3D figure of epilepsy syndromes

Abstract We propose an instructive figure that summarized the classification of epilepsy syndromes according to the 2022 report of the ILAE Task Force on Nosology and Definitions. Our aim is to present on the same figure different concepts such as the names of epilepsy syndromes, their extreme and classical ages of onset, their epilepsy types (generalized, focal, or generalized and focal) but also their membership in groups of epilepsy syndromes as for self‐limited or developmental and epileptic encephalopathies. With this figure, we provide an interactive tool, as supplementary data, helping to present this classification and link it to electro‐clinical mandatory, alerts, and exclusionary criteria of each syndrome, in accordance with the ILAE position papers on syndromes classification and nosology. This report may be used as an illustrative tool for teaching epilepsy syndromes and as a practical and comprehensive aid for the classification of epilepsy individuals' syndromes.


Abstract
We propose an instructive figure that summarized the classification of epilepsy syndromes according to the 2022 report of the ILAE Task Force on Nosology and Definitions. Our aim is to present on the same figure different concepts such as the names of epilepsy syndromes, their extreme and classical ages of onset, their epilepsy types (generalized, focal, or generalized and focal) but also their membership in groups of epilepsy syndromes as for self-limited or developmental and epileptic encephalopathies. With this figure, we provide an interactive tool, as supplementary data, helping to present this classification and link it to electroclinical mandatory, alerts, and exclusionary criteria of each syndrome, in accordance with the ILAE position papers on syndromes classification and nosology. This report may be used as an illustrative tool for teaching epilepsy syndromes and as a practical and comprehensive aid for the classification of epilepsy individuals' syndromes.

K E Y W O R D S
developmental and epileptic encephalopathy, epilepsy syndromes, interactive classification, self-limited epilepsies, teaching tool The production of instructive figures that summarize complex concepts, such as classification of epilepsy syndromes for the education of epileptologists, general practitioners, and patients and their families can be very challenging. We propose the following figure ( Figure 1 First, we classified the epilepsy syndromes according to epilepsy type as reported in the ILAE classification, namely focal, generalized, and combined generalized and focal. 1 Second, we used a concentric scale to illustrate the age of onset of the different epilepsy syndromes, an important criterion reported in the definition of the syndromes. By using a continuous logarithmic scale and not only a qualitative one, we were also able to go beyond childhood including variable age syndromes and syndromes with adult onset. We detailed the extreme range of onset age using dotted lines and the classical age range using a solid line. Third, to identify and visualize the different groups of epilepsy syndromes as per the position papers, 2-6 we filled the groups with specific color (red for developmental and/or epileptic encephalopathies and syndromes with progressive neurological deterioration, turquoise for self-limited epilepsies, orange for idiopathic generalized epilepsies, and pink for genetic generalized epilepsies). Finally, we added the self-limited dimension separating the figure into two blocks, self-limited often drug-responsive epilepsies with white diagonal hatching versus drug-resistant epilepsies and acknowledge that the separation might not be always very clear.
In conclusion, this figure can be used to succinctly illustrate the entire classification but might be also parcellated according to the user's needs. It can be an illustrative tool for teaching epilepsy syndromes and can also be used as a practical aid for syndrome classification of patients.

ACKNOWLEDGMENT
RN acknowledges GEEN-DS chair position institut lmagine is supported by FAMA Fund hosted by Swiss Philanthropy Foundation.

CONFLICT OF INTEREST
None of the authors has any conflict of interest to disclose related to this study. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.

ORCID
The epilepsy syndromes according to the 2017 epilepsy syndrome classification 1 and the 2022 report of the ILAE Task Force on Nosology and Definitions, 2-6 using the full names of the different epilepsy syndromes (A) or their specific abbreviations (B). The different epilepsy syndromes are divided into different colored areas according to their type of seizure: generalized in yellow, focal in blue, or combined focal and generalized in green. The concentric dotted circles indicated the age of onset of the syndrome. For each epilepsy syndrome, the dotted line represented the extreme age of onset and the thick line the classical age. The main groups of epilepsy syndromes are depicted in specific colors: self-limiting epilepsies in turquoise, idiopathic generalized epilepsies in orange, developmental and/or epileptic encephalopathies and syndromes with progressive neurological deterioration in red and genetic generalized epilepsies in purple. Note that idiopathic generalized epilepsies are a subcategory of genetic generalized epilepsies. Developmental and Epileptic Encephalopathy (DEEs) are a group of epilepsy syndromes where impairments (encephalopathy) are due to both the underlying etiology of the epilepsy and frequent seizures or epileptiform discharges, whereas in epileptic encephalopathy (EE), the encephalopathy is due to frequent seizures or epileptiform discharges. A horizontal axis was used to separate self-limited and/or pharmacoresponsive epilepsies (white diagonal hatching) from commonly drug-resistant epilepsies. The letters used for the abbreviations of the different epilepsy syndromes have been bolded. It is important to bear in mind that this figure reflects the current organization of epilepsy syndromes as defined in the 2022 report of the ILAE Working Group on Nosology and Definitions, but it gives scant information on the underlying etiologies.