The role of EEG in the diagnosis and classification of the epilepsy syndromes: a tool for clinical practice by the ILAE Neurophysiology Task Force (Part 2)
ABSTRACTThe concept of epilepsy syndromes, introduced in 1989, was defined as “clusters of signs and symptoms customarily occurring together”. Definition of epilepsy syndromes based on electro‐clinical features facilitated clinical practice and, whenever possible, clinical research in homogeneous groups of patients with epilepsies. Progress in the fields of neuroimaging and genetics made it rapidly clear that, although crucial, the electro‐clinical description of epilepsy syndromes was not sufficient to allow much needed development of targeted therapies and a better understanding of the underlying pathophysiological mechanisms of seizures. The 2017 ILAE position paper on Classification of the Epilepsies recognized that “as a critical tool for the practicing clinician, epilepsy classification must be relevant and dynamic to changes in thinking”. The concept of “epilepsy syndromes” evolved, incorporating issues related to aetiologies and comorbidities. A comprehensive update (and revision where necessary) of the EEG diagnostic criteria in the light of the 2017 revised terminology and concepts was deemed necessary. Part 2 covers the neonatal and paediatric syndromes in accordance with the age of onset. [Published with educational EEG plates atwww.epilepticdisorders.com].
The role of EEG in the diagnosis and classification of the epilepsy syndromes: a tool for clinical practice by the ILAE Neurophysiology Task Force (Part 1)
AbstractRational. The concept of epilepsy syndromes, introduced in 1989, was defined as “clusters of signs and symptoms customarily occurring together”. Definition of epilepsy syndromes based on electro‐clinical features facilitated clinical practice and, whenever possible, clinical research in homogeneous groups of patients with epilepsies. Progress in the fields of neuroimaging and genetics made it rapidly clear that, although crucial, the electro‐clinical description of epilepsy syndromes was not sufficient to allow much needed development of targeted therapies and a better understanding of the underlying pathophysiological mechanisms of seizures. The 2017 ILAE position paper on Classification of the Epilepsies recognized that “as a critical tool for the practicing clinician, epilepsy classification must be relevant and dynamic to changes in thinking”. The concept of “epilepsy syndromes” evolved, incorporating issues related to aetiologies and comorbidities. A comprehensive update (and revision where necessary) of the EEG diagnostic criteria in the light of the 2017 revised terminology and concepts was deemed necessary.Methods. The work was commissioned by the Neurophysiology Task Force of the ILAE Committee on the Diagnostic Methods. Diagnostic criteria and recording procedures were developed by group consensus, reached through an “informal”, internal decision‐making process. Each working group member was allocated a number of syndromes, and a standard structured template was used. International literature was extensively reviewed.Results. We developed a simple diagnostic system that is applicable to all epilepsy syndromes which allows the physician (i) to rate the strength of EEG diagnosis (degree of diagnostic certainty) by weighting EEG findings in relation to the available clinical information or the specific clinical question, and ii) to suggest further EEG diagnostics where conclusive diagnostic evidence is lacking. We also propose a system of syndrome‐specific recording protocols that, used with the relevant clinical presentation or specific clinical question, may maximize activation of epileptic discharges and ultimately help with standardization of EEG recording across departments, worldwide. Because recording methodology also depends on available resources, a two‐tier system was developed to embrace clinical EEG services in resource‐limited and industrialized countries. A clinical practice statement for each of the epilepsy syndromes discussed underscores the crucial role of the clinical information with regards to both the optimization of the EEG recording and mainly its meaningful interpretation. Part I covers Genetic (Idiopathic) generalized epilepsies and syndromes, Reflex epilepsies, structural and genetic focal (lobar) syndromes and Progressive Myoclonus Epilepsies [Published with educational EEG plates on www.epilepticdisorders.com].
Etiologies and characteristics of refractory status epilepticus cases in different areas of the world: Results from a global audit
Summary To describe the demographics, etiologies, types of status epilepticus ( SE ), and outcomes in people with refractory and super‐refractory SE from around the world, we prospectively collected cases of refractory SE ( RSE ) treated with continuous intravenous anesthetic drugs in an intensive care unit setting through online questionnaires using “active surveillance.” We collected information about 776 cases of RSE in 50 countries over 4 years. Control of SE was achieved in 74% of the cases. Neurologic outcomes were poor in 41% of patients, and 24% died. Good outcome was associated with younger age and a history of epilepsy. Etiology strongly influenced the outcome. Patients from Asia were younger, more frequently presented with convulsive SE , and were more frequently affected by infectious etiologies when compared with patients from Europe and the Americas. Despite these differences, outcomes were similar in all countries. Demographics of patients with RSE in a global audit are similar to those in prior single center series, providing evidence of generalizability of those studies. Important differences exist among patients with RSE from different regions of the world, but these do not seem to significantly influence patient outcomes.
Proposed consensus definitions for new‐onset refractory status epilepticus (NORSE), febrile infection‐related epilepsy syndrome (FIRES), and related conditions
SummaryWe convened an international group of experts to standardize definitions of New‐Onset Refractory Status Epilepticus (NORSE), Febrile Infection‐Related Epilepsy Syndrome (FIRES), and related conditions. This was done to enable improved communication for investigators, physicians, families, patients, and other caregivers. Consensus definitions were achieved via email messages, phone calls, an in‐person consensus conference, and collaborative manuscript preparation. Panel members were from 8 countries and included adult and pediatric experts in epilepsy, electroencephalography (EEG), and neurocritical care. The proposed consensus definitions are as follows: NORSE isa clinical presentation, not a specific diagnosis, in a patient without active epilepsy or other preexisting relevant neurological disorder, with new onset of refractory status epilepticus without a clear acute or active structural, toxic or metabolic cause. FIRES is a subcategory of NORSE, applicable for all ages, that requires a prior febrile infection starting between 2 weeks and 24 hours prior to onset of refractory status epilepticus, with or without fever at onset of status epilepticus. Proposed consensus definitions are also provided for Infantile Hemiconvulsion‐Hemiplegia and Epilepsy syndrome (IHHE) and for prolonged, refractory and super‐refractory status epilepticus. This document has been endorsed by the Critical Care EEG Monitoring Research Consortium. We hope these consensus definitions will promote improved communication, permit multicenter research, and ultimately improve understanding and treatment of these conditions.