Claudio Munari Epilepsy Surgery Center

Milano, Italy

Claudio Munari Epilepsy Surgery Center

Milano, Italy

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Andrzejak R.G.,University Pompeu Fabra | David O.,Joseph Fourier University | Gnatkovsky V.,Fondazione Instituto Neurologico Carlo Besta | Wendling F.,University of Rennes 1 | And 5 more authors.
Brain Topography | Year: 2015

In patients diagnosed with pharmaco-resistant epilepsy, cerebral areas responsible for seizure generation can be defined by performing implantation of intracranial electrodes. The identification of the epileptogenic zone (EZ) is based on visual inspection of the intracranial electroencephalogram (IEEG) performed by highly qualified neurophysiologists. New computer-based quantitative EEG analyses have been developed in collaboration with the signal analysis community to expedite EZ detection. The aim of the present report is to compare different signal analysis approaches developed in four different European laboratories working in close collaboration with four European Epilepsy Centers. Computer-based signal analysis methods were retrospectively applied to IEEG recordings performed in four patients undergoing pre-surgical exploration of pharmaco-resistant epilepsy. The four methods elaborated by the different teams to identify the EZ are based either on frequency analysis, on nonlinear signal analysis, on connectivity measures or on statistical parametric mapping of epileptogenicity indices. All methods converge on the identification of EZ in patients that present with fast activity at seizure onset. When traditional visual inspection was not successful in detecting EZ on IEEG, the different signal analysis methods produced highly discordant results. Quantitative analysis of IEEG recordings complement clinical evaluation by contributing to the study of epileptogenic networks during seizures. We demonstrate that the degree of sensitivity of different computer-based methods to detect the EZ in respect to visual EEG inspection depends on the specific seizure pattern. © 2014, Springer Science+Business Media New York.


Varotto G.,Fondazione Irccs Instituto Neurologico C Besta | Varotto G.,Polytechnic of Milan | Franceschetti S.,Fondazione Irccs Instituto Neurologico C Besta | Spreafico R.,Fondazione Irccs Instituto Neurologico C Besta | And 2 more authors.
2010 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC'10 | Year: 2010

The study was aimed at evaluating the changes in dynamical connectivity, between interictal, preictal and ictal condition, among signals derived from StereoEEG recordings in patients with Taylor's type focal cortical dysplasia (FCD type-II), by means of Partial Directed Coherence and indexes derived from graph theory. Results showed that seizures are characterized by an increased synchronization, mainly within the regions involved in the generation of the epileptogenic activity. Our findings reveal that the proposed procedure can be considered a suitable techinque to properly identify the pathological synchronization mechanisms underlying seizure generation and to support the identification of the epileptogenic zone. © 2010 IEEE.


PubMed | University of Bern, Joseph Fourier University, University Pompeu Fabra, Fondazione Instituto Neurologico Carlo Besta and 4 more.
Type: Journal Article | Journal: Brain topography | Year: 2015

In patients diagnosed with pharmaco-resistant epilepsy, cerebral areas responsible for seizure generation can be defined by performing implantation of intracranial electrodes. The identification of the epileptogenic zone (EZ) is based on visual inspection of the intracranial electroencephalogram (IEEG) performed by highly qualified neurophysiologists. New computer-based quantitative EEG analyses have been developed in collaboration with the signal analysis community to expedite EZ detection. The aim of the present report is to compare different signal analysis approaches developed in four different European laboratories working in close collaboration with four European Epilepsy Centers. Computer-based signal analysis methods were retrospectively applied to IEEG recordings performed in four patients undergoing pre-surgical exploration of pharmaco-resistant epilepsy. The four methods elaborated by the different teams to identify the EZ are based either on frequency analysis, on nonlinear signal analysis, on connectivity measures or on statistical parametric mapping of epileptogenicity indices. All methods converge on the identification of EZ in patients that present with fast activity at seizure onset. When traditional visual inspection was not successful in detecting EZ on IEEG, the different signal analysis methods produced highly discordant results. Quantitative analysis of IEEG recordings complement clinical evaluation by contributing to the study of epileptogenic networks during seizures. We demonstrate that the degree of sensitivity of different computer-based methods to detect the EZ in respect to visual EEG inspection depends on the specific seizure pattern.


Colombo N.,Ospedale Ca Granda Niguarda | Tassi L.,Claudio Munari Epilepsy Surgery Center | Deleo F.,Irccs Foundation Neurological Institute C Besta | Citterio A.,Ospedale Ca Granda Niguarda | And 6 more authors.
Neuroradiology | Year: 2012

Introduction: This study aims to review the magnetic resonance imaging (MRI) aspects of a large series of patients with focal cortical dysplasia type II (FCD II) and attempt to identify distinctive features in the two histopathological subtypes IIa and IIb. Methods: We retrospectively reviewed the MRI scans of 118 patients with histological proven FCD IIa (n∈=∈37) or IIb (n∈=∈81) who were surgically treated for intractable epilepsy. Results: MRI was abnormal in 93 patients (79 %) and unremarkable in 25 (21 %). A dysplastic lesion was identified in 90 cases (97 %) and classified as FCD II in 83 and FCD non-II in seven cases. In three cases, the MRI diagnosis was other than FCD. There was a significant association between the presence of cortical thickening (p∈=∈0.002) and the transmantle sign (p∈<∈0. 001) and a correct MRI diagnosis of FCD II. MRI positivity was more frequent in the patients with FCD IIb than in those with FCD IIa (91 % vs. 51 %), and the detection rate of FCD II was also better in the patients with type IIb (88 % vs. 32 %). The transmantle sign was significantly more frequent in the IIb subgroup (p∈=∈0.003). Conclusions: The rates of abnormal MRI results and correct MRI diagnoses of FCD II were significantly higher in the IIb subgroup. Although other MRI stigmata may contribute to the diagnosis, the only significant correlation was between the transmantle sign and FCD IIb. © 2012 Springer-Verlag.


Boido D.,Fondazione Instituto Neurologico Carlo Besta | Kapetis D.,Fondazione Instituto Neurologico Carlo Besta | Gnatkovsky V.,Fondazione Instituto Neurologico Carlo Besta | Pastori C.,Fondazione Instituto Neurologico Carlo Besta | And 6 more authors.
Human Brain Mapping | Year: 2014

Presurgical monitoring with intracerebral electrodes in patients with drug-resistant focal epilepsy represents a standard invasive procedure to localize the sites of seizures origin, defined as the epileptogenic zone (EZ). During presurgical evaluation, intracerebral single-pulse electrical stimulation (SPES) is performed to define the boundaries of eloquent areas and to evoke seizure-associated symptoms. Extensive intracranial exploration and stimulation generate a large dataset on brain connectivity that can be used to improve EZ detection and to understand the organization of the human epileptic brain. We developed a protocol to analyse field responses evoked by intracranial stimulation. Intracerebral recordings were performed with 105-162 recording sites positioned in fronto-temporal regions in 12 patients with pharmacoresistant focal epilepsy. Recording sites were used for bipolar SPES at 1 Hz. Reproducible early and late phases (<60 ms and 60-500 ms from stimulus artefact, respectively) were identified on averaged evoked responses. Phase 1 and 2 responses recorded at all and each recording sites were plotted on a 3D brain reconstructions. Based on connectivity properties, electrode contacts were primarily identified as receivers, mainly activators or bidirectional. We used connectivity patterns to construct networks and applied cluster partitioning to study the proprieties between potentials evoked/stimulated in different regions. We demonstrate that bidirectional connectivity during phase 1 is a prevalent feature that characterize contacts included in the EZ. This study shows that the application of an analytical protocol on intracerebral stimulus-evoked recordings provides useful information that may contribute to EZ detection and to the management of surgical-remediable epilepsies. © 2014 Wiley Periodicals, Inc.


Bellistri E.,Instituto Neurologico Carlo Besta | Sartori I.,Claudio Munari Epilepsy Surgery Center | Pelliccia V.,Claudio Munari Epilepsy Surgery Center | Francione S.,Claudio Munari Epilepsy Surgery Center | And 3 more authors.
International Journal of Neural Systems | Year: 2015

Epilepsy is a disease characterized by aberrant connections between brain areas. The altered activity patterns generated by epileptic networks can be analyzed with intracerebral electrodes during pre-surgical stereo-electroencephalographic (EEG) monitoring in patients candidate to epilepsy surgery. The responses to high frequency stimulation (HFS) at 50Hz performed for diagnostic purposes during SEEG were analyzed with a new algorithm, to evaluate signal parameters that are masked to visual inspection and to define the boundaries of the epileptogenic network. The analysis was focused on 60-80 Hz activity that represented the largest frequency component evoked by HFS. The distribution of HFS-evoked fast activity across all (up to 162) recording contacts allowed to define different clusters of contacts that retrospectively correlated to the epileptogenic zone identified by the clinicians on the basis of traditional visual analysis. The study demonstrates that computer-assisted analysis of HFS-evoked activities may contribute to the definition of the epileptogenic network on intracranial recordings performed in a pre-surgical setting. © 2015 World Scientific Publishing Company.


Gnatkovsky V.,Fondazione Instituto Neurologico | Francione S.,Claudio Munari Epilepsy Surgery Center | Cardinale F.,Claudio Munari Epilepsy Surgery Center | Mai R.,Claudio Munari Epilepsy Surgery Center | And 3 more authors.
Epilepsia | Year: 2011

Purpose: The identification of the epileptogenic zone (EZ) is crucial for planning epilepsy surgery in patients with drug-resistant partial epilepsy. This task may require intracerebral encephalography (EEG) monitoring, the results of which are usually interpreted by visual presurgical inspection. A computer-assisted method for rapidly identifying reproducible ictal patterns based on the analysis of time, frequency, and spatial domains of stereo-EEG (SEEG) signals is described here. Methods: A new method for EZ detection was tested on SEEG recordings performed by intracerebral electrodes in eight patients with pharmacoresistant partial epilepsy. SEEG data were exported to a program developed in LabView. Key Findings: Prevalent frequencies during seizure events were evaluated by Fourier transform and further integral algorithms. Different frequencies and the relative powers were simultaneously evaluated in all recording leads. Patterns characterized by specific and prevalent frequencies were identified in a subset of recording sites during both seizure onset and seizure development. Three-dimensional (3D) maps of the measurements obtained from each recording channel were reconstructed on magnetic resonance coordinates to visualize the spatial distribution of the EZ. With this method, the reproducibility of ictal patterns in the same patient was characterized. The boundaries of the EZ identified with this algorithm correlated well with the EZ recognized with the traditional approach (n = 8). The spatial distribution of specific SEEG signals associated with different types of seizures was also analyzed in two patients. Significance: Wedescribe a computer-assisted method to acquire information on EZ boundaries and to verify reproducibility of seizure patterns from intracerebral recordings performed in patients with pharmacoresistant partial epilepsies. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy Wiley Periodicals, Inc.


PubMed | Instituto Neurologico Carlo Besta and Claudio Munari Epilepsy Surgery Center
Type: Journal Article | Journal: International journal of neural systems | Year: 2015

Epilepsy is a disease characterized by aberrant connections between brain areas. The altered activity patterns generated by epileptic networks can be analyzed with intracerebral electrodes during pre-surgical stereo-electroencephalographic (EEG) monitoring in patients candidate to epilepsy surgery. The responses to high frequency stimulation (HFS) at 50 Hz performed for diagnostic purposes during SEEG were analyzed with a new algorithm, to evaluate signal parameters that are masked to visual inspection and to define the boundaries of the epileptogenic network. The analysis was focused on 60-80 Hz activity that represented the largest frequency component evoked by HFS. The distribution of HFS-evoked fast activity across all (up to 162) recording contacts allowed to define different clusters of contacts that retrospectively correlated to the epileptogenic zone identified by the clinicians on the basis of traditional visual analysis. The study demonstrates that computer-assisted analysis of HFS-evoked activities may contribute to the definition of the epileptogenic network on intracranial recordings performed in a pre-surgical setting.


PubMed | Fondazione Instituto Neurologico Carlo Besta and Claudio Munari Epilepsy Surgery Center
Type: | Journal: Brain and language | Year: 2016

A quantitative method was developed to map cortical areas responsive to cognitive tasks during intracerebral stereo-EEG recording sessions in drug-resistant patients candidate for epilepsy surgery. Frequency power changes were evaluated with a computer-assisted analysis in 7 patients during phonemic fluency tasks. All patients were right-handed and were explored with depth electrodes in the dominant frontal lobe. We demonstrate that fluency tasks enhance beta-gamma frequencies and reduce background activities in language network regions of the dominant hemisphere. Non-reproducible changes were observed in other explored brain areas during cognitive tests execution.

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