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Debrecen, Hungary

Clemens B.,Kenezy Hospital LTD | Puskas S.,Debrecen University | Besenyei M.,Debrecen University | Spisak T.,Debrecen University | And 2 more authors.
Epilepsy Research | Year: 2013

Purpose: The neuronal mechanisms of remission of epilepsy are not known. Based on the principles of the "network theory of epilepsy" we postulated the existence of abnormal cortico-cortical interactions at the onset of epilepsy (Hypothesis-1), and postulated that remission is associated with the decrease or disappearance of the abnormal quantitative EEG findings (Hypothesis-2). Methods: Four children with benign epilepsy with rolandic sharp waves (BERS) were investigated. 21-channel EEG was recorded at the onset of the disease (Setting No. 1) and in remission (Setting No. 2). Local EEG synchronization was estimated by LORETA (low resolution electromagnetic tomography). Remote EEG synchronization (intra-hemispheric, cortico-cortical EEG functional connectivity, EEGfC) was computed by the LSC (LORETA Source Correlation) method, among 23 regions of interest (ROI) in both hemispheres. Both local and remote EEG synchronization were evaluated in very narrow frequency bands of 1. Hz bandwidth (VNB), from 1 to 25. Hz. Results: Individual results were presented. Abnormal but topographically very dissimilar LORETA and LSC findings were found at the onset of the disease. The disappearance of the initial abnormalities was found in Setting No. 2. An unforeseen finding was the presence of abnormal EEGfC results in Setting No. 2. Discussion: The authors confirmed both hypotheses. The dissimilarity of the initial abnormalities is in accord with the network concept of epilepsy and the etiology of BERS. The disappearance of the initial abnormalities reflects "normalization" of network dynamics while the emergence of new EEGfC abnormalities is interpreted as "compensation". Conclusion: EEG-based local and remote connectivity (EEGfC) are appropriate tools to describe network dynamics in the active state of BERS and in remission. © 2013 Elsevier B.V. Source


Clemens B.,Kenezy Hospital LTD | Puskas S.,Debrecen University | Besenyei M.,Debrecen University | Spisak T.,Debrecen University | And 5 more authors.
Epilepsy Research | Year: 2013

Introduction: The neuronal mechanisms of enduring seizure propensity and seizure precipitation in juvenile myoclonic epilepsy (JME) are not known. We investigated these issues, within the framework of the "network concept" of epilepsy. Methods: Design1: 19, unmedicated JME patients were compared with nineteen, age-, and sex-matched normal control persons (NC). A total of 120. s, artifact-free, paroxysm-free, eyes-closed, resting state EEG background activity was analyzed for each person. Design2: interictal and immediate preictal periods of the JME patients were compared in order to explore interictal-preictal network differences. For both comparison designs, statistically significant differences of EEG functional connectivity (EEGfC), nodal and global graph parameters were evaluated. Main results: Design1: maximum abnormalities were: increased delta, theta, alpha1 EEGfC and decreased alpha2 and beta EEGfC in the JME group as compared to the NC group, mainly among cortical areas that are involved in sensory-motor integration. Nodal degree and efficiency of three, medial, basal frontal nodes were greater in JME than in NC, in the alpha1 band. Design2: preictal delta EEGfC showed further increase in the above-mentioned areas, as compared to the interictal state. Discussion: Increased EEGfC indicates a hypercoupled state among the specified cortical areas. This interictal abnormality further increases in the preictal state. Nodal graph statistics indicates abnormal neuronal dynamics in the cortical area that is the ictal onset zone in JME. Significance: Interictal and preictal neuronal dysfunction has been described in terms of network dynamics and topography in JME patients. Forthcoming investigations of seizure precipitation and therapeutic drug effects are encouraged on this basis. © 2013 Elsevier B.V. Source


Cserni G.,Bacs Kiskun County Teaching Hospital | Francz M.,Josa Andras Teaching Hospital | Kalman E.,University of Pecs | Kelemen G.,University of Szeged | And 7 more authors.
Pathology and Oncology Research | Year: 2011

Estrogen receptor (ER) testing has become an important part of breast cancer reporting as the ER status is a predictor of hormonal treatment efficacy. Progesteron receptors (PR) are often tested in parallel, and the best response to hormonal manipulations can be expected in tumors positive for both receptors. The existence of breast cancers with an ER negative and PR positive phenotype is controversial. A series of cases with this phenotype were reevaluated to clarify the existence and the frequency of this entity. A total of 205/6587 (3.1%; range of the rate per department: 0.3-7.1%.) cases reported to have the ER-negative and PR-positive status by immunohistochemistry were collected from 9 Hungarian departments. After careful reevaluation of the tumor slides and control tissues with a 1% cut-off for positivity and restaining of the questionable cases, all but 1 of the reevaluable 182 cases changed their original phenotype. Most cases converted to dual positives (n = 124) or dual negatives (n = 31) or unassessable / questionable. ER-negative and PR-positive breast cancers are very rare if existing. Such a phenotype should prompt reassessment. © 2011 Arányi Lajos Foundation. Source


Clemens B.,Kenezy Hospital LTD | Bessenyei M.,Kenezy Hospital LTD | Fekete I.,Debrecen University | Puskas S.,Debrecen University | And 3 more authors.
Clinical Neurophysiology | Year: 2010

Objective: To investigate and localize the sources of spontaneous, scalp-recorded theta activity in patients with partial epilepsy (PE). Methods: Nine patients with beginning, untreated PE (Group 1), 31 patients with already treated PE (Group 2), and 14 healthy persons were investigated by means of spectral analysis and LORETA, low resolution electromagnetic tomography (1 Hz very narrow band analysis, age-adjusted, Z-scored values). The frequency of main interest was 4-8 Hz. Results: Group analysis: Group 1 displayed bilateral theta maxima in the temporal theta area (TTA), parietal theta area (PTA), and frontal theta area (FTA). In Group 2, theta activity increased all over the scalp as compared to the normative mean (Z = 0) and also to Group 1. Maximum activity was found in the TTA, PTA, and FTA. However, in the PTA and FTA the centers of the abnormality shifted towards the medial cortex. Individual analysis: all the patients showed preferential activation (maximum Z-values) within one of the three theta areas. Conclusions: EEG activity in the theta band is increased in anatomically meaningful patterns in PE patients, which differs from the anatomical distribution of theta in healthy persons. Significance: The findings contribute to our understanding of the sources of theta rhythms and the pathophysiology of PE. © 2010 International Federation of Clinical Neurophysiology. Source


Puskas S.,Debrecen University | Bessenyei M.,Kenezy Hospital LTD | Fekete I.,Debrecen University | Hollody K.,University of Pecs | Clemens B.,Kenezy Hospital LTD
Epilepsy Research | Year: 2010

Objective: Epileptic predisposition means genetically determined, increased seizure susceptibility. Neurophysiological evaluation of this condition is still lacking. In order to investigate " pure epileptic predisposition" (without epilepsy) in this pilot study the authors prospectively recruited ten persons who displayed generalized tonic-clonic seizures precipitated by 24 or more hours of sleep deprivation but were healthy in any other respects. Methods: 21-channel EEGs were recorded in the morning, in the waking state, after a night of sufficient sleep in the interictal period. For each person, a total of 120. s artifact-free EEG was processed to low resolution electromagnetic tomography (LORETA) analysis. LORETA activity (Ampers/meters squared) was computed for 2394 voxels, 19 active electrodes and 1. Hz very narrow bands from 1 to 25. Hz. The data were compressed into four frequency bands (δ: 0.5-4.0. Hz, θ: 4.5-8.0. Hz, α: 8.5-12.0. Hz, β: 12.5-25.0. Hz) and projected onto the MRI figures of a digitized standard brain atlas. The band-related LORETA results were compared to those of ten, age- and sex-matched healthy persons using independent t-tests. p<0.01 differences were accepted as statistically significant. Results: Statistically significant decrease of α activity was found in widespread, medial and lateral parts of the cortex above the level of the basal ganglia. Maximum α decrease and statistically significant β decrease were found in the left precuneus. Statistically not significant differences were δ increase in the medial-basal frontal area and θ increase in the same area and in the basal temporal area. Discussion: The significance of α decrease in the patient group remains enigmatic β decrease presumably reflects non-specific dysfunction of the cortex. Prefrontal δ and θ increase might have biological meaning despite the lack of statistical significance: these findings are topographically similar to those reported in idiopathic generalized epilepsy in previous investigations. Significance: Quantitative EEG characteristics of the genetically determined epilepsy predisposition were given in terms of frequency bands and anatomical distribution. © 2010 Elsevier B.V. Source

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