Continuous Spike-Waves during Slow Sleep Today: An Update

Abstract

In the context of childhood epilepsy, the concept of continuous spike-waves during slow sleep (CSWS) includes several childhood-onset heterogeneous conditions that share electroencephalograms (EEGs) characterized by a high frequency of paroxysmal abnormalities during sleep, which have negative effects on the cognitive development and behavior of the child. These negative effects may have the characteristics of a clear regression or of a slowdown in development. Seizures are very often present, but not constantly. The above makes it clear why CSWS have been included in epileptic encephalopathies, in which, by definition, frequent EEG paroxysmal abnormalities have an unfavorable impact on cognitive functions, including socio-communicative skills, causing autistic features, even regardless of the presence of clinically overt seizures. Although several decades have passed since the original descriptions of the electroclinical condition of CSWS, there are still many areas that are little-known and deserve to be further studied, including the EEG diagnostic criteria, the most effective electrophysiological parameter for monitoring the role of the thalamus in CSWS pathogenesis, its long-term evolution, the nosographic location of Landau-Kleffner syndrome, standardized neuropsychological and behavioral assessments, and pharmacological and non-pharmacological therapies.

Keywords: CSWS; ESES; Landau–Kleffner syndrome; epilepsy; epileptic encephalopathies.

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Paper selection flow chart.

Figure 2

NREM sleep EEG in a boy aged 5 years and 7 months with autism spectrum disorder, intellectual disability, and focal epilepsy, showing subcontinuous diffuse spike–waves (lasting < 85% of NREM sleep), prevailing in the right posterior regions. NREM: nonrapid eye movement. EEG: electroencephalogram.