ABSTRACT
Genetic generalized epilepsy (GGE) is conceptualized as a brain disorder involving distributed bilateral networks. To study these networks, simultaneous EEG-fMRI measurements can be used. However, inside-MRI EEG suffers from strong MR-related artifacts; it is not established whether EEG-based metrics in EEG-fMRI resting-state measurements are suitable for the analysis of group differences at source-level. We evaluated the impact of the inside-MR measurement condition on statistical group comparisons of EEG on source-level power and functional connectivity in patients with GGE versus healthy controls. We studied the cross-modal spatial relation of statistical group differences in seed-based FC derived from EEG and parallel fMRI. We found a significant increase in power and a frequency-specific change in functional connectivity for the inside MR-scanner compared to the outside MR-scanner condition. For power, we found reduced group difference between GGE and controls both in terms of statistical significance as well as effect size. Group differences for ImCoh remained similar both in terms of statistical significance as well as effect size. We found increased seed-based FC for GGE patients from the thalamus to the precuneus cortex region in fMRI, and in the theta band of simultaneous EEG. Our findings suggest that the analysis of EEG functional connectivity based on ImCoh is suitable for MR-EEG, and that relative group difference in a comparison of patients with GGE against controls are preserved. Spatial correspondence of seed-based FC group differences between the two modalities was found for the thalamus.
Subject(s)
Epilepsy, Generalized , Humans , Epilepsy, Generalized/diagnostic imaging , Epilepsy, Generalized/genetics , Magnetic Resonance Imaging , Parietal Lobe , Neural Pathways , ElectroencephalographyABSTRACT
OBJECTIVE: Presurgical high-density electric source imaging (hdESI) of interictal epileptic discharges (IEDs) is only used by few epilepsy centers. One obstacle is the time-consuming workflow both for recording as well as for visual review. Therefore, we analyzed the effect of (a) an automated IED detection and (b) the number of IEDs on the accuracy of hdESI and time-effectiveness. METHODS: In 22 patients with pharmacoresistant focal epilepsy receiving epilepsy surgery (Engel 1) we retrospectively detected IEDs both visually and semi-automatically using the EEG analysis software Persyst in 256-channel EEGs. The amount of IEDs, the Euclidean distance between hdESI maximum and resection zone, and the operator time were compared. Additionally, we evaluated the intra-individual effect of IED quantity on the distance between hdESI maximum of all IEDs and hdESI maximum when only a reduced amount of IEDs were included. RESULTS: There was no significant difference in the number of IEDs between visually versus semi-automatically marked IEDs (74 ± 56 IEDs/patient vs 116 ± 115 IEDs/patient). The detection method of the IEDs had no significant effect on the mean distances between resection zone and hdESI maximum (visual: 26.07 ± 31.12 mm vs semi-automated: 33.6 ± 34.75 mm). However, the mean time needed to review the full datasets semi-automatically was shorter by 275 ± 46 min (305 ± 72 min vs 30 ± 26 min, P < 0.001). The distance between hdESI of the full versus reduced amount of IEDs of the same patient was smaller than 1 cm when at least a mean of 33 IEDs were analyzed. There was a significantly shorter intraindividual distance between resection zone and hdESI maximum when 30 IEDs were analyzed as compared to the analysis of only 10 IEDs (P < 0.001). SIGNIFICANCE: Semi-automatized processing and limiting the amount of IEDs analyzed (~30-40 IEDs per cluster) appear to be time-saving clinical tools to increase the practicability of hdESI in the presurgical work-up.
Subject(s)
Epilepsy , Magnetic Resonance Imaging , Humans , Retrospective Studies , Feasibility Studies , Workflow , Magnetic Resonance Imaging/methods , Epilepsy/diagnosisABSTRACT
Resumen Objetivo. Caracterizar el perfil cognitivo de un grupo de niños con epilepsias focales de etiología genética y desconocida y control de crisis epilépticas. Método. Se realizó una evaluación neuropsicológica con subpruebas de la batería Evaluación Neuropsicológica Infantil (ENI), a 35 niños entre los 7 y los 15 años de edad, con diagnóstico de epilepsias focales de etiología genética o desconocida, tratamiento farmacológico y coeficiente intelectual ≥ 80. Resultados. El grupo de pacientes evidenció déficit significativo en atención auditiva, al comparar su desempeño con los datos normativos de la ENI para población colombiana. No se encontraron diferencias significativas en el desempeño de pacientes con o sin crisis epilépticas durante el último año, etiología genética o desconocida, foco epiléptico en región cerebral frontal o centro-temporal, con o sin diagnóstico previo de trastorno por déficit con o sin hiperactividad (TDAH/TDA). Conclusión. La dificultad atencional observada puede requerir mayor manejo terapéutico, al plantearles una mayor susceptibilidad para desatender a los contenidos de clase que requieren una focalización rápida y efectiva, implicando también tareas de conteo numérico auditivo (como dictados y operaciones matemáticas sencillas), que dependen del adecuado funcionamiento de la atención auditiva.
Abstract Objective. Characterize the cognitive profile of a group of children with focal epilepsies of genetic and unknown etiologies and control of epileptic seizures. Method. This study carried out a neuropsychological assessment using tests from the Evaluación Neuropsicológica Infantil (Neurspsychological Infantile Assessment) (ENI) battery to 35 children between 7 and 15 years old, diagnosed with focal epilepsies of genetic or unknown etiology, pharmacological treatment, and intelligence quotient ≥ 80. Results. Comparing their performance to normative ENI values for the Colombian population and using the percentiles assessment parameters of the test, the group of patients showed a significant deficit in auditory selective attention. No relevant differences were found in the performance of patients with or without seizures during the last year, genetic or unknown etiology, epileptic activity on frontal or centro-temporal brain regions, and the presence or absence of a previous diagnosis of Attention Deficit with or without Hyperactivity (ADHD/ADD). Conclusion. It is possible that this deficit requires more therapeutic management and has negative effects over scholar performance for the assessed children, who demonstrate a greater susceptibility to neglect class contents that require fast and effective attentional focalization, including auditory numeric counting tasks (like dictation and simple mathematic operations).
Resumo Escopo. Caracterizar o perfil cognitivo de um grupo de crianças com epilepsias focais de etiologia genética e desconhecida e controle de crises epilépticas. Metodologia. Foi feita uma avaliação neuropsicológica com sub provas da bateria Avaliação Neuropsicológica Infantil (ANI), a 35 crianças entre os 7 e os 15 anos de idade, com diagnóstico de epilepsias focais de etiologia genética ou desconhecida, tratamento farmacológico e coeficiente intelectual ≥ 80. Resultados. O grupo de pacientes evidenciou déficit significativo em atenção auditiva, ao comparar seu desempenho com os dados normativos da ANI para população colombiana. Não foram achadas diferencias significativas no desempenho de pacientes com ou sem crises epilépticas durante o último ano, etiologia genética ou desconhecida, foco epiléptico em região cerebral frontal ou centro-temporal, com ou sem diagnóstico prévio de Transtorno por Déficit com ou sem Hiperatividade (TDAH/TDA). Conclusão. A dificuldade de atenção observada pode requerer maior gestão terapêutica, ao abordar uma maior susceptibilidade para desatender aos conteúdos de classe que requerem uma focalização rápida e efetiva, implicando também tarefas de contar números de forma auditiva (como ditados e operações matemáticas simples), que dependem do adequado funcionamento da atenção auditiva.
