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Dive into the research topics where Andrea Bernasconi is active.

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Featured researches published by Andrea Bernasconi.


Epilepsia | 2015

Diagnostic methods and treatment options for focal cortical dysplasia.

Renzo Guerrini; Michael Duchowny; Prasanna Jayakar; Pavel Krsek; Philippe Kahane; Laura Tassi; Federico Melani; Tilman Polster; Véronique Marie André; Carlos Cepeda; Darcy A. Krueger; J. Helen Cross; Roberto Spreafico; Mirco Cosottini; Jean Gotman; Francine Chassoux; Philippe Ryvlin; Fabrice Bartolomei; Andrea Bernasconi; Hermann Stefan; Ian Miller; Bertrand Devaux; Imad Najm; Flavio Giordano; Kristl Vonck; Carmen Barba; Ingmar Blümcke

Our inability to adequately treat many patients with refractory epilepsy caused by focal cortical dysplasia (FCD), surgical inaccessibility and failures are significant clinical drawbacks. The targeting of physiologic features of epileptogenesis in FCD and colocalizing functionality has enhanced completeness of surgical resection, the main determinant of outcome. Electroencephalography (EEG)–functional magnetic resonance imaging (fMRI) and magnetoencephalography are helpful in guiding electrode implantation and surgical treatment, and high‐frequency oscillations help defining the extent of the epileptogenic dysplasia. Ultra high‐field MRI has a role in understanding the laminar organization of the cortex, and fluorodeoxyglucose–positron emission tomography (FDG‐PET) is highly sensitive for detecting FCD in MRI‐negative cases. Multimodal imaging is clinically valuable, either by improving the rate of postoperative seizure freedom or by reducing postoperative deficits. However, there is no level 1 evidence that it improves outcomes. Proof for a specific effect of antiepileptic drugs (AEDs) in FCD is lacking. Pathogenic mutations recently described in mammalian target of rapamycin (mTOR) genes in FCD have yielded important insights into novel treatment options with mTOR inhibitors, which might represent an example of personalized treatment of epilepsy based on the known mechanisms of disease. The ketogenic diet (KD) has been demonstrated to be particularly effective in children with epilepsy caused by structural abnormalities, especially FCD. It attenuates epigenetic chromatin modifications, a master regulator for gene expression and functional adaptation of the cell, thereby modifying disease progression. This could imply lasting benefit of dietary manipulation. Neurostimulation techniques have produced variable clinical outcomes in FCD. In widespread dysplasias, vagus nerve stimulation (VNS) has achieved responder rates >50%; however, the efficacy of noninvasive cranial nerve stimulation modalities such as transcutaneous VNS (tVNS) and noninvasive (nVNS) requires further study. Although review of current strategies underscores the serious shortcomings of treatment‐resistant cases, initial evidence from novel approaches suggests that future success is possible.


Annals of Neurology | 2003

Nonsyndromic mental retardation and cryptogenic epilepsy in women with doublecortin gene mutations

Renzo Guerrini; Francesca Moro; Eva Andermann; Elaine Hughes; Daniela D'Agostino; Romeo Carrozzo; Andrea Bernasconi; Frances Flinter; Lucio Parmeggiani; Anna Volzone; Elena Parrini; Davide Mei; Jozef Jarosz; Robin G. Morris; Polly Pratt; Gaetano Tortorella; François Dubeau; Frederick Andermann; William B. Dobyns; Soma Das

DCX mutations cause mental retardation in male subjects with lissencephalypachygyria and in female subjects with subcortical band heterotopia (SBH). We observed four families in which carrier women had normal brain magnetic resonance imaging (MRI) and mild mental retardation, with or without epilepsy. Affected male subjects had SBH or pachygyria‐SBH. In two families, the phenotype was mild in both genders. In the first family, we found a tyr138his mutation that is predicted to result in abnormal folding in the small hinge region. In the second family, we found an arg178cys mutation at the initial portion of R2, in the putative β‐sheet structure. Carrier female subjects with normal MRI showed no somatic mosaicism or altered X‐inactivation in lymphocytes, suggesting a correlation between mild mutations and phenotypes. In the two other families, with severely affected boys, we found arg76ser and arg56gly mutations within the R1 region that are predicted to affect DCX folding, severely modifying its activity. Both carrier mothers showed skewed X‐inactivation, possibly explaining their mild phenotypes. Missense DCX mutations may manifest as non‐syndromic mental retardation with cryptogenic epilepsy in female subjects and SBH in boys. Mutation analysis in mothers of affected children is mandatory, even when brain MRI is normal. Ann Neurol 2003


Neurology | 2004

Posterior quadrantic dysplasia or hemi-hemimegalencephaly: A characteristic brain malformation

Maria Daniela D'Agostino; A. Bastos; C. Piras; Andrea Bernasconi; T. Grisar; V. Gross Tsur; J. Snipes; Csaba Juhász; Harry T. Chugani; Renzo Guerrini; H. Cross; Eva Andermann; François Dubeau; José L. Montes; André Olivier; Frederick Andermann

Introduction: Posterior quadrantic dysplasia (PQD), a developmental malformation involving the temporal, parietal, and occipital lobes of one cerebral hemisphere, leads to intractable epilepsy. Objective: To characterize the clinical features of 19 patients with PQD and analyze the postsurgical outcome of those who underwent resection of dysplastic tissue. Methods: The extent and nature of the malformation were primarily assessed with high-resolution brain imaging. Fourteen patients underwent complete or partial temporoparieto-occipital resection or temporal resection associated with parieto-occipital disconnection. Postoperative follow-up period ranged from 8 months to 7 years. The authors used the Engel classification for postoperative outcome. Results: All patients were sporadic. Clinical features included infantile spasms, partial seizures, mental retardation, mild hemiparesis, and visual field defects. Neuroimaging localized the malformation within the posterior cerebral quadrant contralateral to the neurologic deficit and demonstrated hemi-hemimegalencephaly in 14 of 19 patients and multilobar cortical dysplasia in 5 of 19 patients. The authors observed class I outcome in six patients. Two patients had class II and four patients had class III outcome. Class IV outcome was seen in two patients. After surgery, two patients developed mild hemiparesis, and two developed a visual field defect. Conclusions: Widespread cortical dysplasia is more frequent in the posterior quadrant. In our series, posterior quadrantic dysplasia represents either hemi-hemimegalencephaly or multilobar cortical dysplasia. Individuals with posterior quadrantic dysplasia share a spectrum of clinical features. The intractable epilepsy in these patients may be alleviated by a large quadrantic temporoparieto-occipital resection.


Experimental Brain Research | 2018

How do we decide what to do? : Resting-state connectivity patterns and components of self-generated thought linked to the development of more concrete personal goals

Barbara Medea; Theodoros Karapanagiotidis; Mahiko Konishi; Cristina Ottaviani; Daniel S. Margulies; Andrea Bernasconi; Neda Bernasconi; Boris C. Bernhardt; Elizabeth Jefferies; Jonathan Smallwood

Human cognition is not limited to the available environmental input but can consider realities that are different to the here and now. We describe the cognitive states and neural processes linked to the refinement of descriptions of personal goals. When personal goals became concrete, participants reported greater thoughts about the self and the future during mind-wandering. This pattern was not observed for descriptions of TV programmes. Connectivity analysis of participants who underwent a resting-state functional magnetic resonance imaging scan revealed neural traits associated with this pattern. Strong hippocampal connectivity with ventromedial pre-frontal cortex was common to better-specified descriptions of goals and TV programmes, while connectivity between hippocampus and the pre-supplementary motor area was associated with individuals whose goals were initially abstract but became more concrete over the course of the experiment. We conclude that self-generated cognition that arises during the mind-wandering state can allow goals to be refined, and this depends on neural systems anchored in the hippocampus.


medical image computing and computer assisted intervention | 2016

A Surface Patch-Based Segmentation Method for Hippocampal Subfields

Benoit Caldairou; Boris C. Bernhardt; Jessie Kulaga-Yoskovitz; Hosung Kim; Neda Bernasconi; Andrea Bernasconi

Several neurological disorders are associated with hippocampal pathology. As changes may be localized to specific subfields or spanning across different subfields, accurate subfield segmentation may improve non-invasive diagnostics. We propose an automated subfield segmentation procedure, which combines surface-based processing with a patch-based template library and feature matching. Validation experiments in 25 healthy individuals showed high segmentation accuracy (Dice >82 % across all subfields) and robustness to variations in the template library size. Applying the algorithm to a cohort of patients with temporal lobe epilepsy and hippocampal sclerosis, we correctly lateralized the seizure focus in >90 %. This advantageously compares to classifiers relying on volumes retrieved from other state-of-the-art algorithms.


international conference on pattern recognition | 2002

On the classification of temporal lobe epilepsy using MR image appearance

Simon Duchesne; Neda Bernasconi; Andrea Bernasconi; D. L. Collins

Classification of neurological diseases based on image characteristics often requires extensive modeling and user intervention. While other techniques concentrate on specific structures, the novelty of the method presented here resides in its analysis of the grey-level appearance of large, non-specific Volumes of Interest (VOI) from T1 MRI data. No manual intervention is required other than the selection of the VOI. This work presents the methodological framework and preliminary results towards our aim of classifying normal subjects and patients with Temporal Lobe Epilepsy (TLE) within the Medial Temporal Lobe. For this purpose, principal component analysis is performed on a set of normal subjects for the creation of a multi-dimensional space representative of a normal population. New data for normal and TLE subjects are projected in this space, under the assumption that the distributions of the projections are not identical and can be used for classification. It is shown that linear discriminant analysis of the eigencoordinates of the projected data can be used to classify normals vs TLE with a 70% accuracy based on only 10 eigenvectors. This results can go up to 100% if all eigenvectors defining the grey-level space are used.


medical image computing and computer assisted intervention | 2014

Multivariate Hippocampal Subfield Analysis of Local MRI Intensity and Volume: Application to Temporal Lobe Epilepsy

Hosung Kim; Boris C. Bernhardt; Jessie Kulaga-Yoskovitz; Benoit Caldairou; Andrea Bernasconi; Neda Bernasconi

We propose a multispectral MRI-based clinical decision support approach to carry out automated seizure focus lateralization in patients with temporal lobe epilepsy (TLE). Based on high-resolution T1- and T2-weighted MRI with hippocampal subfield segmentations, our approach samples MRI features along the medial sheet of each subfield to minimize partial volume effects. To establish correspondence of sampling points across subjects, we propagate a spherical harmonic parameterization derived from the hippocampal boundary along a Laplacian gradient field towards the medial sheet. Volume and intensity data sampled on the medial sheet are finally fed into a supervised classifier. Testing our approach in TLE patients in whom the seizure focus could not be lateralized using conventional MR volumetry, the proposed approach correctly lateralized all patients and outperformed classification performance based on global subfield volumes or mean T2-intensity (100% vs. 68%). Moreover, statistical group-level comparisons revealed patterns of subfield abnormalities that were not evident in the global measurements and that largely agree with known histopathological changes.


medical image computing and computer assisted intervention | 2015

MRI-Based Lesion Profiling of Epileptogenic Cortical Malformations

Seok-Jun Hong; Boris C. Bernhardt; Dewi Schrader; Benoit Caldairou; Neda Bernasconi; Andrea Bernasconi

Focal cortical dysplasia (FCD), a malformation of cortical development, is a frequent cause of drug-resistant epilepsy. This lesion is histologically classified into Type-IIA (dyslamination, dysmorphic neurons) and Type-IIB (dyslamination, dysmorphic neurons, and balloon cells). Reliable in-vivo identification of lesional subtypes is important for preoperative decision-making and surgical prognostics. We propose a novel multi-modal MRI lesion profiling based on multiple surfaces that systematically sample intra- and subcortical tissue. We applied this framework to histologically-verified FCD. We aggregated features describing morphology, intensity, microstructure, and function from T1-weighted, FLAIR, diffusion, and resting-state functional MRI. We observed alterations across multiple features in FCD Type-IIB, while anomalies in IIA were subtle and mainly restricted to FLAIR intensity and regional functional homogeneity. Anomalies in Type-IIB were seen across all intra- and sub-cortical levels, whereas those in Type-IIA clustered at the cortico-subcortical interface. A supervised classifier predicted the FCD subtype with 91% accuracy, validating our profiling framework at the individual level.


DLMIA/ML-CDS@MICCAI | 2017

Automated Detection of Epileptogenic Cortical Malformations Using Multimodal MRI

Ravnoor S. Gill; Seok-Jun Hong; Fatemeh Fadaie; Benoit Caldairou; Boris C. Bernhardt; Neda Bernasconi; Andrea Bernasconi

Focal cortical dysplasia (FCD), a malformation of cortical development, is a frequent cause of drug-resistant epilepsy. This surgically-amenable lesion is histologically characterized by cortical dyslamination, dysmorphic neurons, and balloon cells, which may extend into the immediate subcortical white matter. On MRI, FCD is typically associated with cortical thickening, blurring of the cortical boundary, and intensity anomalies. Notably, even histologically-verified FCD may not be clearly visible on preoperative MRI. We propose a novel FCD detection algorithm, which aggregates surface-based descriptors of morphology and intensity derived from T1-weighted (T1w) MRI, T2-weighted fluid attenuation inversion recovery (FLAIR) MRI, and FLAIR/T1w ratio images. Features were systematically sampled at multiple intracortical/subcortical levels and fed into a two-stage classifier for automated lesion detection based on ensemble learning. Using 5-fold cross-validation, we evaluated the approach in 41 patients with histologically-verified FCD and 38 age-and sex-matched healthy controls. Our approach showed excellent sensitivity (83%, 34/41 lesions detected) and specificity (92%, no findings in 35/38 controls), suggesting benefits for presurgical diagnostics.


medical image computing and computer assisted intervention | 2003

Temporal Lobe Epilepsy Lateralization Based on MR Image Intensity and Registration Features

Simon Duchesne; Neda Bernasconi; Andrew L. Janke; Andrea Bernasconi; D. L. Collins

In the context of MR imaging, explicit segmentation followed by stereologic volumetry of the hippocampus (HC) has been the standard approach toward temporal lobe epilepsy (TLE) lateralization of the seizure focus. The novelty of the method presented here resides in its analysis of characteristics of large, non-specific Volumes of Interest from T1 MRI data aiming to lateralize the seizure focus in patients with TLE without segmentation. For this purpose, Principal Components Analysis (PCA) of two image features are united to create a multi-dimensional space representative of a training set population composed of 150 normal subjects. The feature instances consist of grey-level intensity and an approximation of the Jacobian matrix of non-linear registration-derived dense deformation fields. New data for TLE subjects are projected in this space, under the assumption that the distributions of the projections of normal and patients are not identical and can be used for lateralization. Results are presented following PCA modeling of the left medial temporal lobe only for all subjects. It is shown that linear discriminant analysis of the eigencoordinates can be used to lateralize the seizure focus in TLE patients with a 75% accuracy. It is expected that adding a right temporal lobe model will improve lateralization results beyond those of HC volumetry.

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Boris C. Bernhardt

Montreal Neurological Institute and Hospital

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Dewi Schrader

Montreal Neurological Institute and Hospital

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Eva Andermann

Montreal Neurological Institute and Hospital

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Simon Duchesne

Montreal Neurological Institute and Hospital

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