Continuous Spike-Wave during Slow Wave Sleep and Related Conditions

Abstract

Continuous spike and wave during slow wave sleep (CSWS) is an epileptic encephalopathy that presents with neurocognitive regression and clinical seizures, and that demonstrates an electroencephalogram (EEG) pattern of electrical status epilepticus during sleep, as defined by the Commission on Classification and Terminology of the International League Against Epilepsy 1989. CSWS is an age-related condition, typically presenting in children around 5 years of age, with clinical seizures which progress within 2 years to a severe epileptic encephalopathy. The pathophysiology of CSWS is not completely understood, but the corticothalamic neuronal network involved in sleep patterns is thought to be involved. Genetic predisposition and injury in early development are thought to play etiological roles. Treatment strategies have involved traditional anticonvulsants, hormonal therapies, and other newer techniques. Outcomes are fair, and the thought is that earlier diagnosis and intervention preserve neurocognitive development, as in the case of other epileptic encephalopathies. Further understanding of the mechanisms of CSWS may lead to improved therapeutic options and thus outcomes of children with CSWS.

Figure 1

Asymmetric ESES with discharges seen more prominently over the left hemisphere, corresponding to unilateral structural injury; in this case, neonatal left thalamic stroke. Note the absence of spindles in left hemisphere further suggesting the possibility of thalamic injury. Recordings were obtained using standard international 10–20 electrode placement and a single electrocardiogram chest electrode. The recordings were obtained using a reference electrode and reformatted digitally into sequential bipolar and referential montages for review.