Epilepsia
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Electroencephalography-functional magnetic resonance imaging (EEG-fMRI) coregistration has recently revealed that several brain structures are involved in generalized spike and wave discharges (GSWDs) in idiopathic generalized epilepsies (IGEs). In particular, deactivations and activations have been observed within the so-called brain default mode network (DMN) and thalamus, respectively. In the present study we analyzed the dynamic time course of blood oxygen level-dependent (BOLD) changes preceding and following 3 Hz GSWDs in a group of adolescent and adult patients with IGE who presented with absence seizures (AS). Our aim was to evaluate cortical BOLD changes before, during, and after GSWD onset. ⋯ Hemodynamic changes (BOLD increments) occurred in specific cortical areas, namely the precuneus/posterior cingulate, lateral parietal, and frontal cortices, several seconds before EEG onset of GSWD. A dysfunction of these brain regions, some of which belongs to the DMN, may be crucial in generating GSWDs in patients with IGE.
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Intractability in epilepsy is difficult to define, and little is known about its onset, course, and duration. We investigated these aspects (as well as the occurrence of intractability) during long-term follow-up in patients with epilepsy, focusing on possible explanations for the variation in time of onset and duration of intractability. ⋯ There is a large unpredictable variation in time of onset, course, and duration of intractability, with a higher chance of final intractability after a poor course during the first 5 years of follow-up. The natural course of epilepsy probably best explains the variable course of intractability. The effect of medication seems to be minor.
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Photosensitivity or photoparoxysmal response (PPR) is an electroencephalography trait that is highly associated with idiopathic generalized epilepsies (IGEs) and characterized by changes in cortical excitability in response to photic stimulation. Studying functional and structural changes of PPR might provide important insights into the pathogenesis of IGE. Recent studies revealed a functional network consisting of occipital, parietal, and precentral areas that might be implicated in PPR. Herein, we investigate the microstructural changes associated with PPR. ⋯ Our results show that PPR is associated with subcortical microstructural changes in precentral, parietal, and occipital regions. The coexistence of PPR and IGE is associated with white matter abnormalities in the thalamus and precuneus. PPR and epilepsy share similar functional and structural networks in widespread cortical and subcortical areas.
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Anterior temporal lobe resection (ATLR) controls seizures in up to 70% of patients with intractable temporal lobe epilepsy (TLE) but, in the language dominant hemisphere, may impair language function, particularly naming. Functional reorganization can occur within the ipsilateral and contralateral hemispheres. We investigated reorganization of language in left-hemisphere-dominant patients before and after ATLR; whether preoperative functional magnetic resonance imaging (fMRI) predicts postoperative naming decline; and efficiency of postoperative language networks. ⋯ In left TLE, early postoperative reorganization to the contralateral frontal lobe suggests multiple systems support language function. Postoperatively, ipsilateral recruitment involving the posterior hippocampal remnant is important for maintaining language, and reorganization to the contralateral hemisphere is less effective. Preoperative left middle frontal activation for VF was predictive of naming decline in left TLE after ATLR.
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To classify the grade of antiepileptic drug (AED) resistance in a cohort of patients with focal epilepsies, to recognize the risk factors for AED resistance, and to estimate the helpfulness of "new-generation" AEDs. ⋯ The ILAE classification of AED resistance, as well the graded classification proposed by Perucca, was easily exploitable in our patients, although these classifications systems appear to have a limited value in predicting seizure outcome. Actually, a small but not negligible percentage of patients reached seizure freedom after trying several AEDs (including "new" AEDs), suggesting repeated trials may be necessary for seizure control.