Épidémiologie des épilepsies partielles pharmaco-résistantes

Drug-resistant epilepsy in Morocco: description, prevalence and predictive factors in Casablanca-Settat region

Drug-resistant epilepsy (DRE) affects about one-third of people with epilepsy (PWE). Our study aims to estimate the DRE prevalence and its predictive factors in Morocco. A cross-sectional study was conducted over 18 months. PWE with clinical diagnosis of epilepsy, and with an antiseizure treatment duration >12 months were examined in the neurology, neurosurgery, psychiatry, and pediatrics departments, of different sampled clinical sectors for the Casablanca-Settat region. Sociodemographic and clinical data were collected using a questionnaire during consultations. Antiseizure multi-therapy, a seizure freedom duration <12 months, compliance, and adequate posology were the determining factors for classifying DRE. Data were analyzed using Statistical Package for Social Sciences (SPSS) software, version 21.0. Statistical significance was set at p < 0.05 and logistic regression was performed to determine the predictive factors. In our sample of 446 PWE, the median age is 25 years (IQR: 11.75-44.00). The DRE estimated prevalence was 29.4 %. Pseudo-resistant epilepsy (PRE) was 18.0 %. Multivariate logistic regression analysis reports that single marital status (ORa = 1.94; CI95%: 1.02-3.71), comorbidities and concomitant affections (ORa = 2.14; CI95%: 1.27-3.59), structural etiology (ORa = 1.96; CI95%: 1.16-3.30), pre-ictal aura (ORa = 1.90; CI95%: 1.09-3.29), inter-ictal EEG abnormalities (ORa = 2.45; CI95%: 1.24-4.84) and allopathic treatment use (ORa = 2.10; CI95%: 1.30-3.39) are the predictive factors for DRE. We report an alarming DRE prevalence. Associated factors found may contribute to the prognosis and early management. PWE awareness, facilitating healthcare access and the development of epilepsy surgery are the key points to limit DRE in Morocco and prevent its various complications, especially for the pediatric population.

Model-guided control of hippocampal discharges by local direct current stimulation

Neurostimulation is an emerging treatment for drug-resistant epilepsies when surgery is contraindicated. Recent clinical results demonstrate significant seizure frequency reduction in epileptic patients, however the mechanisms underlying this therapeutic effect are largely unknown. This study aimed at gaining insights into local direct current stimulation (LDCS) effects on hyperexcitable tissue, by i) analyzing the impact of electrical currents locally applied on epileptogenic brain regions, and ii) characterizing currents achieving an "anti-epileptic" effect (excitability reduction). First, a neural mass model of hippocampal circuits was extended to accurately reproduce the features of hippocampal paroxysmal discharges (HPD) observed in a mouse model of epilepsy. Second, model predictions regarding current intensity and stimulation polarity were confronted to in vivo mice recordings during LDCS (n = 8). The neural mass model was able to generate realistic hippocampal discharges. Simulation of LDCS in the model pointed at a significant decrease of simulated HPD (in duration and occurrence rate, not in amplitude) for cathodal stimulation, which was successfully verified experimentally in epileptic mice. Despite the simplicity of our stimulation protocol, these results contribute to a better understanding of clinical benefits observed in epileptic patients with implanted neurostimulators. Our results also provide further support for model-guided design of neuromodulation therapy.

[Predictors factors of refractory epilepsy in childhood]

The aim of this study is to identify early predictors of refractory epilepsy. From 600 epileptic children followed for at least 2 years in the department of neurology of Charles Nicolle hospital of Tunis, were identified children with refractory epilepsy. Controls were children who responded well to antiepileptic drugs and who were seizure free for at least 2years. We collected anamnestic, clinical, neuropsychological and radiological data for all children. We identified 67 children with refractory epilepsy, representing 11.6% of the initial population. At diagnosis, the average age was 9.16 years. Some factors have been identified as predictors of drug resistance epilepsy: age of onset less than one year, partial and atonic seizure, combination of several types of attacks, presence of mental retardation and pyramidal syndrome, abnormal electroencephalogram especially focal abnormalities, spike, amplitude abnormalities, interhemispheric asymmetry; and resistance to first antiepileptic drug. Symptomatic epilepsy, especially if associated with radiological lesions such as hippocampal sclerosis and structural brain malformations, was highly correlated with drug resistance. Our study suggests that the initial presentation of epilepsy could predict long-term outcome to drug resistance epilepsy if a detailed analysis of anamnestic, clinical and complementary data is established.

[Objectives and practical aspects of antiepileptic medication]

Antiepileptics are a group of drugs with various pharmacological properties and mechanisms of action. They are grouped together due to the fact that they are used to treat epilepsy. There are around twenty molecules in this group. Particular care needs to be taken when prescribing them for children as they carry risks.

[Evaluation of a pathway of epilepsy surgery in a polyvalent video-EEG center: retrospective analysis of a series of 295 patients]

BACKGROUND AND PURPOSE

The supply for diagnosis and treatment is inadequate in France for epileptic patients eligible for surgery. Our institution includes a Video-electroencephalography (v-EEG) unit and a general neurosurgery department. Our objective was to evaluate the efficacy and morbidity of the surgery performed in a center non-dedicated to epilepsy surgery.

METHODS

We conducted a retrospective study of a cohort of 295 patients explored with long lasting v-EEG from 1991 to 2008 in Tours in which we evaluated the efficacy and morbidity of the surgery distinguishing between hippocampal sclerosis and other epileptogenic lesions.

RESULTS

Phase I directly led to surgery in 31 cases. Of them were 19 hippocampal sclerosis were operated with no surgical morbidity, and 12 other epileptogenic lesions operated with a comorbidity in two patients. Results of surgery were similar to larger studies, with 80% of patients Engel's Class I. Best results were observed in the hippocampal sclerosis group: 94.7 Class I (IA: 84%), versus 58% Class I (IA: 33%) for other etiologies.

CONCLUSION

Despite the small number of operated patients, the surgical treatment keeps its efficiency without adding morbidity. v-EEG centers combined with non-specialists neurosurgical teams can contribute to improve care without reducing their quality.

[Disability and epilepsy]

The purpose of this article is to familiarize radiologists with the different aspects of severe drug resistant epilepsy. These result in three levels of disability: the disease itself (seizures and their impact, underlying cause), social impact (restrictions, safety and precautions, education, activities of daily life) and issues related to the medical treatment (long term medication intake, side effects, complications). First, clinical and EEG diagnosis will be reviewed to move on to MRI with attention to technical and protocol considerations followed by the imaging features of specific entities causing severe drug resistant epilepsy: migration and gyration disorders, Rasmussen's encephalitis, Sturge Weber disease and post-ischemic sequelae. Finally, current data and the imaging features of hemispherotomy, a radical treatment for epilepsy, will be presented.

[CT and MR brain imaging following hemispherotomy]

PURPOSE

The aim of the study was to define the usual and pathological modifications arising in the brain following hemispherotomy for intractable epilepsy in children.

METHODS

Preoperative MRI and postoperative imaging scans (CT in the first week, MRI at 3 months and 1 year after surgery) were reviewed in a series of 52 patients, average age 8 years and 7 months, with intractable epilepsy due to dysplasia, Rasmussen's encephalitis, ischemic lesions and/or Sturge-Weber disease. The posterior fossa, brain parenchyma, ventricles and subdural space were also analyzed.

RESULTS

Hemispheric scarring was a typical finding on CT and MRI as a consequence of the surgical procedure. Also frequently seen were small subdural effusions, bleeding along the surgical scar on early CT, and chronic subdural effusions with no mass effect on mid-term and late MRI scans. Other features - such as large subdural effusions that required external shunts and hydrocephalus - were rare, but severe, and considered to be postoperative complications. In contrast to the complications associated with other surgical techniques such as hemispherectomy, infection, extensive edema or hemosiderosis were never found in our series.

CONCLUSION

Hemispherotomy is a surgical technique performed to treat intractable epilepsy. Our findings will help to identify the typical morphology of postsurgical scars, and to differentiate the usual features and complications seen in the postoperative period on CT and MRI brain scans.

[Healthcare networks in epilepsy: situation in the greater Paris region]

The goal of healthcare networks is to provide global care for patients and to coordinate the actions of the different healthcare professionals to provide the most appropriate treatment based on patient needs. Such networks have been created in Ile-de-France for some neurological diseases but not epilepsy. However, the needs of the population are significant, with 55,000 to 70,000 epilepsy patients in the geographic area. Contacts between the three main adult epilepsy centers, although not formal, form the basis of a dedicated epilepsy network so that the quality of care can be improved and surgical treatment made easier if indicated.