Anatomical categorization of insulo-opercular focal cortical dysplasia and the spatial patterns of stereoelectroencephalography.

Objective: This study was undertaken to anatomically categorize insulo-opercular focal cortical dysplasia (FCD) lesions according to their location and extent, and to summarize corresponding stereoelectroencephalographic (SEEG) patterns to guide preoperative evaluation and surgical planning.

Methods: Patients who underwent epilepsy surgery for insulo-opercular FCD between 2015 and 2022 were enrolled. FCD lesions were categorized into insular, peri-insular, opercular, and complex types based on their location and extent, as ascertained from electroclinical and neuroimaging data.

Intracortical recordings reveal the neuronal selectivity for bodies and body parts in the human visual cortex.

Body perception plays a fundamental role in social cognition. Yet, the neural mechanisms underlying this process in humans remain elusive given the spatiotemporal constraints of functional imaging. Here, we present intracortical recordings of single- and multiunit spiking activity in two epilepsy surgery patients in or near the extrastriate body area, a critical region for body perception.

Thalamocortical Hodology to Personalize Electrical Stimulation for Focal Epilepsy.

Targeted electrical stimulation to specific thalamic regions offers a therapeutic approach for patients with refractory focal and generalized epilepsy who are not candidates for resective surgery. However, clinical outcome varies significantly, in particular for focal epilepsy, influenced by several factors, notably the precise anatomical and functional alignment between cortical regions generating epileptic discharges and the targeted thalamic stimulation sites. Here we hypothesized that targeting thalamic nuclei with precise anatomical and functional connections to epileptic cortical areas (an approach that we refer to as hodological matching) could enhance neuromodulatory effects on focal epileptic discharges.

Spatial and spectral changes in cortical surface potentials during pinching versusthumb and index finger flexion.

Electrocorticographic (ECoG) signals provide high-fidelity representations of sensorimotor cortex activation during contralateral hand movements. Understanding the relationship between independent and coordinated finger movements along with their corresponding ECoG signals is crucial for precise brain mapping and neural prosthetic development. We analyzed subdural ECoG signals from three adult epilepsy patients with subdural electrode arrays implanted for seizure foci identification.

Rasmussen Encephalitis: Clinical Features, Pathophysiology, and Management Strategies-A Comprehensive Literature Review.

Rasmussen encephalitis (RE) is a rare and progressive form of chronic encephalitis that typically affects one hemisphere of the brain and primarily occurs in pediatric individuals. The current study aims to narratively review the literature about RE, including historical information, pathophysiology, and management of this condition. RE often occurs in individuals with normal development, and it is estimated that only a few new cases are identified each year in epilepsy centers.

T2/FLAIR mismatch and diffusion restriction as novel pathophysiological markers in MRI evaluation of central tegmental tract hyperintensity in pediatric patients.

Introduction: Central tegmental tract hyperintensity (CTTH) on T2-weighted imaging is an uncommon neuroimaging finding in pediatric patients with unclear clinical significance. CTTH may represent either a physiological or pathological process. This study evaluates the relationship between CTTH and MRI sequences (FLAIR, DWI) to explore its diagnostic value.

Electroencephalography derived connectivity informing epilepsy surgical planning: Towards clinical applications and future perspectives.

Epilepsy is one of the most diffused neurological disorders, affecting 50 million people worldwide. Around 30% of patients have drug-resistant epilepsy (DRE), defined as failure of at least two tolerated antiseizure medications (ASMs) to achieve sustained seizure freedom. Brain surgery is an effective therapeutic approach in this group, hinging on the accurate localization of the epileptic focus.

Frontal Lobe Epilepsy: Bermuda's Triangle.

Despite great progress in imaging, genetics, surgery, and therapeutics, frontal lobe epilepsy (FLE) continues to be a challenge for neurologists and epileptologists. This manuscript summarizes the latest advancements in FLE discussed at the 2023 Epilepsy Specialist Symposium during the American Epilepsy Society Annual meeting. Correlation between stereoelectroencephalography and clinical symptoms has reinvigorated symptomatology literature in FLE, allowing for more precise aura anatomical localization.

Factors influencing the adequacy of determining hemispheric language lateralization in presurgical epilepsy patients using functional transcranial Doppler sonography (fTCD).

As the adequacy of determining hemispheric language lateralization (HLL) is of special importance for the planning of epilepsy surgery, this study aimed to identify predictive factors for receiving inconclusive HLL results using functional transcranial Doppler sonography (fTCD). Data from 495 epilepsy patients who received fTCD in a standardized fashion was analyzed retrospectively. HLL was left-sided in 324 patients (65.

Lateralization of memory function in temporal lobe epilepsy using scene memory fMRI.

Functional magnetic resonance imaging (fMRI) offers an alternative to the traditional Wada test for presurgical language and memory lateralization that carries almost no risk. However, fMRI lateralization of episodic memory remains challenging because the hippocampus, which is fundamental to episodic memory, is smaller, more prone to susceptibility artifact, and harder to functionally modulate than language regions. We previously showed that a complex scene memory task can lateralize memory function in the mesial temporal lobe.

Analysis of Clinical Utility of Functional MRI in Neurosurgical Decision-Making in Focal Epilepsy.

Background: Functional MRI (fMRI) has proven valuable in presurgical planning for people with brain tumors. However, it is underutilized for patients with epilepsy, likely due to less data on its added clinical value in this population. We reviewed clinical fMRI referrals at the QEII Health Sciences Center (Halifax, Nova Scotia) to determine the impact of fMRI on surgical planning for patients with epilepsy.

Awake surgery with mapping-based resection to treat focal epilepsy in eloquent brain areas.

Objectives: Resective surgery is a potential therapeutic option for select patients with intractable focal epilepsy. However, the presence of ictal onset zones within or surrounding highly functional brain areas presents a surgical challenge, leading to poor seizure and functional outcomes. This report describes our experiences with awake mapping-tailored resection of epileptogenic areas involving eloquent cortices and evaluates their feasibility, tolerance, limitations, and significance.

Simulated resections and responsive neurostimulator placement can optimize postoperative seizure outcomes when guided by fast ripple networks.

In medication-resistant epilepsy, the goal of epilepsy surgery is to make a patient seizure free with a resection/ablation that is as small as possible to minimize morbidity. The standard of care in planning the margins of epilepsy surgery involves electroclinical delineation of the seizure-onset zone and incorporation of neuroimaging findings from MRI, PET, single-photon emission CT and magnetoencephalography modalities. Resecting cortical tissue generating high-frequency oscillations has been investigated as a more efficacious alternative to targeting the seizure-onset zone.

Multimodal and quantitative analysis of the epileptogenic zone network in the pre-surgical evaluation of drug-resistant focal epilepsy.

Surgical resection for epilepsy often fails due to incomplete Epileptogenic Zone Network (EZN) localization from scalp electroencephalography (EEG), stereo-EEG (SEEG), and Magnetic Resonance Imaging (MRI). Subjective interpretation based on interictal, or ictal recordings limits conventional EZN localization. This study employs multimodal analysis using high-density-EEG (HDEEG), Magnetoencephalography (MEG), functional-MRI (fMRI), and SEEG to overcome these limitations in a patient with drug-resistant MRI-negative focal epilepsy.

[Possibilities of stimulating epileptic seizures using deep stereo-EEG electrodes in presurgical diagnosis in patients with drug-resistant epilepsy].

Electrical stimulation mapping using depth stereo-EEG electrodes is an important method in the structure of presurgical diagnostics in patients with drug-resistant forms of epilepsy. Electrical stimulation mapping was first used in the 1960s and has been actively developed since then, but despite such a long history, a unified protocol for the use of this technique has not been developed and different approaches to stimulation mapping are used in different countries. Based on publications on the topic in PubMed and other available resources, we tried to briefly outline the current opinion on the significance of this technique, paying special attention to the methodological approaches of different schools to stimulation parameters when mapping epileptogenic zones, highlighting in a separate section approaches to stimulation of functionally significant zones Finally, we summarize data on the effectiveness of this method in the presurgical diagnostics of epilepsy.

Brain PET Imaging in the Presurgical Evaluation of Drug-Resistant Focal Epilepsy.

Presurgical evaluation aims to localize the seizure onset zone (SOZ) for a tailored resection. Interictal [F]fluorodeoxyglucose PET is now an established test to lateralize and/or localize the SOZ, particularly if MR imaging is negative or if the noninvasive assessment shows discrepancies. PET can show hypometabolic areas associated with SOZ and the potential altered metabolic brain networks.

Enhancing non-invasive pre-surgical evaluation through functional connectivity and graph theory in drug-resistant focal epilepsy.

Background: Epilepsy, characterized as a network disorder, involves widely distributed areas following seizure propagation from a limited onset zone. Accurate delineation of the epileptogenic zone (EZ) is crucial for successful surgery in drug-resistant focal epilepsy. While visual analysis of scalp electroencephalogram (EEG) primarily elucidates seizure spreading patterns, we employed brain connectivity techniques and graph theory principles during the pre-ictal to ictal transition to define the epileptogenic network.

Pre- and post-therapy functional MRI connectivity in severe acute brain injury with suppression of consciousness: a comparative analysis to epilepsy features.

Severe acute brain injury (SABI) with suppressed consciousness is a major societal burden, with early prognosis being crucial for life-and-death treatment decisions. Resting-state functional MRI (rs-fMRI) is promising for prognosis and identifying epileptogenic activity in SABI. While established for SABI prognosis and seizure networks (SzNET) identification in epilepsy, the rs-fMRI use for SzNET detection in SABI is limited.