Hervé Vespignani

Automated cortical projection of EEG sensors: Anatomical correlation via the international 10–10 system

Several studies have described cranio-cerebral correlations in accordance with the 10-20 electrode placement system. These studies have made a significant contribution to human brain imaging techniques, such as near-infrared spectroscopy and trans-magnetic stimulation. With the recent development of high resolution EEG, an extension of the 10-20 system has been proposed. This new configuration, namely the 10-10 system, allows the placement of a high number (64-256) of EEG electrodes. Here, we describe the cranio-cerebral correlations with the 10-10 system. Thanks to the development of a new EEG-MRI sensor and an automated algorithm which enables the projection of electrode positions onto the cortical surface, we studied the cortical projections in 16 healthy subjects using the Talairach stereotactic system and estimated the variability of cortical projections in a statistical way. We found that the cortical projections of the 10-10 system could be estimated with a grand standard deviation of 4.6 mm in x, 7.1 mm in y and 7.8 mm in z. We demonstrated that the variability of projections is greatest in the central region and parietal lobe and least in the frontal and temporal lobes. Knowledge of cranio-cerebral correlations with the 10-10 system should enable to increase the precision of surface brain imaging and should help electrophysiological analyses, such as localization of superficial focal cortical generators.

Dose-dependent Safety and Efficacy of Zonisamide: A Randomized, Double-blind, Placebo-controlled Study in Patients with Refractory Partial Seizures

Summary:  Purpose: To evaluate the safety and efficacy of zonisamide (ZNS) as adjunctive treatment in patients with refractory localization‐related epilepsy.

Bilateral subthalamic nucleus stimulation improves balance control in Parkinson's disease

Background: Parkinson’s disease (PD), the most common basal ganglia degenerative disease, affects balance control, especially when patients change balance strategy during postural tasks. Bilateral chronic stimulation of the subthalamic nucleus (STN) is therapeutically useful in advanced PD, and reduces the motor signs of patients. Nevertheless, the effects of STN stimulation on postural control are still debatable. Aims: To assess the impact of bilateral STN stimulation on balance control in PD and to determine how basal ganglia related sensorimotor modifications act on neurosensorial organisation of balance and motor postural programming. Methods: Twelve subjects aged 45–70 years underwent unified Parkinson’s disease rating scale motor (part III) clinical tests, static and dynamic posturography, including sensory organisation and adaptation tests, shortly before and six months after bilateral implantation of electrodes into the STN. Results: The postoperative static test showed an improvement in postural control precision both in eyes open and eyes closed conditions. The dynamic test highlighted the decreased number of falls and the ability of the patients to develop more appropriate sensorimotor strategies when stimulated. The sensory organisation test showed an improvement of equilibrium score and, thus, a better resolution of sensorial conflicts. Conclusions: STN stimulation allowed a reduction in rigidity and therefore an improvement in the ability to use muscular proprioception as reliable information, resulting in vestibulo-proprioceptive conflict suppression. STN stimulation has a synergistic effect with levodopa for postural control. Accordingly, non-dopaminergic pathways could be involved in postural regulation and STN stimulation may influence the functioning of these pathways.

Focal electrical intracerebral stimulation of a face-sensitive area causes transient prosopagnosia

Face perception is subtended by a large set of areas in the human ventral occipito-temporal cortex. However, the role of these areas and their importance for face recognition remain largely unclear. Here we report a case of transient selective impairment in face recognition (prosopagnosia) induced by focal electrical intracerebral stimulation of the right inferior occipital gyrus. This area presents with typical face-sensitivity as evidenced by functional neuroimaging right occipital face area (OFA). A face-sensitive intracerebral N170 was also recorded in this area, supporting its contribution as a source of the well-known N170 component typically recorded on the scalp. Altogether, these observations indicate that face recognition can be selectively impaired by local disruption of a single face-sensitive area of the network subtending this function, the right OFA.

Semiologic Value of Ictal Autoscopy

Summary:  Purpose: Autoscopy is a pathologic perception of ones body or ones face image within space, either from an internal (“as in a mirror”) or from an external (“out‐of‐body experience”) point of view. Among various psychiatric and neurologic disorders, partial epilepsy is the main etiology. However, the significance of this rare ictal symptom remains controversial. We report this phenomenon in three epilepsy patients and discuss its semiologic value and neuropsychological significance.

More severe disability of North Africans vs Europeans with multiple sclerosis in France

Objective: To compare the clinical disease progression in European (E) and North African (NA) patients with multiple sclerosis (MS) patients in France. Methods: We compared the clinical features of MS in 211 NA patients and 2,945 E patients in a French population–based cohort with definite MS according to McDonald’s criteria. Results: Among the NA patients with MS, 66.4% were women vs 72.9% of the E patients (p = 0.04), 15.6% had a primary progressive form of MS vs 11.7% of the E patients (p = 0.08), and the mean age at onset was 29.9 ± 9.8 years in the NA patients vs 32.9 ± 10.6 years in the E patients (p < 0.0001). In the NA patients, there was a higher proportion of patients with incomplete recovery from the first relapse (p < 0.0001), a shorter time between the first two relapses (p = 0.02), a higher number of relapses in the first 5 years (p = 0.03), and a shorter time to reach an Expanded Disability Status Scale score of 4.0 (p = 0.001) or 6.0 (p < 0.0001). The only statistical difference in these factors between NA patients born in France and those born in North Africa was the mean age at onset of symptoms: it was earlier in NA patients born in France (p < 0.0001). Conclusions: The course of multiple sclerosis is more aggressive in North African than in European patients.

Combined SEEG and source localisation study of temporal lobe schizencephaly and polymicrogyria.

OBJECTIVES Type 1 schizencephaly (SZ) is a cerebral malformation characterised by a cleft lined and surrounded by a polymicrogyric cortex, extending from the pial region to the peri-ventricular heterotopia. Our purpose was to combine and compare dipole source imaging technique and Stereo-EEG (SEEG) technique in determining the irritative and epileptogenic zones in a case of type 1 schizencephaly. METHODS High-resolution (64-channel) video-EEG with electrical source imaging and SEEG recordings were performed during a pre-surgical evaluation for medically intractable epilepsy. RESULTS Anatomo-electro-clinical correlations based on SEEG and source localisation identified two irritative and epileptogenic zones partially overlapping the polymicrogyric cortex surrounding the SZ: an anterior medio-lateral network primarily involving dysplasic limbic structures and a lateral network involving the anterior and middle part of the cleft and polymicrogyric cortex. The most posterior part (at the temporo-parieto-occipital junction) displayed a normal background activity. CONCLUSIONS Both epileptogenic and electrophysiologically normal cortices coexisted within the same widespread malformation: only the anterior part belonged to the anterior medio-lateral epileptogenic network defined by the SEEG. SIGNIFICANCE In cases of widespread cortical malformation such as SZ, source localization techniques can help to define the irritative zone and relevant targets for SEEG.

Acute myeloid leukaemia induced by mitoxantrone in a multiple sclerosis patient

Sirs: Mitoxantrone (MITO) is an anthracenedione antineoplastic agent utilised in the treatment of the most active stages of multiple sclerosis (MS) [2, 8, 10]. Usually MITO is administrated as a singleagent disease-modifying therapy, and MS patients should not receive a cumulative total dosage of MITO exceeding 140 mg/m2. The adverse effects of MITO are cardio toxicity and therapy-related acute myeloid leukaemia (trAML). We report a case in France of a MS patient treated by MITO and cyclophosphamide who developed trAML.

Electrical source imaging in cortical malformation–related epilepsy: A prospective EEG‐SEEG concordance study

Delineation of the epileptogenic zone (EZ) in refractory epilepsy related to malformations of cortical development (MCDs) often requires intracranial electroencephalography (EEG) recordings, especially in cases of negative magnetic resonance imaging (MRI) or discordant MRI and video‐EEG findings. It is therefore crucial to promote the development of noninvasive methods such as electrical source imaging (ESI). We aimed to (1) analyze the localization concordance of ESI derived from interictal discharges and EZ estimated by stereo‐EEG (SEEG); (2) compare the concordance of ESI, MRI, and electroclinical correlations (ECCs) with SEEG‐EZ; and (3) assess ESI added value in the EZ localization.

Right hemispheric dominance of visual phenomena evoked by intracerebral stimulation of the human visual cortex.

Electrical brain stimulation can provide important information about the functional organization of the human visual cortex. Here, we report the visual phenomena evoked by a large number (562) of intracerebral electrical stimulations performed at low‐intensity with depth electrodes implanted in the occipito‐parieto‐temporal cortex of 22 epileptic patients. Focal electrical stimulation evoked primarily visual hallucinations with various complexities: simple (spot or blob), intermediary (geometric forms), or complex meaningful shapes (faces); visual illusions and impairments of visual recognition were more rarely observed. With the exception of the most posterior cortical sites, the probability of evoking a visual phenomenon was significantly higher in the right than the left hemisphere. Intermediary and complex hallucinations, illusions, and visual recognition impairments were almost exclusively evoked by stimulation in the right hemisphere. The probability of evoking a visual phenomenon decreased substantially from the occipital pole to the most anterior sites of the temporal lobe, and this decrease was more pronounced in the left hemisphere. The greater sensitivity of the right occipito‐parieto‐temporal regions to intracerebral electrical stimulation to evoke visual phenomena supports a predominant role of right hemispheric visual areas from perception to recognition of visual forms, regardless of visuospatial and attentional factors. Hum Brain Mapp 35:3360–3371, 2014.