RICERCA ITALIANA     

METHODS FOR CHARACTERIZATION OF EPILECTOGENIC FOCUS FROM EEG SIGNALS AND FUNCTIONAL IMAGES WITH MAGNETIC RESONANCE

Università di Pisa

Abstract

The research program is aimed to define epileptogenic area in patients with partial onset epilepsy. Nowday such area is defined in a approximate way using an indirect approach that defines a number of critical cortical areas and it produces a qualitative index of localization of epileptogenic area. The definition of such areas requires a multidisciplinary approach (neurological, neurophysiologic, neuroradiologic, neurosurgical) based in the first place on video-EEG recording of the seizures.
On the other hand, epileptogenic area definition is mandatory for surgical treatment of patients (about 50%) that are refractory to pharmacology therapy.
Recent technologic developments has produced new investigation techniques. A part from EEG examination, new non invasive and non ionizing imaging techniques are now available such as magnetic resonance, that are able to supply functional data such as metabolism, tissue anisotropy and local oxygen variation.
Such techniques have a number of drawback: 1) they are able to supply only qualitative indices of tissue function; 2) they are characterized by different resolutions that complicate the information integration process; 3) each technique detect processes that are imputable to different districts such as capillary, nervous system or cells.
Therefore, this research program has two important objectives: 1) to extract from each technique quantitative parameters that are correlate with the physiopathologic >>>

Principal Investigator

Luigi LANDINI Università di PISA

Research Objectives

The research program deals with the development of new tools for reconstruction, modeling, quantitative signal and image analysis and information integration, aimed to fully exploiting non invasive magnetic resonance imaging (MRI) techniques and electroencephalographic signal in the diagnosis of epileptic disease.
MRI techniques that are candidate to the study are: structural, spectroscopic, diffusive and functional MRI (fMRI). The block diagram herein reported gives a global idea of the overall activities in the project and the task related to each research unit.



The expectation from medical community is remarkable for the following open questions:
The research program deals with the development and validation of new methodologies for quantitative analysis, model-based interpretation and information fusion aimed to characterize the epileptic focus. In order to perform a global validation of the project, we suggest to address the following steps:
1) Epileptic disease is a wide social problem in terms of diffusion and because it hits infant population too; at least 50% of epileptic patients with partial epileptic onset, is refractary to pharmacological drug. On the other hand, surgical success is based on deep knowledge of epileptic focus in terms of localization and tissue characterization.
2) Nowday, diagnosis is based on qualitative analysis, often performed invasively, of electroencephalographic >>>

Timescale

24 months

National and international background

Complex partial seizures are the most common seizure type in adults with partial onset epilepsy. In nearly 80% of patients with partial epilepsy, the region of seizure onset involves the temporal lobe. Approximately 90% of individuals with temporal lobe epilepsy have partial seizures of amygdala or hippocampal origin or both. Just approximately one third of patients with partial epilepsy have visible structural intra-axial lesions underlying the epileptic brain tissue.
Pathologies identified for partial epilepsy include mesial temporal sclerosis (MTS), malformations of cortical development, vascular malformations, tumors, and other acquired intra-axial lesions.
Abnormal cortical development is increasingly recognized as a cause of epilepsy and developmental disabilities. Histologically proven developmental brain abnormalities are observed in up to 25% of children with intractable seizures.
Despite advances in antiepileptic drug therapy, approximately 45% of patients with partial epilepsy will be refractory to medications. A seizure disorder is considered intractable if the seizures are refractory to such therapy and the patient is disabled by the epilepsy or medical treatment. In this cases epilepsy surgery has proven to be effective and safe for selected patients with intractable partial epilepsy—reported results about seizure freedom range between 70% and 90% among patients with surgically remediable epileptic syndromes.
The objective of >>>