Clinical Neuroscience

[The concept of epileptic networks. Part 1.]

HALÁSZ Péter

SEPTEMBER 30, 2010

Clinical Neuroscience - 2010;63(09-10)

[In this paper we investigate evidences supporting the network concept of epilepsies from different approaches. Firstly the functions of cortical networks in which most of the epileptic networks are embedded, are treated. Then the tentative characteristics of an epileptic network are enumerated and the conversion mechanisms from physiological to epileptic networks are analyzed. Later the role of neuronal oscillations in epileptic networks and aspects of epilepsies provoked by sensory and cognitive tasks is studied. Lastly new fMRI data in mapping BOLD networks underlying spike and seizure discharges are used as arguments in favour of the epileptic network hypothesis. In a second part the well-known epilepsies related, or probably related to physiological networks are shown. Finally consequences of the network approach for creating a new unified epilepsy classification are discussed.]

COMMENTS

0 comments

Further articles in this publication

Clinical Neuroscience

[Devic syndrome - case report, diagnostic and therapeutic principles]

ILJICSOV Anna, BARSI Péter, VÁRALLYAY György, TÁTRAI Erika, SOMFAI Gábor Márk, BERECZKI Dániel, RUDAS Gábor, SIMÓ Magdolna

[Neuromyelitis optica (NMO, Devic-syndrome) is a rare, relapsing autoimmun disease of the central nervous system, which is distinguished from other demyelinating disorders by a recently identified, specific autoantibody. By demonstrating the anti-aquaporin-4 IgG in the serum, a heterogenous group of syndromes can be defined, called NMO-spectrum. In the future, optical coherence tomography may support this diagnosis besides the clinical features, imaging examinations and presence of serum antibody. Early recognition and treatment can improve clinical outcome even in serious condition. Long-term immunosuppressive therapy is advised to prevent further relapses and to stabilize or improve clinical status. Hereby, we report a case of a 51-year-old woman, under treatment for 1.5 years. We summarize the up-to-date knowledge about the pathomechanism, diagnostic strategy and therapy of neuromyelitis optica. We review recent findings and the diagnostic value of a new, non-invasive ophtalmological examination, the optical coherence tomography. According to the first results, this method may be helpful in the early differential diagnosis of optic neuritis.]

Clinical Neuroscience

[What does aphasy with memory and behavioral disturbances?]

SZIRMAI Imre

Clinical Neuroscience

[József Kómár is 75 years old]

KISS Gábor

Clinical Neuroscience

[Hungarian Society Clinical Neurophysiology]

KONDÁKOR István

Clinical Neuroscience

[Analysis of antiparkinsonian drug reduction after bilateral subthalamic deep brain stimulation]

FEHÉR Georgina, BALÁS István, KOMOLY Sámuel, DÓCZI Tamás, JANSZKY József, ASCHERMANN Zsuzsanna, BALÁZS Éva, NAGY Ferenc, KOVÁCS Norbert

[Background - Bilateral deep brain stimulation of the subthalamic nuclei (STN) is a well-established and cost-effective treatment in advanced PD. Objectives - To quantitatively analyze the change in use of antiparkinsonian drugs one year after subthalamic deep brain stimulator (DBS) implantation in patients with idiopathic Parkinson’s disease (PD). Patients and methods - Eighteen consecutive patients with advanced PD underwent bilateral STN DBS implantation were involved in the study. The stimulation achieved a stable and clear clinical benefit in all of the cases. One year after the implantation, drug usage of patients was analyzed and correlated with the postoperative symptomatic improvement measured by the modified Hoehn-Yahr, Schwab and England, and Unified Parkinson’s Disease Rating Scales. Because none of the investigated variables followed the normal distribution, non-parametric Wilcoxon signed-rank, McNemar and Kendell’s τ tests were applied. Results - Preoperatively, the patients used 12.05±4.57 tablets a day out of 3.19±0.97 different antiparkinsonian drugs, which was significantly reduced by deep brain stimulation to the application of 7.00±2.96 tablets out of 1-3 (1.84±0.76) drugs (p<0.001). Meanwhile, the usage of amantadine, MAO-B and COMT inhibitors was also significantly decreased (p<0.05). The dosage of dopaminerg medication was significantly lowered from 1136 mg to 706 mg expressed in levodopa equivalent dosage (p<0.001) whereas the UPDRS-III also improved by 48.6%. Conclusion - Our study is in accordance with previously published international findings that antiparkinsonian medication can be significantly lowered after bilateral STN DBS. Because not only the dosage, but also the applied number of tablets were decreased, it may have resulted in a better compliance and quality of life.]

All articles in the issue

Related contents

Clinical Neuroscience

[The role of sleep in the relational memory processes ]

CSÁBI Eszter, ZÁMBÓ Ágnes, PROKECZ Lídia

[A growing body of evidence suggests that sleep plays an essential role in the consolidation of different memory systems, but less is known about the beneficial effect of sleep on relational memory processes and the recognition of emotional facial expressions, however, it is a fundamental cognitive skill in human everyday life. Thus, the study aims to investigate the effect of timing of learning and the role of sleep in relational memory processes. 84 young adults (average age: 22.36 (SD: 3.22), 21 male/63 female) participated in our study, divided into two groups: evening group and morning group indicating the time of learning. We used the face-name task to measure relational memory and facial expression recognition. There were two sessions for both groups: the immediate testing phase and the delayed retesting phase, separated by 24 hours. 84 young adults (average age: 22.36 (SD: 3.22), 21 male/63 female) participated in our study, divided into two groups: evening group and morning group indicating the time of learning. We used the face-name task to measure relational memory and facial expression recognition. There were two sessions for both groups: the immediate testing phase and the delayed retesting phase, separated by 24 hours. Our results suggest that the timing of learning and sleep plays an important role in the stabilizing process of memory representation to resist against forgetting.]

Clinical Neuroscience

[Effect of two month positive airway pressure therapy on the structure of sleep, cognitive function and anxiety]

CSÁBI Eszter, VÁRSZEGI Mária, SEFCSIK Tamás, NÉMETH Dezsõ

[Obstructive sleep apnea is a common disorder, characterized by repeated episodes of upper airway obstruction during sleep, resulting intermittent hypoxia and disruption of the normal sleep pattern, which caused cognitive dysfunction in these patients. Nasal continuous positive airway pressure is the treatment of choice for this disorder. The aim of the study is to evaluate the effect of short-term positive airway pressure on sleep pattern (polisomnographic measures), cognitive function and anxiety. Twenty four newly diagnosed and previously untreated patients with obstructive sleep apnea were evaluated a battery of neuropsychological tests before and after 2 and a half months of the treatment. We focused on working memory, short and long-term episodic memory, executive functions, anxiety and subjective sleepiness. Our results showed that the two and half month of treatment improved the respiration during sleep, sleep pattern and the subjective sleepiness. We found improvement in short- and long-term verbal memory, and complex working memory. Despite of treatment we did not find improvement in visuospatial learning. These results reveal that 2 and a half months of positive airway pressure treatment restored not only the normal respiration during sleep and normal sleep pattern, but also the cognitive functions. Our study suggests that cognitive dysfunction is at least partial reversible in obstructive sleep apnea patients after positive airway pressure treatment.]

Clinical Neuroscience

[The concept of epileptic networks. Part 2.]

HALÁSZ Péter

[In this paper we investigate evidences supporting the network concept of epilepsies from different approaches. Firstly the functions of cortical networks in which most of the epileptic networks are embedded, are treated. Then the tentative characteristics of an epileptic network are enumerated and the conversion mechanisms from physiological to epileptic networks are analyzed. Later the role of neuronal oscillations in epileptic networks and aspects of epilepsies provoked by sensory and cognitive tasks is studied. Lastly new fMRI data in mapping BOLD networks underlying spike and seizure discharges are used as arguments in favour of the epileptic network hypothesis. In a second part the well-known epilepsies related, or probably related to physiological networks are shown. Finally consequences of the network approach for creating a new unified epilepsy classification are discussed.]

Lege Artis Medicinae

[Dementia and pseudodementia - depression as a risk factor of dementia]

NÉMETH Attila

[Dementia and depression have the highest annual costs for brain disorders (mental and neurologic disorders) in Europe. The prevalence of these disorders is very high in the old age. The depression is common and an underrecognized part of the dementia syndrome because of similar symptomatology and the comorbidity. The correct differential diagnosis is important in the therapeutic approach. The pseudodementia of depression can be improved by antidepressants. The author reviewed the symptomatologic and neurobiological connection of these two disorders.]

Clinical Neuroscience

[SLEEP DISORDERS IN PARKINSON SYNDROMES]

SZŰCS Anna, KOVÁCS Gábor Géza, NARULA Lalit, HALÁSZ Péter

[About 90% of neurodegenerative diseases with parkinsonism are associated with sleep disorders including daytime sleepiness, sleep-related breathing disorders and parasomnias. It is hard to define what ratio of insomnia and daytime hypersomnia is caused by the antiparkinsonian tratment, by the somatic and mentalemotional symptoms of the neurodegenerativ disease and by the neurodegenerative brain process itself. Recent research suggests that the latter group is more important than expected. In Parkinson syndromes the structures included in sleep regulation - mainly within the brainstem - are also affected resulting in specific sleep disorders being the primary biological symptoms of these diseases. The recently described parasomnia - REM sleep behavior disorder - has a specific significance in this respect: it may prevent by several years a high ratio of the parkinsonian disorders - especially synucleinopathies - offering the possibility of prevention by identifying the affected individuals. There seems to exist a similar although less clarified association between daytime sleepiness and Parkinson disease. Analysing the behavior of the orexin system in neurodegenerative diseases may help to learn more about this, recently described neurohumoral system and may clear the association of narcolepsy with neurodegeneration. By understanding the associations of parkinsonian disorders and sleep disorders new therapeutical strategies may be invented and may offer new aspects to understand the mechanism of them.]