Epileptic discharges during sleep: A pathophysiological mechanism common to different clinical syndromes

M. G. Baglietto, F. Ferrillcr, M. Beelke, R. Gaggero, E. De Negri, L. Nobili

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Objective The activation of interictal discharges (lEDs) by NREM sleep is a well known phenomenon in different epileptic conditions of childhood. This activation can he bilateral (but asymmetrical), diffuse or lateralized. The pathophysiological mechanism of this activation is still unknown. Experimental data revealed that the normal sleep oscillations might develop into paroxysmal synchronization. Spectral analysis is a method that quantitatively describes the dynamics of delta (SWA, 0.5-4.5 Hz) and sigma activity (SA, I2-16 Hz) during sleep. Materials and methods In order to define the relationship between synchronizing mechanisms (spindles and delta activities) and IED activation during sleep, we have performed an overnight continuous EEG polysomnography study in 23 epileptic children (8 benign epilepsy with rolandic spikes, 5 benign epilepsy with occipital spikes. 3 Landau-Kleffner syndrome and 7 symptomatic epilepsy) characterized by a strong activation of lEDs during sleep. Relationship between SA and SWA and time series of lEDs were tested by means of correlation techniques after data normalization. Results The activation of lEDs ranged from 25% to 90% of the whole NREM sleep. A higher correlation (/xO.OOl) was found between lEDs and SA with respect to SWA in all the subjects. Conclusions The marked increase and the modulation of lEDs during sleep is mainly influenced by the same pathophysiological mechanism, independently of the epileptic syndrome (idiopathic or symptomatic). The neural mechanisms involved in the generation of sleep spindles activate IED production.

Original languageEnglish
Pages (from-to)351
Number of pages1
JournalItalian Journal of Neurological Sciences
Issue number5
Publication statusPublished - 1999


ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

Cite this

Baglietto, M. G., Ferrillcr, F., Beelke, M., Gaggero, R., De Negri, E., & Nobili, L. (1999). Epileptic discharges during sleep: A pathophysiological mechanism common to different clinical syndromes. Italian Journal of Neurological Sciences, 20(5), 351.