title: ICTAL EEG fast activity in West syndrome: from onset to outcome.
abstract: OBJECTIVE
  To characterize the fast EEG activities associated with infantile spasms in West syndrome, and their value in predicting the recurrence and localization of late seizures.
  
  
  METHODS
  We selected 23 infants who were followed for at least 2 years. Selected EEG recordings underwent autospectra, coherence, and phase analyses in order to assess the changes during follow-up.
  
  
  RESULTS
  Short discharges of fast-rhythms (331 +/- 190 ms) with a lateralized onset were detected in 18 of the 23 infants (78.3%). There were no significant differences in the parameters characterizing ICTAL beta-activity (frequency, duration, inter-hemispheric coherence, or transfer time) between the infants with or without seizure recurrence. However, beta-discharges with a consistent location formed part of the ICTAL EEG in all 10 infants with seizure recurrence, but only in eight (61.5%) of those who remained seizure-free (SF) (p < 0.05). In all but one of the infants experiencing seizure recurrence, the ICTAL discharges associated with the late seizures apparently originated from the same hemisphere as that involved at the beginning of the spasm-associated beta-activity, although the precise location varied.
  
  
  CONCLUSIONS
  Spectral, coherence and phase analyses detected spasm-associated runs of lateralized beta-rhythms in many of our infants with West syndrome. This ICTAL pattern significantly correlated with seizure recurrence. The consistent lateralization of the ICTAL EEG events associated with both the early spasms and late seizures suggests that EEG beta-activities should be considered as indicating local cortical dysfunction in infants who fail to respond to early treatment and often progress toward severe epilepsy.
authors.affiliation: C. Besta Foundation Neurological Institute, Via Celoria 11, Milan, Italy.
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Panzica
authors.forename: Simona
authors.initials: S
authors.lastname: Binelli
authors.forename: Laura
authors.initials: L
authors.lastname: Canafoglia
authors.forename: Marina
authors.initials: M
authors.lastname: Casazza
authors.forename: Elena
authors.initials: E
authors.lastname: Freri
authors.forename: Tiziana
authors.initials: T
authors.lastname: Granata
authors.forename: Giuliano
authors.initials: G
authors.lastname: Avanzini
authors.forename: Silvana
authors.initials: S
authors.lastname: Franceschetti
mesh_terms: D001611:Beta Rhythm / Q000706:statistics & numerical data; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology; D004569:Electroencephalography / Q000706:statistics & numerical data*; D004576:Electromyography / Q000706:statistics & numerical data; D004827:Epilepsy / Q000175:diagnosis / Q000503:physiopathology; D005500:Follow-Up Studies; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D011379:Prognosis; D012008:Recurrence; D013036:Spasms, Infantile / Q000175:diagnosis* / Q000503:physiopathology