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Objective: Refractory epilepsy may have an underlying autoimmune etiology. Our aim was to assess the prevalence of neural autoantibodies in a multicenter national prospective cohort of patients with drug-resistant epilepsy undergoing epilepsy surgery utilizing comprehensive clinical, serologic, and histopathological analyses., Methods: We prospectively recruited patients undergoing epilepsy surgery for refractory focal epilepsy not caused by a brain tumor from epilepsy surgery centers in the Czech Republic. Perioperatively, we collected cerebrospinal fluid (CSF) and/or serum samples and performed comprehensive commercial and in-house assays for neural autoantibodies. Clinical data were obtained from the patients' medical records, and histopathological analysis of resected brain tissue was performed., Results: Seventy-six patients were included, mostly magnetic resonance imaging (MRI)-lesional cases (74%). Mean time from diagnosis to surgery was 21 ± 13 years. Only one patient (1.3%) had antibodies in the CSF and serum (antibodies against glutamic acid decarboxylase 65) in relevant titers; histology revealed focal cortical dysplasia (FCD) III (FCD associated with hippocampal sclerosis [HS]). Five patients' samples displayed CSF-restricted oligoclonal bands (OCBs; 6.6%): three cases with FCD (one with FCD II and two with FCD I), one with HS, and one with negative histology. Importantly, eight patients (one of them with CSF-restricted OCBs) had findings on antibody testing in individual serum and/or CSF tests that could not be confirmed by complementary tests and were thus classified as nonspecific, yet could have been considered specific without confirmatory testing. Of these, two had FCD, two gliosis, and four HS. No inflammatory changes or lymphocyte cuffing was observed histopathologically in any of the 76 patients., Significance: Neural autoantibodies are a rare finding in perioperatively collected serum and CSF of our cohort of mostly MRI-lesional epilepsy surgery patients. Confirmatory testing is essential to avoid overinterpretation of autoantibody-positive findings., (© 2024 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Background and Objectives: Autoimmune encephalitis (AE) refers to a heterogenous group of inflammatory CNS diseases. Subgroups with specified neural autoantibodies are more homogeneous in presentation, trigger factors, outcome, and response to therapy. However, a considerable fraction of patients has AE features but does not harbor detectable autoantibodies and is referred to as antibody-negative AE. Our aim was to describe clinical features, trigger factors, treatments, and outcome of a cohort of comprehensively tested antibody-negative AE patients., Methods: This retrospective monocentric study recruited adult patients whose serum and/or CSF was sent to our tertiary center for neural antibody testing between 2011 and 2020, who entered the diagnostic algorithm as possible antibody-negative AE and had the following: (1) probable antibody-negative AE, definite antibody-negative acute disseminated encephalomyelitis (ADEM), or definite autoimmune limbic encephalitis (LE) according to diagnostic criteria; (2) available data on MRI of the brain, CSF, and EEG; and (3) stored serum and/or CSF samples. These samples were reanalyzed using a comprehensive combination of cell-based and tissue-based assays., Results: Of 2,250 patients tested, 33 (1.5%) were classified as possible antibody-negative AE. Of these, 5 were found to have antibodies by comprehensive testing, 5 fulfilled the criteria of probable AE (3F:2M, median age 67, range 42-67), 4 of definite autoimmune LE (2F:2M, median age 45.5, range 27-60 years), one of definite antibody-negative ADEM, 2 of Hashimoto encephalopathy, one had no samples available for additional testing, and 15 had no further categorization. Of 10 probable/definite AE/LE/ADEM, one had a malignancy and none of them received an alternative diagnosis until the end of follow-up (median 18 months). In total, 80% (8/10) of patients received immunotherapy including corticosteroids, and 6/10 (60%) patients received rituximab, azathioprine, cyclophosphamide, plasma exchange, or IV immunoglobulins. Five (50%) patients improved, one (10%) stabilized, one (10%) worsened, and 3 (30%) died. All deaths were considered to be related to encephalitis. We did not observe differences of immunotherapy-treated patients in likelihood of improvement with or without nonsteroidal immunotherapy (with 2/6, without 1/2)., Discussion: Antibody-negative AE should be diagnosed only after comprehensive testing. Diagnostic effort is important because many patients benefit from immunotherapy and some have malignancies., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

In this paper, we report our experiences from the first 30 patients investigated with stereoelectroencephalography (SEEG) at Sahlgrenska University Hospital, Gothenburg, Sweden. Clinical, neurophysiological, and imaging data were reviewed. Twelve children and 18 adults with drug-resistant epilepsy underwent 33 SEEG procedures. 53% of the patients had normal brain MRI. In total, 347 SEEG electrodes were implanted (median 12 per patient). Twenty patients subsequently had resective surgery based on SEEG findings. Focal cortical dysplasia was found in all cases. In 45% of the patients, vicinity of eloquent cortex limited resections. Epilepsy surgery based on SEEG resulted in seizure freedom in 58% of the cases. Minor complications were seen in eight patients, all of which resolved without sequelae. No major complications were seen. SEEG is a safe and effective method to delineate cortical areas involved in seizure generation.

Our goal was to assess the interrater agreement (IRA) of photoparoxysmal response (PPR) using the classification proposed by a task force of the International League Against Epilepsy (ILAE), and a simplified classification system proposed by our group. In addition, we evaluated IRA of epileptiform discharges (EDs) and the diagnostic significance of the electroencephalographic (EEG) abnormalities. We used EEG recordings from the European Reference Network (EpiCARE) and Standardized Computer-based Organized Reporting of EEG (SCORE). Six raters independently scored EEG recordings from 30 patients. We calculated the agreement coefficient (AC) for each feature. IRA of PPR using the classification proposed by the ILAE task force was only fair (AC = 0.38). This improved to a moderate agreement by using the simplified classification (AC = 0.56; P = .004). IRA of EDs was almost perfect (AC = 0.98), and IRA of scoring the diagnostic significance was moderate (AC = 0.51). Our results suggest that the simplified classification of the PPR is suitable for implementation in clinical practice., (© 2020 International League Against Epilepsy.)

Purpose: The aim of this prospective, video-electroencephalography (video-EEG) controlled study was to evaluate the performance of an accelerometry-based wearable system to detect tonic-clonic seizures (TCSs) and to investigate the accuracy of different seizure detection algorithms using separate training and test data sets., Methods: Seventy-five epilepsy surgery candidates undergoing video-EEG monitoring were included. The patients wore one three-axis accelerometer on each wrist during video-EEG. The accelerometer data was band-pass filtered and reduced using a movement threshold and mapped to a time-frequency feature space representation. Algorithms based on standard binary classifiers combined with a TCS specific event detection layer were developed and trained using the training set. Their performance was evaluated in terms of sensitivity and false positive (FP) rate using the test set., Results: Thirty-seven available TCSs in 11 patients were recorded and the data was divided into disjoint training (27 TCSs, three patients) and test (10 TCSs, eight patients) data sets. The classification algorithms evaluated were K-nearest-neighbors (KNN), random forest (RF) and a linear kernel support vector machine (SVM). For the TCSs detection performance of the three algorithms in the test set, the highest sensitivity was obtained for KNN (100% sensitivity, 0.05 FP/h) and the lowest FP rate was obtained for RF (90% sensitivity, 0.01 FP/h)., Conclusions: The low FP rate enhances the clinical utility of the detection system for long-term reliable seizure monitoring. It also allows a possible implementation of an automated TCS detection in free-living environment, which could contribute to ascertain seizure frequency and thereby better seizure management., (Copyright © 2018. Published by Elsevier Ltd.)

Autoimmune neurologic syndromes can be paraneoplastic (associated with malignancies and/or onconeural antibodies), or non-paraneoplastic. Their clinical presentation is often similar. As prognosis is related to malignancy treatment, better biomarkers are needed to identify patients with malignancy. We investigated cerebrospinal fluid (CSF) markers of neuronal (neurofilament light chain, NFL and total tau protein, T-tau) and glial (glial fibrillary acidic protein) damage. CSF-NFL and T-tau were increased in both paraneoplastic and non-paraneoplastic autoimmune syndromes. Patients with manifest malignancies were older, had less epilepsy, more focal central and peripheral neurological signs and symptoms, and worse long-term outcome, than those without malignancy. CSF-NFL-levels predicted long-term outcome but were not diagnostic for malignancy, after age adjustment., (Copyright © 2017 Elsevier B.V. All rights reserved.)

We tested the relation between a single short tonic-clonic seizure elicited by flurothyl vapors and changes of learning in Morris water maze (MWM) in Wistar rats. Oxidative stress usually accompanies seizures. Large melatonin doses were applied immediately before and after seizures to test consequences on learning impairment. One hour of hypobaric hypoxia (8000 m) three days prior to the seizure served as an activator of intrinsic antioxidant systems. Learning in MWM (7 days) started 24 h after seizures. Following seizures, latencies in MWM were longer than in controls and were shortened by hypoxia and preventive melatonin application. Melatonin was also applied before hypoxia to influence free radical (FR) production and intrinsic antioxidant activation. Some behavioral characteristics were changed and preconditioning effect of hypoxia was reduced. Melatonin after seizure (150 s and 6 h) had negligible effect. Results allow us to hypothesize about the role of FR and the beneficial effect of melatonin on the behavioral consequences of seizures., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Focal cerebral ischemia is an important cause of death and disability. Various experimental models were designed to study the pathophysiological mechanisms underlying ischemic damage and to evaluate putative neuroprotective strategies. The lack of correlation between the results of experimental and clinical studies resulted in much criticism of animal models of stroke. However, experimental models are undoubtedly the most important source of information on stroke pathophysiology, and will definitely remain an integral part of stroke research in the future. Due to much variability between different models, it is important to have a clear understanding of their pathophysiological characteristics - it is essential for correct interpretation of the experimental results. This aim of this review was to summarize the current knowledge about the mechanisms underlying the models of photothrombosis and endothelin-mediated focal ischemia.

Purpose: Postictal inhibition (PI) is a decrease in excitability that follows an epileptic seizure and decreases probability of new seizure occurrence. PI may involve both increased inhibition and persisting elevated excitation. Our experiments tested whether shorter trains of weak stimuli are able to unmask this residual increase of excitability during the PI., Methods: Four epileptic afterdischarges (ADs) were evoked by intense electrical stimulation (20 s, 8 Hz, current intensity at 5x threshold) of the neocortex in two groups (A, B) of Wistar rats. Before the first AD and during the 10-min interictal period, 8-Hz trains of four weak pulses (half of the intensity used for the AD triggering; 4P) were applied every 20 s in group B and a single pulse with similar parameters in group A., Results: The number of interictal epileptiform events evoked by 4P in the group B was significantly higher than that in the group A (evoked by single pulses) except after the second AD. Epileptic events were triggered by 4P also immediately after the AD termination., Conclusions: It is apparent that weak stimulation can trigger epileptic phenomena during PI. Our results indicate that it is no longer possible to perceive PI only as persisting extreme and active inhibition. An appropriate stimulation can reveal more subtle (but important) excitatory events contributing to the functional status during the postictal period.