Clinical Neuroscience

[THE PERISYLVIAN EPILEPTIC NETWORK A unifying concept]

HALÁSZ Péter, KELEMEN Anna, CLEMENS Béla, SARACZ Judit, ROSDY Beáta, RÁSONYI György, SZŰCS Anna

JANUARY 20, 2005

Clinical Neuroscience - 2005;58(01-02)

[In this work the authors provide evidences for a unifying concept of the syndromes of benign focal childhood epilepsies, Landau-Kleffner syndrome, and electrical status epilepticus in sleep treating them as a spectrum of disorders with a common transient, age dependent, non lesional, genetically based epileptogenic abnormality, the nature of which is still not known. The electro-clinical features of these syndromes are congruent with the different degree involvement of the perisylvian cognitive network and with the involvement of the thalamo-cortical associative system of variable degree. These epilepsies are characterized by the abundance of regional epileptiform discharges in sharp contrast with the rare and in several cases lacking seizures. The nature and severity of interictal cognitive symptoms are closely related to localization within the network and amount of epileptic interictal discharges. Spike-wave discharges are attributed to an alternation of overexcitation (spikes) and overinhibition (waves). The recurrent overinhibition represented by the wave of the discharges may interfere with the continuous depolarization of the cells of a large population of neurons, which is a requirement of the overt seizures. The overinhibition also interfere with cognitive processes which are correlated with the continuous presence of the fast (gamma) activity, binding the required cortical areas. Hence the recurrent inhibition works against the existence of the binding fast frequency activity. This is the assumed reason for the co-existence of the relative lack of overt seizures and in the same time for the frequently observed epileptogenic cognitive deficit symptoms ("cognitive epilepsies"). The time course of these syndromes overlaps with important developmental milestones. The frequent epileptic discharges alters the evolution of the perisylvian network developing late after early childhood and is very vulnerable for any interference in this imprinting time for speech and other cognitive functions. This spectrum of disorders represents a type of age linked, mild to severe ‘epileptic encephalopathy’ limited to the perisylvian network, where the cognitive impairment is underlied by epileptic discharges interfering with cognitive development.]

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[There is an increasing number of peripheral nerve disorders with inflammatory and immune mechanisms involved. The precise diagnosis is of utmost importance, since these patients can be successfully treated. Unfortunately, there is no specific marker for any disease of this group. The diagnosis therefore relies on the appropriate consideration of the clinical, neurophysiological and laboratory data, which requires in-depth knowledge of these diseases. In this paper we review the diagnostic criteria and treatment strategies for the major types of chronic inflammatory polyneuropathies.]

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[EXPERIMENTAL DEMYELINATION CAUSED BY PRIMARY OLIGODENDROCYTE DYSTROPHY Regional distribution of the lesions in the nervous system of mice brain]

KOMOLY Sámuel

[Background and purpose - Heterogeneity of multiple sclerosis lesions has been recently indicated: In addition to T-cell-mediated or T-cell plus antibody-mediated autoimmune mechanisms (patterns I-II) two other patterns (III-IV) were described. Patterns III-IV are characterized by primary oligodendrocyte dystrophy, reminiscent of virus- or toxin-induced demyelination rather than autoimmunity. It was described more than 30 years ago that dietary application of a copper-chelating agent called cuprizone results in primary oligodendrocyte degeneration which is followed by demyelination. The aim of the present study was to examine the regional distribution of cuprizone induced oligodendrocyte dystrophy and demyelination in the nervous system of mice. Material a methods - Demyelination was induced in male weanling Swis-Webster mice by feeding them on a diet containing 0.6% (W/W) cuprizone bis(cyclohexanone)-oxalyldihydrazone (G. F. Smith Chemical, Columbus OH) for 8 weeks. Animals were sacrificed after 3, 7, 14, 27, 35, 56 days of cuprizone administration. Samples were taken from corpus callosum, anterior commissure, optic nerve, cervical spinal cord and sciatic nerve. Samples were examined by immunohistochemistry, in situ hybridization for myelin proteins and myelin protein mRNA-s, respectively. Conventional neuropathological stainings and electron microscopy was also performed. Results - Oligodendrocyte degeneration and demyelination followed a particular standard pattern in the central nervous system. Profound myelin loss developed in the superior cerebellar peduncle, anterior comissure and corpus callosum, whereas the optic nerves, velum medullare anterior and spinal cord showed little or no demyelination. Sciatic nerves were unaffected. No infiltration by lymphocytes or blood-brain barrier damage was observed during cuprizone treatment. Conclusion - Cuprizone induced oligodendrocyte damage and demyelination follows a particular standard pattern in the central nervous system of mice. Cuprizone induced demyelination might be considered as a model for human demyelinating disorders with primary oligodendrocyte dystrophy and apoptosis.]

Clinical Neuroscience

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[Limb gird muscular dystrophies (LGMD2) are a clinically and genetically heterogeneous group of hereditary diseases with autosomal recessive trait, characterized by progressive atrophy and weakness predominantly in the proximal limb muscles. The authors present clinical, histological, immunohistochemical and immunoblot results of two sisters suffering from so far unclassified autosomal recessive limb girdle muscular dystrophy. Haplotype analysis for genes possibly involved in autosomal recessive limb girdle muscular dystrophies was performed in the genetically informative family. All of the results pointed to a molecular genetic defect of the calpain-3 (CAPN3) gene. Direct sequencing of the CAPN3 gene revealed compound hetereozygous state for two mutations previously described in association with limb girdle muscular dystrophy, proving pathogenity. The authors would like to emphasize the importance of the above described combined strategy in diagnosing limb girdle muscular dystrophies.]

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Simultaneous subdural, subarachnoideal and intracerebral haemorrhage after rupture of a peripheral middle cerebral artery aneurysm

BÉRES-MOLNÁR Anna Katalin, FOLYOVICH András, SZLOBODA Péter, SZENDREY-KISS Zsolt, BERECZKI Dániel, BAKOS Mária, VÁRALLYAY György, SZABÓ Huba, NYÁRI István

The cause of intracerebral, subarachnoid and subdural haemorrhage is different, and the simultaneous appearance in the same case is extremely rare. We describe the case of a patient with a ruptured aneurysm on the distal segment of the middle cerebral artery, with a concomitant subdural and intracerebral haemorrhage, and a subsequent secondary brainstem (Duret) haemorrhage. The 59-year-old woman had hypertension and diabetes in her medical history. She experienced anomic aphasia and left-sided headache starting one day before admission. She had no trauma. A few minutes after admission she suddenly became comatose, her breathing became superficial. Non-contrast CT revealed left sided fronto-parietal subdural and subarachnoid and intracerebral haemorrhage, and bleeding was also observed in the right pontine region. The patient had leucocytosis and hyperglycemia but normal hemostasis. After the subdural haemorrhage had been evacuated, the patient was transferred to intensive care unit. Sepsis developed. Echocardiography did not detect endocarditis. Neurological status, vigilance gradually improved. The rehabilitation process was interrupted by epileptic status. Control CT and CT angiography proved an aneurysm in the peripheral part of the left middle cerebral artery, which was later clipped. Histolo­gical examination excluded mycotic etiology of the aneu­rysm and “normal aneurysm wall” was described. The brain stem haemorrhage – Duret bleeding – was presumably caused by a sudden increase in intracranial pressure due to the supratentorial space occupying process and consequential trans-tentorial herniation. This case is a rarity, as the patient not only survived, but lives an active life with some residual symptoms.

Clinical Neuroscience

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

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[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

Valproic acid associated pleuropericardial effusion: case report

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Clinical Neuroscience

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Clinical Neuroscience

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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.