Molecular imaging in the diagnosis of Alzheimer's disease and related disorders.

INTRODUCTION: The diagnosis of Alzheimer's disease (AD) and its related disorders rely on clinical criteria. There is, however, a large clinical overlap between the different neurodegenerative diseases affecting cognition and, frequently, there are diagnostic uncertainties with atypical clinical presentations. Current clinical practices can now regularly use positron emission tomography (PET) and single-photon emission computed tomography (SPECT) molecular imaging to help resolve such uncertainties. The Neurology Group of the French Society of Nuclear Medicine and Federations of Memory, Resources and Research Centers have collaborated to establish clinical guidelines to determine which molecular imaging techniques to use when seeking a differential diagnosis between AD and other neurodegenerative disorders affecting cognition. STATE OF KNOWLEDGE: According to the current medical literature, the potential usefulness of molecular imaging to address the typical clinical criteria in common forms of AD remains modest, as typical AD presentations rarely raise questions of differential diagnoses with other neurodegenerative disorders. However, molecular imaging could be of significant value in the diagnosis of atypical neurodegenerative disorders, including early onset, rapid cognitive decline, prominent non-amnestic presentations involving language, visuospatial, behavioral/executive and/or non-cognitive symptoms in AD, or prominent amnestic presentations in other non-AD dementias. CONCLUSION AND PERSPECTIVE: The clinical use of molecular imaging should be recommended for assessing cognitive disturbances particularly in patients with early clinical onset (before age 65) and atypical presentations. However, diagnostic tools should always be part of the global clinical approach, as an isolated positive result cannot adequately establish a diagnosis of any neurodegenerative disorder.

[Nuclear medicine imaging: new radiotracers and future techniques]. / L'imagerie de médecine nucléaire: nouveaux traceurs et techniques d'avenir.

Nuclear medicine imaging is based upon positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging. PET and SPECT are widely used in patients with medically refractory partial epilepsy. For clinical purposes, PET is performed using FDG and SPECT is performed using perfusion agents. PET is also used to better understand the pathophysiological mechanisms of epilepsies. New radiotracers are available for PET and SPECT imaging such as (18)F-fluoro-L-Dopa and (123)I-FP-CIT and others are under development. In addition, there are currently new methodological developments combining techniques such as SPECT associated with computed tomography and in the near future PET combined with MRI. This progress will improve the performance of nuclear medicine imaging techniques.

[Medicoeconomic assessment of epilepsy surgery in adults with medically intractable partial epilepsy. Three-year outcomes from a multicenter French cohort]. / Evaluation médicoéconomique de la chirurgie des épilepsies partielles pharmacorésistantes de l'adulte. Résultats à trois ans d'une étude prospective multicentrique française.

PURPOSE: To compare resective surgery and medical therapy in a cost-effectiveness analysis in a multicenter cohort of adult patients with partial intractable epilepsy. POPULATION AND METHODS: Adult patients with partial, medically intractable, potentially operable epilepsy were eligible and followed every year over five years. Effectiveness was defined as one year without seizure. The long-term costs and effectiveness were extrapolated over the patients' lifetime with a Markov model. Productivity (indirect costs) and quality of life (QOLIE-31, SEALS) were also assessed. Changes before and after surgery were compared between the two groups. RESULTS: Two hundred and eighty-nine patients were included (119 with surgery, 161 medically treated, six not eligible, three lost to follow-up). One year after surgery, 81% of the patients were seizure-free; at two and three years, this rate was 78%. In the medical group, these rates were 10, 18, and 15%, respectively. The cost of the explorations was euro 8464; including surgery, it was euro 19,700. In the medical group, the average annual direct costs were between 3500 and euro 6000. At two years after surgery, the annual direct cost decreased to euro 2768, at three years, it was euro 1233, predominately antiepileptic drug costs. Surgery became cost-effective between seven and eight years. In the surgical group, all the quality-of-life scores improved at one year after surgery and were stable during the second and third years. CONCLUSION: Surgical therapy was cost-effective at the middle term even though indirect costs were not considered.

[Use of generic anti-epilepsy drugs in France: survey of neurologists and review of the literature]. / Utilisation des médicaments génériques des anti-épileptiques en France: résultats d'une enquête auprès des neurologues et revue de la littérature.

INTRODUCTION: The use of generic substitution for antiepileptic drugs is more and more frequent but remains controversial. PURPOSE AND METHODS: This survey aimed to assess physicians' feelings towards effectiveness, tolerability and clinical impact of generic substitution of antiepileptic drugs on their patients. A questionnaire was sent to all French private neurologists and hospital specialists in epilepsy. Their responses were recorded from December 2005 to March 2006. RESULTS: A total of 312 neurologists responded. A few prescribed generic antiepileptic drugs; but a few as well indicated not to switch their prescription. Most of them felt discomfort by generic substitution. One third reported breakthrough seizures or new adverse events after generic substitution and 70p.cent extra phone consultation. DISCUSSION: Neurologists' reluctance with prescribing generic AEDs may be explained by several different facts: no controlled study about the safety and efficacy of generic AEDs as compared with brand name drugs, substitutions by pharmacists without their agreement, lack of medical information about generic AEDs, symbolic dimension of the treatment, and, most of all, the fear of breakthrough seizures in patients good controlled. CONCLUSION: A prospective controlled evaluation of the safety and efficacy of generic substitution in epilepsy needs to be performed.

Brain metabolic abnormalities during gait with freezing in Parkinson's disease.

INTRODUCTION: Freezing of gait (FoG) is a debilitating gait disorder in Parkinson's disease (PD). In advanced PD patients with FoG, the supraspinal locomotor network may be dysregulated (relative to similar patients without FoG) during gait. Here, we sought to characterize the metabolism of locomotor networks involved in FoG. METHODS: Twenty-two PD patients (11 with off-drug FoG and 11 without) each underwent two [(18)F]-fluorodeoxyglucose PET brain scans in the off-drug state: one at rest and another during radiotracer uptake while performing a standardized gait trajectory that incorporated the usual triggers for FoG. RESULTS: For the 11 freezers, FoG was present for 39% (± 23%) of the time during the gait trajectory. The FoG-associated abnormalities were characterized by (i) hypometabolism in frontal regions (the associative premotor, temporopolar and orbitofrontal areas, i.e. Brodmann areas 6 and 8), (ii) hypermetabolism in the paracentral lobule (Brodmann area 5), and (iii) deregulation of the basal ganglia output (the globus pallidus and the mesencephalic locomotor region). CONCLUSION: FoG during a real gait task was associated with impaired frontoparietal cortical activation, as characterized by abnormally low metabolic activity of the premotor area (involved in the indirect locomotor pathway) and abnormally high metabolic activity of the parietal area (reflecting the harmful effect of external cueing).

Association of ipsilateral motor automatisms and contralateral dystonic posturing: a clinical feature differentiating medial from neocortical temporal lobe epilepsy.

BACKGROUND: Clinical features that may help to differentiate medial temporal lobe epilepsy (MTLE) from neocortical temporal lobe epilepsy (NTLE) are lacking. OBJECTIVE: To investigate the localizing and lateralizing value of the association of ipsilateral motor automatisms and contralateral dystonic posturing in patients with medically refractory temporal lobe epilepsy. PATIENTS AND METHODS: Videotapes of 60 patients with well-defined MTLE, NTLE, or both were reviewed to assess the presence and the localizing value of unilateral dystonic posturing associated with motor automatisms. RESULTS: Twenty-eight of the 60 patients exhibited unilateral dystonic posturing. This sign was observed in patients with MTLE and NTLE. It was mostly contralateral to the seizure focus in patients with MTLE and exclusively ipsilateral in patients with NTLE. Unilateral motor automatisms occurred in 26 of the 60 patients with MTLE or NTLE. It was predominantly ipsilateral to the seizure focus in patients with MTLE and exclusively contralateral in patients with NTLE. The association of ipsilateral motor automatisms and contralateral dystonic posturing was found in 14 patients with MTLE but in none of the patients with NTLE. Two patients who had medial and neocortical seizure onset also exhibited this clinical feature. This association was not significantly correlated with the postoperative outcome in patients with MTLE. CONCLUSIONS: The association of ipsilateral motor automatisms and contralateral dystonic posturing may help to differentiate MTLE from NTLE with a reliable lateralizing value. This clinical association may reflect a specific pattern in the spread of the ictal discharge.

Accurate prediction of postoperative outcome in mesial temporal lobe epilepsy: a study using positron emission tomography with 18fluorodeoxyglucose.

BACKGROUND: Recent studies suggest that positron emission tomography may be a reliable predictive indicator of clinical outcome following surgical treatment for epilepsy. OBJECTIVE: We evaluated 30 patients with documented medial temporal lobe epilepsy to determine if prediction of postoperative outcome is improved with the use of positron emission tomography with (18)fluorodeoxyglucose. PATIENTS AND METHODS: We performed a discriminant analysis to determine the combination of metabolic asymmetry indexes in temporal and extratemporal regions defined by magnetic resonance imaging that best predicted the postoperative outcome. Seizure outcome was assessed at least 2 years after surgery: patients were classified as seizure free (n = 14, group A), mostly improved (n = 10, group B), or as having persistent seizures (n = 6, group C). RESULTS: Discriminant analysis was first performed in groups A and C. The temporal pole seemed to be the only temporal region for which metabolism was a significant predictor of the postoperative outcome (F(1,18) = 10.19; P =.005). The predictive value of positron emission tomography with (18)fluorodeoxyglucose was considerably improved by the multivariate analysis (F(4,15) = 7.21; P =.002), which correctly predicted the 2 -year prognosis in 100% of the patients using 4 regions: the temporal pole, the medial temporal region, the anterior part of the lateral temporal neocortex, and the basofrontal region. As a validation, we performed this 4-region analysis in the patients in group B. The difference among the 3 groups was highly significant (F = 15.5, P<.001). CONCLUSION: These findings suggest that the interictal metabolic pattern reliably predicts the 2-year prognosis after surgery in patients with medial temporal lobe epilepsy.

The underlying pathophysiology of ictal dystonia in temporal lobe epilepsy: an FDG-PET study.

BACKGROUND: Unilateral dystonic posturing of limbs occurs frequently in medial temporal lobe epilepsy (MTLE) but its underlying anatomic basis is still unknown. OBJECTIVE: To investigate the pathophysiology of dystonic posturing, we examined the relation between the occurrence of dystonia and interictal cerebral metabolic abnormalities using fluorodeoxyglucose (FDG)-PET in MTLE patients. METHODS: Video recordings of 30 patients with documented MTLE were reviewed to assess the presence of ictal dystonic posturing. Interictal FDG-PET was performed in all patients. RESULTS: Eighteen patients exhibited dystonic posturing--contralateral to the seizure focus in 16 cases, bilateral in one, and ipsilateral in one. Dystonia was statistically associated with more severe hypometabolism in the striatal and in the orbitofrontal regions ipsilateral to the seizure focus. CONCLUSION: Hypometabolism observed in the striatal region of patients with ictal dystonic posturing suggests that the basal ganglia are involved in the generation of ictal dystonic posturing in MTLE.

Progressive facial hemiatrophy and epilepsy: a common underlying dysgenetic mechanism.

Progressive facial hemiatrophy (PFH), a rare disorder characterized by progressive and self-limited atrophy of the skin and the subcutaneous tissues, is often associated with epilepsy but the link between these two conditions is poorly understood. The cause of PFH remains unclear. We report four patients with PFH associated with partial epilepsy in whom brain MRI showed cerebral dysgenesis. The four patients (two men, two women; age range: 24 to 73 years) developed parasagittal PFH in their second decade. Seizures started before the age of 20 years in three patients and were refractory simple, or complex partial seizures. All the patients had focal MRI showing cortical dysgenesis, ipsilateral to PFH, consisting of cortex thickening, gyral effacement, and blurring of the white-gray interface. The underlying white matter was hyperintense on T2-weighted sequences, with nodular areas in two patients. These areas were stable over time, without contrast enhancement, and were consistent with the MRI characteristics of cystic encephalomalacia. These neuroradiologic features suggest a localized cerebral hemispheric defect of congenital origin. Because cells participating in the formation of the fronto-nasal bud derive from common progenitors with the cells that give rise to the cerebral hemisphere, we suggest that an early malformative process affecting one side of the rostral neural tube could underlie both cerebral dysgenesis and facial hemiatrophy.

Is the underlying cause of epilepsy a major prognostic factor for recurrence?

BACKGROUND: We investigated the prognostic value of the type of epilepsies and epileptic syndromes for seizure recurrence. In patients with partial epilepsy, we focused on the prognostic value of any structural brain abnormality and of the location of the epileptogenic region. METHODS: A total of 2,200 adult outpatients were included in a hospital-based observational survey, with a follow-up of 1 to 7 years. Twenty-two percent of the patients exhibited generalized epilepsy, 62% partial epilepsy, and 16% undetermined epilepsy. RESULTS: Seizure control (>1 year without seizure) was achieved in 82% of patients who had idiopathic generalized epilepsy, 35% of those with symptomatic partial epilepsy, 45% of those with cryptogenic partial epilepsy, and 11% of those with partial epilepsy associated with hippocampal sclerosis (HS). Temporal lobe epilepsy (TLE) was the most refractory partial epilepsy, with only 20% of such patients remaining seizure free, compared with 36% of extra-TLE patients. In partial epilepsy, HS, cerebral dysgenesis, and dual pathology (HS and another lesion) were associated with a low rate of seizure-free patients (11%, 24%, and 3%, respectively). No significant difference in seizure control was found between patients with extra-TLE and those with TLE and no HS. CONCLUSIONS: In adults, partial epilepsy is more difficult to treat than idiopathic generalized epilepsy. In patients who have partial epilepsy, the location of the epileptogenic zone does not seem to be a determining factor. Brain abnormalities--especially HS, either alone or associated with another lesion--are a major prognostic factor.

In vivo imaging of muscarinic cholinergic receptors in temporal lobe epilepsy with a new PET tracer: [76Br]4-bromodexetimide.

UNLABELLED: Muscarinic acetyl cholinergic receptors (mAChRs) may be involved in the pathophysiology of partial epilepsy. Previous experimental and imaging studies have reported medial temporal abnormalities of mAChR in patients with medial temporal lobe epilepsy (MTLE). Suitable radiotracers for mAChR are required to evaluate these disturbances in vivo using PET. Dexetimide is a specific mAChR antagonist that has been labeled recently with 76Br. This first study in humans focused on regional distribution and binding kinetics of [76Br]4-bromodexetimide (BDEX) in patients with MTLE. METHODS: Ten patients with well-lateralized MTLE had combined MRI, 18F-fluorodeoxyglucose (FDG) PET and 76Br-BDEX PET studies. Time-activity curves were generated in PET-defined regions of interest, including the medial, polar and lateral regions of the temporal lobe; the basal ganglia; the external and medial occipital cortex; and the white matter. RESULTS: The highest radioactivity concentration was observed in the basal ganglia and in the cortical regions, whereas radioactivity was lower in the white matter. On late images of PET studies, 76Br-BDEX uptake was statistically significantly decreased only in the medial temporal region ipsilateral to the seizure focus (1.37 +/-0.28, P < 0.01) as determined by FDG PET imaging, anatomic MRI and electroencephalogram correlation, compared with the contralateral medial temporal region (1.46 +/- 0.31). CONCLUSION: 76Br-BDEX concentration is reduced in the temporal lobe ipsilateral to the seizure focus in patients with MTLE. This preliminary study suggests that 76Br-BDEX is a suitable radiotracer for studies of mAChR in humans. Further studies are required to investigate the potential value of 76Br-BDEX PET in other neurological disorders with muscarinic disturbances.

Developmental abnormalities of the medial temporal lobe in patients with temporal lobe epilepsy.

PURPOSE: To evaluate MR temporal lobe malformations and their frequency in patients with temporal lobe epilepsy. METHODS: Two hundred twenty-two consecutive adult patients with temporal lobe epilepsy of varying severity were investigated with 1.0-T or 1.5-T MR units using three-dimensional T1-weighted acquisition protocol. RESULTS: Sixteen patients (7.2%) presented with malformations of the temporal lobe. Four patterns of malformations were encountered: (a) heterotopia (n = 1), lining the temporal horn of the lateral ventricle; (b) focal neocortical dysgenesis (n = 6), which consisted of cortical thickening, poor gray/white matter demarcation, abnormal gyration (n = 5), or limited schizencephaly (n = 1); (c) hippocampal malformations (n = 5), which presented as abnormal hippocampal formation associated with a cyst (n = 2), isolated malformation of the subiculum (n = 1), or bilateral hippocampal malformation (n = 2) consisting of an abnormal shape and a misplaced fimbria; (d) complex malformations of the temporal lobe, combining categories a, b, and c (n = 4). The age at onset, severity of the disease, and occurrence of generalized tonicoclonic seizures were not significantly different between patients with malformations and the entire population of patients with temporal lobe epilepsy. CONCLUSION: MR analysis of temporal lobe malformations allowed a precise determination of the extent of the malformations and the presence or absence of associated hippocampal disease, all of which are of great help in the preoperative evaluation of patients with intractable epilepsy.

Early and delayed MR and PET changes after selective temporomesial radiosurgery in mesial temporal lobe epilepsy.

We report a patient with medically refractory mesial temporal lobe epilepsy treated by gamma knife radiosurgery. In lieu of a microsurgical procedure, an entorhinoamygdalohippocampectomy was performed with a gamma knife and low marginal doses (25 Gy). The clinical and imaging studies, including CT, MR imaging, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and long-term follow-up MR examinations, are reported. The patient has been seizure-free since the day of treatment, with no clinical complications. MR studies accurately depicted the effect on the target structures and the transient secondary changes around them. FDG-PET scans showed decreased metabolism after gamma knife surgery throughout the anteromesial part of the epileptogenic temporal lobe. This metabolic decrease was reversible in the lateral temporal cortex. Our case suggests that gamma knife surgery is a promising tool for use as a minimally invasive approach to the treatment of epilepsy.

Hippocampal formations imaging with axial sections parallel to their longitudinal axis.

The complex shape of hippocampal formation (HF) and its obliquity make its morphological analysis difficult using brain imaging techniques. Adapted planes of section are required. The hippocampal axial plane (HAP) parallel to the hippocampus long axis is able to provide a complete and comprehensive view of the structure. HF has a rostrocaudal extent and is divided into three parts, head, body, and tail. Histological sections in the HAP display very well the pattern of the cell layers, with their transversal folding at the head and the tail. At more ventral levels, HF sections consist of parts of the CA1 field and the subicular complex. These are completely embedded in the temporal lobe and separated from its medial surface by the white matter and the cortical plate of the parahippocampal gyrus. More dorsal sections allow the study of the amygdala, uncus and fimbria. Functional images of HF can be accurately defined by combining magnetic resonance imaging (MRI), positron emission tomography (PET), or single photon emission computed tomography (SPECT) in this plane. According to the small dorsal-ventral dimension of the structures, a few slices can cover the whole HF and precise regions of interest may be outlined.

Gabapentin add-on therapy with adaptable dosages in 610 patients with partial epilepsy: an open, observational study. The French Gabapentin Collaborative Group.

The objectives were to evaluate gabapentin add-on therapy in a large population under conditions close to real practice and to determine the therapeutic doses as reached with adaptable dosages. A 6-month multicentre, open-label study, involved addition of gabapentin to pre-existing treatment at the initial dosage of 1200 mg and subsequent adjustment between 900 and 2400 mg/day according to efficacy and tolerability. A study group of 610 adult patients, with partial epilepsy, persistent seizures and a median seizure frequency with a baseline of 7.2 per month were recruited; one-third had less than four seizures per month. Polypharmacy was frequent, with a mean of 2.3 concomitant drugs. After 6 months, 368 patients (62%) continued on gabapentin, at a mean dosage of 1739 mg/day with 44% of responders. On an intention-to-treat basis, median reduction in frequency was 21.2%, and the responder rate was 33.9%. The responder rate increased to 40.7% in the less severe subgroup receiving only one concomitant drug. Seventy-nine patients (13.4%) remained without seizures during the last evaluation period, versus nine (1.5%) during the baseline. Most of them had initially less than four seizures per month. The most frequent adverse effects, somnolence (29.3%), asthenia (14.6%), nausea (7.9%), ataxia (7.7%) and vertigo (7.2%), occurred rapidly after initial titration to 1200 mg/day, and were usually transitory. Weight gain (8.8%) seemed to be related to gabapentin dose. The combination of two recent drugs, vigabatrin and gabapentin, in 190 patients led to similar efficacy levels, with a tendency for more frequent somnolence and asthenia.

Radiosurgery for trigeminal neuralgia and epilepsy.

The role of Gamma Knife surgery in the field of functional surgery recently has evolved dramatically. For treatment of trigeminal neuralgia, Gamma Knife surgery is the least invasive procedure, with a low rate of hypesthesia. If a rate of complete relief similar to that of other surgical techniques could be achieved, this approach will become one of the main techniques used to treat the disease initially. The authors present their experience with a group of 16 patients with mesial temporal lobe epilepsy who have been treated successfully (15 completely seizure-free and 1 with rare, nondisabling seizures) without significant complication. After additional follow-up to demonstrate the absence of long-term consequences, this fascinating new approach could change epilepsy surgery practice dramatically.

[Therapeutic options provided by new antiepileptic drugs]. / Options thérapeutiques offertes par les nouveaux médicaments antiépileptiques.

The introduction on the French market of vigabatrin, gabapentin and lamotrigine has considerably diversified our conventional therapeutical schemes in epilepsies, as will be as amplified by the arrivals of topiramate, tiagabine and oxcarbazepine. Compared to the conventional drugs, these new products present more favorable pharmacokinetics, no or very weak interactions and a better tolerability, specially regarding the cognitive field. They should be used according to their spectrum of activity, function of their modes of action. In add-on trials on partial epilepsy patients all these new products have shown efficacy on partial and secondarily generalized seizures. Seizure frequency is reduced by at least 50 p. 100 in 30 to 50 p. 100 of the patients. A substantial number of patients can be rendered seizure-free with vigabatrin. Lamotrigine has a broader spectrum, as it is also efficacious on the different seizure types of generalized, symptomatic or idiopathic epilepsies. Main adverse events are non-specific central nervous system disturbances such as dizziness, drowsiness, ataxia, tremor or diplopia. More specifically, vigabatrin may induce weight gain and requires closer supervision in case of psychiatric history; lamotrigine which has also probable antidepressant properties, may induce skin rashs, rarely severe. Further data are needed for gabapentin which is now used at daily dosages which are two to three times those used in the initial studies. Gabamimetic agents may be worsening in some cases of generalized epilepsies, more specially on absence and myoclonic seizures. The most obvious benefits, some patients becoming seizure-free, are obtained in cases of intermediate severity, with a bitherapy including one of these new drugs. Developments in children are often delayed. Nevertheless the prognosis, including cognitive outcome, is considerably improved in infantile spasms with vigabatrin and in Lennox-Gastaut syndrome with lamotrigine and felbamate, the latter being highly toxic. For the moment in France, authorities have limited the use of all these new antiepileptic drugs to adjunctive therapy in epilepsies resisting to conventional drugs. But recent monotherapy data show similar efficacy with better tolerability. Once the pivotal, controlled studies have enabled to obtain regulatory approval, all these compounds must undergo a large-scale evaluation phase in order to better define dosages, long-term tolerability, indications and eventual contra-indications in the various epileptic syndromes, including children.

[Strategy of evaluation and surgical results in medial temporal lobe epilepsy]. / Stratégie d'évaluation et résultats chirurgicaux dans l'épilepsie de la face médiale du lobe temporal.

To analyse the presurgical evaluation process of mediotemporal lobe epilepsy (MTLE) in relation to electroclinical characteristics of the patients, we reviewed the presurgical data (clinical, EEG, neuropsychological, MRI, FDG-PET and sometimes intracranial EEG) and the post-operative results of 53 consecutive cases treated by antero-medial temporal resection for MTLE (without lesion other than mediotemporal sclerosis). Forty one patients (77 p. 100) had a typical and well-lateralised presentation and were operated without invasive procedure. Twelve patients (23 p. 100) presented less pure data: unusual or absent auras, divergent scalp EEG features (bitemporal, widespread or extratemporal) or absence of MRI-based hippocampal sclerosis or FDG-PET hypometabolism. They were explored by invasive monitoring which confirmed the medial temporal origin of seizures. Outcome (follow-up: 30 months) was excellent in 88 p. 100 of the pure cases (Engel's class I) and less favorable in the more difficult ones (50 p. 100 of class I). In conclusion, the diagnosis and surgical treatment of MTLE can be performed without invasive investigations in the majority of cases owing to the strong contribution of brain imaging and video EEG monitoring. Some patients however present a less pure presentation suggesting more complex epileptogenic networks and associated to relatively less favorable postsurgical results.

[Cost-effectiveness of epilepsy surgery in a cohort of patients with medically intractable partial epilepsy--preliminary results]. / Evaluation médico-économique de la chirurgie des épilepsies partielles pharmaco-résistantes de l'adulte. Etude coût-efficacité--résultats préliminaires.

OBJECTIVE: Patients with medically intractable epilepsy are potential candidates for surgery if the epileptogenic tissue is localized and resectable. Surgical therapy can eliminate seizures but is very expensive. We followed a prospective adult cohort of intractable epileptic patients in order to perform a cost-effectiveness analysis. POPULATION AND METHODS: Adult patients with a suspected partial medically intractable and operable epilepsy were eligible for evaluation, explorations and/or surgery. Clinical and economical data were collected at the inclusion and every 6 months over at least two years. Two patient groups were analyzed: some underwent a surgery, others did not. Clinical data were compared between both groups. As the data collection was not yet complete, we compared the surgery to a continuation of the preoperative medical management in a cost-effectiveness analysis. Direct medical and nonmedical costs were evaluated according to a societal perspective. The effectiveness was defined as one year without seizure. We assessed the incremental cost-effectiveness ratio (ICER) for the first two years after the surgery. We also modeled long-term costs and effectiveness and extrapolated the results over the patients' lifetime with a Markov model. We computed the ICER and performed a sensitivity analysis. Indirect costs were measured in physical units and intangible costs were assessed with quality-of-life measures (QOLIE-31, SEALS). Data were compared before and after surgery. RESULTS: Among the 286 patients included, 119 did not enter in the analysis: 7 were not eligible, 44 not operable, 31 did not present a follow-up, 37 still underwent exams. Finally, 89 underwent a surgical treatment, and 78 were medically treated. Disease was more severe in surgical patients than in medical patients: seizures frequency, depressive disorders and cognitive impairment were greater. One year after the surgery, 83% patients were seizure free. During the year before inclusion and the year after surgery, direct costs were mainly due to hospitalization. During the second year after surgery, the cost of antiepileptic drugs predominated. One additional year without seizure costs 23 531 euro one year after surgery and 9533 euro two years after surgery. In a long-term perspective, the surgery became cost-effective between 7 and 8 years after the surgery. CONCLUSION: Surgical therapy is a cost-effective treatment in a middle-term even without indirect costs consideration.

[Magnetic resonance imaging of temporal lobe epilepsy]. / L'imagerie par résonance magnétique de l'épilepsie du lobe temporal.

MR has gained more and more importance in the evaluation of patients with temporal lobe epilepsy (TLE). Until recently, hippocampal sclerosis (which is the most frequent cause of temporal lobe epilepsy, accounting for 50-70% of the cases) could not be identified reliably. Using optimized magnetic resonance imaging techniques, hippocampal sclerosis can now be evidenced in a large proportion of patients with TLE. Tumors (10-15%), developmental abnormalities (5-7%), vascular malformations (mostly cavernous angiomas, 1-5%), and traumatic scars (5-10%) represent the other structural lesions associated with TLE. Studies of large series of patients with intractable epilepsy or with varying severity have shown that in only 8.5% and 20%, respectively, a specific imaging abnormality was not found. Specific MR sequences increase the diagnostic value of MR (coronal images perpendicular to the axis of the hippocampal formations, three-dimensional T1 weighted images, inversion recovery images, volumetry or more specific processes such as T1 and T2 relaxometry or spectroscopy). MR also helps guide placement of intra-cerebral and subdural electrodes in surgically relevant cases. All these results have given greater importance to MR in the definition of the epileptic syndrome of TLE and should probably be integrated in the criteria of international classifications.