Clinical Neuroscience

[Plasticity of brain lateralization in epilepsy: fMRI studies]

KALMÁR Zsuzsanna1, WOERMANN Friedrich2, SCHWARCZ Attila3,4, JANSZKY József1,2,3

MARCH 25, 2009

Clinical Neuroscience - 2009;62(03-04)

[Aims - This review is a summary of four studies investigating the effect of epileptic disturbance and other functional factors on the brain lateralization. Methods - Patients were investigated by functional MRI by using visual, sensorimotor, memory, and speech paradigms. Results - 1. Malformations of cortical development localized within speech centers induce contralateral speech reorganization in only 50% of cases. 2. Epileptic disturbance can induce a reorganization in language lateralization independent of the effect of lesion. 3. Bilateral epileptic activity can prevent a reorganization of memory functions contralateral to the seizure onset region. 4. Injury of the right upper limb can induce a left-to-right shift of language lateralization. Conclusions - Our results may have implication during neurorehabilitation process and neurosurgical interventions. Participation of malformations of cortical development in cognitive functions should keep in mind during surgery. Reorganization of speech- and memory functions should also be considered during operations of central nervous system.]

AFFILIATIONS

  1. Pécsi Tudományegyetem, Neurológiai Klinika, Pécs
  2. Epilepsie-Zentrum, Bethel
  3. Pécsi Diagnosztikai Központ, Pécs
  4. Pécsi Tudományegyetem, Idegsebészeti Klinika, Pécs

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Clinical Neuroscience

[Diffusion weighted magnetic resonance imaging of metachromatic leukodystrophy - a case report]

PINTÉR Nándor, KOLLÁR Katalin, RUDAS Gábor, BARSI Péter

[We present the case of a 7 years old boy with the juvenile form of metachromatic leukodystrophy. Beside conventional sequences, a diffusion-weighted magnetic resonance study was performed. On T2-weighted images a diffuse hyperintensity of the cerebral white matter with a typical tigroid pattern was seen as a well-known characteristics of the disease. No difference was detectable on T2-weighted images between the different cerebral white matter regions. Diffusion study showed low apparent diffusion coefficient values in the temporal and orbitofrontal regions and normal values in other cerebral regions compared to the normal appearing cerebellar white matter, wich is partly consistent with the previously reported data. The results of early diffusion studies of the disease are not straightforward and the physical and biochemical backgrounds of the diffusion properties still remain unknown. The more data we collect, the closer we get to the understaning of the diffusion changes in metachromatic leukodystrophy.]

Clinical Neuroscience

[MR imaging of acute disseminated encephalomyelitis and multiple sclerosis in children. A review (in English language)]

PATAY Zoltán

[Inflammatory diseases of the central nervous system (CNS) are relatively rare in children, but their relevance to public health is considerable due to frequent and significant long term morbidity and even mortality. As in adults, acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS) and their variants are the most common entities in this group of pathologies in the pediatric patient population. Recent efforts have focused on establishing standardized diagnostic criteria schemes to facilitate the diagnosis and differential diagnosis of these diseases, however especially with multiple sclerosis those have not been fully validated yet for disease occurring in children. In recent decades the role of MRI has been constantly increasing in the diagnostic work-up of suspected inflammatory diseases of the CNS as well as in the follow-up of patients with confirmed disease. Currently, MRI is the first-line diagnostic imaging modality in ADEM and MS and is fully integrated in the most widely used diagnostic criteria schemes, but it has a key role in clinical therapeutic research trials as well. This paper provides an update on the current concepts and strategies of MRI in inflammatory diseases of the CNS, as well as a review of the imaging semiology of the various disease entities and variants with emphasis on clinical and imaging particularities relevant to the pediatric patient population.]

Clinical Neuroscience

[Application of diffusion weighted imaging in neuroradiology]

BARSI Péter

[Diffusion weighted magnetic resonance (MR) imaging is available on all modern MR scanners. It depicts the motion of water molecules in the brain tissue and intracranial foreign tissues and provides information on changes in the proportion of intra- and extracellular space and the characteristics of foreign intracranial tissues and fluids. It is of utmost importance eg. in the diagnostics and differential diagnostics of acute ischaemic brain lesions, the diagnostics of inflammatory brain processes and in the differential diagnostics of intracranial space-occupying lesions. The examination method of short scanning and post-processing time must be completed with the apparent diffusion coefficient (ADC) maps and it is indispensable in the everyday neuroradiological diagnostics. Diffusion tensor imaging and tractography are able to depict the white matter tracts. They require a longer scanning and post-processing time and have several technical problems yet to be solved, but they provide help in their current state e.g. in the surgical planning of intracranial space-occupying lesions.]

Clinical Neuroscience

[Noninvasive imaging in the diagnosis of cerebral sinus thrombosis]

[Cerebral venous thrombosis is a severe, but potentially reversible disease, when it is promptly recognised and treated. Due to its varied and many aetiological factors and clinical manifestations, non-invasive radiological imaging plays a key role in the diagnostic procedure. Unenhanced and contrast-enhanced computer tomography (CT) and magnetic resonance (MR) imaging, CT angiography (CTA), MR angiography - such as time-of-flight (TOF) and phase-contrast (PC) angiography - are appropriate techniques for detecting cerebral venous flow and brain parenchymal changes. To achive adequate diagnosis timely it is necessary to have a correct knowledge of the venographic techniques, the temporally altering appearance of the thrombus, and the differential diagnostic problems that may occur. In our article, we summarized these characteristics by recent international publications and our own clinical observations and propose recommendations regarding the examination protocol of the dural sinus thrombosis.]

Clinical Neuroscience

[Interhemispheric asymmetry of diffusion parameters in the human brain]

WALTER Norbert, HORVÁTH Ildikó, VANDULEK Csaba, BERÉNYI Ervin, BOGNER Péter, TÓTH Lilla

[Our aim was to study the hemispheric asymmetry of the human brain through the simultaneous measurements of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values within a homogeneous sample in regards to the gender, age and handedness. Method - Eleven young women were included in our diffusion study performed on a 1.5 T MR scanner. We calculated the ADC and FA values in nine-nine region of interest points of the brain. The diffusion values were measured symmetrically in the right and left hemisphere of the brain and were then statistically compared to detect interhemispheric asymmetry. Results - We did not find any significant differences between the data of the two hemispheres in regards to the ADC values. However, we detected a significant right sided asymmetry in case of the globus pallidus in FA values (p=0.04). Conclusion - Our results of our study of young women suggest that diffusion asymmetry does not appear in case of ADC values and only slightly (in one ROI in our study) in FA values.]

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Clinical Neuroscience

[Zonisamide: one of the first-line antiepileptic drugs in focal epilepsy ]

JANSZKY József, HORVÁTH Réka, KOMOLY Sámuel

[Chronic administration of antiepileptic drugs without history of unprovoked epileptic seizures are not recommended for epilepsy prophylaxis. Conversely, if the patient suffered the first unprovoked seizure, then the presence of epileptiform discharges on the EEG, focal neurological signs, and the presence of epileptogenic lesion on the MRI are risk factors for a second seizure (such as for the development of epilepsy). Without these risk factors, the chance of a second seizure is about 25-30%, while the presence of these risk factors (for example signs of previous stroke, neurotrauma, or encephalitis on the MRI) can predict >70% seizure recurrence. Thus the International League Against Epilepsy (ILAE) re-defined the term ’epilepsy’ which can be diagnosed even after the first seizure, if the risk of seizure recurrence is high. According to this definition, we can start antiepileptic drug therapy after a single unprovoked seizure. There are four antiepileptic drugs which has the highest evidence (level „A”) as first-line initial monotherapy for treating newly diagnosed epilepsy. These are: carbamazepine, phenytoin, levetiracetam, and zonisamide (ZNS). The present review focuses on the ZNS. Beacuse ZNS can be administrated once a day, it is an optimal drug for maintaining patient’s compliance and for those patients who have a high risk for developing a non-compliance (for example teenagers and young adults). Due to the low interaction potential, ZNS treatment is safe and effective in treating epilepsy of elderly people. ZNS is an ideal drug in epilepsy accompanied by obesity, because ZNS has a weight loss effect, especially in obese patients.]

Clinical Neuroscience

Effects of valproate, carbamazepine and levetiracetam on Tp-e interval, Tp-e/QT and Tp-e/QTc ratio

YASAR Altun, ERDOGAN Yasar

Aim - To evaluate P-wave dispersion before and after antiepileptic drug (AED) treatment as well as to investigate the risk of ventricular repolarization using the Tpeak-Tend (Tp-e) interval and Tp-e/QT ratio in patients with epileptic disorder. Methods - A total of 63 patients receiving AED therapy and 35 healthy adults were included. ECG recordings were obtained before and 3 months after anti-epileptic treatment among patients with epilepsy. For both groups, Tp-e and Tp-e/QT ratio were measured using a 12-lead ECG device. Results - Tp-e interval, Tpe/QT and Tp-e/QTc ratios were found to be higher in the patient group than in the control group (p<0.05, for all), while QTmax ratio was significantly lower in the patient group. After 3 months of AED therapy, significant increases in QT max, QTc max, QTcd, Tp-e, Tp-e/QT, and Tp-e/QTc were found among the patients (p<0.05). When the arrhythmic effects of the drugs before and after treatment were compared, especially in the valproic acid group, there were significant increases in Tp-e interval, Tp-e/QT and Tp-e/QTc values after three months of treatment (p<0.05). Carbamazepine and levetiracetam groups were not statistically significant in terms of pre- and post-treatment values. Conclusions - It was concluded that an arrhythmogenic environment may be associated with the disease, and patients who received AED monotherapy may need to be followed up more closely for arrhythmia.

Clinical Neuroscience

EEG-based connectivity in patients with partial seizures with and without generalization

DÖMÖTÖR Johanna, CLEMENS Béla, EMRI Miklós, PUSKÁS Szilvia, FEKETE István

Objective - to investigate the neurophysiological basis of secondary generalization of partial epileptic seizures. Patients and methods - inter-ictal, resting-state EEG functional connectivity (EEGfC) was evaluated and compared: patients with exclusively simple partial seizures (sp group) were compared to patients with simple partial and secondary generalized seizures (spsg group); patients with exclusively complex partial seizures (cp group) were compared to patients with cp and secondary generalized seizures (cpsg group); the collapsed sp+cp group (spcp) was compared to those who had exclusively secondary generalized seizures (sg group). EEGfC was computed from 21-channel waking EEG. 3 minutes of waking EEG background activity was analyzed by the LORETA Source Correlation (LSC) software. Current source density time series were computed for 23 pre-defined cortical regions (ROI) in each hemisphere, for the 1-25 Hz very narrow bands (1 Hz bandwidth). Thereafter Pearson correlation coefficients were calculated between all pairs of ROI time series in the same hemisphere. Z-scored correlation coefficients were compared at the group level (t-tests and correction for multiple comparisons by local false discovery rate, FDR). Results - Statistically significant (corrected p<0.05) EEGfC differences emerged at specific frequencies (spsg > sg; cpsg > cp), and at many frequencies (sg > spcp). The findings indicated increased coupling between motor cortices and several non-motor areas in patients with partial and sg seizures as compared to patients with partial seizures and no sg seizures. Further findings suggested increased coupling between medial parietal-occipital areas (structural core of the cortex) and lateral hemispheric areas. Conclusion - increased inter-ictal EEGfC is associated with habitual occurrence of secondary generalized seizures.

Clinical Neuroscience

Relationship between Status Epilepticus Severity Score and etiology in adult NCSE patients

GENC Fatma, ERDAL Abidin, AKCA Gizem, KARACAY Ertan, GÖKSU Özaydın Eylem, KUTLU Gülnihal, GÖMCELI Bicer Yasemin

Purpose - Nonconvulsive status epilepticus (NCSE) is a heterogeneous, severe neurological disorder of different etiologies. In this study, the outcomes of NCSE episodes was assessed in a large series of adult patients. Our objective was to evaluate relationship between Status Epilepticus Severity Score (STESS) and etiology and the role of etiological factors on predicting the outcomes. Method - In this retrospective study, the medical records of 95 patients over 18 years of age who were diagnosed with NCSE between June 2011 and December 2015 were reviewed. Their treatment and follow-up for NCSE was performed at the Epilepsy Unit in Department of Neurology, Antalya Research and Training Hospital. Etiological factors thought to be responsible for NCSE episodes as well as the prognostic data were retrieved. The etiological factors were classified into three groups as those with a known history of epilepsy (Group 1), primary neurological disorder (Group 2), or systemic/unknown etiology (Group 3). STESS was retrospectively applied to patients. Results - There were 95 participants, 59 of whom were female. Group 1, Group 2, and Group 3 consisted of 11 (7 female), 54 (33 female), and 30 (19 female) patients, respectively. Of the 18 total deaths, 12 occurred in Group 2, and 6 in Group 3. The negative predictive value for a STESS score of ≤ 2 was 93.88% (+LR 2.05 95% CI: 1.44-2.9 and -LR 0.3 95% CI 0.10-0.84 ) in the overall study group. While the corresponding values for Group 1 (patients with epilepsy), Group 2 (patients with primary neurological disorder), and group 3 (patients with systemic or unknown etiology) were 100%, 92.59% (+LR 2.06 95%CI: 1.32-3.21 and -LR 0.28 95% CI 0.08-1.02 ) 83.33% (+LR 1.14 95%CI: 0.59-2.9 and -LR 0.80 95% CI 0.23-2.73). Conclusions - This study included the one of the largest patients series ever reported in whom STESS, a clinical scoring system proposed for use in patients with status epilepticus, has been implemented. Although STESS appeared to be quite useful for predicting a favorable outcome in NCSE patients with epilepsy and primary neurological disorders, its predictive value in patients with systemic or unknown etiology was lower. Further prospective studies including larger NCSE samples are warranted.

Clinical Neuroscience

[Decisional collisions between evidence and experience based medicine in care of people with epilepsy]

RAJNA Péter

[Background – Based on the literature and his long-term clinical practice the author stresses the main collisions of evidence and experience based medicine in the care of people with epilepsy. Purpose – To see, what are the professional decisions of high responsibility in the epilepsy-care, in whose the relevant clinical research is still lacking or does not give a satisfactory basis. Methods – Following the structure of the Hungarian Guideline the author points the critical situations and decisions. He explains also the causes of the dilemmas: the lack or uncertainty of evidences or the difficulty of scientific investigation of the situation. Results – There are some priorities of experience based medicine in the following areas: definition of epilepsy, classification of seizures, etiology – including genetic background –, role of precipitating and provoking factors. These are able to influence the complex diagnosis. In the pharmacotherapy the choice of the first drug and the optimal algorithm as well as the tasks during the care are also depends on personal experiences sometimes contradictory to the official recommendations. Same can occur in the choice of the non-pharmacological treatments and rehabilitation. Discussion and conclusion – Personal professional experiences (and interests of patients) must be obligatory accessories of evidence based attitude, but for achieving the optimal results, in some situations they replace the official recommendations. Therefore it is very important that the problematic patients do meet experts having necessary experiences and also professional responsibility to help in these decisions. ]