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Biomedical subjects

Philippe Kahane

Publications and source records attributed to Philippe Kahane.

10 recordsLinked to original sources
PubMed2003

Restricted frontomesial epileptogenic focus generating dyskinetic behavior and laughter.

PURPOSE: Substantial data are missing about the anatomic location of frontal regions supporting gelastic seizures. METHODS: We report the results of stereo-electro-encephalographic recordings performed over several distinct functional premotor and executive fields in a patient whose seizures were characterized by dyskinetic behavior and ictal laughter, in the absence of cerebral MRI abnormalities. RESULTS: The epileptogenic zone was circumscribed in the anterior and ventral part of the supplementary motor area and the underlying dorsal cingulate cortex. There were no or little spreading to cortical neighboring areas. The patient is seizure-free (follow-up of 27 months) after a stereotactic electric radiofrequency lesion of the epileptogenic focus. CONCLUSION: The present data suggest that pericingulate premotor areas are involved in the triggering of the motor component of laughter. In this case, the coexistence of paroxysmal dyskinesias during laughter might reflect the involvement of specific compartment(s) of the basal ganglia.

Adult↗
PubMed2003

Epilepsy and hypothalamic hamartoma: look at the hand Pallister-Hall syndrome.

We report the case of a 29-year-old patient, who suffered from drug resistant laughing seizures since childhood. The clinical examination was normal, except for sequelae of hand and feet surgery during infancy for post-axial polydactyly. Cerebral MRI showed a hypothalamic hamartoma. The association of complex limb abnormalities with hypothalamic hamartoma lead to the diagnosis of Pallister-Hall syndrome. This syndrome is related to a mutation of gene GLI3, located on chromosome 7p13, and its inheritance is autosomal dominant. In the case of laughing seizures, a cerebral MRI should be performed to look for a hypothalamic hamartoma. The observation of such lesions indicates the necessity of standard radiographies of the hands and feet, to search for associated abnormalities. These findings might help to recognize a Pallister-Hall syndrome, thus allowing genetic counseling.

Adult↗
PubMed2003

MRI morphological and volumetric study of the cingulate gyrus and its relevance in partial epileptic patients.

The cingulate gyrus (CG) is often involved during partial epileptic seizures. The purpose of the study was to analyse the CG morphology and to measure the CG volume in epileptic patients, in order to detect subtle MRI abnormalities such as atrophy, which could be indicative of its implication in the epileptogenic area. The population consisted of 20 epileptic patients (31.2 +/- 9.4 years) and 20 normal volunteers (31.8 +/- 7.7 years). The epileptic patients underwent intracerebral recordings, and were sub-divided into five patients presenting with seizures involving the CG (CG 1), seven patients in whom the CG was only secondarily involved (CG 2) and eight patients in whom the CG was not invoved at all (CG 3). All subjects were investigated by MRI (1.5 tesla Gyroscan Philips): axial T1w 3D Gradient Echo acquisitions, thickness 1.5 mm, reconstructions in all planes. At first, we described the sulcal limits of the CG, trying to define a "normalised CG". In a second step, we segmented the CG intrasulcal grey matter using the "Surgiscope Scopeplan" (Elekta). We compared (Mann and Whitney U test [alpha=0.05]), the CG volumes of CG 1 to CG 2 + 3, and the volume of CG 1 and of CG 1 + 2 + 3 to that of normal volunteers. There was no significant difference between CG 1 and CG 2 + 3 (P= 0.89), between CG 1 and normal volunteers (P= 0.75) or between CG1 + 2 + 3 and normal volunteers (P = 0.83). The volumetric analysis showed no atrophy of the CG in epileptic patients and did not distinguish the group in whom seizures involved the CG, from the other groups.

Adult↗
PubMed2002

Surgical pathology of drug-resistant partial epilepsy. A 10-year-experience with a series of 327 consecutive resections.

Herein we reviewed the histopathological findings in 327 consecutive surgical specimens from patients with pharmaco-resistant epilepsy (PRE). Three major pathological groups (78.3% of all cases) were identified: Ammon's horn sclerosis (85 cases as an isolated lesion plus 18 as one part of a dual pathology), tumors (94 cases), and malformations (77 cases). Tumors, often associated with cortical dysplasias (CDs), were all of low histological grade and included 61 dysembryoplastic neuroepithelial tumors (DNTs), 29 gangliogliomas, and 4 pleomorphic xanthoastrocytomas (PXAs). Among the malformations were observed 52 CDs, 13 cavernomas, 8 cortical tubers, and 4 cysts. The remaining findings consisted of 16 scars (mostly post-traumatic) and 4 Rasmussen's encephalitis. Fifty-one (15.6%) specimens contained non-specific changes, and histological samples from 215 patients with presurgical implantation of electrodes revealed iatrogenic changes. All these figures are in agreement with the most recent and comparable series, and confirm the high incidence of DNTs that appear clearly as the most common tumoral entity in PRE. Our data also support the hypothesis of a close histogenetic relationship between DNT, ganglioglioma, and PXA, with a putative common origin from pluripotential progenitor CD34 positive cells of the subpial granular layer. As for CDs, our study confirms the clinical relevance of two main subtypes: severe CD (or Taylor's type CD) with neuronal cytomegaly and balloon cells, and non-Taylor's type CDs with a better outcome. Eventually, this series demonstrates that most patients have significant histopathological lesions, among which, aspects that are relevant to the diagnostic surgical pathologist are highlighted [published with a complete image database on CD-Rom].

Adolescent↗
PubMed2002

Anatomy of the temporal pole region.

The temporopolar region is not clearly defined from an anatomical point of view. A line going through the rostral area of the inferior temporal, occipito temporal and superior temporal sulci is considered to represent its posterior limit on the lateral and inferior sides. On the internal side, this posterior limit corresponds to the rhinal sulcus, an anterior and internal extention of the collateral sulcus. From a cyto-architectonic point of view, the temporopolar region is caracterized by a dysgranular paralimbic cortex which ensures the transition between allo- and isocortical areas. The temporal pole is mainly connected with the amygadala, the hippocampus, the superior temporal gyrus, and the occipitobasal cortex, but also with the orbitary gyrus and the insula with which it forms the insulo-orbito-polar-temporo-complex. The temporal pole occupies the most rostral part of the temporal lobe and can only be accurately defined once the anatomy of the temporal lobe as a whole has been outlined. The architectonic configuration of this region as well as its connections with the limbic system, and the superior, orbital and insular temporal cortices make it a discrete temporal structure. Understanding the anatomical and functional organization of the temporal pole enables us to hypothesize about the role played by this structure in the pathogenesis of the forms of epilepsy originating in mesial temporal lobe structures.

Basal Ganglia↗
PubMed2002

The role of the temporal pole in the genesis of temporal lobe seizures.

Failure of selective amygdalo-hippocampectomy strongly suggests that the so-called mesio-temporal lobe seizures do not always arise from the sole amygado-hippocampo-parahippocampal complex. Studies in temporal lobe epilepsies have shown that even in the presence of hippocampal sclerosis, the temporo-polar region (TP) is often altered, both histologically, anatomically and functionally. These findings are in accordance with our last ten years experience in stereotactic intracerebral EEG recordings (SEEG), during which we frequently observed the simultaneous involvement of both the amygdala (A), the hippocampus (Hc) and the TP at the onset of temporal lobe seizures. Recently, we have reviewed the SEEG findings of 25 patients with a final diagnosis of temporal lobe epilepsy, in whom both mesial, lateral and polar temporal lobe structures were investigated. The analysis of the most representative seizure in each patient showed that a low voltage fast activity was recorded in the TP either initially or within the first 5 seconds in 13/25 patients (TP group, 52%), while in the remaining 12 cases, ictal discharges started in the Hc and/or amygdala with a later involvement of the TP (AH group, 48%). Preliminary results of a further study conducted in 48 patients have confirmed the high frequency of early TP involvement (2/3 of the cases) in temporal lobe seizures, the clinical characteristics of which did not differ from ictal clinical findings usually described in the mesio-temporal lobe epilepsy syndrome. History of prolonged febrile convulsions and diagnosis of Hc sclerosis were more frequent in the AH group, while early consciousness impairment during seizures and anterior temporal white matter changes on MRI were more frequently observed in TP patients. However a clear-cut distinction between the two groups remains rather difficult in the absence of intracerebral recordings.

Amygdala↗
PubMed2002

Deep brain stimulation in epilepsy with particular reference to the subthalamic nucleus.

Alternative methods, for the treatment of medically refractory epileptic patients, who cannot be treated by resective surgery, such as chronic deep brain neurostimulation, are under development. Such methods have been used in the cerebellum, various thalamic nuclei, and in the caudate nucleus. In Grenoble, encouraged by the suppressive effects of pharmacological or electrical inhibition of the STN on different types of seizure in animal models of epilepsy, and by our experience with STN high frequency stimulation (HFS) in patients with movement disorders, we have evaluated the high frequency stimulation of the subthalamic nucleus (STN HFS). STN HFS was performed in five patients suffering from medically intractable seizures and considered unsuitable for resective surgery. A 67% to 80% reduction in seizure frequency was observed in three patients, with a partial symptomatic epilepsy of the central region. An additional patient suffering from severe myoclonic epilepsy (Dravet syndrome) also responded to STN HFS, with a weaker reduction of seizure frequency. The fifth patient who suffered from an autosomal dominant frontal lobe epilepsy with insulo-frontal seizures did not show any improvement. These results suggest that stimulation of STN could be a promising treatment for patients with drug-resistant epilepsy who would not benefit from conventional surgery.

Adolescent↗