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StereoElectroEncephaloGraphy (SEEG) is done to identify the epileptogenic zone of the brain using several multi-lead electrodes whose positions in the brain are pre-operatively defined. Intracranial hemorrhages due to disruption of blood vessels can cause major complications of this procedure ($$<$$ < 1 %). In order to increase the intervention safety, we developed and tested planning tools to assist neurosurgeons in choosing the best trajectory configuration. An automated planning method was developed that maximizes the distance of the electrode from the vessels and avoids the sulci as entry points. The angle of the guiding screws is optimized to reduce positioning error. The planner was quantitatively and qualitatively compared with manually computed trajectories on 26 electrodes planned for three patients undergoing SEEG by four neurosurgeons. Quantitative comparison was performed computing for each trajectory using (a) the Euclidean distance from the closest vessel and (b) the incidence angle. Quantitative evaluation shows that automatic planned trajectories are safer in terms of distance from the closest vessel with respect to manually planned trajectories. Qualitative evaluation performed by four neurosurgeons showed that the automatically computed trajectories would have been preferred to manually computed ones in 30 % of the cases and were judged good or acceptable in about 86 % of the cases. A significant reduction in time required for planning was observed with the automated system (approximately 1/10). The automatic SEEG electrode planner satisfied the essential clinical requirements, by providing safe trajectories in an efficient timeframe.

We present the results of a retrospective study on 10 patients operated on for intractable epilepsy associated with nodular heterotopia as identified by high resolution MRI. Seven patients had unilateral heterotopia, one patient had symmetric bilateral heterotopia and two patients had asymmetric bilateral heterotopia. By stereo-electroencephalogram (SEEG) (nine patients) interictal activity within nodules was similar in all cases, and ictal activity never started from nodules alone but from the overlying cortex or simultaneously in nodules and cortex. Excellent outcomes (Engel class Ia, 1987) were achieved in the seven patients with unilateral heterotopia, showing that surgery can be highly beneficial in such cases when the epileptogenic zone is carefully located prior to surgery by MRI and particularly SEEG. For the bilateral cases surgical outcomes were Engel IIa (one patient) or Engel IIIa (two patients). Histological/immunohistochemical studies of resected specimens showed that all nodules had similar microscopic organization, even though their extent and location varied markedly. The overlying cortex was dysplastic in nine patients, but of normal thickness. We suggest that nodule formation may be the result of a dual mechanism: (i) failure of a stop signal in the germinal periventricular region leading to cell overproduction; and (ii) early transformation of radial glial cells into astrocytes resulting in defective neuronal migration. The intrinsic interictal epileptiform activity of nodules may be due to an impaired intranodular GABAergic system.

Sleep-related hyperkinetic seizures are a common feature of nocturnal frontal lobe epilepsy. Although sleep-related seizures with a temporal lobe origin have been reported, they commonly lack hyperkinetic activity. The authors describe three patients with sleep-related seizures characterized by frenetic, agitated, hyperactive movements (bimanual/bipedal activity, rocking, axial, pelvic, and hemiballistic movements), in whom stereo-EEG investigation and surgical outcome demonstrated a temporal lobe origin of the attacks.

The authors performed an MRI, stereo-EEG, and pathology study on a woman with subcortical band heterotopia and partial epilepsy. Clinical manifestations of seizures always started when ictal discharges were present in outer and heterotopic cortices. Simultaneous activation of both cortices and presence of differentiated neurons in the white matter and the heterotopia strongly suggest that the cortices were anatomically and functionally interconnected.

Since the original description by Taylor, the term focal cortical dysplasia has been used to refer to a wide range of alterations of the cortical mantle. More recently, these conditions have been described from neuroimaging, neuropathological and genetic standpoints, generating several classifications. It is widely recognized that these classifications are unsatisfactory. We propose a simplified classification of focal cortical dysplasias based on easily recognized neuropathological characteristics. We retrospectively re‐examined histological sections of cortex from 52 of 224 (23%) patients operated on for drug‐resistant partial epilepsy in which cortical dysplasia was present but not associated with other brain pathologies except hippocampal sclerosis. Three subgroups were identified: (i) architectural dysplasia (31 patients) characterized by abnormal cortical lamination and ectopic neurones in white matter; (ii) cytoarchitectural dysplasia (six patients) characterized by giant neurofilament‐enriched neurones in addition to altered cortical lamination; and (iii) Taylor‐type cortical dysplasia (15 patients) with giant dysmorphic neurones and balloon cells (all but two patients) associated with cortical laminar disruption. The patients with architectural dysplasia had lower seizure frequency than those with cytoarchitectural and Taylor‐type dysplasia, and the epileptogenic zone was mainly in the temporal lobe. In patients with Taylor‐type dysplasia, the epileptogenic zone was mainly extratemporal, and interictal stereo‐EEG was distinctive. MRI was unrevealing in 34% of patients, but distinctive signal alterations characterized most patients with Taylor‐type dysplasia, while focal hypoplasia with MRI abnormalities was found in architectural dysplasia. Patients with Taylor‐type dysplasia had the best outcome, with 75% seizure‐free (Engel class Ia) after at least a year of follow‐up compared with 50% of cytoarchitectural dysplasia and 43% of architectural dysplasia patients seizure‐free. This three‐category classification is based on easily recognized histopathological characteristics and avoids complicated terminology, while the distinctive ensemble of other characteristics defines clinically homogeneous groups.

Since the original description by Taylor, the term focal cortical dysplasia has been used to refer to a wide range of alterations of the cortical mantle. More recently, these conditions have been described from neuroimaging, neuropathological and genetic standpoints, generating several classifications. It is widely recognized that these classifications are unsatisfactory. We propose a simplified classification of focal cortical dysplasias based on easily recognized neuropathological characteristics. We retrospectively re-examined histological sections of cortex from 52 of 224 (23%) patients operated on for drug-resistant partial epilepsy in which cortical dysplasia was present but not associated with other brain pathologies except hippocampal sclerosis. Three subgroups were identified: (i) architectural dysplasia (31 patients) characterized by abnormal cortical lamination and ectopic neurones in white matter; (ii) cytoarchitectural dysplasia (six patients) characterized by giant neurofilament-enriched neurones in addition to altered cortical lamination; and (iii) Taylor-type cortical dysplasia (15 patients) with giant dysmorphic neurones and balloon cells (all but two patients) associated with cortical laminar disruption. The patients with architectural dysplasia had lower seizure frequency than those with cytoarchitectural and Taylor-type dysplasia, and the epileptogenic zone was mainly in the temporal lobe. In patients with Taylor-type dysplasia, the epileptogenic zone was mainly extratemporal, and interictal stereo-EEG was distinctive. MRI was unrevealing in 34% of patients, but distinctive signal alterations characterized most patients with Taylor-type dysplasia, while focal hypoplasia with MRI abnormalities was found in architectural dysplasia. Patients with Taylor-type dysplasia had the best outcome, with 75% seizure-free (Engel class Ia) after at least a year of follow-up compared with 50% of cytoarchitectural dysplasia and 43% of architectural dysplasia patients seizure-free. This three-category classification is based on easily recognized histopathological characteristics and avoids complicated terminology, while the distinctive ensemble of other characteristics defines clinically homogeneous groups.

Abstract: We reviewed 41 studies on epilepsy surgery in 1645 children and adolescents. The available data vary greatly from one paper to another, particularly as regards the age of the patients included, selection criteria, presurgical methodology, and the type of surgical intervention. Moreover, the surgical results are classified according to very different criteria. Our experience in Grenoble concerning 55 children (age ≤16 years; postoperative follow-up >18 months) is discussed in the light of data in the literature. The need is stressed for a consensus on the type of information that must be supplied by well-detailed studies on homogeneous groups of epilepsy surgery patients.

In a man with orthostatic and effort syncopes due to primary dysautonomia, we measured cerebral blood flow (CBF) — by the 133-Xenon inhalation method — in supine and in sitting positions, and after the i.v. administration of Acetazolamide, a potent cereral vasodilator.

Whole blood viscosity (WBV) at the shear rates of 0.471 sec−1and 63.9 sec−1, plasma viscosity, hematocrit, fibrinogen, plasma total cholesterol, HDL- and LDL-cholesterol, and Cerebral Blood Flow (CBF) - by the 133 Xenon inhalation method - were measured before and soon after LDL-apheresis in four patients affected with familial heterozygous hypercholesterolemia.Heart Rate (HR), Blood Pressure, pC02, p02, and pH in capillary blood, and the anxiety level of patients (by the State-Trait Anxiety Inventory) were also measured at the beginning of each CBF examination.WBV at the shear rate of 0.471 sec−1(p<0.05), fibrinogen (p<0.01), plasma viscosity (p<0.05), total cholesterol (p<0.01) and LDL-cholesterol (p<0.01) significantly (paired t-test) decreased after LDL-apheresis, as compared with baseline measurements.No significant differences were found for hematocrit, HDL-cholesterol, WBV at the shear rate of 63.9 sec−1, HR, MABP, pC02, p02, pH, anxiety, and CBF measured before and after LDL-apheresis.These results show that, despite the significant drop in plasma and low shear WBV induced by LDL-apheresis, CBF remains constant, and this is probably because of its autoregulatory property.