Independent component analysis: a reliable alternative to general linear model for task-based fMRI.

Background: Functional magnetic resonance imaging (fMRI) is a valuable tool for the presurgical evaluation of patients undergoing neurosurgeries. Although many pre-processing steps have been modified according to advances in recent years, statistical analysis has remained largely the same since the first days of fMRI. In this study, we examined the ability of Independent Component Analysis (ICA) to separate the activation of a language task in fMRI, and we compared it with the results of the General Lineal Model (GLM).

Frontal lobe epilepsy and mild malformation with oligodendroglial hyperplasia: Further observations on electroclinical and imaging phenotypes, and surgical perspectives.

Objective: Mild malformation with oligodendroglial hyperplasia (MOGHE) is a recently described clinicopathologic entity, associated with drug-resistant epilepsy and extensive epileptogenic networks. Knowledge is accumulating about particular electroclinical phenotypes, correlations with imaging, and potential prognostic significance for surgical outcomes. The study adds relevant information by documenting the presence of a hyperkinetic frontal lobe seizure phenotype in adolescents and an epileptic encephalopathy phenotype in young children.

Standardization of presurgical language fMRI in Greek population: Mapping of six critical regions.

Background: Mapping the language system has been crucial in presurgical evaluation especially when the area to be resected is near relevant eloquent cortex. Functional magnetic resonance imaging (fMRI) proved to be a noninvasive alternative of Wada test that can account not only for language lateralization but also for localization when appropriate tasks and MRI sequences are being used. The tasks utilized during the fMRI acquisition are playing a crucial role as to which areas will be activated.

Altered Sleep-Related Consolidation and Neurocognitive Comorbidity in CECTS.

Our aim is to use neurophysiological sleep-related consolidation (SRC) phenomena to identify putative pathophysiological mechanisms in CECTS linked to diffuse neurocognitive deficits. We argue that there are numerous studies on the association between seizure aspects and neurocognitive functioning but not as many on interictal variables and neurocognitive deficits. We suggest two additional foci.

Temporal lobe "plus" epilepsy associated with oligodendroglial hyperplasia (MOGHE).

Background: Mild malformation of cortical dysplasia (mMCD) with oligodendroglial hyperplasia (MOGHE) is an epilepsy-related pathologic entity highlighted in post-surgical specimens of frontal lobe epilepsy (FLE) patients.

Aims Of The Study: We present two temporal lobe epilepsy (TLE) cases with MOGHE and discuss clinical, neurophysiological, and neuroimaging features that may be indicative of surgical outcome.

Methods: We identified two cases with MOGHE out of 30 temporal lobe epilepsy (TLE) surgical patient cohort, whose pathological distribution spared the hippocampal structures.

A hemodynamic network involving the insula, the cingulate, and the basal forebrain correlates with EEG synchronization phases of sleep instability.

The cyclic alternating pattern (CAP) encompasses the pseudoperiodic appearance of synchronized brain waves and rhythms and is considered a regulator of the nonrapid eye movement (NREM) sleep vigilance level, reflecting sleep instability. To determine the brain regions responsible for this phenomenon, we scored and analyzed sleep functional magnetic resonance imaging data acquired with simultaneous electroencephalography (EEG-fMRI). Group analysis revealed a set of brain areas showing statistically significant blood oxygen-level dependent signal correlated positively with the synchronization phase of the CAP, most prominent being the insula, the middle cingulate gyrus, and the basal forebrain.

Histopathological Findings in Brain Tissue Obtained during Epilepsy Surgery.

Background: Detailed neuropathological information on the structural brain lesions underlying seizures is valuable for understanding drug-resistant focal epilepsy.

Methods: We report the diagnoses made on the basis of resected brain specimens from 9523 patients who underwent epilepsy surgery for drug-resistant seizures in 36 centers from 12 European countries over 25 years. Histopathological diagnoses were determined through examination of the specimens in local hospitals (41%) or at the German Neuropathology Reference Center for Epilepsy Surgery (59%).

Thin isotropic FLAIR MR images at 1.5T increase the yield of focal cortical dysplasia transmantle sign detection in frontal lobe epilepsy.

Objective: The transmantle sign is a distinctive imaging marker of focal cortical dysplasia (FCD) type II in frontal lobe epilepsy (FLE), which is revealed predominantly by fluid-attenuation inversion recovery (FLAIR) sequences. Although the transmantle sign detection yield is high by routine imaging protocols for epilepsy at 3T, most centers around the world have access to 1.5T MR technology and FLE patients often receive negative imaging reports.

Spike pattern recognition by supervised classification in low dimensional embedding space.

Epileptiform discharges in interictal electroencephalography (EEG) form the mainstay of epilepsy diagnosis and localization of seizure onset. Visual analysis is rater-dependent and time consuming, especially for long-term recordings, while computerized methods can provide efficiency in reviewing long EEG recordings. This paper presents a machine learning approach for automated detection of epileptiform discharges (spikes).

Surgical outcome in neocortical resections of type IIId focal cortical dysplasia with accompanying medial temporal pathology.

Focal cortical dysplasia (FCD) type IIId is a newly proposed type associated with early-life brain insults. Such patients are often considered unsuitable for resective epilepsy surgery, given the usually wide extent of the lesion and the poor correlation of MRI to the epileptogenic pathology. Two patients with intractable epilepsy, early-life ischemic/traumatic injury and MRI findings of extensive unilateral cystic-gliotic and ipsilateral medial temporal sclerotic-malformative lesions were subjected to presurgical evaluation revealing well-localized neocortical ictal onsets.

EEG-fMRI findings in late seizure recurrence following temporal lobectomy: A possible contribution of area tempestas.

Late seizure relapses following temporal lobectomy for drug-resistant temporal lobe epilepsy occur in 18-30% of operated-on cases, and recent evidence suggests that a significant proportion of them are due to maturation and activation of proepileptic tissue having defied initial resection and located at the vicinity of or at a short distance from its borders, usually over the posterior medial, basal temporal-occipital, and lateral temporal regions. Experimental studies in animals and functional imaging studies in humans suggest that the area tempestas, a particular region of the basal-frontal piriform cortex, is critical for kindling and initiation and propagation of seizure activity arising from different cortical foci, especially limbic ones. This case report of a patient with late seizure relapse, three years following an initially successful right temporal lobectomy for ipsilateral medial temporal sclerosis, is the first one in the literature to demonstrate interictal EEG-fMRI evidence of significant BOLD signal changes over the inferior, basal and lateral temporal and temporooccipital cortices posterior to the resection margin, plus a significant BOLD signal change over the ipsilateral basal frontal region, closely corresponding to the piriform cortex/area tempestas.

Extratemporal surface EEG features do not preclude successful surgical outcomes in drug-resistant epilepsy patients with unitemporal MRI lesions.

Of 47 patients with onset of intractable partial seizures and temporal lobe MRI lesions, subjected to presurgical evaluation and temporal lobe surgery, we identified eight (mean age: 24 years; range: 7-52 years) demonstrating surface interictal and/or ictal EEG features suggestive of an extratemporal localisation. All eight patients underwent surgery aiming to predominantly resect the lesion, without extending to the extratemporal region. The patients were prospectively followed (mean follow-up duration: 38 months; range: 12-66 months) and all achieved excellent postoperative seizure control.

Limited resection of focal cortical dysplasia and associated epileptogenic cortex may lead to positive surgical outcome.

A drug-resistant epilepsy patient with premotor type IIb focal cortical dysplasia is described with a positive postoperative outcome following partial resection of the lesion and epileptogenic zone. Presurgical fMRI of the sensorimotor areas showed haemodynamic responses over the posterior border of the lesion and ictal EEG-fMRI revealed activation of both the primary sensorimotor strip and premotor lesion area. Almost continuous 1-2 Hz interictal spiking was recorded during a chronic ECoG study over the primary sensorimotor cortex.

Epileptogenic networks in two patients with hypothalamic hamartoma.

Hypothalamic hamartomas (HH) are typically associated with gelastic seizures but also implicated in the genesis of other seizure types. In order to identify networks involved in seizure generation, we performed EEG-fMRI in two adult patients with HH, the first with predominantly gelastic seizures and the second with complex partial and no typical gelastic seizures. The ictal and interictal analysis of the patient with gelastic seizures revealed the involvement of the HH, the cingulate gyrus, the precuneus and the prefrontal cortex.

Hemispherotomy or lobectomy? The role of presurgical neuroimaging in a young case of a large porencephalic cyst with intractable epilepsy.

A young patient with a large left hemisphere porencephalic cyst underwent neuroimaging investigation (functional magnetic resonance imaging (fMRI), EEG-fMRI, DTI tractography) during presurgical evaluation for intractable epilepsy. The functional workup showed that (a) the healthy hemisphere had undertaken language processing, primary and secondary sensory functions of bilateral upper and lower extremities, and bilateral feet motion, and (b) the porencephalic hemisphere had retained contralateral arm and shoulder motion. EEG-fMRI localized the epileptogenic area occipitally.

An open-label, add-on study of pregabalin in patients with partial seizures: a multicenter trial in Greece.

Introduction: Pregabalin efficacy and safety as an adjunctive treatment for partial seizures was evaluated using an open-label, flexible-dose.

Study Design: In 98 adults with refractory partial epilepsy taking 1-3 anti-epileptic drugs with ≥2 seizures during an 8-week baseline period.

Methods: Pregabalin was increased to ≤600 mg/day during a 9-week dose optimization period with dosage maintained for 12 additional weeks.