Long-term evolution of neuropsychological competences in encephalopathy with status epilepticus during sleep: a variable prognosis.

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.

Interictal autonomic abnormalities in idiopathic Rolandic epilepsy.

We investigated 50 young patients with a diagnosis of Rolandic Epilepsy (RE) for the presence of abnormalities in autonomic tone compared with 50 young patients with idiopathic generalized epilepsy with absences and 50 typically developing children of comparable age. We analyzed time domain (N-N interval, pNN50) and frequency domain (High Frequency (HF), Low Frequency (LF) and LF/HF ratio) indices from ten-minute resting EKG activity. Patients with RE showed significantly higher HF and lower LF power and lower LF/HF ratio than controls, independent of the epilepsy group, and did not show significant differences in any other autonomic index with respect to the two control groups. In RE, we found a negative relationship between both seizure load and frequency of sleep interictal EEG abnormalities with parasympathetic drive levels. These changes might be the expression of adaptive mechanisms to prevent the excessive sympathetic drive seen in patients with refractory epilepsies.

Therapy of encephalopathy with status epilepticus during sleep (ESES/CSWS syndrome): an update.

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.

Cognitive development in Dravet syndrome: a retrospective, multicenter study of 26 patients.

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.

Neurophysiology of CSWS-associated cognitive dysfunction.

The phenomenon of continuous spikes and waves during slow-wave sleep (CSWS) is associated with a number of epileptic syndromes, which share a behavioral phenotype characterized by deterioration of cognitive, behavioral, or sensorimotor functions. Available evidence seems to suggest that spike-wave activity is a result of a complex interaction between cortical and subcortical inhibitory networks and can "per se" produce a transient loss of underlying cortical functions. Syndromes like Landau-Kleffner syndrome, CSWS, and phenomena such as negative myoclonus could share in common--at least at the neurophysiological level--some similarities. Differences in behavioral phenotypes could be explained in term of maturational and genetic differences, as well as by the functional specificity of the involved areas.

Epileptic Encephalopathies with Status Epilepticus during Sleep: New Techniques for Understanding Pathophysiology and Therapeutic Options.

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.

Brain mechanisms of altered consciousness in generalised seizures.

In spite of the inherent difficulties in achieving a biologically meaningful definition of consciousness, recent neurophysiological studies are starting to provide some insight in fundamental mechanisms associated with impaired consciousness in neurological disorders. Generalised seizures are associated with disruption of the default state network, a functional network of discrete brain areas, which include the fronto-parietal cortices. Subcortical contribution through activation of thalamocortical structures, as well as striate nuclei are also crucial to produce impaired consciousness in generalised seizures.

Dravet syndrome: early clinical manifestations and cognitive outcome in 37 Italian patients.

Aims of our study were to describe the early clinical features of Dravet syndrome (SMEI) and the neurological, cognitive and behavioral outcome. The clinical history of 37 patients with clinical diagnosis of SMEI, associated with a point mutation of SCN1A gene in 84% of cases, were reviewed with particular attention to the symptoms of onset. All the patients received at least one formal cognitive and behavior evaluation. Epilepsy started at a mean age of 5.7 months; the onset was marked by isolated seizure in 25 infants, and by status epilepticus in 12; the first seizure had been triggered by fever, mostly of low degree in 22 infants; the first EEG was normal in all cases. During the second year of life difficult-to-treat seizures recurred, mostly triggered by fever, hot bath, and intermittent lights and delay in psychomotor development became evident. At the last evaluation, performed at a mean age of 16+/-6.9 years, mental retardation was present in 33 patients, associated with behavior disorders in 21. Our data indicate that the most striking features of SMEI are: the early onset of seizures in a previously healthy child, the long duration of the first seizure, the presence of focal ictal symptoms, and sensitivity to low-grade fever. Diagnosis of SMEI may be proposed by the end of the first year of life, and a definite diagnosis can be established during the second year based on the peculiar seizure-favoring factors, EEG photosensitivity and psychomotor slowing. The temporal correlation between high seizure frequency and cognitive impairment support the role of epilepsy in the clinical outcome, even if a role of channelopathy cannot be ruled out.