Sleep architecture remains preserved in many children, but abnormal patterns including activation of epileptiform activity and the spectrum of electrical status epilepticus have been described. Conversely, 40–50% of children may show a normal background. Generalized spike-wave and polyspike waves constitute the most frequent abnormality with multifocal spikes and slowing of the background reported in about 50% of children ( Figure 1). Įlectroencephalogram findings are typically normal in the first year of life, but parallel to the onset of afebrile seizures, the EEG shows characteristic changes with the appearance of paroxysmal epileptiform abnormalities. Adults also show persistence of seizures and fever susceptibility nocturnal generalized tonic-clonic is the most common seizure type, and typically far fewer absence and myoclonic seizures are seen. After 5 years of age, convulsive status epilepticus tends to be less frequent, and nocturnal generalized tonic-clonic seizures predominate. Between age 1 and 4 years, episodes of status epilepticus with fever, as well as episodes of nonconvulsive status epilepticus, are frequent. Seizures tend to evolve throughout development. when chastised or when entering an unfamiliar environment) has also been observed to trigger seizures. Although reflex seizures in DS are most often triggered by visual stimuli, stress or emotional state (i.e. observed that strong photosensitivity is associated with a poorer prognosis in children with DS. More than 50% have photosensitive seizures. Reflex or stimulus-provoked seizures, defined as seizures which are reliably evoked by a stimulus, are also very common in DS. Frequent episodes of status epilepticus and ongoing susceptibility to hyperthermia-induced seizures are key clinical features. However, a variety of other seizure types later appear, including myoclonic, atonic, generalized tonic-clonic, absence, complex partial, and, less often, tonic. Beginning around 5 months of age, affected children typically present with generalized or unilateral prolonged febrile seizures. While the presence of frequent and severe seizures during development is likely to impact cognitive function, we hypothesize that the underlying mechanisms responsible for seizures in DS may also directly affect cognitive processes and long-term outcome.Ĭlinical and Electroencephalographic FeaturesĬhildren with DS suffer from seizures that are resistant to therapy and may be frequent and severe. We also present the underlying mechanisms believed to be involved in both seizure susceptibility and cognitive impairment. In this review, we describe the clinical and cognitive features of this syndrome and the current treatments available. Children with DS often have severe intellectual disability and will be dependent on caregiver support throughout their adult life. DS is a childhood epilepsy disorder associated with devastating effects on cognitive development. The incidence has been estimated at between 1:20,000 and 1:40,000, and it occurs more often in males than females with a ratio of 2:1. Dravet syndrome (DS), also termed Severe Myoclonic Epilepsy in Infancy, was first described in 1978 by Charlotte Dravet and later recognized in the 1989 revised classification of epilepsies by the International League Against Epilepsy.
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