and in-hospital death. Secondary outcomes were the emergence of complications during SE, duration of SE, and intensive care unit (ICU) and hospital stays. RESULTS: Of 230 patients, 205 received treatment escalation after first-line medication. Of those, 27.3% were directly treated with artificial coma and 72.7% with second-line nonanesthetic antiseizure drugs. Of the latter, 16.6% were subsequently put on artificial coma after failure of second-line treatment. Multivariable analyses revealed increasing odds for coma induction after first-line treatment with younger age, the presence of convulsions, and an increased SE severity as quantified by the Status Epilepticus Severity Score (STESS). While outcomes and complications did not differ compared to patients with treatment escalation according to the guidelines, coma induction after first-line treatment was associated with shorter SE duration and ICU and hospital stays. CONCLUSIONS: Early induction of artificial coma is performed in more than every fourth patient and especially in younger patients presenting with convulsions and more severe SE. Our data demonstrate that this aggressive treatment escalation was not associated with an increase in complications but with shorter duration of SE and ICU and hospital stays. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that early induction of artificial coma after unsuccessful first-line treatment for SE is associated with shorter duration of SE and ICU and hospital stays compared to the use of a second-line nonanesthetic antiseizure drug instead of or before anesthetics, without an associated increase in complications.

Critical care EEG standardized nomenclature in clinical practice: Strengths, limitations, and outlook on the example of prognostication after cardiac arrest.

We discuss the achievements of the ACNS critical care EEG nomenclature proposed in 2013 and, from a clinical angle, outline some limitations regarding translation into treatment implications. While the recently proposed updated 2021 version of the nomenclature will probable improve some uncertainty areas, a refined understanding of the mechanisms at the origin of the EEG patterns, and a multimodal integration of the nomenclature to the clinical context may help improving the rationale supporting therapeutic procedures. We illustrate these aspects on prognostication after cardiac arrest.

Brain networks involved in generalized periodic discharges (GPD) in post-anoxic-ischemic encephalopathy.

AIM: Generalized periodic discharge (GPD) is an EEG pattern of poor neurological outcome, frequently observed in comatose patients after cardiac arrest. The aim of our study was to identify the neuronal network generating ≤2.5 Hz GPD using EEG source localization and connectivity analysis. METHODS: We analyzed 40 comatose adult patients with anoxic-ischemic encephalopathy, who had 19 channel-EEG recording. We computed electric source analysis based on distributed inverse solution (LAURA) and we estimated cortical activity in 82 atlas-based cortical brain regions. We applied directed connectivity analysis (Partial Directed Coherence) on these sources to estimate the main drivers. RESULTS: Source analysis suggested that the GPD are generated in the cortex of the limbic system in the majority of patients (87.5%). Connectivity analysis revealed main drivers located in thalamus and hippocampus for the large majority of patients (80%), together with important activation also in amygdala (70%). CONCLUSIONS: We hypothesize that the anoxic-ischemic dysfunction, leading to hyperactivity of the thalamo-cortical (limbic presumably) circuit, can result in an oscillatory thalamic activity capable of inducing periodic cortical (limbic, mostly medial-temporal and orbitofrontal) discharges, similarly to the case of generalized rhythmic spike-wave discharge in convulsive or non-convulsive status epilepticus.

Abnormal directed connectivity of resting state networks in focal epilepsy.

OBJECTIVE: Epilepsy diagnosis can be difficult in the absence of interictal epileptic discharges (IED) on scalp EEG. We used high-density EEG to measure connectivity in large-scale functional networks of patients with focal epilepsy (Temporal and Extratemporal Lobe Epilepsy, TLE and ETLE) and tested for network alterations during resting wakefulness without IEDs, compared to healthy controls. We measured global efficiency as a marker of integration within networks. METHODS: We analysed 49 adult patients with focal epilepsy and 16 healthy subjects who underwent high-density-EEG and structural MRI. We estimated cortical activity using electric source analysis in 82 atlas-based cortical regions based on the individual MRI. We applied directed connectivity analysis (Partial Directed Coherence) on these sources and performed graph analysis: we computed the Global Efficiency on the whole brain and on each resting state network. We tested these features in different group of patients. RESULTS: Compared to controls, efficiency was increased in both TLE and ETLE (p < 0.05). The somato-motor-network, the ventral-attention-network and the default-mode-network had a significantly increased efficiency (p < 0.05) in both TLE and ETLE as well as TLE with hippocampal sclerosis. SIGNIFICANCE: During interictal scalp EEG epochs without IED, patients with focal epilepsy show brain functional connectivity alterations in the whole brain and in specific resting-state-networks. This higher integration reflects a chronic effect of pathological activity within these structures and complement previous work on altered information outflow. These findings could increase the diagnostic sensitivity of scalp EEG to identify epileptic activity in the absence of IED.

Focal EEG changes indicating critical illness associated cerebral microbleeds in a Covid-19 patient.

OBJECTIVES: We describe a patient suffering from Covid19-related acute respiratory distress syndrome (ARDS), highlighting the diagnostic role of the EEG in ICU. HISTORY: A Covid-19 patient undergoing mechanical ventilation due to related acute respiratory distress syndrome (ARDS), presented altered mental status in the ICU. Video-EEG revealed a focal monomorphic theta slowing in bilateral frontal-central regions. Concordant with the EEG localization, MRI showed abundant microbleeds located in bilateral white matter junction, various regions of corpus callosum and internal capsule, suggestive of Critical Illness-Associated Cerebral Microbleeds. CSF analysis excluded the presence of encephalitis, SARS-Cov2 RNA-PCR in CSF was negative. Clinical and biological picture was suggestive of cytokine release syndrome. CONCLUSION: This is the first reported case of Critical Illness-Associated Cerebral Microbleeds in the context of Covid-19. Knowledge of Covid-19 is still partial and acute neurological complications should be explored systematically. In our case, EEG helped to rule out non-convulsive status epilepticus, but revealed focal dysfunction, justifying further investigations.EEG plays a crucial role in these patients, allowing investigating the presence of focal or diffuse cerebral dysfunction. This is particularly helpful for Covid-19 patients in the ICU, where the neurological examination is challenging by the severity of the respiratory illness.