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FMRI and epilepsy

Britta Wandschneider, Matthias J Koepp
Functional MRI studies have helped to elucidate underlying mechanisms in complex neurological and neuropsychiatric disorders. Disease processes often involve complex large-scale network interactions, extending beyond the presumed main disease focus. Given both the complexity of the clinical phenotype and the underlying dysfunctional brain circuits, so called pharmaco-fMRI (ph-MRI) studies probe pharmacological effects on functional neuro-anatomy, and can help to determine early treatment response, mechanisms of drug efficacy and side effects, and potentially advance CNS drug development...
2016: NeuroImage: Clinical
Samuel Lapalme-Remis, Gregory D Cascino
PURPOSE OF REVIEW: This article discusses structural and functional neuroimaging findings in patients with seizures and epilepsy. The indications for neuroimaging in these patients and the potential diagnostic utility of these studies are presented. RECENT FINDINGS: Patients presenting with new seizures typically require urgent imaging to rule out a critical underlying cause. MRI is the structural neuroimaging procedure of choice in individuals with epilepsy. Specific epilepsy protocols should be considered to increase the diagnostic yield of neuroimaging in patients with structural lesions associated with focal or generalized seizures...
October 2016: Continuum: Lifelong Learning in Neurology
Svyatoslav Vergun, Wolfgang Gaggl, Veena A Nair, Joshua I Suhonen, Rasmus M Birn, Azam S Ahmed, M Elizabeth Meyerand, James Reuss, Edgar A DeYoe, Vivek Prabhakaran
Functional magnetic resonance imaging studies have significantly expanded the field's understanding of functional brain activity of healthy and patient populations. Resting state (rs-) fMRI, which does not require subjects to perform a task, eliminating confounds of task difficulty, allows examination of neural activity and offers valuable functional mapping information. The purpose of this work was to develop an automatic resting state network (RSN) labeling method which offers value in clinical workflow during rs-fMRI mapping by organizing and quickly labeling spatial maps into functional networks...
2016: Frontiers in Neuroscience
Feng Liu, Yifeng Wang, Meiling Li, Wenqin Wang, Rong Li, Zhiqiang Zhang, Guangming Lu, Huafu Chen
Idiopathic generalized epilepsy (IGE) has been linked with disrupted intra-network connectivity of multiple resting-state networks (RSNs); however, whether impairment is present in inter-network interactions between RSNs, remains largely unclear. Here, 50 patients with IGE characterized by generalized tonic-clonic seizures (GTCS) and 50 demographically matched healthy controls underwent resting-state fMRI scans. A dynamic method was implemented to investigate functional network connectivity (FNC) in patients with IGE-GTCS...
October 11, 2016: Human Brain Mapping
Mani Saignavongs, Carolina Ciumas, Mathilde Petton, Romain Bouet, Sébastien Boulogne, Sylvain Rheims, David W Carmichael, Jean-Philippe Lachaux, Philippe Ryvlin
Recent studies have shown that it is feasible to record simultaneously intracerebral EEG (icEEG) and functional magnetic resonance imaging (fMRI) in patients with epilepsy. While it has mainly been used to explore the hemodynamic changes associated with epileptic spikes, this approach could also provide new insight into human cognition. However, the first step is to ensure that cognitive EEG components, that have lower amplitudes than epileptic spikes, can be appropriately detected under fMRI. We compared the high frequency activities (HFA, 50-150[Formula: see text]Hz) elicited by a reading task in icEEG-only and subsequent icEEG-fMRI in the same patients ([Formula: see text]), implanted with depth electrodes...
August 22, 2016: International Journal of Neural Systems
Marie St-Laurent, Morris Moscovitch, Mary Pat McAndrews
We assessed whether perceptual richness, a defining feature of episodic memory, depends on the engagement and integrity of the hippocampus during episodic memory retrieval. We tested participants' memory for complex laboratory events (LEs) that differed in perceptual content: short stories were either presented as perceptually rich film clips or as perceptually impoverished narratives. Participants underwent functional magnetic resonance imaging (fMRI) while retrieving these LEs (narratives and clips), as well as events from their personal life (autobiographical memories)...
August 27, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
Jianping Li, Xuemei Chen, Wei Ye, Wenyu Jiang, Huihua Liu, Jinou Zheng
OBJECTIVES: This study aimed to investigate alterations in the alertness-related network in patients with right temporal lobe epilepsy (rTLE) and explore the functional mechanisms of impaired alertness. METHODS: We recruited twenty patients with rTLE and eighteen matched healthy controls. All participants took a neuropsychological attention network test (ANT) and underwent resting-state functional magnetic resonance imaging (rs-fMRI) scanning. We extracted the alertness-related network using multiple independent component analysis (MICA)...
September 16, 2016: Epilepsy Research
Sarah A Vinette, Shahleen Premji, Craig A Beers, Ismael Gaxiola-Valdez, Daniel J Pittman, Edward G Slone, Bradley G Goodyear, Paolo Federico
The pre-ictal state is of interest for better understanding pathophysiological processes leading up to seizures and for identifying potential biomarkers for the prediction of these events. We present two cases of patients with focal epilepsy (occipital, insular) who had seizures during functional magnetic resonance imaging (fMRI) scans. Interictal (>30min pre-seizure) control data was available for one participant. The location and timing of pre-ictal blood oxygenation-level dependent (BOLD) signal alterations were examined along with changes in pre-ictal functional connectivity...
September 8, 2016: Epilepsy Research
Khalid Hamandi, Siân E Robson, Malek Zaben, Krish D Singh, William P Gray
No abstract text is available yet for this article.
October 2016: Seizure: the Journal of the British Epilepsy Association
Kees Hermans, Jan de Munck, Rudolf Verdaasdonk, Paul Boon, Gunther Krausz, Robert Prueckl, Pauly Ossenblok
OBJECTIVE: Subtle motion of an epileptic patient examined with co-registered EEG-fMRI may often lead to spurious fMRI activation patterns when true epileptic spikes are contaminated with motion artefacts. In recent years, methods relying on reference signals for correcting these subtle movements in the EEG have emerged. In this study the performance of two reference based devices are compared to the template-based method with regard to their ability to remove movement related artifacts in EEG measured during scanning...
August 25, 2016: IEEE Transactions on Bio-medical Engineering
Qirui Zhang, Fang Yang, Zheng Hu, Zhiqiang Zhang, Qiang Xu, Mantini Dante, Han Wu, Zhipeng Li, Qian Li, Kai Li, Guangming Lu
OBJECTIVES: Our aim was to investigate regional difference in brain activities in response to antiepileptic drug (AED) medications in benign epilepsy with central-temporal spikes (BECTS) using resting-state functional magnetic resonance imaging (fMRI). METHODS: Fifty-seven patients with BECTS underwent resting-state fMRI scans after receiving either valproic acid (VPA) (n = 15), levetiracetam (LEV) (n = 21), or no medication (n = 21). fMRI regional homogeneity (ReHo) parameter among the three groups of patients were compared and were correlated with total doses of AED in the two medicated groups...
August 23, 2016: European Radiology
Elhum A Shamshiri, Tim M Tierney, Maria Centeno, Kelly St Pier, Ronit M Pressler, David J Sharp, Suejen Perani, J Helen Cross, David W Carmichael
Patients with focal epilepsy have been shown to have reduced functional connectivity in intrinsic connectivity networks (ICNs), which has been related to neurocognitive development and outcome. However, the relationship between interictal epileptiform discharges (IEDs) and changes in ICNs remains unclear, with evidence both for and against their influence. EEG-fMRI data was obtained in 27 children with focal epilepsy (mixed localisation and aetiologies) and 17 controls. A natural stimulus task (cartoon blocks verses blocks where the subject was told "please wait") was used to enhance the connectivity within networks corresponding to ICNs while reducing potential confounds of vigilance and motion...
August 20, 2016: Human Brain Mapping
Rodolfo Abreu, Sandro Nunes, Alberto Leal, Patrícia Figueiredo
The study of spontaneous brain activity based on BOLD-fMRI may be seriously compromised by the presence of signal fluctuations of non-neuronal origin, most prominently due to cardiac and respiratory mechanisms. Methods used for modeling and correction of the so-called physiological noise usually rely on the concurrent measurement of cardiac and respiratory signals. In simultaneous EEG-fMRI recordings, which are primarily aimed at the study of spontaneous brain activity, the electrocardiogram (ECG) is typically measured as part of the EEG setup but respiratory data are not generally available...
August 12, 2016: NeuroImage
Evy Cleeren, Elsie Premereur, Cindy Casteels, Karolien Goffin, Peter Janssen, Wim Van Paesschen
Epileptic seizures are network-level phenomena. Hence, epilepsy may be regarded as a circuit-level disorder that cannot be understood outside this context. Better insight into the effective connectivity of the seizure onset zone and the manner in which seizure activity spreads could lead to specifically-tailored therapies for epilepsy. We applied the electrical amygdala kindling model in two rhesus monkeys until these animals displayed consistent stage IV seizures. At this stage, we investigated the effective connectivity of the amygdala by means of electrical microstimulation during fMRI (EM-fMRI)...
2016: NeuroImage: Clinical
Yongfu Hao, Hui Ming Khoo, Nicolas von Ellenrieder, Jean Gotman
PURPOSE: Recent studies have applied the new magnetic resonance encephalography (MREG) sequence to the study of interictal epileptic discharges (IEDs) in the electroencephalogram (EEG) of epileptic patients. However, there are no criteria to quantitatively evaluate different processing methods, to properly use the new sequence. METHODS: We evaluated different processing steps of this new sequence under the common generalized linear model (GLM) framework by assessing the reliability of results...
August 4, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Anna Lorenzen, Marko Wilke, Michael Alber, Monika Milian, Antje Bornemann, Ulrike Ernemann, Sabine Rona
We report on a girl with progressive left frontal tissue destruction starting at the age of almost 8 years. She manifested acutely with epileptic seizures accompanied by Broca aphasia as well as transient right hemiparesis. Due to refractory epilepsy developing over the next years, which originated from the left frontal lobe, the decision was made to proceed to epilepsy surgery. By then, her language functions had recovered despite progressive left frontal tissue-destruction, raising the possibility of a hemispheric shift of language...
October 2016: Neuropediatrics
Katharina Körbl, Julia Jacobs, Michael Herbst, Maxim Zaitsev, Andreas Schulze-Bonhage, Jürgen Hennig, Pierre LeVan
OBJECTIVES: Ballistocardiographic (BCG) artifacts resemble interictal epileptic discharges (IEDs) and can lead to incorrect IED identification in EEG-fMRI. This study investigates IEDs marked in EEGs corrected using information from a moiré phase tracking (MPT) marker. METHODS: EEG-fMRI from 18 patients was processed with conventional methods for BCG removal, while 9 patients used a MPT marker. IEDs were marked first without ECG information. In a second review, suspicious IEDs synchronous with the BCG were discarded...
August 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Ilana Klovatch-Podlipsky, Tomer Gazit, Firas Fahoum, Boris Tsirelson, Svetlana Kipervasser, Uri Kremer, Bruria Ben-Zeev, Hadassah Goldberg-Stern, Orna Eisenstein, Yuval Harpaz, Ory Levy, Adi Kirschner, Miriam Y Neufeld, Itzhak Fried, Talma Hendler, Mordekhay Medvedovsky
OBJECTIVE: Although simultaneous recording of EEG and MRI has gained increasing popularity in recent years, the extent of its clinical use remains limited by various technical challenges. Motion interference is one of the major challenges in EEG-fMRI. Here we present an approach which reduces its impact with the aid of an MR compatible dual-array EEG (daEEG) in which the EEG itself is used both as a brain signal recorder and a motion sensor. METHODS: We implemented two arrays of EEG electrodes organized into two sets of nearly orthogonally intersecting wire bundles...
July 8, 2016: NeuroImage
S Balter, G Lin, K M Leyden, B M Paul, C R McDonald
Advanced, noninvasive imaging has revolutionized our understanding of language networks in the brain and is reshaping our approach to the presurgical evaluation of patients with epilepsy. Functional magnetic resonance imaging (fMRI) has had the greatest impact, unveiling the complexity of language organization and reorganization in patients with epilepsy both pre- and postoperatively, while volumetric MRI and diffusion tensor imaging have led to a greater appreciation of structural and microstructural correlates of language dysfunction in different epilepsy syndromes...
July 5, 2016: Brain and Language
Anny Reyes, Thomas Thesen, Xiuyuan Wang, Daniel Hahn, Daeil Yoo, Ruben Kuzniecky, Orrin Devinsky, Karen Blackmon
OBJECTIVE: We assessed whether presurgical resting state functional magnetic resonance imaging (fMRI) provides information for distinguishing temporal lobe epilepsy (TLE) with mesial temporal sclerosis (TLE-MTS) from TLE without MTS (TLE-noMTS). METHODS: Thirty-four patients with TLE and 34 sex-/age-matched controls consented to a research imaging protocol. MTS status was confirmed by histologic evaluation of surgical tissue (TLE-MTS = 16; TLE-noMTS = 18). The fractional amplitude of low-frequency fluctuations (fALFFs) in the blood oxygen level-dependent (BOLD) resting-state fMRI signal, a marker of local metabolic demand at rest, was averaged at five regions of interest (ROIs; hippocampus, amygdala, frontal, occipital, and temporal lobe), along with corresponding volume and cortical thickness estimates...
September 2016: Epilepsia
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