Publications by authors named "Marcel Heers"

Focal cortical dysplasias (FCDs) are local malformations of the human neocortex and a leading cause of intractable epilepsy. FCDs are classified into different subtypes including FCD IIa and IIb, characterized by a blurred gray-white matter boundary or a transmantle sign indicating abnormal white matter myelination. Recently, we have shown that myelination is also compromised in the gray matter of FCD IIa of the temporal lobe.

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Article Synopsis
  • A 48-year-old patient had sudden memory loss (amnesia) 10 weeks after brain surgery for epilepsy.
  • Doctors thought it might be related to the epilepsy, but tests showed no signs of seizures during the memory loss episode.
  • This situation shows why it's important for doctors to recognize different types of memory problems after epilepsy surgery so patients don't get treated unnecessarily.
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Article Synopsis
  • The study investigated the effectiveness of semiautomated electric source imaging (ESI) using long-term video-electroencephalographic (EEG) monitoring to assess the epileptic potential of temporopolar encephaloceles (TEs) in patients with temporal lobe epilepsy.
  • Researchers analyzed data from 32 patients, validating findings with invasive stereo-EEG and postsurgical outcomes, using IEDs to create an ESI mapping for each patient.
  • Results showed a 62.5% concordance of ESI with TEs and indicated that ESI could predict a seizure-free outcome post-surgery, with stronger signals recorded from sphenoidal electrodes.
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Purpose: To evaluate the diagnostic accuracy of epilepsy-dedicated 3 Tesla MRI including post-processing by correlating MRI, histopathology, and postsurgical seizure outcomes.

Methods: 3 Tesla-MRI including a magnetization-prepared two rapid acquisition gradient echo (MP2RAGE) sequence for post-processing using the morphometric analysis program MAP was acquired in 116 consecutive patients with drug-resistant focal epilepsy undergoing resection surgery. The MRI, histopathology reports and postsurgical seizure outcomes were recorded from the patient's charts.

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Purpose: Cenobamate (CNB) is a new antiseizure medication (ASM) for the treatment of focal epilepsy in adults. While efficacy of CNB was confirmed in controlled clinical trials, its effects on cognition are unclear. Cognitive adverse effects of ASM affect quality of life and retention rate.

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Background: Eye-movement patterns during facial emotion recognition are under-researched in patients with focal epilepsy (PWFE). Previous studies including other neurological patients indicate that bilateral mesiotemporal damage could be associated with impaired emotion recognition and abnormal eye-movement patterns.

Aims: The current study addresses the question whether PWFE, in whom fronto-(mesio-)temporal networks are often disturbed, also show abnormal eye-movement patterns during facial emotion recognition.

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Objective: To determine the diagnostic yield of in-hospital video-electroencephalography (EEG) monitoring to document seizures in patients with epilepsy.

Methods: Retrospective analysis of electronic seizure documentation at the University Hospital Freiburg (UKF) and at King's College London (KCL). Statistical assessment of the role of the duration of monitoring, and subanalyses on presurgical patient groups and patients undergoing reduction of antiseizure medication.

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Objectives: High counts of averaged interictal epileptiform discharges (IEDs) are key components of accurate interictal electric source imaging (ESI) in patients with focal epilepsy. Automated detections may be time-efficient, but they need to identify the correct IED types. Thus we compared semiautomated and automated detection of IED types in long-term video-EEG (electroencephalography) monitoring (LTM) using an extended scalp EEG array and short-term high-density EEG (hdEEG) with visual detection of IED types and the seizure-onset zone (SOZ).

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Objective: The detection of focal cortical dysplasia (FCD) in magnetic resonance imaging is challenging. Voxel-based morphometric analysis and automated FCD detection using an artificial neural network (ANN) integrated into the Morphometric Analysis Program (MAP18) have been shown to facilitate FCD detection. This study aimed to evaluate whether the detection of FCD can be further improved by feeding this approach with magnetization prepared two rapid acquisition gradient echoes (MP2RAGE) instead of magnetization-prepared rapid acquisition gradient echo (MPRAGE) datasets.

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Purpose: To evaluate a MRI postprocessing tool for the enhanced and rapid detection of focal cortical dysplasia (FCD).

Methods: MP2RAGE sequences of 40 consecutive, so far MRI-negative patients and of 32 healthy controls were morphometrically analyzed to highlight typical FCD features. The resulting morphometric maps served as input for an artificial neural network generating a FCD probability map.

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The use of cannabidiol (CBD) for treatment of pharmacoresistant epilepsies is increasing. CBD is metabolized via UDP-glucuronosyltransferase (UGT) and cytochrome 450 (CYP) enzymes, but information on interactions with common anticonvulsive drugs is incomplete. We report a case series of five patients receiving adjunctive treatment with CBD who showed increases in brivaracetam (BRV) levels by 95% to 280%.

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The foremost aim of presurgical epilepsy evaluation is the delineation of the seizure onset zone (SOZ). There is increasing evidence that fast epileptic activity (FEA, 14-250 Hz) occurring interictally, i.e.

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Objective: Technology for localizing epileptogenic brain regions plays a central role in surgical planning. Recent improvements in acquisition and electrode technology have revealed that high-frequency oscillations (HFOs) within the 80-500 Hz frequency range provide the neurophysiologist with new information about the extent of the epileptogenic tissue in addition to ictal and interictal lower frequency events. Nevertheless, two decades after their discovery there remain questions about HFOs as biomarkers of epileptogenic brain and there use in clinical practice.

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The purpose of this study is to develop and quantitatively assess whether fusion of EEG and MEG (MEEG) data within the maximum entropy on the mean (MEM) framework increases the spatial accuracy of source localization, by yielding better recovery of the spatial extent and propagation pathway of the underlying generators of inter-ictal epileptic discharges (IEDs). The key element in this study is the integration of the complementary information from EEG and MEG data within the MEM framework. MEEG was compared with EEG and MEG when localizing single transient IEDs.

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We investigated two important means for improving source reconstruction in presurgical epilepsy diagnosis. The first investigation is about the optimal choice of the number of epileptic spikes in averaging to (1) sufficiently reduce the noise bias for an accurate determination of the center of gravity of the epileptic activity and (2) still get an estimation of the extent of the irritative zone. The second study focuses on the differences in single modality EEG (80-electrodes) or MEG (275-gradiometers) and especially on the benefits of combined EEG/MEG (EMEG) source analysis.

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Distributed inverse solutions aim to realistically reconstruct the origin of interictal epileptic discharges (IEDs) from noninvasively recorded electroencephalography (EEG) and magnetoencephalography (MEG) signals. Our aim was to compare the performance of different distributed inverse solutions in localizing IEDs: coherent maximum entropy on the mean (cMEM), hierarchical Bayesian implementations of independent identically distributed sources (IID, minimum norm prior) and spatially coherent sources (COH, spatial smoothness prior). Source maxima (i.

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Introduction: Spike-based magnetoencephalography (MEG) source localization is an established method in the presurgical evaluation of epilepsy patients. Focal cortical dysplasias (FCDs) are associated with focal epileptic discharges of variable morphologies in the beta frequency band in addition to single epileptic spikes. Therefore, we investigated the potential diagnostic value of MEG-based localization of spike-independent beta band (12-30Hz) activity generated by epileptogenic lesions.

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To increase the reliability for the non-invasive determination of the irritative zone in presurgical epilepsy diagnosis, we introduce here a new experimental and methodological source analysis pipeline that combines the complementary information in EEG and MEG, and apply it to data from a patient, suffering from refractory focal epilepsy. Skull conductivity parameters in a six compartment finite element head model with brain anisotropy, constructed from individual MRI data, are estimated in a calibration procedure using somatosensory evoked potential (SEP) and field (SEF) data. These data are measured in a single run before acquisition of further runs of spontaneous epileptic activity.

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Introduction: Blood oxygenation level-dependent (BOLD) signal changes at the time of interictal epileptic discharges (IEDs) identify their associated vascular/hemodynamic responses. BOLD activations and deactivations can be found within the epileptogenic zone but also at a distance. Source imaging identifies electric (ESI) and magnetic (MSI) sources of IEDs, with the advantage of a higher temporal resolution.

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To elucidate, in a pilot-study, whether noninvasive transcutaneous vagus nerve stimulation (t-VNS) is a safe and tolerable alternative treatment option in pharmacoresistant epilepsy. t-VNS was applied to 10 patients with pharmacoresistant epilepsies. Stimulation via the auricular branch of the vagus nerve of the left tragus was delivered three times per day for 9 months.

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Introduction: Presurgical work-ups of patients with pharmacoresistant epileptic seizures can require multiple diagnostic methods if magnetic resonance imaging (MRI) combined with video-EEG monitoring fails to show an epileptogenic lesion. Yet, the added value of available methods is not clear. In particular, only a minority of epilepsy centres apply magnetoencephalography (MEG).

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Objective: Unilateral monofocal temporal magnetoencephalography (MEG) findings might determine epileptogenicity of a lesion in symptomatic epilepsy during presurgical evaluation. To evaluate the additive effect of video-electroencephalography (vEEG), monofocal temporal lobe MEG findings were compared to electrophysiological findings from vEEGs of patients with lesional epilepsy.

Methods: In 28 patients with drug-resistant lesional temporal lobe epilepsy (TLE), epileptogenicity of the lesion was determined by monofocal temporal MEG localisations.

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Objective: Magnetoencephalography (MEG) is used for focus localization in presurgical evaluation of patients with focal epilepsies. In this proof-of-concept study, general anesthesia with etomidate was used to improve effectiveness of MEG-recordings.

Methods: MEG-recordings of six patients with focal epilepsy were performed before and after application of etomidate.

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