Continuous spikes and waves during sleep (CSWS) is an epileptic encephalopathy characterized in most patients by (1) difficult to control seizures, (2) interictal epileptiform activity that becomes prominent during sleep leading to an electroencephalogram (EEG) pattern of electrical status epilepticus in sleep (ESES), and (3) neurocognitive regression. In this paper, we will summarize current epidemiological, clinical, and EEG knowledge on CSWS and will provide suggestions for treatment. CSWS typically presents with seizures around 2–4 years of age. Neurocognitive regression occurs around 5-6 years of age, and it is accompanied by subacute worsening of EEG abnormalities and seizures. At approximately 6–9 years of age, there is a gradual resolution of seizures and EEG abnormalities, but the neurocognitive deficits persist in most patients. The cause of CSWS is unknown, but early developmental lesions play a major role in approximately half of the patients, and genetic associations have recently been described. High-dose benzodiazepines and corticosteroids have been successfully used to treat clinical and electroencephalographic features. Corticosteroids are often reserved for refractory disease because of adverse events. Valproate, ethosuximide, levetiracetam, sulthiame, and lamotrigine have been also used with some success. Epilepsy surgery may be considered in a few selected patients. 1. Introduction Continuous spikes and waves during sleep (CSWS) is an epileptic encephalopathy, that is, a condition in which the epileptic processes themselves are thought to contribute to the disturbance in cerebral function. CSWS is characterized by (1) seizures, (2) neurocognitive regression, and (3) an electroencephalography (EEG) pattern of electrical status epilepticus during sleep (ESES) [1–6]. ESES is characterized by marked sleep potentiation of epileptiform activity in the transition from wakefulness to sleep that leads to near-continuous bilateral (or occasionally lateralized) slow spikes and waves that occupy a significant proportion of nonrapid eye movement (non-REM) sleep [2, 4]. In this review, we summarize epidemiological, etiological, clinical, and EEG features in CSWS based on available data. We also suggest an approach to manage this syndrome and present it in the framework of a more general childhood seizure susceptibility syndrome. 2. Definitions The terms “ESES,” “CSWS,” and “Landau-Kleffner syndrome” have been used interchangeably in the literature to refer to the EEG pattern of frequent spike-waves or to the associated epileptic encephalopathy
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