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This article provides recommendations on the minimum standards for recording routine ("standard") and sleep electroencephalography (EEG). The joint working group of the International Federation of Clinical Neurophysiology (IFCN) and the International League Against Epilepsy (ILAE) developed the standards according to the methodology suggested for epilepsy-related clinical practice guidelines by the Epilepsy Guidelines Working Group. We reviewed the published evidence using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The quality of evidence for sleep induction methods was assessed by the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) method. A tool for Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used to assess the risk of bias in technical and methodological studies. Where high-quality published evidence was lacking, we used modified Delphi technique to reach expert consensus. The GRADE system was used to formulate the recommendations. The quality of evidence was low or moderate. We formulated 16 consensus-based recommendations for minimum standards for recording routine and sleep EEG. The recommendations comprise the following aspects: indications, technical standards, recording duration, sleep induction, and provocative methods., (Copyright © 2023 International Federation of Clinical Neurophysiology, Inc, International League Against Epilepsy. Published by Elsevier B.V. All rights reserved.)

Objective: The default mode network (DMN) is deactivated by stimulation. We aimed to assess the DMN reactivity impairment by routine EEG recordings in stroke patients with impaired consciousness., Methods: Binocular light flashes were delivered at 1 Hz in 1-minute epochs, following a 1-minute baseline (PRE). The EEG was decomposed in a series of binary oscillatory macrostates by topographic spectral clustering. The most deactivated macrostate was labeled the default EEG macrostate (DEM). Its reactivity (DER) was quantified as the decrease in DEM occurrence probability during stimulation. A normalized DER index (DERI) was calculated as DER/PRE. The measures were compared between 14 healthy controls and 32 comatose patients under EEG monitoring following an acute stroke., Results: The DEM was mapped to the posterior DMN hubs. In the patients, these DEM source dipoles were 3-4 times less frequent and were associated with an increased theta activity. Even in a reduced 6-channel montage, a DER below 6.26% corresponding to a DERI below 0.25 could discriminate the patients with sensitivity and specificity well above 80%., Conclusion: The method detected the DMN impairment in post-stroke coma patients., Significance: The DEM and its reactivity to stimulation could be useful to monitor the DMN function at bedside., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The authors working with Termobit Prod SRL RO during this project were disclosed in the affiliations. AB and CS are shareholders at Termobit Prod Srl. The research grant structure required that the private partner, Termobit Prod, partially fund their own activities. MM was PI and was funded only through grant funds awarded to Termobit, without having a commercial interest in the company. All other authors involved in this study, representing public institutions (AMR, IRM, JC, ACP, AMZ, LZ) were funded from grant funds and have no stock interest or consultancies with Termobit Prod or FHC, Inc. Authors have filed a patent proposal for the presented method., (Copyright © 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Purpose: Epilepsy patients consider driving issues to be one of their most serious concerns. Ideally, decisions regarding fitness to drive should be based upon thorough evaluations by specialists in epilepsy care. In 2009, an EU directive was published aiming to harmonize evaluation practices within European countries, but, despite these recommendations, whether all epileptologists use the same criteria is unclear. We therefore conducted this study to investigate routine practices on how epileptologists at European epilepsy centers evaluate fitness to drive., Methods: A questionnaire was sent to 63 contact persons identified through the European Epi-Care and the E-pilepsy network. The questionnaire addressed how fitness-to-drive evaluations were conducted, the involvement of different professionals, the use and interpretation of EEG, and opinions on existing regulations and guidelines., Results: The questionnaire was completed by 35 participants (56 % response rate). Results showed considerable variation regarding test routines and the emphasis placed on the occurrence and extent of epileptiform discharges revealed by EEG. 82 % of the responders agreed that there was a need for more research on how to better evaluate fitness-to-drive in people with epilepsy, and 89 % agreed that regulations on fitness to drive evaluations should be internationally coordinated., Conclusion: Our survey showed considerable variations among European epileptologists regarding use of EEG and how findings of EEG pathology should be assessed in fitness-to-drive evaluations. There is a clear need for more research on this issue and international guidelines on how such evaluations should be carried out would be of value., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: Sleep is an active process with an important role in memory. Epilepsy patients often display a disturbed sleep architecture, with consequences on cognition. We aimed to investigate the effect of sleep on cortical networks' organization., Methods: We analyzed cortico-cortical evoked responses elicited by single pulse electrical stimulation (SPES) using intracranial depth electrodes in 25 patients with drug-resistant focal epilepsy explored using stereo-EEG. We applied the SPES protocol during wakefulness and NREM - N2 sleep. We analyzed 31,710 significant responses elicited by 799 stimulations covering most brain structures, epileptogenic or non-epileptogenic. We analyzed effective connectivity between structures using a graph-theory approach., Results: Sleep increases excitability in the brain, regardless of epileptogenicity. Local and distant connections are differently modulated by sleep, depending on the tissue epileptogenicity. In non-epileptogenic areas, frontal lobe connectivity is enhanced during sleep. There is increased connectivity between the hippocampus and temporal neocortex, while perisylvian structures are disconnected from the temporal lobe. In epileptogenic areas, we found a clear interhemispheric difference, with decreased connectivity in the right hemisphere during sleep., Conclusions: Sleep modulates brain excitability and reconfigures functional brain networks, depending on tissue epileptogenicity., Significance: We found specific patterns of information flow during sleep in physiologic and pathologic structures, with possible implications for cognition., (Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: To investigate functional coupling between brain networks using spectral changes induced by single-pulse electric stimulation (SPES)., Method: We analyzed 20 patients with focal epilepsy, implanted with depth electrodes. SPES was applied to each pair of adjacent contacts, and responses were recorded from all other contacts. The mean response amplitude value was quantified in three time-periods after stimulation (10-60, 60-255, 255-500ms) for three frequency-ranges (Gamma, Ripples, Fast-Ripples), and compared to baseline. A total of 30,755 responses were analyzed, taking into consideration three dichotomous pairs: stimulating in primary sensory areas (S1-V1) vs. outside them, to test the interaction in physiologic networks; stimulating in seizure onset zone (SOZ) vs. non-SOZ, to test pathologic interactions; recording in default mode network (DMN) vs. non-DMN., Results: Overall, we observed an early excitation (10-60ms) and a delayed inhibition (60-500ms). More specifically, in the delayed period, stimulation in S1-V1 produced a higher gamma-inhibition in the DMN, while stimulation in the SOZ induced a higher inhibition in the epilepsy-related higher frequencies (Ripples and Fast-Ripples)., Conclusion: Physiologic and pathologic interactions can be assessed using spectral changes induced by SPES., Significance: This is a promising method for connectivity studies in patients with drug-resistant focal epilepsy., (Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Purpose: To investigate whether hyperventilation (HV) for 5min increases the diagnostic yield of electroencephalography (EEG) compared to 3min HV., Methods: data were evaluated from 1084 consecutive patients, from three European centres, referred to EEG on suspicion of epilepsy. Seizures and interictal EEG abnormalities precipitated during the first 3min and during the last 2min of the HV period (totally 5min) were determined., Results: Eight hundred seventy-seven patients (81%) completed 5min HV. Seizures were precipitated during the first 3min of HV in 21 patients, and during the last 2min in four more patients. Interictal EEG abnormalities were precipitated in the first 3min of HV in 16 patients, and during the last 2min in 7 more patients. Psychogenic nonepileptic seizures occurred in eight patients during the first 3min of HV and in two more patients during the last 2min. No adverse events occurred during the last 2min of HV, but eight patients (1%) stopped HV during the last 2min because they were not able to hyperventilate further., Conclusion: 16% of seizures and 30% of interictal EEG abnormalities triggered by HV occurred during the last 2min of HV, suggesting the clinical usefulness of prolonged hyperventilation for 5min. The vast majority of patients (99%) who are able to hyperventilate for 3min can complete 5min HV, without additional adverse events., (Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: The aim of this survey was to review and compare the current approaches to epilepsy management in central and eastern EU (CEEU) countries., Method: The questionnaire was sent to ten invited experts from Bulgaria, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia, and Slovenia. It focused on the treatment of adults., Results: The number of neurologists and epilepsy reference centers is highly variable in CEEU countries. None of the analyzed states has a formal specialization in epileptology. No universal state-approved criteria for reference centers exist in Czech Republic, Estonia, Hungary, Latvia, and Slovenia. Generally, the protocols for epilepsy treatment in CEEU countries, including drug-resistant epilepsy, are in accordance with international guidelines; however, most countries have their own national standards of care and some have local clinical guidelines. Also, the reimbursement systems for antiepileptic drugs in CEEU countries are highly variable. Seven countries have epilepsy surgery centers. The costs of epilepsy surgeries are fully reimbursed, procedures performed abroad may also be covered. The length of time spent on waiting lists for surgery following the completion of preoperative investigations varies from two weeks to three years. The fraction of patients who qualified and were operated on within 12 months ranges from 20% to 100%., Conclusion: The lack of unified procedures pertaining to the evaluation and therapy of epilepsy is reflected by marked differences in access to treatment modalities for patients from CEEU countries., (Copyright © 2013 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)