Clinical Neuroscience

[Magnetic resonance measuring and analitic methods in epilepsy]

BARSI Péter

SEPTEMBER 23, 2011

Clinical Neuroscience - 2011;64(09-10)

[Neuroradiology and magnetic resonance imaging (MRI) as its leading tool play a basic role in the diagnostics of epilepsy. The result of the MRI examination is of utmost importance in patients with therapy resistent focal epilepsy possibly requiring neurosurgical intervention. Based on the continuously developing MRI techniques, we can use an optimal imaging protocol. Cerebral structures can be evaluated on a microanatomical level on high-resolution images with thin slices. The three-dimensional (3D) sequence has high spatial resolution, properly distinguishes cerebral grey and white matter, provides the possibility of surface rendering and volumetry, as well as an anatomical basis for other methods like tractography, functional MRI and neuronavigation. Diffusion weighted and diffusion tensor imaging (DWI, DTI) and tractography has an important role in differential diagnostics and tractography visualizes the main white matter tracts and their relation with brain pathologies. MR perfusion (MRP) provides help in differential diagnostics and may have a future role in the determination of the epileptogenic focus in multifocal pathologies. MR spectroscopy (MRS) is important in differential diagnostics, lateralization of focal epilepsy and in the confirmation of hippocampal sclerosis. Several of these methods need special hardware, software and expertise, but the basic MRI protocol for epilepsy can be implemented in all modern MR scanners of middle or high field strength.]

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Clinical Neuroscience

[Functional magnetic resonance imaging for cortical mapping in epilepsy]

KOZÁK Lajos Rudolf, TÓTH Vivien, BARSI Péter, RUDAS Gábor

[It is not only the total curative resection of pathological tissue or the minimization of symptoms to be considered in epilepsy surgery or other neurosurgical procedures, it is equally desirable to maintain the best possible quality of life. Cortical mapping methods can help achieve this goal by delineating eloquent areas, i.e. brain regions that are vital for providing an acceptable quality of life, albeit not prone to compensatory reorganization. These areas include among others the Broca and Wernicke regions for speech, the primary motor, sensory and visual cortices. Functional MRI gained importance in the last decade as a non-invasive clinical cortical mapping technique. This method is capable of localizing cortical areas selectively activated by a given task condition. Thus, selecting appropriate tasks can help mapping eloquent brain regions. Using functional MRI provides information that is complementary to other mapping methods. Moreover, it can replace invasive methods such as the Wada test. Here, we explain the background of functional MRI, compare it to other clinical mapping methods, explain the intricacies of paradigm selection, and show the limitations of the technique while also pointing out alternative uses.]

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[LORETA (Low Resolution Electromagnetic Tomography): A three-dimensional EEG source localization method]

CLEMENS Béla

[The author presents a brief overview of the EEG source localization method LORETA (Low Resolution Electromagnetic Tomography) with special reference to the not widely discussed data.]

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[The methodology and objectives of registrating high frequency oscillation in epilepsy]

CLEMENS Zsófia

[Technological advances in digital EEG allowed the recording the full frequency band of the EEG. Activity beyond the traditional 0.3-70 Hz band reflects both physiological and pathological processes. High frequency activity recorded from the epileptic brain has been related to both epileptogenicity and epileptogenesis. The article reviews research avenues, clinical applications, and the methodology of detecting and quantifying high frequency activity.]

Clinical Neuroscience

[Prolonged EEG-monitoring]

HALÁSZ Péter

[Prolonged EEG monitoring and video-EEG monitoring are basic methods on the level of epilepsy centers. These methods are able to make differences between epilepsy and non epileptic paroxysmal manifestations like psychogenic non epileptic seizures, parasomniac phenomena, narcolepsy. The application of the method, at least the video-EEG variant, needs team work, high level organisation, highly educated staff and high tech electrographic devices. Running the method even with these requirements is beneficial from the cost-benefit aspect as well.]

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[Role of deep brain stimulation in epilepsy]

JANSZKY József, BALÁS István, KOVÁCS Norbert

[The deep brain stimulation (DBS) is an emerging treatment option in brain disorders in which randomized multicenter trials proved its efficacy leading to licensing different DBS methods in various brain diseases. More recently more and more brain structures have become candidates for being “target” in a possible DBS treatment of epilepsy. At present, only the DBS of the anterior nucleus of the thalamus (ANT) can be considered as a proved method for epilepsy treatment. Other potential targets for DBS treatment in epilepsy are the subthalamic nuclei, and the amygdala- hippocampus complex. There are some ongoing randomized studies to investigating their therapeutical role. The therapeutical outcome of ANT-DBS treatment in drug-resistant epilepsy seems to be better than the new antiepileptic drugs, but much worse than the results of a potential epilepsy surgery. At about 10% of patients may become seizure-free and 50% of patients may have a significant improvement. Nowadays ANT-DBS should be considered as an “ultima ratio” in those adult drug-resistant epilepsy patients with normal intelligence in which neither new antiepileptic drugs nor resective epilepsy surgery are a reasonable therapeutical options.]

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