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• Ultra-longterm EEG recordings provide additional information on ictal epileptic events over periods of many months. • Objective information on seizure occurrence has a wide spectrum of use cases, including epilepsy diagnosis, differentiation of epileptic and non-epileptic seizure types and their time course. • Ultra-longterm EEG can be useful for diagnostic classification, risk assessment, treatment monitoring and medicolegal decisions. We assessed clinical cases to investigate the spectrum of indications for ultra-longterm EEG monitoring using a subcutaneous implantable device in adult patients with focal epilepsy. Electronic charts were reviewed from patients undergoing ultra-longterm recordings at the European Epilepsy centers Barcelona, Freiburg and Vienna. Specific patient settings approached in the three centers were analyzed, and the main clinical question was extracted. Results from recordings were analyzed based on the specific results and information obtained. 24 patients in whom ultra-longterm recordings were available were analyzed. A total of 11 main indications for subcutaneous long-term EEG recordings were identified, including the identification of active epilepsy in patients with low seizure frequency, under- and overreporting of patients, differentiation of non-epileptic from epileptic events, assessment of seizure severity, circadian and multidian rhythms of seizure occurrence, validation of treatment efficacy, improvement of patient-based reporting and medicolegal evidence for seizure freedom. This is reported with patient-specific case vignettes. Ultra-longterm monitoring using subcutaneous implantable EEG devices can provide relevant diagnostic and treatment information in a large spectrum of clinical situations. This is discussed considering the intrinsic limitations of the method related to spatial coverage, sensitivity and validity as a biomarker of ongoing seizures. [ABSTRACT FROM AUTHOR]

Resumen Objetivos La SPECT de perfusión ictal-interictal, subtraction ictal SPECT coregistered to MRI (SISCOM) y 18 F-FDG-PET (interictal), desempeñan un papel fundamental en la valoración prequirúrgica del paciente epiléptico fármaco-resistente. Los objetivos de este trabajo fueron establecer la reproducibilidad del análisis visual de la SPECT y SISCOM y la capacidad de la SPECT, SISCOM y PET en la identificación del foco epileptógeno. Material y métodos Se realizó una SPECT 99m Tc-HMPAO (ictal-interictal) y SISCOM (Analyze 7.0) en 47 pacientes epilépticos fármaco-resistentes (24 M, 19-60 años). En 13 pacientes se repitió el SISCOM utilizando el programa FocusDET. El análisis de las imágenes fue realizado por 2 observadores. Se valoró la reproducibilidad utilizando el índice Kappa. Los resultados conjuntos de la SPECT, SISCOM y PET, en 16 pacientes, fueron comparados con la localización del área resecada y el seguimiento clínico poscirugía (escala de Engel) o con la estereo-EEG. Resultados Grado de acuerdo interobservador de la SPECT 91% índice Kappa 0,86. Grado de acuerdo interobservador SISCOM Analyze 7.0 82%, índice Kappa 0,80. El Analyze 7.0 mostró un elevado número de resultados no concluyentes, superior al del análisis visual. El SISCOM FocusDET mostró un grado de acuerdo interobservador 92% con un índice Kappa 0,87 y menor número de resultados no concluyentes que el Analyze. La valoración conjunta SPECT, SISCOM y PET permitió identificar 87% focos epileptógenos: 79% temporales, 26% parieto-temporales y 7% frontales. Conclusión La SPECT ictal-interictal y el SISCOM mostraron una elevada reproducibilidad. La valoración conjunta de la SPECT ictal-interictal, SISCOM y PET permitió mejorar la rentabilidad diagnóstica de la valoración individualizada. Aims Brain perfusion SPECT (ictal-interictal), SPECT images and subtraction ictal SPECT coregistered to MRI (SISCOM) and 18 F-FDG-PET (interictal), play an important role in the pre-surgical diagnosis of patients with medically refractory epilepsy. This study aimed to establish: the reproducibility of visual ictal-interictal SPECT and SISCOM analysis altogether with the capacity of SPECT, SISCOM and PET to determine the epileptogenic zone. Material and methods 99m Tc-HMPAO SPECT ictal-interictal and SISCOM (Analyze 7.0) were performed on 47 refractory epilepsy patients (24 F, 19-60 yrs). In 13 patients, SISCOM was also performed using a new program (Focus DET). Ictal-interictal SPECT and SISCOM images were analysed independently by two nuclear medicine physicians (observer 1 and 2). Kappa concordance coefficient was used to evaluate the reproducibility. In sixteen patients, SPECT, SISCOM and PET findings were compared with the resected area during the surgery, and surgical outcome using Engel scale or with the stereo EEG-(SEEG). Results The ictal-interictal SPECT interobserver agreement was 91%, Kappa index 0.86, SISCOM (Analyze 7.0) interobserver agreement percentage was 82%, Kappa index 0.80, Analyze 7.0 showed a higher inconclusive results than visual SPECT analysis. SISCOM FocusDET interobserver agreement was 92%, Kappa index 0.87, with lower inconclusive results than Analyze 7.0. SPECT, SISCOM and PET combined findings identified 87% seizure onset zone: 79% temporal, 26% parieto-temporal and 7% frontal. Conclusions Ictal-interictal SPECT and SISCOM showed a high reproducibility in this sample of patients with drug-refractory epilepsy. SPECT,SISCOM and PET combined findings improved detection of epileptogenic zone in comparison with the individual assessment. [ABSTRACT FROM AUTHOR]

Long-term video-EEG monitoring (LTVEEG-m) is the diagnostic test of certainty of epilepsy. The European Commission recommends one epilepsy unit with LTVEEG-m for every 3,000 patients with refractory epilepsy. In Spain, there was one center accredited every 10,600 patients with RE in 2019. There are different publications on LTVEEG-m about clinical effectiveness; however, very scarce scientific evidence has been shown on the efficiency of using of LTVEEG-m. This study aims to conduct an economic evaluation of the LTVEEG-m versus no LTVEEG-m (continuing with antisei:zure drugs) in RE patients, which should support funding decision-making of the LTVEEG-m in Spain. Based on a prospective cohort of patients referred for refractory epilepsy for LTVEEG-m in the epilepsy unit of the Germans Trias i Pujol Hospital, a cost-effectiveness analysis was conducted using a decision tree followed by a Markov model which simulated the costs and health outcomes of individuals treated under both alternatives (LTVEEG-m vs. no LTVEEG-m) for a lifetime horizon from a hospital perspective. The effectiveness measure was quality-adjusted life years (QALYs). An extensive sensitivity analyses was run, including a probabilistic sensitivity analysis. In the base case analysis, the LTVEEG-m led to higher QALYs and health care costs with an estimated mean incremental cost of 17,472 EUR and an incremental effectiveness of 8 QALY s, generating an incremental cost effectiveness ratio of 2,175 EUR per QALY, a lower figure than the cost effectiveness threshold of 20,000 EUR per QALY in Spain. The sensitivity analysis showed the robustness of the results. The probability that LTVEEG-m is a cost-effective technology against the no LTVEEG-m was 100%. LTVEEG-m is an efficient diagnostic test compared to not use the LTVEEG-m and continuing with anti-sei:zure drugs. This is a pioneering study in Europe and scalable to other similar economic contexts to Spain. Key messages: There is a huge lack of epilepsy units using the LTVEEG-m as a diagnostic test of certainty of epilepsy for refractory epileptic patients in Spain, disregarding the European recommendations. LTVEEG-m is an efficient diagnostic test compared to not use the LTVEEG-m and continuing with anti-sei:zure drugs. This is a pioneering study in Europe and scalable to similar Spanish economic context. [ABSTRACT FROM AUTHOR]