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Summary Purpose:  To clarify the role of epilepsy and genetic background in determining the cognitive outcome of patients with Dravet syndrome. Methods:  In this retrospective study, we reviewed the clinical history and cognitive development of 26 patients who had been followed with standardized evaluations since seizure onset. The cognitive outcome was quantified as differential general quotient (dGQ) between ages 12 and 60 months. Statistical analysis correlated the dGQ with genotype and epilepsy course. Key Findings:  Epilepsy started at the mean age of 5.6 months. All patients experienced prolonged convulsive seizures, whereas absences and myoclonus were reported in 17. Cognitive outcome was poor in almost all patients; the mean dGQ was 33 points, varying from 6–77 points. The analysis of individual cognitive profiles identified seven patients in whom the dGQ was <20 points; the main clinical characteristic in this subset of patients was lack of early absences and myoclonus. The statistical analysis of the whole series failed to reveal significant differences in cognitive outcome with regard to the presence of SCN1A mutations and their type. In particular, mutation‐carrier patients with the best cognitive outcome harbored either missense or truncating mutations. Significance:  Dravet syndrome encompasses different epileptic and cognitive phenotypes that probably result from both genetic and epigenetic factors. In this series, early appearance of myoclonus and absences was associated with the worst cognitive outcome.

Electrical status epilepticus in sleep (ESES)/continuous spikes and waves during slow sleep (CSWS) is an age‐related, self‐limiting disorder characterised by epilepsy with different seizure types, global or selective neuropsychological regression, motor impairment, and a typical EEG pattern of continuous epileptiform activity for more than 85% of non‐rapid eye movement (NREM) sleep. Although the first description of ESES/CSWS dates back to 1971, an agreement about the optimal treatment for this condition is still lacking. ESES/CSWS is rare (incidence is 0.2‐0.5% of all childhood epilepsies) and no controlled clinical trials have been conducted to establish the efficacy of different antiepileptic drugs; only uncontrolled studies and case reports are reported in the literature. Treatment options for ESES/CSWS include some antiepileptic drugs (valproic acid, ethosuximide, levetiracetam, and benzodiazepines), steroids, immunoglobulins, the ketogenic diet, and surgery (multiple subpial transections). In this study, the comparative value of each of these treatments is reviewed and a personal therapeutic approach is proposed.

Summary Purpose The aim of this study was to evaluate the long‐term cognitive outcome in children with continuous spikes and waves during slow wave sleep (CSWS syndrome). Methods We reviewed the neuropsychological tests of 25 children diagnosed with CSWS between 1987 and 2010 and with a mean follow‐up of 13.5 years. Key Findings Cognitive performances worsened during CSWS in virtually all patients. Seven patients (28%) with nonlesional epilepsy had a positive outcome; three patients (12%) showed persistence of motor deficit without involvement of cognitive functions; and seven patients (28%) who presented a long duration of CSWS (mean = 28.1 months) had a negative cognitive outcome. In 6 patients (24%) with structural or metabolic disorders before CSWS onset cognitive outcomes did not change; 2 patients (8%) had a negative outcome irrespective of the duration or presence of other neurologic disorders before CSWS onset. Forty‐four percent of children with CSWS demonstrated permanent cognitive impairment. Significance The long‐term outcome of CSWS syndrome is variable and seems to depend on treatment response, disease duration, and underlying etiology.

Encephalopathy with status epilepticus during sleep (ESES) is an epileptic encephalopathy, as defined by the International League Against Epilepsy (ILAE) Task Force on Classification and Terminology, that is, a condition in which the epileptic processes themselves are believed to contribute to the disturbance in cerebral function. Clinical manifestations of ESES are heterogeneous: apart from different seizure types, they consist in combinations of cognitive, motor, and behavioural disturbances associated with a peculiar electroencephalographic pattern of paroxysmal activity significantly activated during slow sleep, which culminates in a picture of continuous spikes and waves during sleep (CSWS). The pathophysiological mechanisms underlying this condition are still incompletely understood. Establishing a clear-cut correlation between EEG abnormalities and clinical data, though interesting, is very complex. Computer-assisted EEG analyses especially if combined with functional magnetic resonance imaging (EEG-fMRI) and metabolic neuroimaging have recently emerged as useful approaches to better understand the pathophysiological processes underlying ESES. Treatment of ESES is not just limited to seizures control but it should be focused on controlling neuropsychological outcome through an improvement of the continuous epileptiform activity. General agreement on treatment guidelines is still lacking. Implementation of new techniques might allow a better understanding of the pathophysiology of ESES and could enhance therapeutics options.