Publications by authors named "D van der Velden"
Objective: To determine the effect of inverse methods and timepoints of interictal epileptic discharges (IEDs) used for high-density electric source imaging (hd-ESI) in pharmacoresistant focal epilepsies.
Methods: We retrospectively evaluated the hd-ESI and [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) of 21 operated patients with pharmacoresistant focal epilepsy (Engel I). Volumetric hd-ESI was performed with three different inverse methods such as the inverse solution linearly constrained minimum variance (LCMV, a beamformer method), standardized low resolution electromagnetic tomography (sLORETA) and weighted minimum-norm estimation (wMNE) and at different IED phases.
Article Synopsis
- Genetic generalized epilepsy (GGE) is a brain disorder characterized by widespread connectivity issues, which can be studied using simultaneous EEG and fMRI, but there are challenges due to MRI-related artifacts affecting the EEG data.
- This study explored the effects of these artifacts on group comparisons of EEG power and functional connectivity between GGE patients and healthy controls, finding that while some power differences were reduced in significance, measures of functional connectivity (ImCoh) remained consistent across conditions.
- Notably, increased functional connectivity was observed in GGE patients, particularly from the thalamus to the precuneus cortex, suggesting that using ImCoh for EEG analysis within the MRI is valid and that group differences can be effectively maintained despite the measurement conditions
Image templates are a common tool for neuroscience research. Often, they are used for spatial normalization of magnetic resonance imaging (MRI) data, which is a necessary procedure for analyzing brain morphology and function via voxel-based analysis. This allows the researcher to reduce individual shape differences across images and make inferences across multiple subjects.
View Article and Find Full Text PDFObjective: 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.
View Article and Find Full Text PDFThe Angstrom-scale space between graphene and its substrate provides an attractive playground for scientific exploration and can lead to breakthrough applications. Here, we report the energetics and kinetics of hydrogen electrosorption on a graphene-covered Pt(111) electrode using electrochemical experiments, in situ spectroscopy, and density functional theory calculations. The graphene overlayer influences the hydrogen adsorption on Pt(111) by shielding the ions from the interface and weakening the Pt-H bond energy.
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