A realistic multimodal modeling approach for the evaluation of distributed source analysis: application to sLORETA.

OBJECTIVE: Electrical source localization (ESL) deriving from scalp EEG and, in recent years, from intracranial EEG (iEEG), is an established method in epilepsy surgery workup. We aimed to validate the distributed ESL derived from scalp EEG and iEEG, particularly regarding the spatial extent of the source, using a realistic epileptic spike activity simulator. APPROACH: ESL was applied to the averaged scalp EEG and iEEG spikes of two patients with drug-resistant structural epilepsy. The ESL results for both patients were used to outline the location and extent of epileptic cortical patches, which served as the basis for designing a spatiotemporal source model. EEG signals for both modalities were then generated for different anatomic locations and spatial extents. ESL was subsequently performed on simulated signals with sLORETA, a commonly used distributed algorithm. ESL accuracy was quantitatively assessed for iEEG and scalp EEG. MAIN RESULTS: The source volume was overestimated by sLORETA at both EEG scales, with the error increasing with source size, particularly for iEEG. For larger sources, ESL accuracy drastically decreased, and reconstruction volumes shifted to the center of the head for iEEG, while remaining stable for scalp EEG. Overall, the mislocalization of the reconstructed source was more pronounced for iEEG. SIGNIFICANCE: We present a novel multiscale framework for the evaluation of distributed ESL, based on realistic multiscale EEG simulations. Our findings support that reconstruction results for scalp EEG are often more accurate than for iEEG, owing to the superior 3D coverage of the head. Particularly the iEEG-derived reconstruction results for larger, widespread generators should be treated with caution.

[Indications for intermittent diazepam prophylaxis in febrile seizures]. / Indikation der intermittierenden Diazepamprophylaxe bei Fieberkrämpfen.

BACKGROUND: In a prospective controlled study we evaluated the efficacy of intermittent diazepam prophylaxis in the recurrence rate of febrile seizures (FS). PATIENTS: A total of 139 children aged between 6 and 36 months, who had a first FS, were enrolled in the study and were randomly allocated to two groups: group (A) that received diazepam prophylaxis and group (B) without prophylaxis. METHODS: All children were followed up for at least 3 years after their first FS. The prophylaxis group (n = 68) received rectal diazepam the first two days of a febrile illness, whenever the temperature was > 38 degrees C (0.33 mg/kg every 8 h on the first day, and 0.33 mg/kg every 12 h on the second day of fever, max. dosage 7.5 mg). The no-prophylaxis group (n = 71) did not receive any prophylaxis at all. Each group was stratified to low, intermediate and high risk subgroups according to the following clinical data: age at the first febrile seizure

Focal cortical dysplasia: prevalence, clinical presentation and epilepsy in children and adults.

Focal cortical dysplasias (FCD) are defined as circumscribed malformations of cortical development. They result from an impairment of neuronal proliferation, migration and differentiation. In the diagnosis of focal epilepsy FCD prevalence ranges between 5% and 25%, depending on patient collective and imaging techniques. Several 'cryptogenic' epilepsies may be caused by FCD but have not been diagnosed because of the lack of high-quality magnetic resonance imaging assessment. Retrospective analysis of patients who have undergone epilepsy surgery can be biased because of the fact that they represent a mere subset of potential FCD diagnoses. Epilepsy typically manifests within the first years of life, but has been documented up to the age of 60 years. Cognitive impairment commonly accompanies early onset. Epilepsy is often refractory to antiepileptic drug (AED) treatment. Clinical observations and pathophysiological findings illustrate intrinsic epileptogenicity. Upregulation of drug transporter proteins has been found in FCD tissue. There is no specific drug treatment in FCD, as any AED used in focal epilepsy could prove effective. A sequential AED therapy should be designed individually and take side effects as well as developmental progresses into consideration. Fifty to sixty-five percent of FCD patients are rendered seizure-free after surgery. Presurgical evaluation should be initiated after two unsuccessful AED trials. Both risks and potential benefits regarding seizure control and developmental impairment need to be considered on an individual basis when deciding between surgical intervention and conservative treatment. Current knowledge on epilepsy course and psychomotor development in FCD is limited in the absence of qualified long-term studies combining imaging with cognitive evaluation.

[Congenital muscular dystrophy with laminin-a2 deficiency in early infancy: diagnosis and long-term follow-up]. / Kongenitale Muskeldystrophie mit Merosin-(Laminin-a2)-Mangel im frühen Säuglingsalter: Diagnostik und Langzeitverlauf.

Congenital muscular dystrophy (CMD) is a heterogeneous group of neuromuscular disorders characterized by muscle weakness and hypotonia at birth or within the first few months of life. It is inherited in an autosomal recessive pattern. About half of the patients have a deficiency of the alpha-2-chain of laminin (merosin). We describe a case of congenital muscular dystrophy in an infant with laminin-a2-chain deficiency, which appeared hypotonia in early infancy. Diagnosis was made by clinical features and the histological and immunohistochemical studies on muscle biopsy.