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Purpose Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterized by a facial port-wine stain, a glaucoma, and a leptomeningeal angioma. Epilepsy occurs in more than 75% of affected children, and seizures occurring in the first year of life are associated with a poor neurological prognosis. The aim of this study was to identify possible predictive markers of epilepsy on electroencephalogram (EEG) performed prior to seizure onset in children with SWS. Methods This study included children with a diagnosis of SWS who had an EEG performed prior to seizure onset. Patients who did not develop epilepsy had a minimum follow-up of 3-years. We compared EEG characteristics of patients who developed epilepsy with patients who did not develop epilepsy by the time of their follow-up. Results Eleven children were included in this study. EEG was performed at the median age of 2.1 months (range 1.0–22.1). Six children developed seizures with a time interval between EEG and seizure onset ranging from 2 days to 21 months. EEG background activity was asymmetric in 8 patients, 5 of whom later developed epilepsy. Focal interictal spikes or sharp waves were exclusively recorded in patients who developed later epilepsy (4 out of 6). One of these patients had a supposed false positive EEG as he did not developed epilepsy until 21 months later and one patient had a false negative EEG with seizures occurring 2 days after a normal EEG. Conclusion Spikes on EEG might be a useful marker to identify patients with SWS at risk of developing epilepsy. Their predictive value should be assessed in larger prospective studies.

The aim was to localize the interictal cerebral perfusion abnormalities of focal cortical dysplasia (FCD) in children with Arterial Spin Labeling MRI (ASL) in a retrospective study of nine consecutive children explored with multimodal investigation during interictal periods. We analyzed brain morphology with a 1.5T MRI and a dedicated protocol for epilepsy. Brain perfusion was quantified with pseudo continuous ASL. Brain metabolism was imaged with (18)FDG-PET in six patients. Microvessel histology was studied in five children who underwent epilepsy surgery with CD34 immunostaining on FCD and control samples. Localized decrease of cerebral blood flow (CBF) was found on visual analysis in all patients with ASL. It was co-localized with the structural MRI abnormalities in every case, with PET hypo-metabolism in 5/6 cases, and with histologically proven FCD type IIb in 5/5 cases (all seizure free after surgery). CBF was lower (Kruskal-Wallis test, p=0.001) in FCD than in normal cortex. The total count of CD34+ microvessels was similar in FCD and control cases, but microvasculature showed disorganized architecture. Interictal ASL is a non-invasive method that may help to localize the epileptogenic zone showing hypo-perfusion in FCD. Whether this finding could be generalized to MRI-negative FCD needs to be further studied.

Purpose : To distinguish various types of childhood severe cryptogenic/idiopathic generalised epilepsy on the basis of reproducible diagnostic criteria, using multiple correspondence analysis (MCA). Methods : We applied MCA to a series of 72 children with no evidence of brain damage, starting epilepsy between 1 and 10 years, with two or more types of generalised seizures. We excluded patients with infantile spasms or typical absences. MCA was performed on all clinical and EEG parameters, first throughout follow-up, then restricted to the first year of the disease. Results : When including all follow-up variables, there were three groups: (1) Thirty-seven children with male predominance, familial history of epilepsy, simple febrile convulsions, massive myoclonus, tonic–clonic fits. Outcome was favourable, with no seizures and mildly affected cognitive functions. Interictal EEG showed short sequences of irregular 3-Hz spike-waves. (2) In 18 children, clinical characteristics were similar to those of the first group at the early stage, but 95% exhibited myoclonic status and vibratory tonic seizures, with persisting seizures on follow-up. EEG showed long sequences of generalised irregular spike and slow waves. Those two groups meet the characteristics of childhood onset myoclonic-astatic epilepsy (MAE) with respectively, favourable and unfavourable outcome. (3) Eleven children had later onset, atypical absences, tonic and partial seizures, and no myoclonus, or vibratory tonic seizures. All had mental retardation and persisting seizures. EEG showed long sequences of slow spike-wave activity and half the patients had spike and slow wave foci. These patients met the major characteristics of Lennox–Gastaut syndrome. Initial parameters failed to distinguish the first two groups, but Lennox–Gastaut syndrome (the third group) was distinct from both groups of myoclonic astatic epilepsy from the onset. Within MAE groups combined, clinical and EEG risk factors for mental retardation could be identified. Conclusion : It is possible to validate statistically the distinction between discrete epileptic syndromes. Myoclonic astatic epilepsy is therefore distinct from Lennox–Gastaut syndrome, and the distinction appears from the first year of the disorder.

Mutations in the ARX gene are responsible for a wide variety of mental retardation conditions including X-linked infantile spasms (ISSX) and generalized dystonia. However, electroclinical descriptions in patients with ISSX carrying ARX mutations are scarce. Here, we report on the electroclinical features of a 4-year-old boy with an expansion of the trinucleotide repeat in the ARX gene. Epilepsy started at 2 months of age with subclinical spasms that consisted of episodes of eye rolling combined with atypical hypsarrhythmia. Later, the condition evolved into severe mental retardation with polymorphic ictal episodes that consisted of nocturnal brief axial contractions followed by dyskinetic movement of all four limbs and diurnal clusters of chaotic movements combined with myoclonic jerks. EEG recording of these episodes lead to the diagnosis of non-ictal dyskinetic movements. This combination of early infantile spasms followed by a complex movement disorder contributes further to extent the pleiotropy of the ARX-linked "interneuronopathy" and should lead the clinician to ARX mutation screening.

Summary Purpose To describe resistant epileptic encephalopathies that significantly improved after an acute febrile episode (FE). Methods We reviewed the clinical history of patients with daily pharmacoresistant seizures referred to the Saint-Vincent de Paul Hospital in the last 5 years. Four patients experienced seizure arrest in relation with a febrile episode. Results The four patients suffered from epileptic encephalopathy. Three were symptomatic, one cryptogenic. They presented spasms and atypical absences, beginning after the age of 1 year. All seizures stopped at the onset of fever, and significant EEG improvement was observed. The seizure-free period ranged from 2 to 24 months. Discussion and conclusion The close link between the occurrence of FE and the disappearance of seizures and EEG improvement, contrasting with the previous pharmacoresistance of this epileptic encephalopathy, supports a non fortuitous association. Several mechanisms could explain this phenomenon, including viral etiology, hyperthermia, inflammatory-immune reaction and ACTH release. Better understanding this phenomenon could open new therapeutic perspectives.