Background: There have been difficulties in achieving a uniform terminology in the literature regarding issues of classification with respect to focal cortical dysplasias (FCDs) associated with epilepsy. Objectives: To review and refine the current terminology and classification issues of potential clinical relevance to epileptologists, neuroradiologists, and neuropathologists dealing with FCD. Methods: A panel discussion of epileptologists, neuropathologists, and neuroradiologists with special expertise in FCD was held. Results: The panel proposed 1) a specific terminology for the different types of abnormal cells encountered in the cerebral cortex of patients with FCD; 2) a reappraisal of the different histopathologic abnormalities usually subsumed under the term “microdysgenesis,” and suggested that this terminology be abandoned; and 3) a more detailed yet straightforward classification of the various histopathologic features that usually are included under the heterogeneous term of “focal cortical dysplasia.” Conclusion: The panel hopes that these proposals will stimulate the debate toward more specific clinical, imaging, histopathologic, and prognostic correlations in patients with FCD associated with epilepsy.

Terminology and classification of the cortical dysplasias.

10·5 million children worldwide are estimated to have active epilepsy. Over the past 15 years, syndrome-oriented clinical and EEG diagnosis, and better aetiological diagnosis, especially supported by neuroimaging, has helped to clarify the diversity of epilepsy in children, and has improved management. Perinatal and postinfective encephalopathy, cortical dysplasia, and hippocampal sclerosis account for the most severe symptomatic epilepsies. Ion channel defects can underlie both benign age-related disorders and severe epileptic encephalopathies with a progressive disturbance in cerebral function. However, the reasons for age-related expression in children are not understood. Neither are the mechanisms whereby an epileptic encephalopathy originates. Several new drugs have been recently introduced but have provided limited therapeutic benefits. However, treatment and quality of life have improved because the syndrome-specific efficacy profile of drugs is better known, and there is heightened awareness that compounds with severe cognitive side-effects and heavy polytherapies should be avoided. Epilepsy surgery is an important option for a few well-selected individuals, but should be considered with great caution when there is no apparent underlying brain lesion.

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(06)68182-8.pdf

Epilepsy in Children

Malformations of cortical development are common causes of developmental delay and epilepsy. Some patients have early, severe neurological impairment, but others have epilepsy or unexpected deficits that are detectable only by screening. The rapid evolution of molecular biology, genetics, and imaging has resulted in a substantial increase in knowledge about the development of the cerebral cortex and the number and types of malformations reported. Genetic studies have identified several genes that might disrupt each of the main stages of cell proliferation and specification, neuronal migration, and late cortical organisation. Many of these malformations are caused by de-novo dominant or X-linked mutations occurring in sporadic cases. Genetic testing needs accurate assessment of imaging features, and familial distribution, if any, and can be straightforward in some disorders but requires a complex diagnostic algorithm in others. Because of substantial genotypic and phenotypic heterogeneity for most of these genes, a comprehensive analysis of clinical, imaging, and genetic data is needed to properly define these disorders. Exome sequencing and high-field MRI are rapidly modifying the classification of these disorders.

/pdf/malformations-of-cortical-development-clinical-features-and-373qlaaid7.pdf

Malformations of cortical development: clinical features and genetic causes

Encephalopathy with electrical status epilepticus during sleep or ESES is an age-dependent and self-limited syndrome whose distinctive features include a characteristic age of onset (with a peak around 4-5 years), heterogeneous seizures types (mostly partial motor or unilateral seizures during sleep and absences or falls while awake), a typical EEG pattern (with continuous and diffuse paroxysms occupying at least 85% of slow wave sleep) and a variable neuropsychological regression consisting of IQ decrease, reduction of language (as in acquired aphasia or Landau-Kleffner syndrome), disturbance of behaviour (psychotic states) and motor impairment (in the form of ataxia, dyspraxia, dystonia or unilateral deficit). Despite the long-term favourable outcome of epilepsy and status epilepticus during sleep (SES), the prognosis is guarded because of the persistence of severe neuropsychological and/or motor deficits in approximately half of the patients. No specific treatment has been advocated for this syndrome, but valproate sodium, benzodiazepines and ACTH have been shown to control the seizures and the SES pattern in many cases, although often only temporarily. Subpial transection is proposed in some instances as in non-regressive acquired aphasia. Recent data support the concept that ESES syndrome may include a large subset of developmental or acquired regressive conditions of infancy.

Encephalopathy with electrical status epilepticus during slow sleep

Encephalopathy with electrical status epilepticus during slow sleep or ESES syndrome including the acquired aphasia.

Background and Objective: Patients with cortical malformations often have intractable seizures and are candidates for epilepsy surgery. Within an unselected series of patients with various forms of cortical malformation, nine patients with multilobar polymicrogyria had electrical status epilepticus during sleep (ESES) accompanied by infrequent focal motor seizures. Eight patients also had intractable atonic drop attack seizures. Because ESES usually is accompanied by a good long-term seizure prognosis, the objective of this study was to examine ESES outcome among patients with a structural lesion that is usually highly epileptogenic and has a low seizure remission trend. Methods: The nine patients had follow-up periods lasting 4 to 19 years. All underwent brain MRI, serial sleep EEG recordings, and cognitive testing during and after ESES. Results: ESES and drop attack seizures appeared between the ages of 2 and 5 years(mean, 4 years) and ceased between the ages of 5 and 12 years (mean, 8 years). At the last visit patients were 8 to 23 years of age (mean, 14.5 years) and were either seizure free or had very infrequent focal motor seizures during sleep. Three patients were free from antiepileptic drugs. In no patient was definite cognitive deterioration apparent after ESES in comparison with earlier evaluations. Conclusions: Age-related secondary bilateral synchrony underlying ESES may be facilitated in multilobar polymicrogyria. The good seizure outcome contrasts with that usually found in the presence of cortical malformations. For children with polymicrogyria and drop attack seizures, surgical treatment of the epilepsy should be considered cautiously, and sleep EEG recordings should be performed systematically.

Multilobar polymicrogyria, intractable drop attack seizures, and sleep-related electrical status epilepticus

Resume Il s'agit d'une etude retrospective de l'electro-encephalogramme (EEG) de 64 sujets atteints d'une epilepsie partielle symptomatique severe, ayant debute avant l'âge de 12 ans et dont le suivi a ete au minimum de 5 ans apres le debut des crises. L'etude longitudinale des EEG intercritiques a ete pratiquee chez tous les sujets et les remarques suivantes ont ete faites: frequence des traces normaux ou peu anormaux en debut d'evolution, apparition plus ou moins tardive d'anomalies de l'activite de fond, d'anomalies multifocales et d'anomalies generalisees a type de pointes ondes lentes (POL). L'EEG critique a ete etudie chez 32 patients: il existe une bonne correlation entre le siege des anomalies intercritiques et le point de depart des decharges critiques, et la semeiologie EEG varie peu au cours de l'evolution.

X. Salas-Puig

Papers

Multilobar polymicrogyria, intractable drop attack seizures, and sleep-related electrical status epilepticus

Particularites electro-encephalographiques des epilepsies partielles symptomatiques severes de l'enfant