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Franck Semah

Publications and source records attributed to Franck Semah.

10 recordsLinked to original sources
PubMed2006

Valproic acid in epilepsy : pregnancy-related issues.

Valproic acid (sodium valproate) is widely used as a first-line antiepileptic agent. As with many antiepileptic drugs, there are a number of consequences associated with the use of valproic acid in women of child-bearing potential. Most pregnancies have a favourable outcome in women with epilepsy, and these women should not be discouraged from becoming pregnant. Unlike many other antiepileptic drugs, valproic acid has no significant pharmacokinetic interactions with the steroid hormones used in oral contraceptives. During pregnancy, the major risks to mother and child result from loss of seizure control on the one hand, and an elevated risk of major congenital malformations due to antiepileptic drug treatment on the other. In particular, an elevated risk of major congenital malformations associated with valproic acid use has been a consistent finding in studies of patient registries and several large case series. In addition, developmental delay, characterised by low verbal IQ, has also been reported in children exposed to valproic acid in utero, although the relative risk is not precisely known. For these reasons, pregnancies in women being treated with valproic acid need to be planned, and the benefit-risk ratios associated with continuing valproic acid or changing treatment need to be discussed with the patient. When treatment with valproic acid is the most appropriate treatment to achieve optimal seizure control, a number of measures can be implemented to minimise risk to the fetus. These include the use of the lowest possible effective dose of valproic acid in monotherapy (ideally <1000 mg/day), appropriate folic acid supplementation and close antenatal monitoring. Regular counselling is a prerequisite for informed planning of pregnancies and optimisation of the probability of a healthy outcome. Future research on valproic acid and pregnancy should involve risk assessment in large, population-based prospective studies.

Abnormalities, Drug-Induced↗
PubMed2005

Involvement of the basal ganglia in refractory epilepsy: an 18F-fluoro-L-DOPA PET study using 2 methods of analysis.

UNLABELLED: Studies in animal models and epileptic patients have led to the suggestion that the basal ganglia (BG) are involved in seizures. PET with 6-18F-L-3,4-fluorodihydroxyphenylalanine (18F-fluoro-L-DOPA) has recently demonstrated a reduction of striatal dopamine uptake in drug-resistant epileptic patients with ring chromosome 20 (r20) using a multiple-time graphical analysis. The aim of the present study was to evaluate the involvement of dopamine in other epileptic syndromes using a multiple-time graphical analysis and the all-brain statistical parametric mapping (SPM) analysis. METHODS: Patients with drug-resistant epilepsy were divided into 3 groups: group 1, with r20 epilepsy (n = 16; mean age +/- SD, 21.5 +/- 5.4 y); group 2, with resistant generalized "absence-like" epilepsy (n = 10; mean age, 32.3 +/- 11.4 y); and group 3, with drug-resistant temporal lobe epilepsy with hippocampal sclerosis (n = 9; mean age, 35.2 +/- 10.3 y). We compared 2 strategies of analysis of the 18F-fluoro-L-DOPA uptake constant (K(i), min(-1)) in BG using a multiple-time graphical analysis using regions of interest (the gold-standard method) and an SPM analysis using a voxel-by-voxel statistical t test to avoid a priori hypotheses in the analysis. Each epileptic group was compared with a group of healthy volunteers (n = 10; mean age, 45.1 +/- 16.5 y). RESULTS: A decrease of the mean K(i) value was observed in the striatum in all groups of patients with both types of analysis. With multiple-time graphical analysis, the reduction was evident using the averaged K(i) values over both hemispheres in each BG. Unilateral decreases in each BG were detected in SPM analysis. A ratio of decrease of 18F-fluoro-L-DOPA uptake was observed in the 3 groups of patients. Only the SPM analysis showed a decrease of 18F-fluoro-L-DOPA uptake ipsilateral to the seizure side in patients with temporal lobe epilepsy. Moreover, the all-brain SPM analysis showed a decrease of 18F-fluoro-L-DOPA uptake in the substantia nigra bilaterally (P < 0.001). CONCLUSION: This result confirms the involvement of dopamine neurotransmission in seizure control related to the type of epileptic syndrome. The difference in epileptic types may depend in part on the seizure frequency.

Adult↗
PubMed2005

Can we predict refractory epilepsy at the time of diagnosis?

The early prediction of intractability is a major challenge in epileptology. Some prognostic factors have been pointed out, most of which simply underlined that partial epilepsy is more difficult to control than idiopathic generalized epilepsy (IGE). Indeed, the main predictors are the presence of a brain lesion demonstrated by neuroimaging or suggested by a neurological deficit or a developmental delay, as well as electroclinical evidence of non idiopathic partial epilepsy. Little is known about the relationship between the location of the epileptogenic area and the chance of being seizure-free in patients with partial epilepsy. Some data suggest that temporal lobe epilepsy (TLE) is more difficult to control than other partial epilepsies, but this might only reflect the prognostic impact of hippocampal sclerosis. Indeed, several studies have shown that the majority of patients with MRI evidence of hippocampal sclerosis develop refractory epilepsy. This observation also applies to patients with malformation of cortical development (MCD). The response to the first AED is another early predictor of refractory epilepsy. At the time of diagnosis, several prognostic factors are available to predict drug resistance, but further studies are still needed to better delineate the specific role of each of these factors, and to offer a more accurate prediction of long term seizure outcome.

Drug Resistance↗
PubMed2004

The choice of antiepileptic drugs in newly diagnosed epilepsy: a national French survey.

The choice of an antiepileptic drug (AED) in patients with epilepsy is mainly based on efficacy and safety of each drug. However, these criteria of drug selection should be further evaluated according to the epileptic syndromes, and adjusted to the sex and age of the patient. Unfortunately, very few studies have been conducted based on these latter criteria. We conducted a survey on the management of epilepsy treatment in adults. This survey was undertaken in France, and led to the establishment of a French consensus on antiepileptic drug treatment in adult patients with newly diagnosed epilepsy. Patients were grouped into 18 categories according to the epileptic syndrome (absence epilepsy, juvenile myoclonic epilepsy, undetermined idiopathic generalized epilepsy, symptomatic or cryptogenic partial epilepsy and unclassified epilepsy), and to the patient's gender and age. Our survey suggests that there is a consensus among French epileptologists for the choice of AEDs, mainly based on the epilepsy syndrome. Gender also plays a crucial role. Sodium valproate and lamotrigine are the two drugs of choice for generalized epilepsies, as well as for undetermined epilepsies. Lamotrigine is often prefered for women of childbearing age. First line AEDs in partial epilepsy are carbamazepine (particularly for men), lamotrigine (particularly for women), and gabapentin (in the elderly). In cases of failure and/or intolerance to one of these AED, the principal alternatives are oxcarbazepine, sodium valproate and topiramate.

Adolescent↗
PubMed2003

Metabolic changes and electro-clinical patterns in mesio-temporal lobe epilepsy: a correlative study.

Interictal hypometabolism is commonly found in mesio-temporal lobe epilepsy (MTLE), but its pathophysiology remains incompletely understood. We hypothesized that metabolic changes reflect the preferential networks involved by ictal discharges. We analysed the topography of interictal hypometabolism according to electro-clinical patterns in 50 patients with unilateral hippocampal sclerosis (HS) and consistent features of MTLE. Based on electro-clinical correlations, we identified four groups: (i) mesial group (13 cases) characterized by mesial seizure onset without evidence of early spread beyond the temporal lobe; (ii) anterior mesio-lateral group (AML; 18 cases) with early anterior spread involving the anterior lateral temporal cortex and insulo-fronto-opercular areas; (iii) widespread mesio-lateral group (WML; 15 cases) with wide spread (involving both anterior and posterior lateral temporal and perisylvian areas); and (iv) bitemporal (BT) group (four cases) with early contralateral temporal spread. Results of [18F]fluorodeoxyglucose-PET imaging in each group were compared with those of 10 control subjects using statistical parametric mapping software (SPM99). MRI data and surgical outcome in each group were compared with metabolic findings. Hypometabolism was limited to hippocampal gyrus, temporal pole and insula in the mesial group. Gradual involvement of lateral temporal cortex, insula and perisylvian areas was observed in the AML and WML groups. The BT group differed from the others with mild bitemporal involvement, bilateral insular hypometabolism and longer epilepsy duration. MRI structural abnormalities outside of the mesial formations were detected in 65% of the cases. Neither the severity of HS nor temporal atrophy appeared related to the topography of hypometabolism. However, temporal hypometabolism was more extended when temporo-polar signal changes were detected. Among operated patients (n = 43), seizure-free outcome was obtained in 82%. Surgical outcome appeared more favourable in the mesial group. However, the difference between the four groups was not significant. Our results suggest that hypometabolism in MTLE may be related to ictal discharge generation and spread pathways, even if structural changes and epilepsy duration may also play a role.

Adolescent↗
PubMed2002

Temporal pole hypometabolism may be linked to a reduction of grey matter in temporal lobe epilepsy.

In order to gain further insight into the pathophysiology of temporal pole hypometabolism, we decided to perform a voxel-based automated analysis of structural MRI in epileptic patients with or without temporal pole hypometabolism. After fully automated segmentation of cerebral grey matter from structural T1-weighted MRI scans, we applied the automated technique of statistical parametric mapping (SPM) to the analysis of grey matter of nine control subjects, and 18 patients with right medial temporal lobe epilepsy with (n = 13) or without (n = 5) significant temporal pole hypometabolism. Group comparisons between subject controls and epileptic patients with temporal pole hypometabolism showed a reduction of grey matter located into the superior part of the right temporal pole, the right hippocampus and the left parahippocampal gyrus. Epileptic patients without temporal pole hypometabolism did not exhibit temporal pole grey matter abnormalities. These findings suggest that a reduction of temporal pole neocortical grey matter might contribute to temporal pole hypometabolism in temporal lobe epilepsy.

Adult↗
PubMed2002

Correlation between PET and SISCOM in temporal lobe epilepsy.

UNLABELLED: The subtraction of interictal from ictal SPECT coregistered to 3-dimensional (3D) MRI (SISCOM) and (18)F-FDG PET are 2 techniques that are involved in the definition of the epileptogenic zone in refractory partial temporal lobe epilepsy (TLE). The aim of this study was compare, region by region, the functional patterns obtained by both strategies, SISCOM and PET, in patients with unilateral TLE. METHODS: Perfusion data using SISCOM and metabolic data using (18)F-FDG PET scans were acquired from 17 patients with unilateral TLE. The functional metabolism and perfusion maps were overlaid onto a 3D rendering of the patient's anatomic MRI scans. RESULTS: The functional patterns that were observed with PET and SISCOM were found mainly in the ipsilateral and contralateral temporal lobes, in the orbitofrontal and insular cortices. Despite the high rate of concordance, in some cases discrepancies could be observed between PET and SISCOM abnormalities: In the mesial regions, as in the anterior neocortex, PET abnormalities were found more frequently than SISCOM changes. SISCOM abnormalities were found more frequently in the posterior temporal neocortex. In the extratemporal cortex, SISCOM abnormalities were more widespread. CONCLUSION: The marked rate of concordance between PET and SISCOM abnormalities observed in relatively extensive regions shows that, in TLE, seizures were generated and spread in metabolically abnormal regions.

Adult↗
PubMed2002

Temporoporal metabolic abnormalities in temporal lobe epilepsies.

Positron emission tomography (PET) may be used to map regional cerebral glucose metabolism using 18F-deoxyglucose-PET in patients with partial epilepsy. An area of reduced glucose metabolism, that is commonly more extensive than the underlying anatomical abnormality, is reported in most of the patients with medically refractory partial epilepsy. These functional changes are useful in the delineation of the epileptogenic focus prior to surgery. Nevertheless, in patients with mesial temporal lobe epilepsy (MTLE) without mass lesion, the hypometabolism involves a large area of the temporal lobe, including the mesial structures, the temporal pole and part of the lateral temporal cortex. In such patients with MTLE, subcortical structures and extratemporal lobe areas are also often hypometabolic. The reasons for this large hypometabolism remain debated. In MTLE patients, the most severe hypometabolism is found in the temporo-polar region. The clinical significance of this temporo-polar hypometabolism is unknown. The pathophysiology of interictal hypometabolism probably involves several mechanisms, such as neuronal loss, deafferentation, postictal depression, and others epilepsy-related phenomena. The relationship between interictal temporo-polar hypometabolism and seizure onset or seizure spread remain speculative.

Epilepsy, Temporal Lobe↗
PubMed2002

PET imaging in epilepsy: basal ganglia and thalamic involvement.

Positron emission tomography imaging has revealed basal ganglia and thalamic abnormalities in cerebral blood flow, metabolism and neurotransmission in patients with partial epilepsy. Although these changes remain of uncertain significance, this involvement could be associated with the initiation, propagation or control of seizures. This paper will review the imaging data obtained using positron emission tomography in patients with partial and generalized epilepsy.

Basal Ganglia↗