Relationship of sleep interictal epileptiform discharges to sigma activity (12-16 Hz) in benign epilepsy of childhood with rolandic spikes

L. Nobili, F. Ferrillo, M. G. Baglietto, M. Beelke, F. De Carli, E. De Negri, G. Schiavi, G. Rosadini, M. De Negri

Research output: Contribution to journalArticlepeer-review


Objective: The activation of interictal epileptic discharges (IEDs) by NREM sleep is a well-known phenomenon in benign epilepsy of childhood with rolandic spikes (BECRS). The activating properties of NREM sleep on IEDs have been attributed to increased synchronization within thalamocortical neurons. During NREM sleep two synchronizing mechanisms lead to the appearance of spindles and delta waves on the EEG. Spectral analysis technique is a suitable method that can be used to quantitatively describe the dynamics of delta (slow wave activity (SWA) 0.5-4.0 Hz) and sigma activity (12.0-16.0 Hz) during sleep. Methods: In order to define more accurately the relationship between synchronizing mechanisms (spindles and delta activities) and IEDs during sleep in BECRS, we have performed overnight continuous EEG polysomnography studies in 9 patients (mean age 7.4 ± 2.5 years). The temporal series of SWA and sigma values, derived from spectral analysis, have been obtained from a spike-free derivation lead. The IEDs count has been performed on the most active lead. Relationships between sigma and SWA and time series of IEDS were tested by means of correlation techniques after data normalization. Results: Our results revealed a significant higher correlation between IEDs and sigma activity with respect to SW in all the subjects, in total sleep time. The same analysis limited to NREM sleep highlights the better correlation between sigma and IEDs. Conclusions: Data suggest that during sleep of BECRS patients, IEDs are more sensitive to the promoting action of the spindle-generating mechanism than to the SWA-producing one.

Original languageEnglish
Pages (from-to)39-46
Number of pages8
JournalClinical Neurophysiology
Issue number1
Publication statusPublished - Jan 1999


  • Epilepsy
  • Sleep
  • Spectral analysis
  • Spindle

ASJC Scopus subject areas

  • Clinical Neurology
  • Physiology (medical)
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Sensory Systems


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